Source: UNIVERSITY OF ARKANSAS submitted to
SOIL FERTILITY, PLANT NUTRITION, SOIL AMENDMENTS AND CROP MANAGEMENT SYSTEMS FOR ARKANSAS SOILS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0186090
Grant No.
(N/A)
Project No.
ARK01864
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2006
Project End Date
Sep 30, 2011
Grant Year
(N/A)
Project Director
Norman, R. J.
Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703
Performing Department
CROP AND SOIL ENVIRONMENTAL SCIENCE
Non Technical Summary
Nitrogen fertilizer must be used efficiently in rice production because it is the most expensive input a rice farmer makes, it has such a major impact on rice yields and if it escapes into the surrounding environment can cause great harm. Thus, we must study the fate of N in rice production so we can use it correctly and efficiently. Several possible ways to improve N fertilizer efficiency in rice production would be to: i) minimize ammonia volatilization loss of the preflood N; ii) develop a N soil test so the N applied to rice is more accurate; and iii) investigate and understand the nutrient utilization efficiency of the new high yielding hybrid rice varieties. management practices for this important cash crop.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110200040%
1021530101060%
Goals / Objectives
A. Delineate the nutrient uptake patterns and differences between conventional (i.e., short statured and semidwarf) rice varieties and hybrids. B. Determine the extent that urea, ammonium sulfate and urea treated with the urease inhibitor NBPT, trade name Agrotain, is lost via ammonia volatilization when applied prior to flooding and the flood not applied for several days in conventionally tilled and conservation tilled systems. Additionally, determine the extent that ammonia volatilization loss influences total N uptake and grain yield of delayed-flood rice. C. Evaluate and/or develop a routine analytical technique for determining the amount of N mineralized by a soil during the cropping season. mineralized by a soil during the cropping season.
Project Methods
Laboratory incubation studies, field studies in small plots, and to a limited degree commercial rice fields will be utilized. Plant and soil samples will taken for nutrient analysis, static chambers will be utilized to measure ammonia volatilization, and the stable isotopic tracer N-15 will utilized to improve quantitative and qualitative measurements of N when appropriate.

Progress 10/01/06 to 09/30/11

Outputs
OUTPUTS: Laboratory and incubation studies as well as all analytical analyses were conducted at the University of Arkansas Main campus. Field studies were conducted at six experiment stations and ten commercial rice fields. The research project involved three graduate students as part of their thesis and dissertation research. The information gained from the research was disseminated to communities of interest as follows: i) the Rice Research Board, Rice Foundation, and industry through annual reports and presentations; with other scientists at regional and national meetings, and in refereed publications; and with extension agents, consultants, dealers and farmers through presentations at county and state meetings, field days, workshops/in-service trainings and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. PARTICIPANTS: The research has been funded primarily by the Arkansas Rice Research Board and the Rice Foundation, and partially funded by Agrotain International, Honeywell, Weyerhaeuser, and RiceTec. Collaborating scientists are University of Arkansas graduate students Anthony Fulford, Chris Rogers, and Trent Roberts; University of Arkansas professors Drs. Nathan Slaton and Charles Wilson; and Dr. Tim Walker of Mississippi State University, Dr. Dustin Harrell of Louisiana State University, and Dr. Garry McCauley of Texas A & M University. The collaboration of scientist's from other rice producing states in the south is an effort at developing a soil based N test for the entire southern rice growing region. The test is named the Nitrogen-Soil Test for Rice or N-ST*R. A calibration curve for silt loam soils has been completed and was validated in Arkansas in 2010 with the help of county extension personnel in nine small plot tests located at experiment stations and in commercial fields. These validation studies are also being used to educate the extension agents, consultants, farmers and other rice scientists of the utility of the method. Validation studies will continue in 2011 on silt loam soils in Arkansas and begin in other cooperating states. When the soil based N test for rice is perfected and ready for use by the rice industry than training meetings will have to be conducted to inform them on the utility of the method and how to properly use the method. We currently have N-ST*R data from eleven site-years on clay soils and need many more clay soil locations and soils with a wider range of native N fertility before a robust calibration curve can be constructed for clay soils and validation studies to begin. Knowledge gained from the studies on the influence of urease inhibitors and N source on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice is being presented at professional training meetings to educate extension agents, consultants, dealers, farmers and others in the fertilizer and rice industry on the viable urease inhibitors and N sources to use in delayed flood rice. The results of the 2010 research comparing midseason N application times for the new varieties has been presented to the Arkansas Rice Research Board and is being presented at professional training meetings this winter to educate extension agents, consultants and farmers. TARGET AUDIENCES: The audiences that will benefit the most from the knowledge gained are rice farmers, extension agents, consultants, fertilizer dealers and students. The knowledge when placed in their hands will improve the efficiency with which the rice crop utilizes the N fertilizer applied and in turn make rice production more profitable, sustainable, and environmentally sound. Knowledge gained will be added to curricula used in classroom and extension training workshops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Most delayed-flood rice fields require 5 to 10 days to flood after the urea has been applied preflood. Consequently, a study was conducted to evaluate the use of less NH3 volatile N sources for the preflood N application. When flooding was delayed for 5 and 10 days after N application, NH3 volatilization was the least for urea + NBPT and (NH4)2SO4 and they produced the highest rice N uptakes and yields. The urea-ammonium sulfate (UAS) blend which had NH3 volatilization losses at 5 and 10 days after application intermediate between urea and (NH4)2SO4 or urea + NBPT, also had N uptakes and grain yields intermediate between these N sources. Urea should only be used if 2 days or less are required to flood a field. If 3 to 5 days are required to flood a field then UAS has some merits, but it is not as consistent as (NH4)2SO4, or urea + NBPT. When greater than 5 days are required to flood, (NH4)2SO4 or urea + NBPT should be used. Field studies were conducted in Arkansas and Mississippi to determine if Nutrisphere-treated urea could be applied up to 11 days prior to flooding with minimal loss of rice grain yield. Although there was a significant influence of N rate and application timing on rice grain yield, there was no significant influence from Nutrisphere. Rice grain yield significantly decreased as the time between N fertilizer application and flooding was increased from 1 to 10-11 days whether the urea was treated or not treated with Nutrisphere. This finding brought into question Nutrisphere's urease-inhibition claims and the initiation of a laboratory incubation study. In the incubation study, ammonium sulfate had the least amount of ammonia volatilized followed by Agrotain-treated urea. Urea and Nutrisphere-treated urea had the most ammonia volatilized. Nutrisphere did not significantly inhibit ammonia volatilization of urea and is thus not an effective urease inhibitor. Development of the Illinois Soil N Test (ISNT) has rejuvenated the search for a soil-based N test to measure potentially mineralizable soil-N. Twenty-five N response trials were conducted between 2004 and 2008 to correlate alkaline hydrolyzable-N (AHN), as quantified by the ISNT and DSD methods, with rice response parameters such as percent relative grain yield (RGY) and calibrate AH-N to predict the fertilizer N rate required to achieve 95% RGY. Alkaline hydrolyzable-N was significantly and positively correlated with all rice response parameters except check plot grain yield and percent RGY using AH-N at the 45-60 cm depth. Coefficients of determination were greatest for percent RGY at the 0-30 and 0-45 cm depth for the ISNT (r2=0.57) and DSD (r2=0.73), respectively. Calibration of the fertilizer N rate to achieve 95% RGY resulted in similar trends as the correlation of rice response parameters, but with higher r2 values. Alkaline hydrolyzable-N explained 68% and 89% of the RGY variability in calibration for the ISNT using the 0-30 cm depth and the DSD using the 0-45 cm depth, respectively. These successful calibrations can be attributed to the N dynamics that exist in direct-seeded, delayed-flood rice production systems and identification of the proper sampling depth.

