Source: IOWA STATE UNIVERSITY submitted to
CROP PRODUCTION AND MANAGEMENT STRATEGIES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0184815
Grant No.
(N/A)
Project No.
IOW03603
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 1999
Project End Date
Jun 30, 2007
Grant Year
(N/A)
Project Director
Westgate, M.
Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
AGRONOMY
Non Technical Summary
(N/A)
Animal Health Component
50%
Research Effort Categories
Basic
40%
Applied
50%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2032410102020%
2031699106020%
2052410106020%
2052300114020%
2062410102020%
Goals / Objectives
1. Develop management strategies that improve the efficiency of crop production. 2. Develop integrated weed management systems for cropping systems. 3. Improve the production and utilization of forages. 4. Enhance the understanding of the basic biology of seed development, maturation, germination, and dormancy to improve seed quality, improve emergence and early season growth of crop species, and allow for more natural management of weed and crop seed banks. 5. Improve reliability of plant production systems during severe climatic variability to gain increased production efficiency with higher average yields. 6. Improve quality, uniformity, value, and marketability of agricultural products by developing genetically improved crops with higher-value products. 7. Develop energy production from renewable agriculture waste biomass, such as corn-stalk stover, which also would reduce risk of no-till planting and improve soil health.
Project Methods
1) Conduct soybean and corn production and management studies at ISU Research Farms throughout IA. These farms are found on six different soil associations and will provide production information on these soils and in different environments. 2) Identify factors that favor the success of weeds in current cropping systems. Develop management systems that exploit weakness in the life cycles of important weed species. Investigate interactions of physiological and ecological stress between weeds and crops. Study the weeds/herbicides/management relationship and determine how that impacts weed population dynamics. Examine how weeds are affected by soil quality improvements resulting from applications of crop residues, composts, and manures, and increases in crop diversity. Characterize important weedy traits of foxtails that most directly ensure their success in agroecosystems. Elucidate biotic and environmental factors regulating their behavior and use this information to develop improved, sustainable weed management systems. 3) Identify factors that limit the nutritive value of forage grasses and legumes. Determine how fiber characteristics of grasses influence their digestible energy concentration and consumption by livestock. Determine genotypic and environmental effects on legume protein quality and utilization. Develop strategies for improving seasonal distribution and utilization of forages. Study spatial and temporal factors affecting growth, development, and quality of grasses and legumes. Develop and evaluate technologies for site-specific management of pastures based on soil and landscape attributes. Study warm-season grasses and legumes in complementary systems with cool-season grasses for pasturing growing cattle. 4) Understand the basic biology, biochemistry and molecular biology of seed dormancy. Understand the influence of environment on seed quality and dormancy in a range of crop, forage and weed species. Study seed germination under low temperature conditions. Study the acquisition of desiccation tolerance in maize. 5) Use molecular, whole plant, and modeling to manipulate the flowering process in corn to increase the success of pollination in adverse environments. Define relationships between carbohydrate delivery to and metabolism within the ovary, and the role of carbohydrate metabolism in kernel formation under water-limited conditions. 6) Test the response of seed protein and oil content to temperature. Test the potential of using simple sequence repeats to improve the efficiency of selection for seed protein and oil content using near isogenic lines that vary in seed protein and oil content. Develop soybean populations to incorporate the temperature-stability and high-protein characteristics of PI132.217 into superior varieties adapted to northern regions. 7) Study anaerobic digestion of corn stover or mixtures of stover and liquid swine manure to methane for heat or electricity. Study methane production from biomass under acid conditions. Addition investigators are Barnhart SK, Dekker JH, Farnham D, Gibson L, Goggi S, Hartzler RG, Liebman M, Muenchrath D, Mullen RE, Owen MDK, Salvador RJ, Weidenhoeft M, Westgate M.

Progress 10/01/99 to 06/30/07

Outputs
OUTPUTS: Soybean production: Research was conducted to evaluate current management recommendations for profitable soybean production. Results suggest current soybean management recommendations in Iowa need to be adjusted. Improvements in efficiency and farmer profitability are expected if new recommendations are adapted. Localized recommendations may be required to optimize production across diverse Iowa soils. Weed control management: Experimental and registered herbicides were evaluated for crop phytotoxiciy and weed control in over 85 field studies. Herbicides were evaluated in genetically modified and specialty corn and soybeans. Crop phytotoxicity also was evaluted in corn inbreds. Differing application timings and tillage regimes were evaluated as well as management of pasture weeds and woody species. Extent of phytotoxicity and weed control varied with herbicide mode of action and weed spectrum. Inbreds showed comparable crop safety for experimental herbicide with the same mode of action as registered herbicides. Weed seed dynamics: We tested the hypothesis that yield, weed suppression, and profit characteristics of low-external-input (LEI) cropping systems can match or exceed those of conventional systems. We compared a conventionally managed 2-yr rotation system [corn/soybean] with a 3-yr corn/soybean/small grain + red clover rotation, and a 4-yr corn/soybean/small grain + alfalfa/alfalfa rotation. Corn and soybean yields were as high or higher in the LEI systems. Synthetic N fertilizer use was 59% to 74% lower in the 3-yr and 4-yr systems; herbicide use was reduced 76% to 82%. Without subsidy payments, net returns were 4-yr system g.t. 2-yr system g.t. 3-yr system. With subsidies, differences in net returns were smaller, but rank order was maintained. Certain LEI systems can be economically competitive with conventional systems in regions of high production potential. Modeling reproductive development: We developed a new conceptual framework to link plant growth and time to silking by describing silking at the population level as a quantitative trait at and at the plant level as a qualitative trait. This approach enabled us to visualize gaps in current knowledge essential to advance crop modeling of maize canopy phenology. It provides a foundation to evaluate genotype x environment interactions on time to silking, and a rational basis to identify and evaluate genes regulating flowering dynamics in maize. Failure to account for sink-limited kernel set contributes to simulation error under field conditions that affect pollen shed or silking. We developed algorithms for a Flowering Model to simulate sink-limited kernel set, calibrated it against kernel production in hybrid seed production fields, and then linked it to CERES-Maize, a corn yield model used globally. Integrating the capacity to simulate sink limited kernel set with source-limited kernel set increased simulation accuracy dramatically. Modified CERES-Maize also accounted for a much greater range of variability in the biological processes controlling kernel set. PARTICIPANTS: Individuals contributing to this report: Dr. Mark Westgate. Principal Investigator. Provided research input on modeling maize reproductive development. Dr. Michael D. Owen. Co-PI. Provided research input on herbicide evaluations. Dr. Matt Liebman. Co-PI. Provided research input on low input management systems. Dr. Palle Pedersen. Co-PI. Provided research input on soybean management systems. TARGET AUDIENCES: Information disseminated to crop producers, extension agents, crop consultants, and similarly interested parties in agricultural businesses through Extension Crop Schools, Field tours, web site updates, and individual consultations. Research results were presented to the scientific community at regional and national scientific meetings, and evaluated through publication in peer reviewed journals.

Impacts
The results in 2007 supports previous research findings that reliable, environmentally safe and economically sustainable weed control strategies can be achieved. These strategies are being adopted and implemented by producers planting increasing acreages of genetically modified corn and soybean and specialty trait crops. Studies on weed population dynamics enhance evolution of farming practices, decision-making tools, and management systems that increase crop production efficiency while improving protection of soil and water resources. The models developed in this project constitute excellent tools for understanding the impacts on weeds of crop rotation systems, tillage practices, and ecological processes such as seed predation. Farmers and agricultural professionals have expressed considerable interest in research concerning weed ecology and management when results are presented at farm field days and winter meetings. Insights provided by this project into weed population dynamics will enhance the evolution of farming practices, decision-making tools, and management systems that increase crop production efficiency while improving protection of soil and water resources. The models developed in this project constitute excellent tools for understanding the impacts on weeds of crop rotation systems, tillage practices, and ecological processes such as seed predation. Measurements of weed seed losses to rodent seed predators indicated that an average of 72% of velvetleaf and 62% of giant foxtail seeds were consumed from November 2005 until March 2006; between November 2006 and April 2007, 91% of velvetleaf seeds and 84% of giant foxtail seeds were consumed. Population dynamics models indicate that seed losses of this magnitude strongly contribute to the success of weed suppression in diversified crop rotation systems receiving lower-than-normal doses of herbicides. Additional modeling efforts indicate that delaying tillage enhances seed losses to predators. Accurately quantifying developmental relationships between whole plant and reproductive growth has important implications for understanding yield formation in maize. The models developed provides a novel approach to evaluate genotype x environment interactions, and a framework to evaluate genes regulating flowering dynamics and grain yield. These advances have been recognized by the scientific community. Lizaso, J.I., A.E. Fonseca, and M.E. Westgate. 2007. Source-limited and sink-limited kernel set: Complementary approaches to simulate kernel number in CERES-Maize. Selected as a 'Research Highlight' by the Crop Science Society of America and was the most sited article in the September2007 issue of Crop Science. Borras, L., M.E. Westgate, J. Astini, and L. Echarte. 2007. Coupling time to silking with plant growth rate in maize. Field Crops Research 102: 73-85. Listed as #1 of the 25 'Hottest Articles' in Agricultural and Biological Sciences published in Field Crops Research in the April/June 07 listing by Science Direct.

Publications

  • Harbur, M.M. and Owen, M.D.K. 2007. Relative population density affects nitrogen responses by competing plants. Weed Sci. (In Press).
  • Leon, R.G., Bassham, D., and Owen, M.D.K. 2006. Germination and proteome analyses reveal intra-specific genetic variation in seed dormancy regulation of common waterhemp (Amaranthus tuberculatus). Weed Sci. 54:305-315.
  • Leon, R.G., Bassham, D., and Owen, M.D.K. 2006. Inheritance of deep seed dormancy and stratification-mediated dormancy alleviation in Amaranthus tuberculatus. Seed Sci. Res. 16:193-202.
  • Leon, R.G., Bassham, D., and Owen, M.D.K. 2007. Thermal and hormonal regulation of the dormancy-germination transition in Amaranthus tuberculatus seeds. Weed Res. 47:335-344.
  • Leon, R.G. and Owen, M.D.K. 2006. Tillage systems and seed dormancy effects on common waterhemp (Amaranthus tuberculatus) seedling emergence. Weed Sci. 54:1037-1044.
  • Liebman, M., Gibson, L.R., Sundberg, D.N., Heggenstaller, A.H., Westerman, P.R., Chase, C.A., Hartzler, R.G., Menalled, F.D., Davis, A.S., and Dixon, P.M. 2007. Agronomic and economic performance characteristics of conventional and low-external-input cropping systems in the central Corn Belt. Agron. J. (In press).
  • Lizaso, J.I., Fonseca, A.E., and Westgate, M.E. 2007. Source-limited and sink-limited kernel set: Complementary approaches to simulate kernel number in CERES-Maize. Crop Sci. 47:2078-2088.
  • O'Rourke, M.E., Liebman, M., and Rice, M.E. 2007. Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems. Environmental Entomology (In press).
  • Owen, M.D.K. 2007. Weed Species shifts in glyphosate resistant crops. Pest Manag. Sci. (In press).
  • Pedersen, P., Grau, C.R., Cullen, E., Koval, N., and Hill, J.H. 2007. Potential for integrated management of soybean virus disease. Plant Disease 91:1255-1259.
  • Picasso, V.D., Brummer, E.C., Liebman, M., Dixon, P.M., and Wilsey, B.J. 2007. Crop species diversity affects productivity and weed suppression in perennial polycultures under two management strategies. Crop Sci. (In press).
  • McLaughlin, W., and Pedersen, P. 2007. Influence of genotypes on soybean growth and development in a no-tillage system. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Osenga, J. and Pedersen, P. 2007. Effect of seed treatment in a no-tillage soybean production system in Iowa. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Owen, M.D.K. 2006. Herbicide resistance, weed population shifts, and weed management stewardship: Is anything new? Proc. Integrated Crop Management Conf. Iowa State Univ. 18:143-149.
  • Owen, M.D.K. 2006. Weed management update-who cares? Proc. Integrated Crop Management Conf. Iowa State Univ. 18:149-153.
  • Owen, M.D.K. 2007. Weed management in 2008: New opportunities, existing issues and anticipated problems. Proc. Integrated Crop Management Conf. Iowa State Univ. 19:157-168.
  • Owen, M.D.K., Lux, J.F., and Franzenburg, D.D. 2006. Corn inbred response to BAS 799 and other growth regulator herbicides. Proc. North Cent. Weed Sci. Soc. 61:36 (in CD).
  • Owen, M.D.K. 2006. Herbicide resistant weeds-who cares/why worry? Proc. North Cent. Weed Sci. Soc. 61:221 (in CD).
  • Pedersen, P. 2007. Soybean plant population for maximum economic return. p. 33-39. IN Proc. 19th Annual Integrated Crop Management Conf., Ames, IA. Nov. 28-29, 2007. Iowa State Univ., Ames.
  • Pedersen, P. 2007. Rotation effect from soybean will maximize corn productivity. A9 symposium "Understanding the Agronomic Issues Related to the Biofuel Demand". 2007 Intl. ASA-CSSA-SSSA meeting, New Orleans, LA.
  • Pedersen, P. 2007. Rotation effect from soybean will maximize corn productivity. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Anex, R.P., Lynd, L.R., Laser, M.S., Heggenstaller, A.H., and Liebman, M. 2007. Growing energy, closing cycles: the potential for enhanced nutrient cycling through the coupling of agricultural and bioenergy systems. Crop Sci. 47:1327-1335.
  • Beckie, H.J. and Owen, M.D.K. 2007. Herbicide-resistant crops as weeds in North America. CAB Reviews 2(44) 22 p.
  • Borras, L., Westgate, M.E., Astini, J., and Echarte, L. 2007. Coupling time to silking with plant growth rate in maize. Field Crops Res. 102:73-85.
  • Borza, J.K., Westerman, P.R., and Liebman, M. 2007. Comparing estimates of seed viability in three foxtail (Setaria) species using the imbibed seed crush test with and without additional tetrazolium testing. Weed Tech. 21:518-522.
  • Elmore, R., Westgate, M., Abendroth, L., and Hurburgh, C.R. 2007. Advice to growers of Agrisure(TM) Rootworm Trait (MIR 604) hybrids and their neighbors. April 30, 2007. Integrated Crop Management. p. 127.
  • Hatterman-Valenti, H.M., Pitty, A., and Owen, M.D.K. 2006. Effect of environment on giant foxtail (Setaria faberi) leaf wax and fluazifop-P absorption. Weed Sci. 54:604-614.
  • Harbur, M.M. and Owen, M.D.K. 2006. Influence of relative time of emergence on nitrogen responses of corn and velvetleaf. Weed Sci. 54:917-922.
  • Pedersen, P. and Tylka, G.L. 2007. Soybean cyst nematode and nematicide affect growth pattern of various soybean varieties in Iowa. J. Nematol. 39:98.
  • Rotundo, J., Borras, L., and Westgate, M. 2007. Responses of high and low protein soybeans to an increase in assimilate supply per seed. Amer. Soc. Agron. Annu. Meeting, Nov. 4-8, New Orleans, LA.
  • Zelaya, I.A. and Owen, M.D.K. 2006. Interspecific hybridization in Asteraceae: case studies in Ambrosia, Conyza, and Helianthus. Abs. WSSA 46:312 (in CD).
  • Sala, R.G., Andrade, F.H., and Westgate, M.E. 2007. Maize Kernel Moisture at Physiological Maturity as Affected by the Source-Sink Relationship during Grain Filling. Crop Sci. 47:711-714.
  • Sala, R.G., Westgate, M.E., and Andrade, F.H. 2007. Relationship among kernel volume, water content and final kernel weight to source/sink manipulations in maize. Field Crops Res. 101:19-25.
  • Scursoni, J., Forcella, F., Gunsolus, J., Owen, M., Oliver, R., Smeda, R., and Vidine, R. 2006. Weed diversity and soybean yield with glyphosate management along a north-south transect in the United States. Weed Sci. 54:713-719.
  • Zelaya, I., Owen, M.D.K. and VanGessel, M. 2006. First confirmed hybrid in the American Conyza: implications for transfer of glyphosate resistance. Amer. J. Bot. 94(4):660-673.
  • Borras, L., Westgate, M.E., and Astini, J.P. 2007. Physiological processes to understand genotype x environment interactions in maize silking dynamics. p. 105-114. IN J.H.J. Spiertz, P.C. Struik, and H.H. van Laar (eds.) Scale and Complexity in Plant Systems Research. Wageningen UR Frontis Series Vol 21. Springer, The Netherlands.
  • Assem, S., Westgate, M., Borras, L., and Wang, K. 2007. Improving freeze tolerance of soybean seedlings. Amer. Soc. Agron. Annu. Meeting, Nov. 4-8, New Orleans, LA.
  • De Bruin, J. and Pedersen, P. 2007. Soil fumigation and variety selection to study soybean cyst nematode in Iowa. J. Nematol. 39:94.
  • De Bruin, J.L. and Pedersen, P. 2007. Changes in protein and oil composition in high-yield soybean production systems. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Elmore, R., Abendroth, L, Lamkey, K., and Westgate, M. 2007. 300 bushel Corn: Is it possible? Amer. Soc. Agron. Annu. Meeting, Nov. 4-8, New Orleans, LA.
  • Haegele, J. and Westgate, M. 2007. Effect of Late-Season Water Stress on Maize Kernel Starch Structure. Amer. Soc. Agron. Annu. Meeting, Nov. 4-8, New Orleans, LA.
  • Iyer, V.V., Studham M.E., Westgate, M.E., Wurtele, E.S., and Shanks, J.V. 2007. Metabolic Flux Analysis On Soybean Isolines With Different Seed Compositions. AIChE Annual Meeting, Salt Lake City, Utah.
  • Leon, R.G., Bassham, D., and Owen, M.D.K. 2006. Temperature and hormonal regulation of seed dormancy alleviation in Amaranthus tuberculatus. Abs. WSSA 46:109 (in CD).
  • Liebman, M., Heggenstaller, A.H., Danielson, B.J., and Westerman, P.R. 2007. Functional impacts of biodiversity: indigenous mice and insects reduce weed population growth rates in low-external-input cropping systems. p. 762-763. IN Proc. 16th Intl. Plant Protection Congress, 15-18 October 2007, Glasgow, Scotland, UK. British Crop Protection Council, Alton, UK.
  • Ling, L., Zhou W., Zhou, W., Periappuram, C., Nettleton, D., Westgate, M., Nikolau, B., and Wurtele, E.S. 2007. System biology approach to understand seed composition. National Plant Lipid Cooperative (NPLC) 2007 Meeting.
  • Lizaso, J.I., Fonseca, A.E., and Westgate, M.E. 2007. Source-limited and sink-limited kernel set: Two complementary approaches to simulate kernel number with CERES-Maize. 37th Biological Systems Simulation Conference. April 17-19, Beltsville, MD.