Publications

  • Franzen, D., Goos, R. Jay, Norman, Rick J., Walker, Timothy W., Roberts, Trenton L., Slaton, Nathan A., Endres, Gregory , Ashley, Roger, Staricka, James, and Lukach, John. 2011. Field and laboratory studies comparing Nutrisphere-N-urea with urea in North Dakota, Arkansas and Mississippi. J. Plant Nutri. 34:1198-1222.
  • Fulford, A.M., Norman, R.J., Roberts, T.L., Slaton, N.A., Wilson Jr., C.E., Frizzell, D.L., Branson, J.D., and Rogers, C.W. 2011. Site-specific nitrogen fertilizer management of rice grown on clayey soils. p. 194-200. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Slaton, N.A., Norman, R.J., Roberts, T.L., DeLong, R.E., Massey, C., and Clark, S. 2011. Rice and soybean response to selected humic acid or biological enhancing soil amendments. p.259-265. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Slaton, N.A., Norman, R.J., Roberts, T.L., DeLong, R.E., Massey, C., Clark, S., and J. Branson. 2011. Evaluation of new fertilizers and different methods of application for rice production. p.266-277. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Stiegler, Chris J., Richardson, Michael D., Karcher, Douglas E., Roberts, Trenton L., and Norman, Richard J. 2011. Field-based measurement of ammonia volatilization following foliar applications of urea to putting green turf. Crop Sci. 51:1767-1773.
  • Golden, Bobby, Slaton, Nathan, Norman, Richard, Gbur, Edward, and Wilson, Charles. 2011. Nitrogen release from environmentally smart nitrogen fertilizer as influenced by soil series, temperature, moisture, and incubation method. Commun. Soil Sci. Plant Anal. 42:15, 1809-1824.
  • Massey, Colin C., Slaton, Nathan A., Norman, Richard J., Gbur, Jr., Edward E., DeLong, Russell E., and Golden, Bobby R. 2011. Bermudagrass forage yield and ammonia volatilization as affected by nitrogen fertilization. Soil Sci. Soc. Am. J. 75:638-648.
  • Norman, R.J., Roberts, T.L., Wilson Jr., C.E., Slaton, N.A., Frizzell, D.L., and Branson, J.D. 2011. Response of two rice varieties to midseason nitrogen fertilizer application timing. p. 219-222. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., Fulford, A.M., Williamson, S., Branson, J.D., Frizzell, D.L. 2011. Field validation of the nitrogen soil test for rice produced on silt loam soils. p.223-228. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., and Ross, W.J. 2011. Predicting rice response to nitrogen fertilizer using soil total nitrogen. p.229-234. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Roberts, T.L., Ross, W.J., Norman, R.J., Slaton, N.A., and Wilson, Jr., C.E. 2011. Predicting nitrogen fertilizer needs for rice in Arkansas using alkaline hydrolyzable-nitrogen. Soil Sci. Soc. Am. J. 75:1161-1171.
  • Scott, J.T., Mattice, J.D., and Norman R.J. 2011. A comparison of total nitrogen concentrations to recommended water quality criteria for the cache river basin. p.244-252. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.
  • Slaton, Nathan A., Norman, Richard J., and Kelley, Jason. 2011. Winter wheat yield response to a urea amended with a urease inhibitor and fertilization time. Online. Crop Management doi:10.1094/CM-2011-0126-01-RS. Slaton, N.A., Norman, R.J., Roberts, T.L., DeLong, R.E., Massey, C., and Clark, S. 2011. Rice response to nitrogen and potassium fertilization rate. p.252-258. In R.J. Norman and K.A.K. Moldenhauer (eds.), B.R. Wells Rice Research Studies 2011. Univ. of Ark., Agr. Exp. Sta. Res. Ser. 591.


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Laboratory and incubation studies as well as all analytical analyses were conducted at the University of Arkansas Main campus. Field studies were conducted at six experiment stations and ten commercial rice fields. The research project involved three graduate students as part of their thesis and dissertation research. The information gained from the research was disseminated to communities of interest as follows: i) the Rice Research Board, Rice Foundation, and industry through annual reports and presentations; with other scientists at regional and national meetings, and in refereed publications; and with extension agents, consultants, dealers and farmers through presentations at county and state meetings, field days, workshops/in-service trainings and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. PARTICIPANTS: The research has been funded primarily by the Arkansas Rice Research Board and the Rice Foundation, and partially funded by Agrotain International, Honeywell, Weyerhaeuser, and RiceTec. Collaborating scientists are University of Arkansas graduate students Anthony Fulford, Chris Rogers, and Trent Roberts; University of Arkansas professors Drs. Nathan Slaton and Charles Wilson; and Dr. Tim Walker of Mississippi State University, Dr. Dustin Harrell of Louisiana State University, and Dr. Garry McCauley of Texas A & M University. The collaboration of scientist's from other rice producing states in the south is an effort at developing a soil based N test for the entire southern rice growing region. The test is named the Nitrogen-Soil Test for Rice or N-ST*R. A calibration curve for silt loam soils has been completed and was validated in Arkansas in 2010 with the help of county extension personnel in nine small plot tests located at experiment stations and in commercial fields. These validation studies are also being used to educate the extension agents, consultants, farmers and other rice scientists of the utility of the method. Validation studies will continue in 2011 on silt loam soils in Arkansas and begin in other cooperating states. When the soil based N test for rice is perfected and ready for use by the rice industry than training meetings will have to be conducted to inform them on the utility of the method and how to properly use the method. We currently have N-ST*R data from eleven site-years on clay soils and need many more clay soil locations and soils with a wider range of native N fertility before a robust calibration curve can be constructed for clay soils and validation studies to begin. Knowledge gained from the studies on the influence of urease inhibitors and N source on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice is being presented at professional training meetings to educate extension agents, consultants, dealers, farmers and others in the fertilizer and rice industry on the viable urease inhibitors and N sources to use in delayed flood rice. The results of the 2010 research comparing midseason N application times for the new varieties has been presented to the Arkansas Rice Research Board and is being presented at professional training meetings this winter to educate extension agents, consultants and farmers. TARGET AUDIENCES: The audiences that will benefit the most from the knowledge gained are rice farmers, extension agents, consultants, fertilizer dealers and students. The knowledge when placed in their hands will improve the efficiency with which the rice crop utilizes the N fertilizer applied and in turn make rice production more profitable, sustainable, and environmentally sound. Knowledge gained will be added to curricula used in classroom and extension training workshops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Urea is the primary nitrogen (N) source used for the large preflood N application in delayed-flood rice (Oryza sativa L.), however, urea is prone to substantial NH3 volatilization losses if fields are not flooded quickly. Most delayed-flood rice fields require 5 to 10 days to flood. Consequently, a study was conducted on the Dewitt silt loam soil at the Rice Research and Extension Center to evaluate the effectiveness of two urease inhibitors, Agrotain (Agrotain International; St. Louis, MO) and Arborite (Weyerhaeuser Company; Vanceboro, NC), for minimizing the ammonia volatilization of urea when a flood cannot be applied timely. The urease inhibitor NBPT sold under the trade name Agrotain has been the only effective stabilizer of urea fertilizer since its introduction in 2002. Weyerhaeuser recently released their version of the urease inhibitor NBPT under the trade name Arborite. Urea, Arborite treated urea, and Agrotain treated urea where applied 1, 5 and 10 days prior to flooding at rates of 60 and 120 lb N/acre. Agrotain treated urea and Arborite treated urea lost little N to ammonia volatilization over a 21 day incubation whereas urea lost over 40%. In the field study, Arborite treated urea and Agrotain treated urea applied at 5 and 10 days prior to flooding resulted in similar total N uptakes and rice grain yields which were significantly higher than the rice grain yield obtained with untreated urea applied at the same times. The success of the Nitrogen-Soil Test for Rice on silt loam soils in Arkansas has to research on clay soils and the involvement of LSU, MSU, and TAMU. We currently have N-ST*R data from eleven site-years on clay soils and the preliminary results indicate N-ST*R can predict the mineralization potential of a clay soil with an accuracy similar to a silt loam soil. Also, preliminary results suggest that clay soils may only have to be sampled to a 12-inch depth versus an 18-inch depth for silt loam soils. The diffusion method appears more accurate than the distillation method on clay soils with the sites we have collected to date. However, we need many more clay soil locations and a wider range of native N fertility before a robust calibration curve can be constructed for clay soils. Research has not been conducted on proper timing of midseason N fertilizer on rice for about twenty years and thus, the new rice varieties have not been studied as to the best time to apply midseason N for the best yield response. Consequently, we implemented a study in 2010 to determine the extent that new rice varieties respond to midseason N fertilizer application and the time width of the application window. Midseason N was applied at 45 lbs N/acre at 1/2 inch internode elongation, 1/2 inch internode elongation + 1 week, and 1/2 inch internode elongation + 2 weeks to the cultivars Cheniere, CLXL 745, and Taggart. The best yield response from midseason N application for each cultivar was 15 bu/acre. The largest yield increase was measured when the midseason N was applied at 1/2 inch internode + 1 week and 1/2 inch internode elongation + 2 weeks, not at 1/2 inch internode elongation as currently recommended.

Publications

  • Bajwa, S.G., Mishra, A.R., and Norman, R.J. 2010. Canopy reflectance response to plant nitrogen. Precision Agric: 11:488-506.
  • Golden, B.R., Slaton, N.A., Norman, R.J., DeLong, R.E., and Wilson, C.E. 2010. Nitrification contributions to nitrogen losses from preflood urea in delayed-flood rice culture. In Rice Technical Working Group Abstracts. 33rd Meeting, Biloxi, MS. Feb. 22-25, 2010.
  • Norman, R.J., Enochs, A.J., Roberts, T.L., Slaton, N.A., Wilson, Jr., C.E., Frizzell, D.L., and Branson, J.D. 2010. Nitrogen content in floodwater of drill-seeded, delayed-flood rice following fertilization at preflood and midseason. In Rice Technical Working Group Abstracts. 33rd Meeting, Biloxi, MS. Feb. 22-25, 2010.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., and Ross, W.J. 2010. N-ST*R: A soil-based nitrogen test for fertilizer recommendations in Arkansas rice production. p. 190-196. In R.J. Norman and K.A.K. Moldenhauer (eds.). B.R. Wells Rice Research Studies 2009. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 581.
  • Slaton, N.A., Golden, B.R., and Norman, R.J. 2010. Rice response to urea and two polymer-coated urea fertilizers. p. 211-219. In R.J. Norman and K.A.K. Moldenhauer (eds.). B.R. Wells Rice Research Studies 2009. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 581.
  • Roberts, T.L., Norman, R.J., Walker, T.W., Harrell, D.L., and McCauley, G.N. 2010. Across soils and state boundaries: Evaluation of N-ST*R, A soil-based nitrogen test for midsouth rice production. In Rice Technical Working Group Abstracts. 33rd Meeting, Biloxi, MS. Feb. 22-25, 2010.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E. 2010. Alkaline hydrolyzable-nitrogen changes with soil depth: Implications for calibration of predicted nitrogen rates. p. 181-189. In R.J. Norman and K.A.K. Moldenhauer (eds.). B.R. Wells Rice Research Studies 2009. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 581.
  • Bajwa, S.G., Mishra, A.R., and Norman, R.J. 2010. Plant nitrogen accumulation dynamics in Rice (Oryza sativa L.) in response to nitrogen management. Comm. Soil Sci. & Plant Anal. 41: 4, 454-471.
  • Watkins, K.B., Hignight, J.A., Norman, R.J., Roberts, T.L., Slaton, N.A., Wilson, Jr., C.E., and Frizzell, D.L. 2010. Comparison of economical nitrogen rates for rice in Arkansas. Agron. J. 102: 1099-1108.
  • Roberts, T.L., Norman, R.J., Fulford, A.M., Slaton, N.A., and Wilson, Jr., C.E. 2010. Field validation of N-ST*R: A soil-based nitrogen test for silt loam soils. In Abstracts [CD-ROM]. 2010 Joint Annual Meetings. Oct. 31-Nov. 3, 2010. Long Beach, CA.
  • Norman, R.J., Fulford, A.M., Roberts, T.L., Slaton, N.A., and Wilson, Jr., C.E. 2010. Development of a soil-based nitrogen test for clay soils. In Abstracts [CD-ROM]. 2010 Joint Annual Meetings. Oct. 31-Nov. 3, 2010. Long Beach, CA.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Fulford, A.M., and DeLong, R.E. 2010. Short-term influence of crop rotation on wheat yield and alkaline-hydrolyzable nitrogen. In Abstracts [CD-ROM]. 2010 Joint Annual Meetings. Oct. 31-Nov. 3, 2010. Long Beach, CA.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., and Fulford, A.M. 2010. Field Validation of N-ST*R: A precision nitrogen management tool for direct-seeded, delayed-flood rice. In Rice Technical Working Group Abstracts. 33rd Meeting, Biloxi, MS. Feb. 22-25, 2010.
  • Watkins, K.B., Hignight, J.A., Norman, R.J., Roberts, T.L., Slaton, N.A., Wilson, Jr., C.E., and Frizzell, D.L. 2010. Calculation of economic optimum nitrogen application rates for arkansas rice. In Rice Technical Working Group Abstracts. 33rd Meeting, Biloxi, MS. Feb. 22-25, 2010.