Progress 01/01/06 to 12/31/06

Outputs
Soybean production: Evaluation of current management practices indicated a need to adjust recommendation for Iowa soybean production. Preliminary indications are for improved efficiency and profitability, as well as a need to localize recommendations for diverse soils. Biology of seed development: A cDNA library was developed for corn seed exposed to freezing injury. Twelve differentially expressed clones were sequenced and published in the Maize GeneBank (GenBank Accession No. BQ740226 to BQ740247). Expression of dehydrin-like proteins was observed in young seedlings grown from seed exposed to freezing. Tetrazolium test predicted field emergence of frost-damaged seed lots. Cold and the accelerated aging tests also could be used to predict field emergence. Weed control management: Experimental and registered herbicides were evaluated for crop phytotoxiciy and weed control in genetically modified corn and soybeans and in corn and soybeans with specialty traits in over 60 field studies. Levels of phytotoxicity and weed control varied with herbicides mode of action and weed spectrum. Favorable environmental conditions in 2006 resulted in normal levels of phytotoxicity with good to excellent herbicidal activity on the weeds evaluated. An inbred corn study showed relative crop safety of experimental herbicide compared registered herbicides with the same mode of action. Research conducted on grower fields across Iowa investigated herbicide application timing and its impact on soybean injury and yield. Additional crop and pest information was also observed in this work to determine possible effects on crop and pest relationships. Weed seed dynamics: Velvetleaf seed densities decreased increased 68% in 2-year rotation, 31% in the 3-year rotation, and 51% in the 4-year rotation. Giant foxtail, seed densities were reduced 97% in the 2-year rotation, 55% in the 3-year rotation, and 81% in the 4-year rotations. These reductions occurred despite increases in weed seeds per square meter of soil and were not explained by rates of seedling emergence or seed decay. The results indicate that diversified, low-external-input systems can be agronomically and economically competitive with less diverse, conventionally managed systems, and that ecological processes such as seed predation can promote effective weed management with less reliance on herbicides. Modeling reproductive development: A new conceptual approach for analysing maize female flowering responses to genetic and environmental variation in plant growth was developed. This approach can be applied to resolve contrasting genotypic behaviour under a range of environmental conditions. The model is based on well-established population dynamics and captures intrinsic plant-to-plant variability within maize canopies. Specific genotype parameters were identified that integrate biomass production and partitioning into a framework to describe the flowering response of a particular genotype in a particular environment.

Impacts
Enhanced understanding of the fundamental interactions between management systems, pest, and pathogens will lead to improved yield stability and profitability. Research on seed development indicates seed quality of inbred parents can be transferred to their hybrid offspring. The location of seed production and cropping system used (conventional vs. organic) affects seed quality; low-protein inbred lines have lower vigor than high-protein inbred lines; and germplasm with lower seed protein is prone to greater mechanical damage. Weed research supports previous research findings that reliable, environmentally safe and economically sustainable weed control strategies can be achieved. These strategies are being adopted and implemented by producers planting an ever increasing acreage of genetically modified corn and soybean and specialty trait crops. Studies on weed population dynamics enhance evolution of farming practices, decision-making tools, and management systems that increase crop production efficiency while improving protection of soil and water resources. The models developed in this project constitute excellent tools for understanding the impacts on weeds of crop rotation systems, tillage practices, and ecological processes such as seed predation. Accurately quantifying developmental relationships between whole plant and reproductive growth has important implications for understanding yield formation in maize. The model developed provides a novel approach to evaluate genotype x environment interactions, and a framework to evaluate genes regulating flowering dynamics.

Publications

  • Viner, B., Goggi, A.S., Arritt, R.W., Westgate, M.E., Clark, C.A. and Takle, E.S. 2006. A Screening Technique for Methods of Pollen Confinement. 17th Conference on Biometeorology and Aerospace Meteorology, 22-26 May. San Diego, CA.
  • Westerman, P.R., Liebman, M. and Dixon, P.M. 2006. Analysis of the effects of cropping system diversification on weed suppression using stochastic periodic matrix models. Abstr. of the 2006 Intl. Annual Meetings, ASA, CSSA, SSSA: http://a-c-s.confex.com/crops/2006am/techprogram/P24264.HTM.
  • Westgate, M.E. and Borras, L. 2006. Source and Sink Limitations on Grain Yield in Modern Corn Hybrids. Amer. Soc. Agron. Annu. Meeting, Nov. 8-14. Indianapolis, IN.
  • Williams, A.M. and Pedersen, P. 2006. Mycorrhizal and soil-borne pathogen colonization of four soybean varieties in Iowa. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Williams, A.M. and Pedersen, P. 2006. Effect of fungicide seed treatment on mycorrhizae colonization of soybean. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Young, B.G., Luke, K.A.F., Shaw, D.R., Owen, M.D.K., Weller, S.C., Wilcut, J.W. and Wilson, R.G. 2006. Grower utilization of Roundup Ready crops and perceived performance of glyphosate-based weed management systems. Proc. North Cent. Weed Sci. Soc. 61:224. (on CD).
  • deGeus, Y. 2006. Project title: Seed quality of high protein corn lines in organic and conventional systems. M.S. Thesis. Iowa State Univ., Ames.
  • DeVries, M.L. 2006. Project title: Methods for identifying frost injury in immature maize seed. Ph.D. Dissertation. Iowa State Univ., Ames.
  • O'Rourke, M.E., Heggenstaller, A., Liebman, M. and Rice, M.E. 2006. Post-dispersal weed seed predation by invertebrates in conventional and low-external-input crop rotation systems. Agric., Ecosys. and Environ. 116:280-288.
  • Sadaka, S.S., Richard, T.L., Loecke, T.D. and Liebman, M. 2006. Determination of compost respiration rates using pressure sensors. Compost Science and Utilization 14:124-131.
  • Schulte, L.A., Liebman, M., Asbjornsen, H. and Crow, T.R. 2006. Agroecosystem restoration through strategic integration of perennials. J. Soil and Water Conservation 61(6):164-169.
  • Schwarte, A.J., Gibson, L.R., Karlen, D.L., Dixon, P.M., Liebman, M. and Jannink, J.-L. 2006. Planting date effects on winter triticale grain yield and yield components. Crop Sci. 46:1218-1224.
  • Westerman, P.R., Liebman, M., Heggenstaller, A.H. and Forcella, F. 2006. Integrating measurements of seed availability and removal to estimate weed seed losses due to predation. Weed Sci. 54:566-574.
  • Hartzler, R.G and Buhler, D.D. 2006. Ecological management of agricultural weeds. IN O. Koul and G.W. Cuperus (eds.) Ecologically Based Integrated Pest Management. Oxford University Press, New York.
  • Menalled, F.D., Liebman, M. and Renner, K.A. 2006. The ecology of weed seed predation in herbaceous cropping systems. p. 297-327. IN H.P. Singh, D.R. Batish, and R.K. Kohli (eds.) Handbook of Sustainable Weed Management. Haworth Press, Binghamton, NY.
  • Arritt, R., Viner, B., Westgate, M. and Clark, C. 2006. Viability of maize pollen during long-range transport. 8th International Congress on Aerobiology, Neuchatel, Switzerland.
  • Astini, J.P., Fonseca, A., Lopez Sanches, H., Goggi, S., Lizaso, J., Westgate, M. and Arritt, R. 2006. Predicting Out-crossing in Grain and Seed Production Fields. Amer. Soc. Agron. Annu. Meeting, Nov. 8-14, Indianapolis, IN.
  • Borras, L. and Westgate, M.E. 2006. Modeling common patterns in seed development using a seed water relations mechanistic framework Plant-Gene-Crop Workshop. Wageningen, the Netherlands. April 23-28.
  • Borras, L., Westgate, M. and Astini, J. 2006. Understanding gene x environment interactions in maize silking dynamics based on assimilate production and partitioning. Plant-Gene-Crop Workshop. Wageningen, The Netherlands. April 23-28.
  • Conley, S.P. and Pedersen, P. 2006. Recovery of node removal on soybean at two plant populations. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Da Costa, V.A., Pedersen, P. and Tylka, G.L. 2006. Can aldicarb be used to manage SCN in Iowa. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • De Bruin, J.L. and Pedersen, P. 2006. Identifying soybean varieties with yield potential and genetic stability. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Nikolau, B.J., Syrkin Wurtele, E., Nettleton, D., Shanks, J.V., Westgate, M., Hammond, E.G., Wang, T., Sundararajan, S. and Hayes, D. 2006. The role of systems-biology in the development of soybean-based biorenewable source of fuels and lubricants. Molecular and Cellular Biology of the Soybean Conference Lincoln, NE.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2006. Corn Inbred Response to BAS 799 and Other Growth Regulator Herbicides Applied Postemergence. Proc. North Cent. Weed Sci. Soc. Vol 61.
  • Owen, M.D.K., Pedersen, P., Tylka, G.L., Franzenburg, D.D., Gebhart, G.D., Lux, J.F., Marett, C.C. and Roland, J.M. 2006. Effect of Integrated Herbicide Management Strategies on Soybean Yield. Proc. North Cent. Weed Sci. Soc. Vol. 61.
  • Owen, M.D.K. 2006. Herbicide resistant weeds--who cares/why worry. Proc. North Cent. Weed Sci. Soc. 61:221. (In CD).
  • Pedersen, P. 2006. Row spacing is critical for high yielding soybeans. p. 39-43. IN Proc. 18th Annual Integrated Crop Management Conference, Ames, IA. Nov. 29 - Nov. 30 2006. Iowa State Univ., Ames, IA.
  • Pedersen, P. 2006. Soybean Integrated Pest Management: An Iowan Agronomist's Perspective. 5th National IPM Symposium, St. Louis:16.
  • Pedersen, P. and Roland, J. 2006. Effects of seed treatments on various soybean plant populations. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • De Bruin, J.L. and Pedersen, P. 2006. Soybean variety selection for early planting dates. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Elmore, R.W., Pedersen, P., Duffy, M.D. and Abendroth, L.J. 2006. Incorporating transgenic crops into farm systems in the Midwest US. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Hall, H.S., DeVries, M. and Goggi, A.S. 2006. The effects of moisture content and frost damage on seeds in a maize population. In: 2006 Agronomy Abstracts. The ASA-CSSA-SSSA International Annual Meetings. November 12-16, 2006. Indianapolis, IN.
  • Heggenstaller, A.H., Menalled, F.D., Liebman, M. and Westerman, P.R. 2006. Seasonal patterns in post-dispersal weed seed predation in three cropping systems. Abstracts of the 2006 International Annual Meetings, American Society of Agronomy, Crop Science Society of America, Soil Science Society of America: http://a-c-s.confex.com/crops/2006am/techprogram/P20965.HTM.
  • Herzmann, D.E., Wolt, J., Arritt, R., Westgate, M. and Goggi, S. 2006. Modeling Out Crossing Probabilities for Maize in Iowa. Amer. Soc. Agron. Annu. Meeting, Nov. 8-14, Indianapolis, IN.
  • Larriera, M.A., Westgate, M. and Orf, J. 2006. Breeding for Greater Stability of Protein and Oil Content in Soybean. Amer. Soc. Agron. Annu. Meeting, Nov. 8-14, Indianapolis, IN.
  • Liebman, M., Gibson, L.R., Sundberg, D.N., Heggenstaller, A.H., Westerman, P.R., Chase, C.A., Menalled, F.D., Davis, A.S. and Dixon, P.M. 2006. Agronomic, economic, and ecological characteristics of conventional and low-external-input cropping systems in the U.S. Corn Belt. Abstracts of the 2006 International Annual Meetings, American Society of Agronomy, Crop Science Society of America, Soil Science Society of America: http://a-c-s.confex.com/crops/2006am/techprogram/P21259.HTM.
  • Periappuram, C.C., Li, L., Qiu, F., Wang, D., Nettleton, D., Westgate, M.E., Wurtele, E.S. and Nikolau, B.J. 2006. Transcriptomic analysis of soybean seed development and regulation of seed composition. Molecular and Cellular Biology of the Soybean; 11th Biennial Conference. Lincoln, NE. August 5-8.
  • Rotundo, J., Westgate, M. and Tylka, G. 2006. Variation in soybean yield and composition: association with soil properties and SCN. Amer. Soc. Agron. Annu. Meeting, Nov. 8-14. Indianapolis, IN.
  • Swoboda, C.M. and Pedersen, P. 2006. Effect of strobilurin fungicide on soybean yield components. Agron. Abstr. [CD-ROM computer file]. ASA, Madison, WI.
  • Borras, L. and Westgate, M.E. 2006. Predicting maize kernel sink capacity early in development. Field Crops Res. 95:223-233.
  • Burkart, M., James, D., Liebman, M. and van Ouwerkerk, E. 2006. Integrating principles of nitrogen dynamics in a method to estimate leachable nitrogen under agricultural systems. Water Sci. Tech. 53(2):289-301.
  • DeVries, M. and Goggi, A.S. 2006. Determining the extent of frost damage in maize seed using the tetrazolium test. Crop Management doi:10.1094/CM-2006-0414-01-RS.
  • Hartzler, R.G., Singer, J.W., Buhler, D.D. and Kohler, K.A. 2006. Effect of repeated glyphosate use on weed communities in a soybean-corn rotation. Crop Management at www.cropmanagement.org.doi:10.1094/CM-2006-0308-01-RS.
  • Hartzler, R.G., Liebman, M. and Westerman, P.R. 2006. Weed seed predation in agricultural fields. Iowa State University, Weed Science Extension, Ames, IA. On-line at: http://www.weeds.iastate.edu/mgmt/2006/seedpredation.pdf.
  • Heggenstaller, A.H. and Liebman, M. 2006. Demography of Abutilon theophrasti and Setaria faberi in three crop rotation systems. Weed Res. 46: 138-151.
  • Heggenstaller, A.H., Menalled, F.D., Liebman, M. and Westerman, P.R. 2006. Seasonal patterns in post-dispersal seed predation of Abutilon theophrasti and Setaria faberi in three cropping systems. J. Appl. Ecol. 43:999-1010.
  • Ireland, D.S., Wilson, Jr. D.O, Westgate, M.E., Burris, J.S. and Lauer, M.J. 2006. Managing reproductive isolation in hybrid seed corn production. Crop Sci. 46:1445-1455.
  • Liebman, M. and Sundberg, D.N. 2006. Seed mass affects the susceptibility of weed and crop species to phytotoxins extracted from red clover shoots. Weed Sci. 54:340-345.
  • McAndrews, G.M., Liebman, M., Cambardella, C.A. and Richard, T.L. 2006. Residual effects of composted and fresh solid swine manure on soybean growth and yield. Agron. J. 98:873-882.


Progress 01/01/05 to 12/31/05

Outputs
Soybean production systems: Preliminary research suggests current recommendations for soybean management in Iowa need to be adjusted. Production efficiency and farmer profitability can be improved. Recommendations may need to be adjusted for diverse soils. Weed ecology: Field experiments were conducted to characterize demography of velvetleaf and giant foxtail competition in conventional and reduced-herbicide rotations. When herbicide use is reduced, rotations that include triticale and alfalfa facilitate velvetleaf suppression. Rotations that include alfalfa suppress giant foxtail populations, if seedling mortality is sufficiently high. Greater losses of weed seeds to predators occur in systems that maximize vegetative cover throughout the year. A model integrating seed dispersal, seed burial and seed demand was developed. Factors related to seed availability were more important in determining seed losses due to predation than those related to seed demand. Pasture management: Field experiments to evaluate site-specific adaptation of legumes to landscape positions showed 1) species richness and diversity index were greatest on backslope positions, 2) slope and soil ECa data identify sites where legumes can be successful in pastures, and 3) legumes should be seeded on backslope positions in pastures, N fertilizer not be applied, and grass competition be reduced before seeding legumes in pastures. Studies on the productivity and nutritive value of cool-season pastures, value of warm-season grasses for summer grazing, and effects of pasture sequence on productivity of season-long grazing systems showed greater weight gains for cattle grazing sequences that included pastures interseeded with kura clover, rotating cattle to warm-season grass pastures during summer was less advantageous than having them remain on cool-season pastures, and grazing sequences with warm-season grass pastures performed well under some conditions. Quality and value of agricultural products: Seed produced under a conventional cropping system had better seed quality than in an organic system. Seed quality under organic system was affected by late planting, low temperatures during pollination and premature harvest due to potential frost. Seed quality is crucial for a satisfactory crop establishment in target environments under restricted conditions. Modeling seed set in hybrid seed production: A model 'Nick Manager' was developed to simulate kernel set in hybrid seed production. Predicted kernel set in six commercial seed fields with harvested kernel number varying from 8.4 to 23.1 million kernels per female ha was closely correlated with measured values. With a minimum of information about the inbred pair, the program also can be used to define management strategies that maximize seed production per female hectare or establish initial production requirements for new combination of inbreds. The Anthesis-Silking Interval and the Pollen Sources Interval had the greatest impacts on kernel production. But 'Nick Manager' is designed to allow the user to adjust several management variables simultaneously to assess their additive and synergistic effects.

Impacts
Soybean production: Enhanced understanding of interactions between management systems, pest, and pathogens that will lead to improved yield stability and profitability. Weed ecology: Insights into weed population dynamics enhance evolution of farming practices, decision-making tools, and management systems that increase production efficiency while protecting soil and water resources. The models being developed help researchers understand impacts of crop rotation and tillage practices on weeds. Pasture management: Recommendations for pasture improvement should be made based on landscape position, stocking method, defined management cells, and on-site characteristics. Spatial variation should be used to optimize seasonal production based on plant species growth patterns. Grazing management should be based on seasonal productivity of management cells. Site-specific management of pastures could be used to optimize productivity. Modeling kernel formation: The approach developed for simulating kernel production provides a rational basis for minimizing out-crossing or self-pollination. It is an enabling technology designed to help managers achieve the desired balance between kernel production and seed purity. It also provides a practical mechanism to quantify the impact of alternative field management strategies on optimizing seed yield and genetic purity in maize hybrid seed production. Combined with our models to quantity the dispersal of adventitious pollen, this technology is applicable to management of pharmaceutical and industrial products in transgenic corn.