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Laboratory and incubation studies as well as all analytical analyses were conducted at the University of Arkansas Main campus. Field studies were conducted at six experiment stations and eight commercial rice fields. The research project involved three graduate students as part of their thesis and dissertation research. The information gained from the research was disseminated to communities of interest as follows: i) the Rice Research Board, Rice Foundation and industry through annual reports and presentations; with other scientists at regional and national meetings, and in refereed publications; and with extension agents, consultants, dealers and farmers through presentations at county and state meetings, field days, workshops/in-service trainings and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. PARTICIPANTS: The research has been funded primarily by the Arkansas Rice Research Board and the Rice Foundation, and partially funded by Agrotain International, Honeywell, Weyerhaeuser, and RiceTec. Collaborating scientists are University of Arkansas graduate students Alice Enochs, Anthony Fulford, and Trent Roberts; University of Arkansas professors Drs. Nathan Slaton and Charles Wilson; and Dr. Tim Walker of Mississippi State University, Dr. Dustin Harrell of Louisiana State University, and Dr. Garry McCauley of Texas A & M University. The collaboration of scientist's from other rice producing states in the south is an effort at developing a soil based N test for the entire southern rice growing region. The test is named the Nitrogen-Soil Test for Rice or N-ST*R. A calibration curve has completed and was validated in Arkansas in 2009 with the help of county extension personnel in eight small plot tests located at experiment stations and in commercial fields. These validation studies are also being used to educate the extension agents, consultants, farmers and other rice scientists of the utility of the method. Validation studies will continue in 2010 in Arkansas and begin in other cooperating states. When the soil based N test for rice is perfected and ready for use by the rice industry than training meetings will have to be conducted to inform them on the utility of the method and how to properly use the method. Knowledge gained from the studies on the influence of urease inhibitors and N source on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice is being presented at professional training meetings to educate extension agents, consultants, dealers, farmers and others in the fertilizer and rice industry on the viable urease inhibitors and N sources to use in delayed flood rice. The results of the research comparing hybrid rice to self pollinated rice has been presented to RiceTec and the Arkansas Rice Research Board and will be presented at professional training meetings this winter to educate extension agents, consultants and farmers. TARGET AUDIENCES: The audiences that will benefit the most from the knowledge gained are rice farmers, extension agents, consultants, fertilizer dealers and students. The knowledge when placed in their hands will improve the efficiency with which the rice crop utilizes the N fertilizer applied and in turn make rice production more profitable, sustainable, and environmentally sound. Knowledge gained will be added to curricula used in classroom and extension training workshops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Nitrogen (N) fertilizer has the potential to enter streams, rivers, and lakes via irrigation return flow from rice fields. A study was conducted to determine the days after urea fertilization that floodwater should be held to minimize N loss via irrigation return flow. Floodwater N concentrations (18.9 mg N/L maximum) from preflood N rates of 60 and 120 lb N/acre to a dry soil surface decreased to control levels (0 lb N/acre) within 6 days of application. Application of 180 lb N/acre caused floodwater N concentrations to remain above control levels for up to 11 days after fertilization. Midseason N fertilizer applications (i.e., 30 and 60 lb N/acre) increased floodwater N concentrations (32.5 mg N/L maximum) greater than preflood N applications, but also decreased to background levels within 5 days after application. Results from this study indicate a prudent recommendation would be to retain floodwater on rice fields for at least 6 days after application of typical preflood and midseason N rates and up to 11 days after atypically large preflood N application rates. Field studies were conducted comparing the ammonia volatility and influence on rice N uptake and grain yield of urea, Agrotain coated urea, ammonium sulfate and an ammonium sulfate-urea mixture (UAS). When flooding was delayed for 5 or 10 days after N application, ammonia volatilization was the least for Agrotain coated urea (2-10%) and ammonium sulfate (4-5%) and they produced the highest rice N uptake and yield. The UAS blend that had ammonia volatilization losses (11-15%) at 5 and 10 days after application that were intermediate between urea (17-24%) and ammonium sulfate or Agrotain coated urea also had N uptake and grain yield intermediate between these N sources. Urea should only be used if about 2 days are required to flood a field. If 3 to 5 days are required to flood a field, then UAS has some merits but it is not as consistent as ammonium sulfate or Agrotain coated urea. When greater than 5 days are required to flood, ammonium sulfate or Agrotain coated urea should be used. In the search for a soil-based N test we are comparing the diffusion method of the Illinois Soil Nitrogen Test (ISNT) with Direct Steam Distillation (DSD). One objective of the study was to identify the changes in alkaline hydrolyzable-N (AH-N) with soil depth as quantified by the ISNT and DSD. Soil samples were collected from 0-60 cm in 15-cm depth increments and analyzed for AH-N (ISNT and DSD) and total N (TN). Alkaline hydrolyzable-N ranged from 22 to 280 mg N kg soil-1 and the highest values were not always in the top 15 cm of the soil. Total N ranged from 191 to 1542 mg N kg soil-1 and the highest values were always in the top 15 cm. Alkaline hydrolyzable-N accounted for 11-38% of soil TN and was variable across sites and depths. Variation in AH-N and the fraction of TN quantified as AH-N with site and soil depth indicates the importance of proper sampling depth (i.e., to the rooting depth of a given crop) for correlation and calibration of crop response using either the ISNT or DSD.

Publications

  • Watkins, K.A., Hignight, J.A., Norman, R.J., Wilson, C.E., Jr., Slaton, N.A., and Frizzell, D.L. 2009. Maximizing returns to nitrogen application in Arkansas rice production. p. 322-328. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2008. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 571.
  • Golden, B.R., Slaton, N.A., Norman, R.J., Wilson, C.E., Jr., and DeLong, R.E. 2009. Evaluation of polymer-coated urea for directed-seeded, delayed-flood rice production. Soil Sci. Soc. Am. J. 73: 375-383.
  • Norman, R.J., Wilson, C. E., Jr., Slaton, N.A., Griggs, B.R., Bushong, J.T., and Gbur, E.E. 2009. Nitrogen fertilizer sources and timing before flooding dry-seeded, delayed-flood rice. Soil Sci. Soc. Am. J. 73: 2184-2190.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, C.E., Jr., Ross, W.J., and Bushong, J.T. 2009. Direct steam distillation as an alternative to the Illinois soil nitrogen test. Soil Sci. Soc. Am. J. 73:1268-1275.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, C.E., Jr. 2009. Changes in Alkaline Hydrolyzable Nitrogen Distribution with Soil Depth: Fertilizer Correlation and Calibration Implications. Soil Sci. Soc. Am. J. 73: 2151-2158.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, C.E., Jr. 2009. Alkaline hydrolyzable-nitrogen changes with soil depth: Implications for fertilizer correlation and calibration. In Abstracts [CD-ROM]. 2009 Joint Annual Meetings. Nov. 1-5, 2009. Pittsburgh, PA. ASA, Madison, WI.
  • Golden, B.R., Slaton, N.A., Norman, R.J., and DeLong, R.E. 2009. Nitrifications role in nitrogen loss of urea applied preflood to delayed-flood rice. In Abstracts [CD-ROM]. 2009 Joint Annual Meetings. Nov. 1-5, 2009. Pittsburgh, PA. ASA, Madison, WI.
  • Enochs, A.J., Roberts, T.L, Slaton, N.A., Norman, R.J., Wilson, C.E., Jr., Frizzell, D.L., and Branson, J.D. 2009. Nitrogen content in floodwater of drill-seeded, delayed-flood rice following urea fertilization. p. 200-206. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2008. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 571.
  • Roth, C.R., Roberts, T.L., and Norman, R.J. 2009. Variable rates of Agrotain on ammonia volatilization loss of urea applied to a Dewitt silt loam. p. 240-245. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2008. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 571.


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Laboratory and incubation studies as well as all analytical analyses were conducted at the University of Arkansas Main campus. Field studies were conducted at four experiment stations and six commercial rice fields. The research project involved three graduate students as part of their thesis and dissertation research. The information gained from the research was disseminated to communities of interest as follows: i) the Rice Research Board, Rice foundation and industry through annual reports and presentations; ii) with other scientists at regional and national meetings, and in refereed publications; and iii) with extension agents, consultants, dealers and farmers through presentations at county and state meetings, field days, workshops/in-service trainings and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. PARTICIPANTS: The research has been funded primarily by the Arkansas Rice Research Board, and partially funded by Agrotain Int., Honeywell and RiceTec. Collaborating scientists are University of Arkansas graduate students Alice Enochs, and Trent Roberts; University of Arkansas professors Drs. Jeremy Ross, Mary Savin, Nathan Slaton and Charles Wilson; and Dr. Tim Walker of Mississippi State University, Dr. Dustin Harrell of Louisiana State University, and Dr. Garry McCauley of Texas A & M University. The collaboration of scientist's from other rice producing states in the south is an effort at developing a soil based N test for the entire southern rice growing region. When the soil based N test for rice is perfected and ready for use by the rice industry than training meetings will have to be conducted to inform them on the utility of the method and how to properly use the method. Knowledge gained from the studies on the influence of urease inhibitors and N source on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice is being presented at professional training meetings to educate extension agents, consultants, dealers, farmers and others in the fertilizer and rice industry on the viable urease inhibitors and N sources to use in delayed flood rice. The results of the research comparing hybrid rice to self pollinated rice has been presented to RiceTec and the Arkansas Rice Research Board and will be presented at professional training meetings this winter to educate extension agents, consultants and farmers. TARGET AUDIENCES: The audiences that will benefit the most from the knowledge gained are rice farmers, extension agents, consultants, fertilizer dealers and students. The knowledge when placed in their hands will improve the efficiency with which the rice crop utilizes the N fertilizer applied and in turn make rice production more profitable, sustainable, and environmentally sound. Knowledge gained will be added to curricula used in classroom and extension training workshops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Hybrids accumulate significantly greater amounts of the three major nutrients (i.e., N, P, K) from the soil compared to the self pollinated rice varieties and they have a slightly higher concentration of the nutrients in their tissue compared to the self pollinated varieties. The hybrids do not take up N fertilizer more efficiently but they can take up more native soil N than the self-pollinated varieties and appear to be able to acquire more native soil P and K than the self-pollinated varieties. Laboratory and field studies were conducted comparing the ammonia volatility and influence on rice grain yield of urea, Agrotain coated urea, and Nutrisphere coated urea applied at different times prior to flooding. When the N fertilizers were applied 5 and 10 days prior to flooding rice yields were significantly greater for Agrotain treated urea compared to untreated urea. Nutrisphere treated urea and untreated urea applied 5 and 10 days prior to flooding produced similar rice grain yields indicating the Nutrisphere was apparently not inhibiting or minimizing ammonia volatilization of urea. Consequently, laboratory/incubation studies were conducted to see if Nutrisphere had any influence on the ammonia volatility of urea. The laboratory study determined untreated urea and Nutrisphere treated urea volatilized ammonia similarly and in much greater amounts compared to Agrotain treated urea. Development of the Illinois Soil N Test (ISNT) has rejuvenated the search for a soil-based N test to measure potentially mineralizable soil-N. Accurate quantification of amino sugar-N has been achieved using the ISNT, but issues concerning sample variability and analysis time have led to the discovery of a 10 M NaOH direct steam distillation (DSD) procedure. Our primary objective was to determine if DSD could be used as a reliable alternative to the ISNT. Laboratory experiments were conducted to compare the two methods based on recovery of N from pure organic compounds, specificity tests to determine amine group hydrolysis, and recovery of N-15 labeled glucosamine-N added to soils. Both methods recovered appreciable amounts of amino sugar-N from pure compounds and the ISNT had a higher recovery of N from all amino sugar compounds. Recovery of N from glutamine and asparagine was higher using DSD. Direct N-15 techniques for recovery of glucosamine-N added to six soils showed no significant difference between the two methods within a soil, but resulted in significant differences among soils. Glucosamine N-15 recovery significantly and positively correlated with soil total N. Although the ISNT and DSD measure different amounts of amino sugar-N and transition amino acid-N, they recover relatively the same amount of hydrolyzable-N for a given soil indicating differences between the methods may not be that significant as both appear to quantify a pool of potentially mineralizable-N. Direct steam distillation appears to be a viable alternative for the ISNT in correlation and calibration of crop response for N-fertilizer recommendations due to the short analysis time per sample (6 min.) and the accurate estimation of potentially mineralizable-N.

Publications

  • Roberts, T.L., Norman, R.J., Ross, W.J., Wilson, Jr., C.E., Slaton, N.A., and Bushong, J.T. 2008. Nitrogen recommendations for rice in Arkansas using the Illinois soil nitrogen test and direct steam distillation. In Abstracts [CD-ROM]. 2008 Joint Annual Meetings. Oct. 5-9, 2008. Houston, TX. ASA, Madison, WI.
  • Frizzell, D.L., Dawson, V., Norman, R.J., Wilson, Jr., C.E., Branson, J.D., Roberts, T.L., and Slaton, N.A. 2008. Nutrient uptake comparisons between RiceTec XL723 and Trenasse. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Golden, B.R., Slaton, N.A., Norman, R.J., DeLong, R.E., and Wilson, Jr., C.E. 2008. Assessment of Polymer Coated Urea for delayed-flood rice. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Norman, R.J., Wilson, Jr., C.E., Roberts, T.L., Walker, T.W., Frizzell, D.L., Enochs, A.J., Branson, J.D., and Slaton, N.A. 2008. Evaluation of Agrotain and Nutrisphere coated ruea applied preflood to delayed-flood rice. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Golden, B.R., Slaton, N., Delong, R., and Norman, R. 2008. Evaluation of polymer-coated urea as an alternative to preflood urea for delayed-flood rice. In Abstracts [CD-ROM]. American Society of Agronomy Southern Branch Meeting. ASA Southern Region Branch Meetings. Feb. 3-5, 2008. Dallas, TX. ASA, Madison, WI.
  • Enochs, A.J., Roberts, T.L., Slaton, N.A., Norman, R.J., Wilson Jr., C.E., Frizzell, D.L., and Branson, J.D. 2008. Nitrogen content in floodwater of drill-seeded, delayed-flood rice following urea fertilization. In Abstracts [CD-ROM]. 2008 Joint Annual Meetings. Oct. 5-9, 2008. Houston, TX. ASA, Madison, WI.
  • Enochs, A.L., Roberts, T.L., Norman, R.J., Walker, T., and Wilson Jr., C.E. 2008. Effect of Nutrisphere on ammonia volatilization loss of urea and the grain yield of drill-seeded, delayed flood rice. In Abstracts [CD-ROM]. 2008 Joint Annual Meetings. Oct. 5-9, 2008. Houston, TX. ASA, Madison, WI.
  • Golden, B.R., Massey, C.G., Slaton, N.A., Maschmann, E.T., and Norman, R.J. 2008. Nitrogen Release from Polymer Coated Urea in Five Arkansas Soils. In Abstracts [CD-ROM]. 2008 Joint Annual Meetings. Oct. 5-9, 2008. Houston, TX. ASA, Madison, WI.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., Ross, J.R., and Bushong, J.T. 2008. Soil-based nitrogen tests for nitrogen recommendations in Arkansas. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Roberts, T.L., Norman, R.J., Walker, T.W., Harrell, D.L., and McCauley, G.N. 2008. Regional assessment of soil-based nitrogen tests for rice production in the midsouth USA. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Savin, M.C., Tomlinson, P.J., Norman, R.J., Daigh, A., Brye, K.R., and Miller, D.M. 2008. Nitrogen in surface water and silt-loam soil cores following fertilization application and surface ponding. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Walker, T.W., Satterfield, J.M., Bajwa, S., Norman, R.J., Harrell, D.L., Bond, J.A. and Varco, J.J. 2008. An evaluation of commercially available imagery of rice crop canopy affected by nitrogen nutrition. In Rice Technical Working Group Abstracts. 32nd Meeting, San Diego, CA. Feb. 18-21, 2008.
  • Norman, R.J., Roberts, T.L., Enochs, A.J., Slaton, N.A., and Wilson Jr., C.E. 2008. Evaluation of Agrotain and Nutrisphere coated urea applied preflood to delayed-flood rice. In Abstracts [CD-ROM]. American Society of Agronomy Southern Branch Meeting. ASA Southern Region Branch Meetings. Feb. 3-5, 2008. Dallas, TX. ASA, Madison, WI.
  • Enochs, A.J., Roberts, T.L., Slaton, N.A., Norman, R.J., Wilson Jr., C.E., Frizzell, D.L., and Branson, J.D. 2008. Nitrogen content in floodwater of drill-seeded, delayed-flood rice following urea fertilization. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2007. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 560.
  • Norman, R.J., Roberts, T.L., Walker, T.W., Wilson, Jr., C.E., Enochs, A.J., and Slaton, N.A. 2008. Effect of Nutrisphere on ammonia volatilization of urea and the grain yield of drill-seeded, delayed-flood rice. p.175-182. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2007. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 560.
  • Roberts, T.L., Norman, R.J., Slaton, N.A., Wilson, Jr., C.E., and Ross, J.R. 2008. Evaluation of two soil-based nitrogen tests to enhance fertilizer recommendations in Arkansas rice production. p. 195-201. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2007. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 560.
  • Savin, M.C., Daigh, A.L., Tomlinson, P.J., and Norman, R.J. 2008. Urea persistence in ponded surface water and a silt loam soil used for rice production. p. 202-208. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2007. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 560.
  • Bushong, J.T., T.L. Roberts, W.J. Ross, R.J. Norman, N.A. Slaton, C.E. Wilson, Jr. 2008. Evaluation of distillation and diffusion techniques for estimating hydrolyzable amino sugar-nitrogen as a means of predicting nitrogen mineralization. Soil Sci. Soc. Amer. J. 72:992-999.