Publications

  • Guretzky, J.A., Moore, K.J., Knapp, A.D. and Brummer, E.C. 2004. Emergence and survival of legumes seeded into pastures varying in landscape position. Crop Sci. 44:227-233.
  • Guretzky, J.A., Moore, K.J., Burras, L.C. and Brummer, E.C. 2004. Distribution of legumes along gradients of slope and soil electrical conductivity (EC) in pastures. Agron. J. 96:547-555.
  • McAndrews, G.M., Franke, K., Moore, K. and George, R. 2004. Forage yield and nutritive value of oat interseeded with berseem clover and sweetclover. Crop Management doi:10.1094/CM-2004-0301-01-RS.
  • Moore, K. J., White, T.A., Hintz, R.L., Patrick, P.K. and Brummer, E.C. 2004. Sequential grazing of cool and warm-season pastures. Agron. J. 96:1103-1111.
  • White, T.A., Barker, D.J. and Moore, K.J. 2004. Vegetation diversity, growth, quality and decomposition in managed grasslands. Agriculture Ecosystems and Environment 101:73-84.
  • Guretzky, J.A., Moore, K.J., Brummer, E.C. and Burras, C.L. 2005. Species diversity and functional composition of pastures that vary in landscape position and grazing management. Crop Sci. 45:282-289.
  • Tarr, A.B., Moore, K.J. and Dixon, P.M. 2005. Spectral reflectance as a covariate for estimating pasture productivity and composition. Crop Sci. 45:996-1003.
  • Tarr, A.B., Moore, K.J., Bullock, D.G., Dixon, P.M. and Burras, C.L. 2005. Improving map accuracy of soil variables using soil electroconductivity as a covariate. Precision Agriculture 6:255-270.
  • Lopez-Sanchez, H., Goggi, A.S. and Rai, S. 2005. Detection of the CaMV-35S promoter sequence in maize pollen and seed. Seed Technology 27:211-222.
  • Westerman, P.R. and Liebman, M. 2005. Long-term weed management using diverse crop rotation systems. p. 62-64 IN Proc. of the 17th Annual Integrated Crop Management Conference, Iowa State University Extension, Agribusiness Education Program, Ames, IA. On-line: http://www.aep.iastate.edu/files/05icm/05icm-pest.swf.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied prepackaged and tank-mixture herbicides in corn, Nashua, IA, 61:49.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied KIH-485, s-metolachlor & benoxacor, KIH-485 & atrazine, and s-metolachlor & atrazine & benoxacor for weed control in corn, Nashua, IA, 61:86.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. KIH-485, s-metolachlor & benoxacor, KIH-485 & atrazine, and s-metolachlor & atrazine & benoxacor for woolly cupgrass control in corn, Ogden, IA, 61:88.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied KIH-485, s-metolachlor & benoxacor, KIH-485 & atrazine, and s-metolachlor & atrazine & benoxacor for weed control in corn, Ames, IA, 61:90.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. KIH-485, s-metolachlor & benoxacor, KIH-485 & atrazine, and s-metolachlor & atrazine & benoxacor for shattercane control in corn, Ames, IA. 61:92.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied alachlor, pendimethalin, flumioxazin, chlorimuron & sulfentrazone, and cloransulam followed by postemergence glyphosate applications in soybean, Ames, IA. 61:136.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence s-metolachlor & benoxacor, MANA-282, MANA-283, and s-metolachlor & atrazine & benoxacor applied alone and followed by postemergence applications of glyphosate in corn, Ames, IA. 61:183.
  • Schneider, E., Westgate, M. and Ghaffarzadeh, M. 2005. Alternative Approaches to Estimate the Dynamic of Silk Exsertion in Maize. Amer. Soc. Agron. Ann. Meeting, Nov. 6, Salt Lake City, UT.
  • Pedersen, P. 2005. Improve soybean yields through more intensive crop management. 2005 Indiana CCA conference, 13-14 December, 2005. [CD-ROM computer file], Indianapolis, IN.
  • Pedersen, P. 2005. Early planting of soybean is a must for high soybean yields. p. 17-21. IN Proc. 17th Annual Integrated Crop Management Conference, Ames, IA. Nov. 30-Dec. 1, 2005. Iowa State Univ., Ames, IA.
  • Pedersen, P. 2005. Demonstrating the use of a living mulch system in grain crop production. Minnesota Water and Annual Water Resources Joint Conference, Oct. 25-26, 2005, Minneapolis, MN.
  • Pedersen, P. and Roland, J. 2005. Demonstrating the use of a living mulch system in grain crop production in Iowa. Agriculture and the Environment Conference, March 8-9, Ames, 2005. [CD-ROM computer file], Iowa State University Extension.
  • Florine, S.E., Moore, K.J., Fales, S.L. and Hintz, R.L. 2005. The relationship between species diversity and productivity of cool-season grassland. Proc. XX International Grassland Congr. p. 642.
  • DeVries, M. and Goggi, S. 2005. Freezing Characteristics of Maize Seeds during a Frost Event. IN 2005 Agronomy Abstracts. The ASA-CSSA-SSSA International Annual Meetings. November 6-10, 2005. Salt Lake City, UT.
  • de Geus, Y.N., Pollak, L. and Goggi, A.S. 2005. Seed Quality of High Protein Corn Lines in Organic and Conventional Systems. IN 2005 Agronomy Abstracts. The ASA-CSSA-SSSA International Annual Meetings. November 6-10, 2005. Salt Lake City, UT.
  • Grau-Bullon, G. and Goggi, S. 2005.Use of Plant-Made Essential Oils as Biological Seed Treatment in Soybean. IN 2005 Agronomy Abstracts. The ASA-CSSA-SSSA International Annual Meetings. November 6-10, 2005. Salt Lake City, UT.
  • Heggenstaller, A.H. 2005. Cropping system effects on weed population processes. M.S. Thesis. Iowa State Univ., Ames.
  • O'Rourke, M.E. 2005. Carabid beetle communities and invertebrate seed predation in conventional and diversified crop rotation. Ph.D. Dissertation. Iowa State Univ., Ames.
  • Higinio Lopez-Sanchez. 2005. Assessing corn pollen flow and outcross in seed and grain production fields. Ph.D. Dissertation. Iowa State Univ., Ames.
  • Schneider, E.S. 2005. Improving the accuracy of kernel set simulation in hybrid seed production. M.S. Thesis. Iowa State Univ., Ames.
  • Westgate, M.E., Schneider, E. and Ghaffarzadeh, M. 2005. Limitations to Grain Yield within the Female Block of a Maize Hybrid Seed Field. Amer. Soc. Agron. Ann. Meeting, Nov. 6, Salt Lake City, UT.
  • Borras, L. and Westgate, M.E. 2005. Identifying the common patterns in seed development. Amer. Soc. Agron. Ann. Meeting, Nov. 6, Salt Lake City, UT.
  • Astini, J., Fonseca, A., Clark, C., Lizaso, J., Westgate, M. and Arritt, R. 2005. Simulating Out-crossing in Maize Seed Production Fields. Amer. Soc. Agron. Annual Meeting, Nov. 6, Salt Lake City, UT.
  • Menalled, F.D., Landis, D. and Liebman, M. 2005. Habitat management and invertebrate weed seed predation in herbaceous crop systems. Ecological Society of America 2005 Meeting Abstracts: http://abstracts.co.allenpress.com/pweb/esa2005/ document/?ID=48028.
  • Westerman, P.R., Liebman, M., Heggenstaller, A.H., Dixon, P., Menalled, F.D. and Davis, A.S. 2005. Modeling the impacts of seed predators on weed population dynamics. Ecological Society of America 2005 Meeting Abstracts: http://abstracts.co.allenpress.com/pweb/esa2005/document/?ID=50656.
  • Pedersen, P. 2005. Knocking down the soybean yield barriers. 2005 Illinois CCA convention, 15 December, 2005. [CD-ROM computer file], Springfield, IL.
  • Pedersen, P. 2005. Effects of soil pH on soybean grain yield and composition. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Pedersen, P. and Conley, S.P. 2005. Node removal affects soybean grain yield and composition. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Costa, V.L., Pedersen, P. and Tylka, G.L. 2005. Effect of Soil pH on Performance of Soybean Cyst Nematode Resistant Varieties. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • De Bruin, J.L. and Pedersen, P. 2005. Managing for yield: the choice of planting date and plant population. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • De Bruin, J.L. and Pedersen, P. 2005. In-depth analysis of changes in soybean growth and development at varying plant spacing. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Swoboda, C.M. and Pedersen, P. 2005. Effect of strobilurin fungicide on soybean growth and yield. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Williams, A.M. and Pedersen, P. 2005. Root characteristics of three soybean varieties in Iowa. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Williams, A.M. and Pedersen, P. 2005. Early incidence of three soybean (Glycine max L. Merr.) soilborne pathogens in Iowa. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Burkart, M., James, D., Liebman, M. and Herndl, C. 2005. Impacts of integrated crop-livestock systems on nitrogen dynamics and soil erosion in western Iowa watersheds. J. Geophysical Research-Biogeosciences 110, G01009, doi:10.1029/2004JG000008 (on-line).
  • Menalled, F.D., Buhler, D.D. and Liebman, M. 2005. Germination and early growth responses of crop and weed species to composted swine manure under greenhouse conditions. Weed Technology 19:784-789.
  • Westgate, M.E., Fonseca, A. and Lizaso, J. 2005. Manipulating flowering dynamics in corn to optimize pollination and kernel set. Proc. 59th Annual Corn & Sorghum Seed Research Conf. Dec. 8-10, Chicago, IL.
  • Krell, R.K., Pedigo, L.P., Rice, M.E., Westgate, M.E. and Hill, J.H. 2005. Using planting date to manage bean pod mottle virus in soybean. Crop Protection 24:909-914.
  • Lizaso, J.I., Batchelor, W.D., Boote, K.J. and Westgate, M.E. 2005. Development of a Leaf-Level Canopy Assimilation Model for CERES-Maize. Agron. J. 97:722-733.
  • Lizaso, J.I., Batchelor, W.D., Boote, K.J., Westgate, M.E., Rochette, P. and Moreno-Sotomayor, A. 2005. Evaluating a Leaf-Level Canopy Assimilation Model Linked to CERES-Maize. Agron. J. 97:734-740.
  • Fonseca, A.E., Lizaso, J.I., Westgate, M.E., Grass, L. and Dornbos, Jr., D.L. 2005. Simulating Potential Kernel Production in Maize Hybrid Seed Fields. Crop Sci. 44:1696-1709.
  • Menalled, F.D., Kohler, K.A., Buhler, D.D. and Liebman, M. 2005. Organic soil amendment effects on weed seedbank dynamics. Agriculture, Ecosystems, and Environment 111:63-69.
  • Ohno, T., Griffin, T.S., Liebman, M. and Porter. G.A. 2005. Chemical characterization of soil phosphorus and organic matter in different cropping systems in Maine, U.S.A. Agriculture, Ecosystems, and Environment 105:625-634.
  • Schwarte, A.J., Gibson, L.R., Karlen, D.L., Liebman, M. and Jannink, J.-.L. 2005. Planting date effects on winter triticale dry matter and nitrogen accumulation. Agron. J. 97:1333-1341.
  • Westerman, P.R., Liebman, M., Menalled, F.D., Heggenstaller, A.H., Hartzler, R.G. and Dixon, P.M. 2005. Are many little hammers effective? Velvetleaf population dynamics in two- and four-year crop rotation systems. Weed Sci. 53:382-392.


Progress 01/01/04 to 12/31/04

Outputs
Weed Management: Velvetleaf density in a 4-yr rotation should decline if cumulative losses of seeds produced in soybeans exceed 40%. Models including estimates of seed predation indicate weed control efficacy in soybean greater than or equal to 93% in a 2-yr rotation will prevent increases in velvetleaf density. Efficacy could drop to 86% in a 4-yr rotation. Crop rotations that exploit weed seed predation can contribute to effective weed suppression with less reliance on herbicides. Plant growth in stressful environments: Maize genotypes from international sources were evaluated for tolerance, acclimation, and recovery from stress using electrical conductivity, apparent photosynthesis, chlorophyll fluorescence, and xanthophylls content. The role of pathogens in cold tolerance also is being evaluated. Increased marketability of soybeans: Metabolic Flux Analysis was adapted for use on developing soybean seeds. This breakthrough technology measures the metabolic impact of changes in gene activity at the whole seed level. It is being used to determine the molecular and biochemical bases for genetic and environmental variation in soybean seeds composition. Confinement of genes from transgenic corn plants: Simulation models were developed to quantify pollen production, kernel formation, and risk of out-crossing in commercial seed production fields. A pollen dispersal model was created to quantify the long-distance transport of corn pollen. These tools help the corn seed industry optimize hybrid production and minimize genetic impurity. The pollen dispersal model is used to assess the potential for unintended transfer of transgenes to non-transgenic corn plants. Efficiency of crop production: Research is underway to identify key areas where farmers can adjust their production systems to optimize economic return and minimize negative environmental impacts. Variables under study include crop rotations, replant decisions, soil fertility, seed inoculums, and hail injury. Preliminary results suggest current recommendations can be adjusted to improve efficiency and farmer profitability. Production and utilization of forages: Research to improve forage quality and seasonal distribution of forage production included introduction of species with greater nutritive value and better warm-season growth, stockpiling forages, and improved management practices. Protein quality, N fertilization, establishment and persistence, dormancy, site-specific adaptation, and spatial optimization were examined. Genetic and environmental influences on protein fractions and ruminal degradation are under study. Triticale management: Winter triticale has the potential to introduce valuable economic and environmental benefits to U.S. grain production systems. Research was conducted to identify planting dates that allow maximum productivity after soybean. Forage and grain yields were greatest at southwest Iowa locations. Results indicate a two to three week period would be available after soybean harvest for planting without diminished yield.

Impacts
Research on risk of out-crossing and gene flow fill critical knowledge gaps to refine corn industry isolation standards and support regulatory policies on field deployment of transgenic corn producing pharmaceuticals and industrial compounds. Understanding responses of maize to low temperature enables the development of genotypes with less risk of establishment failure or yield reduction. Such studies increase understanding of plant response to external stimuli and their impacts on plant development. The shift in US agriculture to contractual agreements between end users and producers requires access to genotypes with specific traits and quality characteristics of value to end users. Knowledge of genes regulating seed development and composition will accelerate develop of soybeans having seed composition characteristics suited for identity preserved markets of the near future. Farmers and agricultural professionals have expressed great interest in research concerning weed ecology and management when results are presented at farm field days and winter meetings. Insights into weed population dynamics enhance the evolution of management systems that increase production efficiency and improve soil and water resources. Managing production costs is critical for soybean producers. Seed and chemical costs account for a large part of the soybean production costs. New herbicide technologies allow farmers to reduce replant populations when required. A more efficient nutrient management plan for soybean will improve farmer's profitability but will also protect soil and water resources.

Publications

  • Paz, J.O., Batchelor, W.D., Pedersen, P. and Lizaso, J.I. 2004. WebGro: A web-based soybean management decision support system. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Pedersen, P. 2004. Do we really need to inoculate our fields. p. 23-27. IN Proc. 16th Annual Integrated Crop Management Conference, Ames, IA. 1-2 Dec. 2003. Iowa State Univ., Ames.
  • Periappuram, C.C., Li, L., Nettleton, D.S., Westgate, M.E., Wurtele, E.S. and Nikolau, B.J. 2004. Functional genomics of soybean composition. Third Intl. Congress on Plant Metabolomics. 3-6 June, Ames, IA.
  • Schneider, E.S. and Westgate, M.E. 2004. A Simple Technique for Estimating Silk Exertion Dynamic in Maize. In Agron. Abstr., ASA, Madison, WI.
  • Shanks, J. V., Iyer, V., Sriram, G., Fulton, D.B., Zhou, R. and Westgate, M.E. 2004. Integrating Genetic and Environmental Impacts on Seed Composition Using Metabolic Flux Analysis. In Agron. Abstr., ASA, Madison, WI.
  • Westgate, M.E., Fonseca, A. and Lizaso, J. 2004. Manipulating flowering dynamics in corn to optimize pollinatin and kernel set. The 59th Annual Corn & Sorghum Seed Research Conf. Dec 8-10, Chigaco, IL.
  • Westgate, M.E. 2004. Effect of stress on ear size. Illinois State CCA Conference. Dec. 16. Urbana, IL. Westgate, M.E. 2004. Pollination stress and kernel set in corn. Indiana State CCA Conference. Dec. 14, 15. Indianapolis, IN.
  • Westgate, M.E., Brumm, T. and Hurburgh, C. 2004. Genotype/environment Interactions on Soybean Seed Composition. In Agron. Abstr., ASA, Madison, WI.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence s-metolachlor and benoxacor, MAN-282, MANA-283, and s-metolachlor and atrazine and benoxacor applied alone and followed by postemergence applications of glyphosate in corn, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied alachlor, pendimethalin, flumioxazin, chlorimuron and sulfentrazone, and cloransulam followed by postemergence glyphosate applications in soybean, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied prepackaged and tank-mixture herbicides in corn, Nashua, IA.
  • Owen, M.D.K., Lux, J.F. Franzenburg, D.D. 2004. Preemergence applied KIH-485, s-metolachlor and benoxacor, KIH-485 and atrazine, and s-metolachlor and atrazine and benoxacor for weed control in corn, Nashua, IA.
  • Arritt, R., Clark, C.A., Westgate, M.E. and Goggi, A.S. 2004. Numerical simulations and field studies of maize pollen dispersion. 16th Biometeorology and Aerobiology.
  • Fonseca, A.E., Lizaso, J.I., Westgate, M.E., Grass, L. and Dornbos, D.L., Jr. 2004. 'Risk Index' for Out-Crossing in Hybrid Seed Corn. In Agron. Abstr., ASA, Madison, WI.
  • Heggenstaller, A.H., Liebman, M., Westerman, P.R. and Menalled, F.D. 2004. Impacts of differential weed seedling recruitment in conventional and diversified cropping systems. Ecolog. Soc. of Amer. 2004 Meeting Abstracts 214.
  • Leon, R.G. and Owen, M.D.K. 2004. Are seedling emergence patterns in artificial seed banks representative of emergence patterns in natural seed banks. Abstr. WSSA 44:62 (in CD).
  • Liebman, M., Westerman, P.R., Menalled, F.D., Heggenstaller, A.H., Hartzler, R.G. and Dixon, P.M. 2004. Weed responses to diversified cropping systems: velvetleaf population trajectories in two-year and four-year rotations. Ecolog. Soc. of Amer. 2004 Meeting Abstracts: 300-301.
  • Lizaso, J.I., Fonseca, A., Batchelor, W.D. and Westgate, M.E. 2004. Simulating kernel numbers in maize by combining source-limited and sink-limited kernel set. In Agron. Abstr., ASA, Madison, WI.
  • Lopez-Sanchez, H., Goggi, S., Westgate, M.E., Arritt, R. and Clark, C. 2004. Corn pollen flow in seed and grain production fields. In Agron. Abstr., ASA, Madison, WI.
  • Nikolau, B.J., Periappuram, C.C., Ling, L., Nettleton, D.S., Syrkin Wurtele, E. and Westgate, M.E. 2004. Gene expression profiles associated with increasing seed protein content. In Agron. Abstr., ASA, Madison, WI.
  • Leon, R.G., Knapp, A.D. and Owen, M.D.K. 2004. Effect of temperature on the germination of common waterhemp (Amaranthus tuberculatus), giant foxtail (Setaria faberi) and velvetleaf (Abutilon theophrasti). Weed Sci. 52:67-73.
  • Leon, R.G. and Owen, M.D.K. 2004. Artificial and natural seed banks differ in seedling emergence patterns. Weed Sci. 52:531-537.
  • Liebman, M., Menalled, F.D., Buhler, D.D., Richard, T.L., Sundberg, D.N., Cambardella, C.A. and Kohler, K.A. 2004. Impacts of composted swine manure on weed and corn nutrient uptake, growth, and seed production. Weed Sci. 52:365-375.
  • Loecke, T.D., Liebman, M., Cambardella, C.A. and Richard, T.L. 2004. Growth responses of corn to composted and fresh solid swine manure. Crop Sci. 44:177-184.
  • Loecke, T.D., Liebman, M., Cambardella, C.A. and Richard, T.L. 2004. Corn response to composting and time of application of solid swine manure. Agron. J. 96:214-223.
  • Menalled, F.D., Liebman, M. and Buhler, D.D. 2004. Impact of composted swine manure and tillage on soybean-common waterhemp (Amaranthus rudis) interactions Weed Sci. 52:605-613.
  • Nordby, D.E. and Hartzler, R.G. 2004. Influence of corn on common waterhemp (Amaranthus rudis) growth and fecundity. Weed Sci. 52:255-259.
  • Paz, J., Batchelor, W.D. and Pedersen, P. 2004. WebGro: A web-based soybean management decision support system. Agron. J. 96:1771-1779.
  • Pedersen, P., Boote, K.J., Jones, J.W. and Lauer, J.G. 2004. Evaluation of the CROPGRO-Soybean model for the upper Midwest. Agron. J. 96:556-564.
  • Pedersen, P. and Lauer, J.G. 2004. Soybean growth and development response to rotation sequence and tillage system. Agron. J. 96:1005-1012.
  • Pedersen, P. and Lauer, J.G. 2004. Soybean growth and development in various management systems and planting dates. Crop Sci. 44:508-515.
  • Pedersen, P. and Lauer, J.G. 2004. Soybean yield components response to management system and planting date. Agron. J. 96:1372-1381.
  • Singer, J.W., Kohler, K.A., Liebman, M., Richard, T.L., Cambardella, C.A. and Buhler, D.D. 2004. Tillage and compost affect yield of corn, soybean, and wheat and soil fertility. Agron. J. 96:531-537.
  • Sriram, G., Fulton, D.B., Zhou, R., Westgate, M.E., Spalding, M.H. and Shanks, J.V. 2004. Quantification of Metabolic Fluxes in Developing Soybean (Glycine max) Embryos Using Biosynthetically Directed Fractional 13C Labeling, 2-D [13C, 1H] NMR and Rigorous Isotopomer Balancing. Plant Physiol. 136:3043-3057.
  • Aberle, E.Z., Gibson, L.R., Knapp, A.D., Dixon, P.M., Moore, K.J., Brummer, E.C. and Hintz, R. 2003. Optimum planting procedures for eastern gamagrass. Agron. J. 95:1054-1062.
  • Bertram, M.G. and Pedersen, P. 2004. Adjusting management practices using glyphosate-resistant soybean cultivars. Agron. J. 96:462-468.
  • Boyer, J.S. and Westgate, M.E. 2004. Grain yields with limited water. J. Exp. Bot. 55: 2385-2394.
  • Davis, A.S., Dixon, P. M. and Liebman, M. 2004. Using matrix models to determine cropping system effects on the demography of an annual weed. Ecolog. Appl. 14:655-668.
  • Duppong, L.M., Delate, K., Liebman, M., Horton, R., Romero, F., Kraus, G., Petrich, J. and Chowdbury, P.K. 2004. The effect of natural mulches on crop performance, weed suppression and biochemical constituents of catnip and St. John's wort. Crop Sci. 44:861-869.
  • Fonseca, A.E., Lizaso, J.I., Westgate, M.E., Grass, L. and Dornbos, D.L. 2004. Simulating potential kernel set in maize hybrid seed production. Crop Sci. 44:1696-1709.
  • Gibson, L. and Liebman, M. 2004. A laboratory exercise for teaching depth of weed emergence concepts. Weed Tech. 18:473-479.
  • Hartzler, R.G, Battles, B.A. and Nordby, D.E. 2004. Effect of common waterhemp emergence date on growth and fucundity in soybean. Weed Sci. 52:242-245.
  • Lemke, B.M., Gibson, L.R., Knapp, A.D., Dixon, P.M., Moore, K.J. and Hintz, R. 2003. Maximizing seed production in eastern gamagrass. Agron. J. 95:863-869.
  • Westgate, M.E. and Fonseca, A.E. 2004. Relationship Between Desiccation and Viability of Maize Pollen. In Agron. Abstr., ASA, Madison, WI.
  • Tharp, B.E., Kells, J.J., Bauman, T.T., Harvey, R.G., Johnson, W.G., Loux, M.M., Martin, A.R., Maxwell, D.J., Owen, M.D.K., Regehr, D.L., Warnke, J,E., Wilson, R.G., Wrage, L.J, Young, B.G. and Dalley, C.D. 2004. Assessment of weed control strategies for corn in the North-Central United States. Weed Technol. 18:203-210.
  • Tian, X., Knapp, A.D., Gibson, L.R., Struthers, R., Moore, K.J., Brummer, E.C. and Bailey, T.B. 2003. Response of eastern gamagrass seed to gibberellic acid buffered below its pKa. Crop Sci. 43:927-933.
  • Zelaya, I. and Owen, M.D.K. 2004. Evolved resistance to ALS-inhibiting herbicides in common sunflower (Helianthus annuus L.), giant ragweed (Ambrosia trifida L.), and shattercane (Sorghum bicolor L.) in Iowa. Weed Sci. 52:538-548.
  • Westgate, M.E., Purcell, L.C. and Whigham, K. 2004. Soybean: Agronomy. p. 146-155. IN C. Wrigley, H. Corke, and C. Walker (eds.) Encyclopedia of Grain Science. Elsevier Science Ltd. London.
  • Arwatchanakarn, A. 2004. Dehydrin-like protein expression profiles of maize seedlings during germination, low temperature stress, and genotype. M.S. Thesis. Iowa State Univ., Ames.
  • Fonseca, A.E. 2004. Quantitative assessment of kernel set and risk of out-crossing in maize based on flowering dynamics. Ph.D. Dissertation. Iowa State Univ., Ames.
  • Graef, R.L. 2004. Legume identity and timing of incorporation affect corn and soil responses to green manure. M.S. Thesis. Iowa State Univ., Ames.
  • Grote, K. 2004. Characterization of inducible cold tolerance in photosynthetic maize seedlings and the behavior of selected xanthophyll compounds. M.S. Thesis. Iowa State Univ., Ames.
  • Ireland, D.S. 2004. The influence of cultural practice, biology and environment on maize pollen travel. Ph.D. Dissertation. Iowa State Univ., Ames.
  • Khatounian, C.A. 2004. Weed control in no-till organic soybean in southern Brazil. Ph.D. Dissertation. Iowa State Univ., Ames.
  • Reschly, B. 2004. Dormancy regulation in conventional and oleic sunflower lines (Helianthus annuus L.). M.S. Thesis. Iowa State Univ., Ames.
  • Swart, B.M. 2004. Effect of glyphosate on common cocklebur, velvetleaf, and common waterhemp seed production, viability, germination, and dormancy. M.S. Thesis. Iowa State Univ., Ames.
  • Graef, R.L., Cambardella, C. and Liebman, M. 2004. Legume identity and timing of incorporation effects on soil responses to green manure. p. 20-21 IN Annual Progress Reports-2003, Northeast Research and Demonstration Farm, ISRF03-13. Agric. and Home Econ. Expt. Stn., Iowa State Univ., Ames.
  • Liebman, M. and Haden, D. 2004. Impacts of rotation length, forage legume identity, and composted manure on organic crop production. p. 16-17 IN Annual Progress Reports-2003, Northwest Research and Demonstration Farm, ISRF03-29, 31. Agric. and Home Econ. Expt. Stn., Iowa State Univ., Ames.
  • Liebman, M., Hartzler, R.G., Westerman, P.R., Menalled, F.D., Heggenstaller, A.H. and Dixon, P.M. 2004. Velvetleaf responses to two-year and four-year crop rotation systems. p. 21-22 IN Annual Progress Reports-2003, Agronomy and Agricultural Engineering Farms and Horticulture Station, ISRF03-38, 16, 30, 36. Agric. and Home Econ. Expt. Stn., Iowa State Univ., Ames.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Carfentrazone and glyphosate applied postemergence for weed control in corn, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. KIH-485, s-metolachlor & benoxacor, KIH-485 and atrazine, and s-metolachlor and atrazine and benoxacor for woolly cupgrass control in corn, Ogden, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. KIH-485, s-metolachlor and benoxacor, KIH-485 and atrazine, and s-metolachlor and atrazine and benoxacor for shattercane control in corn, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Two pass systems including applications of early preplant and preemergence followed by postemergence for weed control in no-tillage corn production, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Postemergence tank-mixture applications of lactofen plus glyphosate in soybean, Ames, IA.
  • Owen, M.D.K., Lux, J.F. and Franzenburg, D.D. 2004. Preemergence applied KIH-485, s-metolachlor and benoxacor, KIH-485 and atrazine, and s-metolachlor and atrazine and benoxacor for weed control in corn, Ames, IA.


Progress 01/01/03 to 12/31/03

Outputs
Efficiency of crop production: Research on soybean production systems indicates management recommendations for Iowa need to be adjusted. Research is underway to identify management opportunities to optimize economic and environmental benefits. Weed management: Iowa biotypes of giant ragweed required less than three weeks to achieve 95% germination. Emergence patterns across environments indicated emergence rate is controlled genetically. Population dynamics of velvetleaf and giant foxtail varied among crops and years of rotation in systems containing corn, soybean, triticale, and alfalfa and reduced rates of chemical inputs. Removal of weed seed by predators was crop-specific and associated with canopy development. Simulations indicated requirements for weed control by herbicides and cultivation could be reduced by greater weed seed predation. Decreases of 40% of the velvetleaf seeds are possible. Production and utilization of forages: Research to improve forage quality and seasonal distribution of forage production included introduction of species with greater nutritive value and better warm-season growth, stockpiling forages, and improved management practices. Legume species, warm-season grasses, and annual forages are being tested. Protein quality, N fertilization, establishment and persistence, dormancy, site-specific adaptation, and spatial optimization were examined. Genetic and environmental influences on protein fractions and ruminal degradation are under study. Biology of seed development: A library of TZ staining images was collected from frosted and non-frosted corn seed. Screening protocols for characterizing responses to low temperature stress are being developed. Research on seed dormancy in eastern gamagrass (Tripsicum dactyloides) revealed components of seed dormancy, and optimum planting times for stand establishment. Application of GA3 improved priming efficacy. Fall planting of dormant seed remains the most reliable means to establish eastern gamagrass. Quality and value of agricultural products: Potential for improving the quality of maize inbred seed in being evaluated in sustainable and conventional cultivation systems. Near-isogenic soybean lines were developed that vary in seed protein by 11%. Gene activity early in seed development was a key determinant of protein accumulation. A soybean microarray chip containing 9000 genes associated with plant biochemistry and seed development was developed to compare gene expression in the near-isogenic lines. In vitro culture studies indicated seed composition was determined by events in the seed. Models were developed to simulate pollen production, pollen dispersal, and out-crossing in seed production fields. Risk of out-crossing from a GMO source was tested by varying competition between local and adventitious pollen source. Pollen and seed samples are being analyzed for presence of transgenes in non-GMO seed. Energy from biomass: Testing switchgrass for biomass production involves site-specific management, evaluation of CRP land for biomass/fuel quality, fermentation of crop residues for organic acid production/industrial uses, and evaluation of kenaf as a fiber crop for Iowa.

Impacts
Outcomes of research on risk of out-crossing and gene flow fill critical knowledge gaps to improve industry standards for isolation of seed production fields and APHIS policy regulating field deployment of transgenic corn created to produce plant made pharmaceuticals and industrial compounds. Transformation of US agricultural industry from a public, commodity based model to one driven by contractual agreements between end users and producers requires access to genotypes with specific traits and quality characteristics. Knowledge of genes regulating seed development and composition accelerates the development of soybeans having seed traits suited for identity preserved markets. An improved staining protocol to reliably quantify freezing injury in corn has helped seed companies and seed brokers in Iowa identify freeze-damaged seed lots. Development of effective weed management programs allows for locally adapted systems of giant ragweed management. New herbicide technologies enable soybean producers to reduce soybean plant population when replanting in the spring. Agricultural professionals are greatly interested in research concerning weed ecology and management. Insights provided by the weed seed predation project enhances the evolution of farming practices, decision-making tools, and management systems that increase crop production efficiency while improving protection of soil and water resources. The models being developed represent the state of the art for understanding the impacts of crop rotation systems and tillage practices on weeds.