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Field research to address the objectives was conducted at four experiment stations and five commercial rice fields using replicated/randomized studies. All laboratory experiments and analyses were conducted at the University of Arkansas main campus in Fayetteville. The research projects involve at least four graduate students as part of their thesis or dissertation research. Because of the preliminary nature of the results on the comparison of hybrid rice nutrient uptake to self pollinated rice nutrient uptake, presentations and/or annual reports of the findings have only been given to the Arkansas Rice Research Board, RiceTec, and soil fertility scientists working in rice. Knowledge gained from the laboratory and field studies on the influence of tillage practice, N source, and application time on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice grown on a clay and silt loam soil has been shared with the Arkansas Rice Research Board through annual reports and presentations; with other scientists at regional and national meetings, and in refereed publications; and with the fertilizer industry, dealers, extension agents, consultants and rice farmers through presentations at county and state meetings, field days, workshops and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. Progress on the development of a soil based N test for rice has been shared only with the Arkansas Rice Research Board in annual reports and presentations and with other scientists at regional and national meetings, and in refereed and Arkansas Experiment Station publications. The fertilizer industry, dealers, extension agents, consultants and the rice farmers will be informed of the progress on the development of the soil based N test for rice in 2008 via presentations at county and state meetings and in publications by the Arkansas Agricultural Experiment Station and Cooperative Extension Service as well as by the popular press. PARTICIPANTS: The research has been funded primarily by the Arkansas Rice Research Board, and partially funded by Agrotain Int., Honeywell and RiceTec. Collaborating scientists are University of Arkansas graduate students Jacob Bushong, Barney Griggs, Alice Enochs, and Trent Roberts; University of Arkansas professors Drs. Jeremy Ross, Mary Savin, Nathan Slaton and Charles Wilson; and Dr. Tim Walker of Mississippi State University, Dr. Dustin Harrell of Louisiana State University, and Dr. Garry McCauley of Texas A & M University. The collaboration of scientist's from other rice producing states in the south is an effort at developing a soil based N test for the entire southern rice growing region. When the soil based N test for rice is perfected and ready for use by the rice industry than training meetings will have to be conducted to inform them on the utility of the method and how to properly use the method. Knowledge gained from the studies on the influence of tillage practice, N source, soil type, and application time on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice can and will be presented at professional training meetings to educate extension agents, farmers and others in the fertilizer and rice industry on the proper manner to fertilize rice with N at preflood application time. TARGET AUDIENCES: The audiences that will benefit the most from the knowledge gained are rice farmers, extension agents, consultants, fertilizer dealers and students. The knowledge when placed in their hands will improve the efficiency with which the rice crop utilizes the N fertilizer applied and in turn make rice production more profitable, sustainable, and environmentally sound. Knowledge gained will be added to curricula used in classroom and extension training workshops.

Impacts
The first year of data indicates the hybrids accumulate significantly more nutrients from the soil compared to the self pollinated rice varieties and they have a higher concentration of the nutrients in their tissue compared to the self pollinated varieties. Perhaps, the soil should be sampled following the growing of hybrid rice since significantly more nutrients have been removed from the soil compared to a self pollinated variety. Field studies determined the influence of tillage practice, N source, and application time on NH3 volatilization, total-N uptake, and grain yield of delayed flood rice grown on a clay and silt loam soil. Ammonia volatilization was the highest (14 to 32 percent) and total-N uptake and grain yield of rice the lowest when urea was applied 14 d preflood. Ammonium sulfate applied 14 d preflood lost little N via NH3 volatilization and resulted in total-N uptakes and grain yields of rice similar to urea applied 1 d preflood. The stale-seedbed had no affect on NH3 volatilization of ammonium sulfate, but did affect urea in one year on the silt loam soil, but the two tillage systems still produced rice with similar total-N uptakes and grain yields. Ammonia volatilization was more rapid and greater when urea was applied to the silt loam compared to the clay. If a rice field can be flooded in a few days after N application than ammonium sulfate or Agrotain treated urea should be used. In a separate infiltration and diffusion study urea moved much deeper into the soil than ammonium sulfate and Agrotain coated-urea moved deeper into the soil compared to urea when flooding was delayed 5 days after N application. Urea movement below the oxidized soil layer would limit the nitrification/diffusion/denitrification loss mechanism. Laboratory and field trials evaluated three analytical methods, an alkali diffusion technique, an alkali direct steam distillation technique, and soil total N, for determining the N mineralization potential of a soil. The laboratory studies obtained a strong correlation between the three methods and mineralizable soil N. Field studies to date on silt loam soils show a strong correlation (r2 of 0.87 to .89) between percent relative grain yield and the N liberated with the alkali diffusion technique and alkali direct steam distillation technique when the soil was sampled to the 18 inch depth. The predictive value of the soil's total N content for use in N fertilizer application also increased with depth, but did not result in coefficients of determination as high as either of the other two techniques. These results suggest sampling depth plays a major role in a soil test's ability to measure the potentially mineralizable soil N the plant accesses. A soil N test will enable more accurate N fertilizer rate recommendations for rice by allowing site specific N fertilizer decisions rather than using a regional soil type approach. Implementation of the soil N test will enable the optimal use of N fertilizer leading to the most economical rice yield with minimal disease and lodging while lowering the potential impact of the N fertilizer to the surrounding environment.