Publications

  • Lizaso, J.I., Batchelor, W.D., Westgate, M.E. and Echarte, L. 2003. Enhancing the capacity of CERES-Maize to compute light capture. Agric. Systems 76:293-311.
  • Lizaso, J.I., Westgate, M.E., Batchelor, W.D. and Fonseca, A. 2003. Predicting potential kernel set in maize from simple flowering characteristics. Crop Sci. 43:892-903.
  • Borras, L., Westgate, M.E. and Otegui, M.E. 2003. Control of Kernel Weight and Kernel Water Relations by Post-flowering Source-sink Ratio in Maize. Ann. Bot. 91:857-867.
  • Davis, A.S. and Liebman, M. 2003.Cropping system effects on Setaria faberi seedbank dynamics. Aspects of Appl. Biol. 69:83-91.
  • Davis, A.S. and Liebman, M. 2003. Cropping system effects on giant foxtail demography: I. Green manure and tillage timing. Weed Sci. 51:919-929.
  • Davis, A.S., Dixon, P.M. and Liebman, M. 2003. Cropping system effects on giant foxtail demography: II. Retrospective perturbation analysis. Weed Sci. 51:930-939.
  • Fonseca, A. E., Westgate, M.E., Grass, L. and Dornbos, Jr., D.L. 2003. Tassel morphology as an indicator of potential pollen production in maize. Online. Crop Management doi:10.10.94/CM-2003-0804-01-RS.
  • Gibson, L. and Liebman, M. 2003. A laboratory exercise for teaching critical period for weed control concepts. Weed Tech. 17:394-402.
  • Gibson, L. and Liebman, M. 2003. A laboratory exercise for teaching plant competition and relative growth rate concepts. Weed Tech. 17:403-411.
  • Lizaso, J.I., Batchelor, W.D. and Westgate, M.E. 2003. A leaf area model to simulate cultivar specific expansion and senescence of maize leaves. Field Crops Res. 80:1-17.
  • Pedersen, P. and Lauer, J.G. 2003. Soybean agronomic response to management systems in the upper Midwest. Agron. J. 95:1146-1151.
  • Pedersen, P. and Lauer, J.G. 2003. Corn and soybean rotation effect on row spacing and tillage system. Agron. J. 95:965-971.
  • Westgate, M.E., Lizaso, J. and Batchelor, W.D. 2003. Quantitative relationships between pollen shed density and grain yield in maize. Crop Sci. 43:934-942.
  • Young, B.G., Young, J.M., Matthews, J.L., Owen, M.D.K., Zelaya, I.A., Hartzler, R.G., Wax, L.W., Rorem, F.W. and Bollero, G.A. 2003. Soybean development and yield as affected by three postemergence herbicides. Agron. J. 95:1152-1156.
  • Liebman, M., Bastiaans, L. and Baumann, D.T. 2003. Weed management in low-external-input and organic farming systems. p. 285-315. In Inderjit (ed.) Weed Biology and Management, Kluwer Academic Publishers, Dordrecht, The Netherlands.
  • Westgate, M.E., Otegui, M.E. and Andrade, F.H. 2003. Physiology of the Corn Plant. Ch. 2.1. In C.W Smith, J. Betran and E. Runge (ed.) Corn. Wiley and Sons, New York.
  • Fonseca, A.E., Westgate, M.E. and Lizaso, J. 2003. Flowering dynamics and kernel set in maize. Application to seed production. INTA, FAUBA Corn Breeders Conference, Pergamino Argentina.
  • Arritt, R., Ashton, B., Falk, M., Fonseca, A., Goggi, S., Hatfield, J., Osterreich, W., Ireland, D., Reise, J., Takle, G., Todey, D. and Westgate, M. 2003. Predicting pollen production, dispersal, and out-crossing in maize. INTA, FAUBA Corn Breeders Conference, Pergamino Argentina.
  • Westgate, M. 2003. Soybean response to bean leaf beetle. ISU Extension Soybean Management Short Course. Ames, IA.
  • Argotsinger, E., Westgate, M.E., Pedersen, P. and Batchelor, W.D. 2003. Calibrating CROPGRO-soybean for planting date in Iowa. Agron. Abstr., ASA. Madison, WI.
  • Arritt R.W., Westgate, M.E., Fonseca, A. and Riese, J.M. 2003. Development of an Adventitious Pollen Risk Assessment model. 1st European Congress on the Coexistance of Genetically Modified Crops with Conventional and Organic Crops (GMCC-03). Helsingor, Denmark.
  • Arritt, R.W., Westgate, M.E., Ireland, D. and Bodem, J.M. 2003. Adventitous pollen risk assessment model. 3rd European Symposium on Aerobiology GMCC-03.
  • Davis, A.S. and Liebman, M. 2003. Differential predation of giant foxtail (Setaria faberi) seeds in contrasting crop sequences. Abstr. Weed Sci. Soc. Amer. 43:48.
  • Davis, A.S., Dixon, P.M. and Liebman, M. 2003. Retrospective perturbation analysis of cropping system effects on giant foxtail demography. Abstr. Weed Sci. Soc. Amer. 43:25.
  • Fonseca, A.I., Lizaso, J.I., Grass, L., Westgate, M.E. and Dornbos, D. 2003. Predicting yield response to inbred management in hybrid seed production. Agron. Abstr., ASA. Madison, WI.
  • Fonseca, A.I., Westgate, M.E. and Arritt, R. 2003. Loss of maize pollen viability varies with temperature and vapor pressure. Agron. Abstr., ASA. Madison, WI.
  • Ireland, D., Lizaso, J., Fonseca, A. and Westgate, M.E. 2003. Predicting risk of out-crossing in hybrid seed production. Agron. Abstr., ASA. Madison, WI.
  • Nordby, D.E. and Hartzler, R.G. 2003. Effect of tillage on common waterhemp emergence and vertical distribution of seed in the soil. Proc. North Central Weed Sci. Soc. 60:55.
  • Pedersen, P. and Lauer, J.G. 2003. Corn and Soybean Response to Rotation Sequence and Tillage System. p. 35-41. Proc. 15th Annual Integrated Crop Management Conference. Iowa State Univ., Ames, IA.
  • Pedersen, P. and Lauer, J.G. 2003. Economic comparisons of corn and soybean cropping practices in Wisconsin. Agron. Abstr. [CD-ROM computer file], ASA, Madison, WI.
  • Pedersen, P. and Lauer, J.G. 2003. Economic comparisons of corn and soybean rotation sequences. Agron. Abstr. [CD-ROM computer file], ASA. Madison, WI.
  • Sriram, G., Iyer, V., Zhou, R., Shanks, J. and Westgate, M.E. 2003. Metabolic flux analysis of sucrose metabolism into protein, oil, and starch in soybean seeds. Agron. Abstr., ASA. Madison, WI.
  • Van Ouwerkerk, E.N.J., James, D.E., Richard, T.L., Burkart, M.R. and Liebman, M. 2003. A multi-model approach for sustainable agriculture in the US corn belt. Amer. Soc. Agric. Eng. (ASAE) Meeting Paper No. 033009. Joseph, MI.
  • Westgate, M., Pedersen, P. and Batchelor, W. 2003. Calibrating CROPGRO-soybean for planting date in Iowa. Agron. Abstr. [CD-ROM computer file], ASA. Madison, WI.


Progress 01/01/02 to 12/31/02

Outputs
1. Efficiency of crop production. Delayed planting decreases yield loss due to bean leaf beetle and pod mottle virus, but did not decrease virus incidence or seed mottling. Optimum planting date depended on year and growing conditions during flowering. 2. Weed management systems. Research trials indicated optimum forms and application times for swine manure had species-specific impacts on weeds, positive effects on soil physical and chemical properties, positive effects on corn and soybean growth and yield. To control the size of the weed seed bank and to protect crops from the competitive effects of weeds, effective weed management strategies should be in place when composted swine manure is used as a soil amendment. 3. Production and utilization of forages. A greenhouse study revealed substantial competitive effects of smooth bromegrass on growth of switchgrass and big bluestem, which was greater under cooler temperatures. These results suggest that management practices that reduce smooth bromegrass biomass in spring and/or early summer are likely to suppress its dominance over the warm-season species. 4. Biology of seed development. Research on stand establishment in eastern gamagrass has demonstrated that fall plantings provide a high probability of success while spring plantings are generally unsuccessful. 5. Reliability of plant production systems. Research is underway to establish rational screening protocols for characterizing responses to low temperature stress using unique maize genotypes tolerant to low temperature stress. Treatments include temperature/duration variables, recovery from stress, and acclimation capability. 6. Quality and value of agricultural products. Near isogenic lines of soybeans varying in seed protein content by as much as 12% have been developed for biochemical and molecular studies. A metabolic flux model has been developed for soybean seeds that can define changes in metabolic pathways required to increase seed protein content. 7. Energy from agricultural biomass. Anaerobic digestion of baled corn stover, sweet sorghum and sugars is being used to produce ethanol. Yield of ethanol from sorghum was about 5000 L/ha, and about 3500 L/ha from sugar beets. 8. Maize biodiversity. Morphological, phenological, and disease susceptibility data were collected on maize accessions native to the arid and semiarid US Southwest, and seed increased for future studies. Capacity to emerge from extraordinary depths and seedling characteristics associated with emergence were documented.

Impacts
Earlier planting of soybean increases insect and virus pressure, which limit yield and marketability. Overcoming these pressures will ensure early planting remains a viable option for producers. Insights into soil-crop-weed relationships will advance farming management systems to increase crop production efficiency while protecting soil and water resources. Forage producers can establish management zones to optimize production and quality of forages. Multivariate approaches using vegetation indices may be useful in predicting biomass and species composition in defined management zones. Understanding the effects of low temperature on maize stand establishment will lead to expanded use of reduced tillage systems and improve yield stability. Eastern gamagrass has tremendous potential for wildlife habitat, forage, and biomass production. Managing its dormancy is critical to expand its use. Widespread planting will improve the seasonal distribution and utilization of forages. Identifying genes controlling seed composition will speed the development of soybean genotypes with valuable seed components. Such genotypes are essential as soybean markets shift to trait based pricing. More efficient methods of producing chemicals from agricultural biomass will increase the value of farm products. Documentation of the characteristics of maize germplasm will expand the utility of these genetic resources for crop improvement. Enhanced fundamental understanding of the attributes of maize adapted to stress environments will contribute to improved yield stability under adverse conditions.

Publications

  • Menalled FD, M Liebman and DD Buhler. 2002. Differential response of crop and weed seeds to composted swine manure applications. Ecol. Soc. Amer. 2002 Meeting Abstracts: http://199.245.200.45/pweb/?SOCIETY=esa&YEAR=2002&ID=5483.
  • Menalled FD, M Liebman and DD Buhler. 2002. Impact of composted swine manure on crop and weed establishment and growth. Proc. of the 5th Workshop of the European Weed Research Society Working Group on Physical and Cultural Weed Control (11-13 March 2002, Pisa, Italy), p. 183. Institut de Malherbologie, Ste. Anne de Bellevue, Quebec, Canada.
  • Westgate ME, R Arritt, S Goggi, E Takle, R Bhushan, D Ireland, J Riese and M Falk. 2002. Predicting pollen production, dispersal, and outcrossing in maize. In Agronomy Abstracts, ASA, Madison, WI.
  • Zhou R and ME Westgate. 2002. Partitioning of sucrose into protein, oil, and starch in soybean cotyledons cultured in planta and in vitro. In Agronomy Abstracts, ASA, Madison, WI.
  • Lizaso J, W Batchelor and ME Westgate. 2002. Predicting potential kernel numbers in maize under assimilate-limited and pollen-limited conditions. In Agronomy Abstracts, ASA, Madison, WI.
  • Lizaso J, W Batchelor and ME Westgate. 2002. A leaf area model to simulate cultivar-specific expansion and senescence of maize leaves. In Agronomy Abstracts, ASA, Madison, WI.
  • Arritt R, J Reise and ME Westgate. 2002. Development and verification of a Lagrangian model for pollen dispersal. In Agronomy Abstracts, ASA, Madison, WI.
  • Fonseca A, ME Westgate and J Lizaso. 2002. Flowering dynamics and kernel set in maize vary with plant population density and nitrogen fertilizer levels. In Agronomy Abstracts, ASA, Madison, WI.
  • Fonseca A and ME Westgate. 2002. Maize tassel morphology as an indicator of pollen production. In Agronomy Abstracts, ASA, Madison, WI.
  • Orf J, J Peterson, ME Westgate, C Shumway and J Schussler. 2002. Development of near-isogenic lines of soybean varying in seed protein and oil content. In Agronomy Abstracts, ASA, Madison, WI.
  • Conklin AE, MS Erich, M Liebman, D Lambert, E Gallandt and WA Halteman. 2002. Effects of red clover (Trifolium pratense) green manure and compost soil amendments on the growth and health of wild mustard (Brassica kaber) seedlings. Plant and Soil 238:245-256.
  • Davis AS and M Liebman. 2001. Nitrogen source influences wild mustard growth and competitive effect on sweet corn. Weed Sci. 49:558-566.
  • Liebman M and ER Gallandt. 2002. Differential responses to red clover residue and ammonium nitrate fertilizer by common bean and wild mustard. Weed Sci. 50:521-529.
  • Liebman M and CP Staver. 2001. Crop diversification for weed management. p. 322-374. IN: Liebman M, CL Mohler and CP Staver (eds). Ecological Management of Agricultural Weeds. Cambridge University Press, Cambridge, UK.
  • Liebman M and CL Mohler. 2001. Weeds and the soil environment. p. 210-268. IN Liebman, M., Mohler, C.L. and Staver, C.P. (ed) Ecological Management of Agricultural Weeds. Cambridge University Press, Cambridge, UK.
  • Mohler CL, M Liebman and CP Staver. 2001. Weed management: the broader context. p. 494-518. IN: Liebman M, CL Mohler and CP Staver (eds). Ecological Management of Agricultural Weeds. Cambridge University Press, Cambridge, UK.
  • Richard TL, M Liebman, CA Cambardella and TL Loecke. 2002. Land application of biotechnology byproduct compost and other organic matter amendments. Final project report submitted to Chamness Technology, Inc., Blairsburg, IA.
  • Braden IS, KJ Moore, RL Hintz, MH Wiedenhoeft, EC Brummer and MP Hoffman. 2002. Pasture enhancement of warm-season grass pastures using a complex mixture of legumes. p. 18-19. IN Annual Progress Reports-2001, Western Research and Demonstration Farm, ISRF01-10, Iowa State University, Cooperative Extension Service, Ames, IA.
  • Moore KJ, MH Wiedenhoeft, EC Brummer, JR Russell, R Hintz, T White, J Secor and D Maxwell. 2002. Sequential grazing systems of cool- and warm-season pastures. IN Annual Progress Reports-2001, McNay Research Farm, Iowa State University, Publication ISRF01-35, Cooperative Extension Service, Ames, IA.
  • Davis AS, PM Dixon and M Liebman. 2002. Retrospective perturbation analysis of cropping system effects on weed population growth rate. Ecol. Soc. Amer. 2002 Meeting Abstracts: http://199.245.200.45/pweb/?SOCIETY=esa&YEAR=2002&ID=4716.
  • Davis AS and M Liebman. 2002. Response of giant foxtail (Setaria faberi Herrm.) demographic parameters in maize (Zea mays L.) to varied tillage and soil amendment practices: empirical and modeling studies. D.C. Cloutier (ed.) Proc. of the 5th Workshop of the European Weed Research Society Working Group on Physical and Cultural Weed Control (11-13 March 2002, Pisa, Italy), p. 5. Institut de Malherbologie, Ste. Anne de Bellevue, Quebec, Canada.
  • Liebman M, T Richard, DN Sundberg, DD Buhler and FD Menalled. 2002. Impacts of composted swine manure on maize and three annual weed species. Proc. of the 5th Workshop of the European Weed Research Society Working Group on Physical and Cultural Weed Control (11-13 March 2002, Pisa, Italy), p. 173. Institut de Malherbologie, Ste. Anne de Bellevue, Quebec, Canada.
  • Franzenburg DD, JF Lux and MDK Owen. 2002. Effect of soil-applied herbicide application timing on foxtail species control and corn yield. Proc. North Cent. Weed Sci. Soc. 57:18.
  • Zelaya I and MDK Owen. 2002. Evaluation of methods to determine shikimic acid in plants. Proc. North Cent. Weed Sci. Soc. 57:39.
  • Leon R and MDK Owen. 2002. Temperature regulation of seed dormancy of three weeds. Proc. North Cent. Weed Sci. Soc. 57:49.
  • Harbur MM and MDK Owen. 2002. Effect of nitrogen application timing and corn density on the competitiveness of three Iowa weed species. Proc. North Cent. Weed Sci. Soc. 57:54.
  • Leon R and MDK Owen. 2002. Effect of light and temperature interactions on weed seed dormancy. Proc. North Cent. Weed Sci. Soc. 57:121.
  • Zelaya IA and MDK Owen. 2002. Selection of glyphosate resistance in common waterhemp (Amaranthus tuberculatus [Moq. Ex d.] J.D.). Proc. North Cent. Weed Sci. Soc. 57:159.
  • Owen MDK. 2002. Glyphosate resistant waterhemp in Iowa. Proc. North Cent. Weed Sci. Soc. 57:210.
  • Owen MDK and I Zelaya. 2002. Impact of herbicide resistant crops in North America-a northern perspective. Proc. 13th Australian Weeds Conf.:655:659.
  • Hartwigsen JA and AS Goggi. 2002. Expression of a dehydrin-like protein in maize seedlings germinated from seed exposed to freezing. J. Plant Biol. 45(2):459-455.
  • Argotsinger E, ME Westgate and W Batchelor. 2002. Predicting date of planting effects on soybean grown in Iowa. In Agronomy Abstracts, ASA, Madison, WI.
  • Rogis CJ, LR Gibson and AD Knapp. 2002. Stratification and gibberellic acid effects on seed dormancy in eastern gamagrass. In Agronomy Abstracts, ASA, Madison, WI.
  • Karlen DL, K Delate, LR Gibson and EC Brummer. 2002. Transition challenges associated with implementing organic agriculture research. In Agronomy Abstracts, ASA, Madison, WI.
  • Nordby DE and RG Hartzler. 2002. Influence of corn on common waterhemp growth and fecundity. North Central Weed Sci. Soc. Abstr. 57:145.
  • Hartzler RG, K Harrison, C Sprague and L Wax. 2002. Emergence characteristics of giant ragweed biotypes from Ohio, Illinois and Iowa. North Central Weed Sci. Soc. Abstr. 57:51.
  • Hartzler RG. 2002. Adaptation of weeds to management practices. The 14th Annual Integrated Crop Management Conference Proceedings. 14:127-132.
  • Barker DJ, KJ Moore and JA Guretzky. 2002. Spatial variation in species richness under contrasting topologies and grazing regimes. Proc. American Forage and Grassland Conf. p. 222-225.
  • Braden IS, KJ Moore, RL Hintz, MH Wiedenhoeft, EC Brummer and MP Hoffman. 2002. Composition and spatial distribution of legume mixtures within warm-season grass pastures. Proc. American Forage and Grassland Conf. p. 276-280.
  • Guretzky JA, KJ Moore, EC Brummer and MH Wiedenhoeft. 2002. Multi-scale sampling of plant diversity in pastures varying in grazing management. Proc. American Forage and Grassland Conf. p. 80-84.
  • White TA, KJ Moore, MH Wiedenhoeft, EC Brummer and JR Russell. 2002. Sequentially grazing cool and warm-season pastures to increase cattle weight gain in Iowa. Proc. American Forage and Grassland Conf. p. 269-273.
  • Westgate ME, K Kaiser, K Boehdram and W Batchelor. 2002. Interaction between SCN and herbicide stress on soybean yield formation. In Agronomy Abstracts, ASA, Madison, WI.
  • Kaiser K, ME Westgate, G Tylka, R Horton, T Ochsner and W Batchelor. 2002. Root vs Shoot contribution to SCN resistance. In Agronomy Abstracts, ASA, Madison, WI.
  • Barker DA, KJ Moore, TA White and MB Dodd. 2002. Plant diversity and functional characteristics of temperate pastures. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Barker DJ, KJ Moore and JA Guretzky. 2002. Spatial variation in species richness under contrasting topologies and grazing regimes. Proc. American Forage and Grassland Conf. p. 10.
  • Braden IS, KJ Moore, RL Hintz, MH Wiedenhoeft, EC Brummer and MP Hoffman. 2002. Composition and spatial distribution of legume mixtures within warm-season grass pastures. Proc. American Forage and Grassland Conf. p. 29.
  • Braden IS, TA White and KJ Moore. 2002. Competitive Effects of an Exotic Cool-season forage grass on two native warm-season grasses. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Brueland BA, KJ Moore, RI Carter and DR Dobill. 2002. Crop adviser institute-Preliminary program evaluation. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • White TA, DJ Barker and KJ Moore. 2002. The importance of local scale processes to landscape scale patterns of grassland vegetation diversity. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • White TA, KJ Moore, MH Wiedenhoeft, EC Brummer and JR Russell. 2002. Sequentially grazing cool and warm-season pastures to increase cattle weight gain in Iowa. Proc. American Forage and Grassland Conf. p. 25.
  • Wiedenhoeft MH, K Moore, L Burras and R Killorn. 2002. Using laptop computers in the classroom to enhance hands-on activities. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Bousselot JM and D Muenchrath. 2002. Emergence Capabilities of Southwest U.S. Maize Landraces. In 2002 Am. Soc. of Agronomy Abstr. No. C03-bousselot102259-Poster, Abstract CD-ROM.
  • Sayers A, M Lauer and D Muenchrath. 2002. Simulated Foliar Disease Progression Effect on Seed Size and Yield of Inbred Maize Genotypes. In 2002 Am. Soc. of Agronomy Abstr. No.C04-sayers125929-Poster, Abstract CD-ROM.
  • Sandor JA, JB Norton, R Pawluk, JA Homburg, DA Muenchrath, CS White, SE Williams, CL Havener and PD Stahl. 2002. Soil knowledge embodied in a Native American runoff agroecosystem. p. 1063. In Abstracts Volume III, Symposia 22-36, of the 17th World Congress of Soil Science, Bangkok, Thailand, 14-21 August 2002.
  • Zelaya IA and MDK Owen. 2002. Amarathus tuberculatus (Mq. ex DC) J. D. Sauer: potential for selection of glyphosate resistance. Proc. 13th Australian Weeds Conf. 13:630-633.
  • Franzenburg D, J Lux and MDK Owen. 2002. Effect of soil-applied herbicide application timing on foxtail species control and corn yield. Proc. North Central Weed Sci. Soc. 57:18.
  • Franzenburg DD and MDK Owen. 2002. Effect of location and burial depth on woolly cupgrass (Eriochloa villosa) seed germination. Weed Tech. 16:719-723.
  • Franzenburg DD, JF Lux and MDK Owen. 2002. Effect of soil-applied herbicide application timing on foxtail species control and corn yield. Proc. North Cent. Weed Sci. Soc. 57:abstract 18.
  • Owen MDK. 2002. Weed population shifts may not represent a problem. Proc. Weed Sci. Soc. Amer. 42:222.
  • Lizaso JI, WD Batchelor and ME Westgate. 2002. Using the normalized difference vegetation index and a crop simulation model to predict a soil spatial variability. Transactions of the ASAE Vol. 45(4):1217-1222.
  • Uribelarrea M, J Carcova, ME Otegui and ME Westgate. 2002. Pollen production, pollen dynamics, and kernel set in maize. Crop Sci. 42:1910-1919.
  • Brummer EC, KJ Moore and NC Bjork. 2002. Agronomic consequences of dormant-nondormant alfalfa mixtures. Crop Sci. 94:782-785.
  • Hoy MD, KJ Moore, JR George and EC Brummer. 2002. Alfalfa yield and quality as influenced by establishment method. Agron. J. 94:65-71.
  • Lemus R, EC Brummer, KJ Moore, NE Molstadb, CL Burras and MF Barker. 2002. Biomass yield and quality of twenty switchgrass populations in southern Iowa, USA. Biomass and Bioenergy 23:433-442.
  • Riday H, EC Brummer and KJ Moore. 2002. Heterosis of forage quality in alfalfa. Crop Sci. 42:1088-1093.
  • Vogel KP, AA Hopkins, KJ Moore, KD Johnson and IT Carlson. 2002. Winter survival in switchgrass populations bred for high IVDMD. Crop Sci. 42:1857-1862.
  • Muenchrath DA, M Kuratomi, JA Sandor and JA Homburg. 2002. Observational study of maize production systems of Zuni farmers in semiarid New Mexico. J. of Ethnobiology 22(1):1-33.
  • Sandor JA, JB Norton, R Pawluk, JA Homburg, DA Muenchrath, CS White, SE Williams, CL Havener and PD Stahl. 2002. Soil knowledge embodied in a Native American runoff agroecosystem. p. 931-1-10. Proc. of the 17th World Congress of Soil Science, Bangkok, Thailand, 14-21 August 2002.
  • Liebman M. 2001. Weed management: a need for ecological approaches. p. 1-39. IN Liebman, M., Mohler, C.L. and Staver, C.P. (ed) Ecological Management of Agricultural Weeds. Cambridge University Press, Cambridge, UK.
  • Liebman M. 2001. Managing weeds with insects and pathogens. p. 375-408. IN Liebman, M., Mohler, C.L. and Staver, C.P. (ed) Ecological Management of Agricultural Weeds. Cambridge University Press, Cambridge, UK.
  • Brueland BA, KJ Moore, RI Carter and DR Dobill. 2002. Crop adviser institute-A new path for continuing education. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Guretzky JA, KJ Moore, EC Brummer and MH Wiedenhoeft. 2002. Multi-scale sampling of plant diversity in pastures varying in grazing management. Proc. American Forage and Grassland Conf. p. 2.
  • Guretzky JA and KJ Moore. 2002. Legume distribution among management zones in pastures classified using fuzzy-C-means. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Hintz RL, KJ Moore, MH Wiedenhoeft and EC Brummer. 2002. Tall fescue response to nitrogen fertilization for stockpiled grazing. Proc. American Forage and Grassland Conf. p. 324.
  • Richard TL, S Proulx, KJ Moore, C Tobia and T Patrick. 2002. Enzyme enhanced ensilage for biomass pretreatment. Institute of Biological Engineering.
  • Tarr AB, KJ Moore and PM Dixon. 2002. Geostatistical relationships among spectral imagery, species composition and productivity in a grass-legume pasture. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, SSSA, Madison, WI.
  • Tarr AB, KJ Moore, PM Dixon, CL Burras and RL Hintz. 2002. Geostatistical use of soil electroconductivity in optimizing sampling techniques. Proc. American Forage and Grassland Conf. p. 297.


Progress 01/01/01 to 12/31/01

Outputs
1. Efficiency of crop production. Application of seed fungicides improved yields of soybeans planted in March and April. Field studies showed that kernel number per plant is determined by plant growth rate during the flowering period in corn. 2. Weed management systems. 3. Production and utilization of forages. Enzyme-enhanced ensilage of corn stover holds promise for biomass storage and pretreatment to shift biomass hydrolysis to the storage phase. Remote sensing tools were tested as a way to identify field variability and reduce sampling needed to depict the variability observed with remote sensing tools. Precision agriculture technologies were used to characterize spatial variability in species composition across four cool season grass-legume pastures. 4. Biology of seed development. Gene expression in response to frost stress was compared in healthy seedlings and in seedlings germinated from frost-stressed seed. Nearly 100 gene fragments were expressed differently in seedlings from frost-stressed seed. A study of seedling abnormalities associated germination from low seed moisture contents (imbibitional injury) showed that germination percentage increased with increased seed moisture content. 5. Reliability of plant production systems. Polyamine profiles of maize seedlings were characterized to determine the relationships between profiles and various stresses that affected seedling development. Studies are underway to develop screening protocols for cold tolerance, investigate the role of stress and genotype on the respiratory transition during seedling growth, and assess gene expression during cold acclimation. 6. Quality and value of agricultural products. Sampling of seeds from genetic lines varying in seed protein content is complete. RNA has been extracted in preparation for gene expression (microarray) analysis. Amplification soybean EST clones from the public EST database has begun. Replicated experiments testing the response of seed composition (protein, oil, and starch) to temperature during seed filling are completed. A preliminary metabolic flux model was developed to examine interactions between genotype and temperature, which influence accumulation of seed components. Soybean transformation to alter seed protein accumulation continues on schedule. New software algorithms were developed for analyzing gene expression profiles. 7. Energy from agricultural biomass. A system was developed to study Two-Stage anaerobic digestion of corn stover to methane. Studies of anaerobic digestion of corn stover to ethanol, acetic acid, glycerol, and lactic acid were continued using various inhibitors of sugar metabolism. A system was developed to ferment raw sugar beets for ethanol. The process yielded the equivalent of about 8000 L/ha of ethanol. 8. Maize biodiversity . Fourteen maize accessions native to the arid and semiarid U.S. Southwest and one check population were grown for morphological, phenological, and disease susceptibility ratings and seed increase. A protocol was developed to evaluate the capacity of these cultivars to emerge from extraordinary soil depths under controlled conditions.