Publications

  • Norman, R.J., Frizzell, D.L., Wilson, Jr., C.E., and Slaton, N.A. 2007. Influence of urea and Agrotain applied to a dry clay soil several days prior to flooding on the grain yield of delayed flood rice. p.294-297. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2006. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 550.
  • Reiter, M., Daniel, T., Richardson, M., Hinkle, R., Slaton, N., and Norman, R. 2007. influence of binding agents on inorganic nitrogen and phosphorus release from a nitrogen fortified poultry litter and biosolids granulated fertilizer during rainfall simulations. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Roberts, T., Ross, J., Norman, R., Slaton, N., and Wilson, C. 2007. Direct steam distillation or ISNT diffusion? Assessment of the two methods in recovering selected organic N compounds. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Roberts, T., Ross, J., Norman, R., Wilson, Jr., C., Slaton, N., and Bushong, J. 2007. Soil based nitrogen tests for rice production: taking it to another depth. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Golden, B., Slaton, N., Delong, R., and Norman, R. 2007. Nitrogen release from polymer-coated urea via a buried-bag technique. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Savin, M., Daigh, A., Tomlinson, P., and Norman, R. 2007. Urea persistence is a ponded silt loam soil used for rice production. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Savin, M.C., Miller, D.M., Tomlinson, P., Brye, K.R., and Norman, R.J. 2007. Movement of fertilizer nitrogen applied to a dry silt loam-soil during four days of surface ponding. p. 325-331. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2006. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 550.
  • Tomlinson, P.J., Savin, M.C., Miller, D.M., Brye, K.R., and Norman, R.J. 2007. Fertilizer nitrogen movement during four days of surface water ponding. In ASA-CSSA-SSSA International Annual Meetings Abstracts. [CD-ROM]. New Orleans, LA. Nov. 4-8, 2007. ASA, Madison, WI.
  • Bushong, J.T., Norman, R.J., Ross, W.J., Slaton, N.A., Wilson, Jr., C.E., and Gbur, E.E. 2007. Evaluation of several indices of potentially mineralizable soil nitrogen. Comm. Soil Sci. & Plant Anal. 38:2799-2813.
  • Frizzell, D.L., Norman, R.J., Wilson, Jr., C.E., Slaton, N.A., and Bollich, P.K. 2007. Seasonal accumulation of 15N-lableled nitrogen fertilizer by two rice cultivars. p.287-293. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2006. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 550.
  • Griggs, B.R., Norman, R.J., Wilson, Jr., C.E., and Slaton, N.A. 2007. Ammonia volatilization and nitrogen uptake for conventional and conservation tilled dry-seeded, delayed flood rice. Soil Sci. Soc. Am. J. 71:745-751.


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

Outputs
The rice cultivars studied in 2006 were the: experimental varieties 1182 and 4484, Jupiter, Pace, Pirogue, Presidio, Trenasse, Horizon Ag Clearfield CL131 and CL171, and the RiceTec hybrids XL723, CLXP729, and CLXL730. The two experimental varieties, 1182 and 4484, as well as Pirogue and Presidio reached maximum yield on silt loam soils when 120 lb N/A was applied in a split application of 75 lb N/A at preflood followed by 45 lb N/A at midseason; while on clay soils they required 30 lb N/A more at preflood to maximize grain yield. Pace and the two Clearfield varieties CL131 and CL171 performed best on silt loam soils when 120 to 150 lb N/A were applied in split application of 75 to 105 lb N/A preflood followed by 45 lb N/A at midseason. When they were grown on clay soils 30 lb N/A more was required at preflood to maximized grain yield. The RiceTec hybrids XL723, CLXP729 and CLXL730 achieved maximum grain yield on the silt loam soils when 120 to 150 lb N/A were applied in a split application of 75 to 105 lb N/A preflood followed by 45 lb N/A at midseason. However, when the RiceTec hybrids were grown on clay soils a preflood N rate of 135 to 165 lb N/A were required to achieve maximum grain yield. The Louisiana bred varieties Trenasse and Jupiter obtain maximum grain yield on silt loam soils when 150 lb N/A was applied in a split application of 105 lb N/A at preflood followed by 45 lb N/A at midseason. Like most of the other varieties Trenasse and Jupiter required 30 lb N/A more at preflood on clay soils compared to silt loam soils to reach maximum grain yield. Studies on the utility of "starter" fertilizer for clay soils to facilitate early growth of semidwarfs found that DAP and to a lesser extent ammonium sulfate and urea applied preplant increased rice growth early in the season to result in a shorter time span between planting and flooding. The starter N fertilizers at times resulted in a grain yield increase. Urea and Agrotain were applied to rice grown on a clay soil 1, 5, 7 and 10 days prior to flooding. When urea and Agrotain were applied to a clay soil 1 day prior to flooding both resulted in similar grain yields. However, as the time between N application and flooding was increased to 5, 7 and 10 days; rice grain decreased significantly when urea was the N source, but not when Agrotain was the N source. The 2006 results with Agrotain and urea are very similar to the 2005 results. The 2005 results were that when the flood was delayed for 7 and 10 days after N fertilizer application Agrotain resulted in significantly higher grain yields compared to urea. Thus, from these two years of data the recommendation in Arkansas will be that when rice is grown on a clay soil and the field can not be flooded in a week or less after N fertilizer application than Agrotain should be used. The development of the Rice Soil N Test (RSNT) is now at the field development stage and results to date indicate that the RSNT appears to be a viable method. When rice grain yield was regressed with the RSNT over 16 location/years a regression coefficient or R2 value of 0.6 was achieved. Further research will continue in 2007 on the RSNT.

Impacts
The variety by N study determines the proper N fertilizer rate for all new rice varieties in the state of Arkansas prior to their commercial release. This ensures the new rice varieties obtain their full yield potential when grown commercially in Arkansas. Starter ferilizers have shown to be of benefit on clay soils. When rice is grown on a clay soil and the field can not be flooded in a week or less after N fertilizer application than Agrotain should be used to minimize ammonia volatilization losses. The development of the Rice Soil N Test (RSNT) is now at the field development stage and results to date indicate that the RSNT appears to be a viable method.

Publications

  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Frizzell, A.L Richards, M.W. Duren, J.W. Gibbons, and K.A..K. Moldenhauer. 2006. Grain yield response of fifteen new rice cultivars to nitrogen fertilization. p.276-290. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2005. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 540.
  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Frizzell, W.J. Ross, J.T. Bushong, and A.L. Richards. 2006. Influence of urea and agrotain applied to a dry and muddy silt loam soil several days prior to flooding on ammonia volatilization and grain yields of delayed-flood rice. p. 291-297. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2005. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 540.
  • Brye, K.R., N.A. Slaton, and R.J. Norman. 2006. Soil physical and biological properties as affected by land leveling in a clayey aquert. Soil Sci. Soc. Am. J. 70:631-642.
  • Golden, B.R, N.A. Slaton, R.J. Norman, E.E. Gbur, K.R. Brye, and R.E. DeLong. 2006. Recovery of nitrogen in fresh and pelletized poultry litter by rice. Soil Sci. Soc. Am. J. 70:1359-1369.
  • Slaton, N.A., C.E. Wilson, Jr., R.J. Norman, and R.E. DeLong. 2006. Correlation of soil pH and Mehlich-3 phosphorus with postflood rice phosphorus concentrations in Arkansas. Comm. Soil Sci. & Plant Anal. 37:2819-2831.
  • Gibbons, J.W., K.A.K. Moldenhauer, K. Gravois, F.N. Lee, J.L. Bernhardt, J.F. Meullenet, R. Bryant, R.J. Norman, R.L. Cartwright, M. Anders, K. Taylor, J. Bulloch, and M.M. Blocker. 2006. Registration of Medark rice. Crop. Sci. 46:2316.
  • Gibbons, J.W., K.A.K. Moldenhauer, K. Gravois, F.N. Lee, J.L. Bernhardt, J.F. Meullenet, R. Bryant, R.J. Norman, M. Anders, R.L. Cartwright, K. Taylor, J. Bulloch, and M.M. Blocker. 2006. Registration of Cybonnet rice. Crop. Sci. 46:2317.
  • Copenhaver, L.M., M.C. Savin, D.M. Miller, P.J. Tomlinson, K.R. Brye, and R.J. Norman. 2006. Infiltration and short-term movement of nitrgoen in asilt-loam soil typical of rice cultivation in Arkansas. Discovery 7:14-18.
  • Norman, R.J., J.-F. Meullenet, K.A. K. Moldenhauer (eds.). 2006. B.R. Wells rice research studies 2005. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 540. pp 424.
  • Burgos, N.R., R.J. Norman D.R. Gealy, and H. Black. 2006. Competitive N uptake between rice and weedy rice. Field Crops Research. 99:96-105.