Impacts
Earlier planting of soybean increases producer options for managing spring planting. Knowledge of plant factors limiting yield provides greater accuracy of early season yield-predictions models. Establishing warm-season grasses in pastures improves the efficiency of forage growth for livestock. Addition of legumes to grass pastures improves forage quality and reduces use of nitrogen fertilizer. Knowledge of gene expression will lead to improved management of frost injury in commercial seed corn. Awareness that media used for testing the germination of the seed can influence the germination test results can help seed producers deal with problems caused by low-moisture seed by using the most accurate test. Understanding the basis for effects of low temperature stress on maize stand establishment forms the basis for ameliorating these problems, and for future studies aimed at plant signaling mechanisms and signal cascades. Identifying genes controlling seed composition will speed the development of soybean genotypes with valuable seed components. Such genotypes are essential as soybean markets shift to trait based pricing. More efficient methods of producing chemicals from agricultural biomass will increase the value of farm products. Documenting characteristics of stress-adapted maize germplasm will expand the utility of these genetic resources and contribute to yield stability of new commercial germplasm. Capacity to emerge may enable producers to plant earlier and/or in no-till systems with reduced risk of stand reductions.

Publications

  • Brummer EC and KJ Moore. 2001. A simple method to increase alfalfa yields in the establishment year. p. 21-22. IN Leopold Center Progress Report, Volume 10, Leopold Center for Sustainable Agriculture, Ames, IA.
  • Brummer EC, KJ Moore, M Smith and NC Bjork. 2001. Alfalfa yields from mixtures of dormant and non-dormant varieties. Western Research and Demonstration Farm Annual Progress Report-2000. Iowa State Univ. Coop. Ext. Serv, ISRF00-10, Ames. p 14-15.
  • Westgate ME. 2001. Osmotic Potential. IN BA Stewart and T Howell (eds) Encyclopedia of Water Science. Marcel Dekker, Inc, New York (In Press).
  • Westgate ME. 2001. Physiology of high yielding corn and soybeans. IN T Yamada (ed.) Proc. Simposio sobre rotacao soja/mihlo no planto direto, Sao Paulo, Brazil.
  • Wiedenhoeft M and SK Barnhart. 2001. Evaluating new forages. Armstrong Research and Demonstration Farm Progress Report. Iowa State Univ. Coop. Ext Serv. ISRF00-12, Ames. p. 55-56.
  • Janovick NA, JR Russell, DR Strohbehn, DG Morrical, SK Barnhart, D Maxwell and LJ Secor. 2001. Evaluation of year-round forage management systems for spring- and fall-calving beef cows. 2001 Beef Res. Rep. Iowa State Univ. Coop. Ext. Serv., Ames. AS-645:42-53.
  • Barnhart SK. 2001. Forage testing laboratories. Iowa State Univ. Coop. Ext. Serv. PM 1098a, Ames.
  • Farnham D. 2001. Corn planting guide. University Extension, Iowa State Univ. PM 1885, Ames.
  • Darmosarkoro W, MM Harbur, DR Buxton, KJ Moore, TE Devine and IC Anderson. 2001. Growth, Development, and Yield of Soybean Lines Developed for Forage. Agron. J. 93:1028-1034.
  • Harmoney KR, KJ Moore, EC Brummer, CL Burras and JR George. 2001. Spatial legume composition and diversity across seeded landscapes. Agron. J. 93:992-1000.
  • Battles BA. 2001. Factors influencing weed spatial distributions. M.S. Thesis. Iowa State Univ., Ames.
  • Kagima DK. 2001. Influence of seed bank augmentation on performance of metolachlor. M.S. Thesis. Iowa State Univ., Ames.
  • Hartzler RG and B Battles. 2001. Reduced fitness of velvetleaf (Abutilon theophrasti) surviving glyphosate. Weed Technol. 15:492-496.
  • Buhler DD and RG Hartzler. 2001. Emergence and persistence of Abutilon theophrasti, Amaranthus rudis, Eriochloa villosa and Setaria faberi. Weed Sci. 49:230-236.
  • Pineda R, AD Knapp, JC Hoekstra and DC Johnson. 2001. Integrated square wave detection of biogenic amines in soybean seeds following their separations by liquid chromatography. Anal. Chim. Acta. 449:111-117.
  • Tian X, AD Knapp, KJ Moore, EC Brummer and TB Bailey. 2002. Cupule removal and caryopsis scarification improves germination of Eastern gamagrass seed. Crop Sci. 42:185-189.
  • Braden IS, KJ Moore, TL Hintz, MH Wiedenhoeft, EC Brummer and MP Hoffman. 2001. Pasture improvements with mixed composition of warm-season grasses and legumes. Western Research and Demonstration Farm Annual Progress Report-2000. Iowa State Univ. Coop. Ext. Serv. ISRF00-10, Ames. p. 16-17.
  • Hallam A, IC Anderson and DR Buxton. 2001. Comparative economic analysis of perennial, annual, and intercrops for biomass production. Biomass and Bioenergy 21:407-424.
  • Darmosarkoro W, MM Harbur, DR Buxton, KJ Moore, TE Divine and IC Anderson. 2001. Growth, developement, and yield of soybean lines developed for forage. Agron J. 93:1028-1034.
  • Barnhart SK, JR Russell, MJ Hersom and DE Farnham. 2001. Transgenic maize hybrid crop residues: nutritive value and their effects on performance of grazing beef cows. Proc. XIX Intl. Grassland Congress. Sao Pedro, Brazil. p. 735-736.
  • Barnhart SK. 2001. Liquid swine manure as a fertilizer source for annual and perennial grass forage. Northern Research and Demonstration Farm Progress Report. Iowa State Univ. Coop. Ext Serv. ISRF00-22, Ames. p. 27-28.
  • Barnhart SK. 2001. Liquid swine manure as a fertilizer source for established alfalfa. Northern Research and Demonstration Farm Progress Report. Iowa State Univ. Coop. Ext. Serv. ISRF00-22, Ames. p. 29-30.


Progress 01/01/00 to 12/31/00

Outputs
Research continues across the state to identify and improve management strategies that will increase the efficiency of crop production while maintaining environmental compatibility. Research results are used in a variety of formats to help producers and agribusinesses make informed decisions. Soybean research determined best management practices for row spacing, herbicide-resistant variety evaluation, and planting date X population. Results were used to train agronomists from agribusiness. An example, research results showed farmers that intermediate row spacing for soybeans usually produce yields which are 2-3 bushels per acre greater than wide row yields. Also, we confirmed that a planting density for soybean at 458,000 seeds per hectare is suitable for achieving optimum grain yield in most management schemes used by Iowa growers. Various experiments were conducted to improve the production and utilization of forages. Models to predict flower development in maize were combined with EPA models to predict particulate dispersal. This is used to assess the risk of contaminating pollen entering an isolated seed production field. Variation in seed composition (protein, oil, starch) among soybean lines with largely different levels of seed components in mature seeds was determined early in seed development. The patterns of partitioning within seeds established early in development were maintained until maturity. Thus, environmental conditions during early seed development could be particularly critical. Lastly, anaerobic digestion studies of corn stover were conducted to determine methods of inhibiting methane production in order to produce chemicals such as acetate, butanol, and glycerol.

Impacts
Information on row spacing, plant density, and planting date studies helped producers make informed decisions regarding their production systems. Stockpiling forage for autumn grazing is an effective means of extending the grazing season beyond the forage growing season. The legume of choice for use as a protein source for stockpiled forage will depend on the nutritional needs of the livestock and nutritional characteristics of other forages available to them. Based on phone calls, emails, and personal contacts received during the past year, an increasing number of corn producers around the Midwest are looking to take advantage of the potential for increased yield by mixing corn hybrids in the same field. A webpage was initiated in 1996 and has become a primary means for disseminating information concerning weed management. Articles focus primarily on current issues on research results. The website frequently is the only source for this information for many of our extension clients. The website averaged 340 users and more than 1000 pages viewed per day.

Publications

  • Hartzler RG and Buhler DD. 2000. Occurrence of common milkweed in cropland and adjacent areas in Iowa. Crop Protection 19:363-366.
  • Taylor KL and Hartzler RG. 2000. Effect of seed bank augmentation on herbicide efficacy. Weed Technol. 14:261-267.
  • Hartzler RG, Buhler D, Gunsolus J, Boerboom C and Wax L. 2000. Weed emergence sequences. IPM-64.
  • Wilby RL, Hay LE, Gutowski WJ Jr, Arritt RW, Takle ES, Pan Z, Leavesley GH and Clark MP. 2000. Hydrological responses to dynamically and statistically downscaled climate model output. Geophysical Research Letters, 27:1199-1202.
  • Sleugh B, Moore KJ, Brummer EC, Knapp AD, Russell J and Gibson L. 2000. Forage nutritive value of various amaranth species at different harvest dates. Crop Sci. (In press).
  • Sleugh B, Moore KJ, Brummer EC, Knapp AD, Russell J and Gibson L. 2000. Forage potential of various amaranth species. Proc. American Forage and Grassland Council Annual Meeting. July 16-19, 2000. pp. 76-80.
  • Struthers RS, Gibson LR and Knapp AD. 1999. Environmental impacts on germination of eastern gamagrass seed. Agron. Abstr. p. 118.
  • Aberle EZ, Gibson LR, Knapp AD, Moore KJ and Hintz RL. 2000. Determination of optimum planting procedures of eastern gamagrass in a northern climate. Agron. Abstr. p. 131.
  • Moore KJ and Anderson BA. 2000. Warm-season grasses: Research trends and issues. CSSA Special Publ. No. 30. CSSA, Madison, WI.
  • Ramsel PS and Farnham DE. 2000. Planting date, row spacing, and starter fertilizer effect on corn yield in a rainfed environment. Agron. Abstr. p. 36.
  • Myli JR and Farnham DE. 2000. Stand reduction effects on various ear measurements of corn grown at high population densities. Agron. Abstr. p. 36.
  • Russell JR, Farnham D, Berryman RK, Hersom MJ, Pugh A and Barrett K. 2000. Nutritive value of the crop residues from Bt-corn hybrids and their effects on performance of grazing beef cows. Beef Res. Rpt., AS 643. Iowa State Univ., Ames. February 2000. pp. 56-61.
  • Hanna HM, Hartzler RG and Erbach DC. 2000. High-speed cultivation and banding for weed management in no-till corn. Appl. Eng. Agric. 16:359-365.
  • Moore KJ and Buxton DR. 2000. Fiber composition and digestion of warm-season grasses. pp. 23-33. In: KJ Moore and BA Anderson (eds.) Native Warm-Season Grasses: Research Trends and Issues. CSSA Special Publ. CSSA, Madison, WI.
  • Sleugh BB, Moore KJ, George JR and Brummer EC. 2000. Binary legume-grass mixtures improve forage yield, quality, and seasonal distribution. Agron. J. 92:24-29.
  • Brummer EC and Moore KJ. 2000. Persistence of perennial cool-season grass and legume cultivars under continuous grazing by beef cattle. Agron. J. 92:466-471.
  • Moore K, Dobill D, Petersen T and Koch J. 2000. Master of science in agronomy: a chronicle of distance learning. Dept. of Agronomy, Iowa State Univ., Ames, IA.
  • Harmoney KR, et al. 2000. Establishment and persistence of legumes on sites varying in aspect, landscape position, and soil type. pp. 21-25. IN Leopold Center Progress Report, Vol. 9. Leopold Center for Sustainable Agriculture, Ames, IA.
  • Knapp A, Brummer C and Moore K. 2000. Eastern gamagrass (Tripsicum dactyloides) seed dormancy. pp. 13-16. In: Leopold Center Progress Report, Vol. 9. Leopold Center for Sustainable Agriculture, Ames, IA.
  • Moore KJ, George JR, Brummer EC, Brueland B, Hintz R, Secor J and Maxwell D. 2000. Sequential grazing systems for beef cattle production. pp. 22-25. In: Annual Progress Reports-1999. McNay Research Farm, Iowa State Univ. Publ. ISRF99-35, Coop. Ext. Serv., Ames, IA.
  • Buhler DD, Liebman M and Obrycki JJ. 2000. Theoretical and practical challenges to an IPM approach to week management. Weed Sci. 48:274-280.
  • Griffin T, Liebman M and Jemison J Jr. 2000. Cover crops for sweet corn production in a short-season environment. Agron. J. 92:144-151.
  • Liebman M. 2000. Opportunities to integrate soil, crop, and weed management in low-external-input farming systems. pp. 26-31. In: National Research Council (ed.) Professional Societies and Ecologically Based Pest Management: Proceedings of a Workshop. National Academy Press, Washington, DC.
  • Liebman M and Davis AS. 2000. Integration of soil, crop, and weed management in low-external-input farming systems. Weed Res. 40:27-47.
  • Ohno T, Doolan K, Zibilske LM, Liebman M, Gallandt ER and Berube C. 2000. Phytotoxic effects of red clover amended soils on wild mustard seedling growth. Agriculture, Ecosystems, and Environment 78:187-192.
  • Saini HS and Westgate ME. 2000. Reproductive development in grain crops during drought. Advan. Agron. 68:59-96.
  • Zinselmeier C, Habben JE, Westgate ME and Boyer JS. 2000. Carbohydrate metabolism in setting and a borting maize ovaries. pp. 1-13. In: ME Westgate and KL Boote (eds.) Physiology and Modeling Kernel Set in Maize. CSSA Special Publ. 29.
  • Edmeades GO, Bolanos J, Elings A, Banziger M and Westgate ME. 2000. The role and regulation of the anthesis-silking interval. pp. 43-73. In: ME Westgate and KJ Boote (eds.) Physiology and Modeling Kernel Set in Maize. CSSA Special Publ. 29.