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

Outputs
The variety x nitrogen (N) fertilizer interaction study determines the proper N fertilizer rates for the new rice cultivars across the array of soil and climatic conditions, which exist in the Arkansas rice growing region. Banks, Cheniere, Clearfield CL131, Cybonnet, Jupiter, Spring, Trenasse, USDA experimental line 4484, and the RiceTec hybrids XP721, XP723, XP728, XP729, Clearfield CLXP730, XP731, and XP732 were the new rice varieties evaluated for N fertilizer response in 2005. Banks, Cheniere, CL131, Jupiter and Trenasse usually required 90 lb N/acre to achieve maximum grain yield when grown on silt loam soils and 150 to 180 lb N/acre when grown on clay soils. Cybonnet and Spring typically required 120 lb N/acre to achieve maximum grain yield when grown on silt loam soils and 180 lb N/acre when grown on clay soils. The RiceTec hybrids usually achieved maximum grain when 90 lb N/acre was applied preflood and 0 to 30 lb N/acre was applied at late boot. The late boot N application of 30 to 60 lb N/acre seldom resulted in a grain yield increase, but this is typical in Arkansas. The late boot N application is recommended on the hybrids mainly to minimize lodging and secondly to increase rice grain yield. Studies were conducted to compare two CoRoN liquid N sources, HM9310 and HM0108, of Helena Chemical applied at low rates to the standard N rate and source, urea, normally used at midseason in rice. Neither of the experimental N sources, HM9310 or HM0108, applied at 10 or 20 lb N/acre at midseason produce rice grain yields equivalent to those produced when 45 or 60 lb N/acre as urea was applied at midseason. The fact that rice varieties typically take up 150 to 200 lb N/acre to produce maximum grain yields would suggest that an application of only 10 or 20 lb N/acre would be just too small to have much of an impact even if all of the N applied at midseason was taken up. One should be reminded that urea applied at midseason is taken up with a 65 to 80% efficiency, and if urea is applied at a 40 or 60 lb N/acre rate and another N fertilizer is applied at 10 or 20 lb N/acre rate it cannot compete even if taken up by the rice with an unattainable 100% efficiency. A N soil test that predicts N mineralization in rice soils has long eluded researchers. The objective of this study was to compare proposed analytical methods for predicting N mineralization with the NH4+-N mineralized after a 14 d anaerobic incubation on Arkansas silt loam rice soils. The proposed methods were i.) acid oxidation, ii.) ultraviolet absorbance of NO3- reduced and unreduced soil extracts, and iii.) diffusion of amino sugar-N using the Illinois Soil N Test. Linear regression models revealed that the acid oxidation procedure, the ultraviolet absorbance of NO3- unreduced soil extracts, and the diffusion of amino sugar-N using the Illinois Soil N Test all accurately predicted the NH4+-N mineralized after a 14 d anaerobic incubation. In conclusion, if the 14 d anaerobic incubation procedure is a reliable indicator of N uptake in rice, then it can be assumed the aforementioned methods should accurately predict N mineralization in the field. Boron fertilization studies were conducted with soybean grown on alkaline silt loam soils at four sites to evaluate crop response to B fertilization rate and time of application during 2005. Tissue B concentrations were increased by B fertilization, but B fertilization had no significant influence on soybean yields. The N-, P-, and K-fertilizer values of poultry litter applied preplant to flood-irrigated rice were evaluated at five sites in 2005. Only about 25 to 30% of the total N in poultry litter is recovered by rice during the first growing season. The total P and K in fresh and pelletized poultry litter provide similar amounts of available P and K to flood-irrigated rice as inorganic P and K fertilizers when applied at equal P and K rates. Trials conducted in 2005 showed the N-fertilizer value of poultry litter declines as the time of application before seeding is increased, stand loss due to salt injury can occur when high rates of litter are applied preplant to rice, and that litter applied to the soil surface produced similar rice yields as incorporated litter. Rice grown on clay soils did not show growth or yield benefits from fertilization with granular Zn rates up to 30 lb Zn/acre at ten sites. Data from 23 site-years of research with clayey soils were summarized to assess the need for Zn fertilization of clay soils. Results show that soil pH plus Mehlich-3 extractable Zn can be used to estimate Zn concentrations of rice seedlings grown in clayey soils. Fertilizer recommendations were revised to indicate the need for Zn fertilization when soil pH is above 6.0 and Mehlich-3 Zn is <1.6 ppm. Various other fertilization trials including N, K, and P fertilizers were also initiated with rice, soybean, and wheat. Data from these trials will be used to correlate Mehlich-3 extractable nutrients with crop responses to fertilization and calibrate the P and K fertilizer recommendations for these crops. Significant rice yield increases from K fertilization were found at 5 of 7 sites in 2005. Trials evaluating rice and soybean response to annual K fertilization rate showed that after 4 years significant rice (20 to 40 bu/acre) and soybean (10 to 20 bu/acre) yield losses occur when no or sub-optimal K rates (<50 lb K/acre) are applied to silt loam soils. Phosphorus fertilization had no influence on rice yields at two sites. Soybean yields were increased significantly by P fertilization at 1 of 6 sites and by K fertilization at 2 of 6 sites. Wheat yields were significantly increased by P fertilization at 2 of 4 sites. Trials were conducted to evaluate the influence of seeding date and cultivar on kernel smut of rice at three sites. No consistent trend was found between seeding date and kernel smut severity and incidence. However, kernel smut usually increased as cultivar susceptibility to kernel smut increased. Progress was made towards ascertaining the impact agriculture has had on soil physical, chemical, and biological properties that were once influenced by prairie vegetation (Objective 1). A new study was initiated at the Pea Ridge National Military Park in Garfield, AR to evaluate the effect of land use, soil type, and prairie restoration age on soil physical, chemical, and biological properties. Progress was made towards evaluating the sustainability of management practices and cropping systems in terms of soil biogeochemical properties that relate to soil quality (Objective 2). A field study was continued in east-central Arkansas on a clay soil evaluating the short- and long-term impacts of land leveling on soil-quality-related parameters. Similar to previous finding on a silt-loam soil, land leveling significantly altered the magnitude, variance, and spatial distributions of numerous soil physical, chemical, and biological properties. Deep-tillage, as a means to alleviate surface compaction caused by land leveling activities, has not resulted in a significant positive effect on post-leveling crop yield. A second field study was continued in eastern Arkansas to evaluate the effects of alternative wheat-residue management practices, residue level, burning, and tillage, on soybean germination and development and soil quality. An additional production variable was added in 2005 to investigate the impacts of irrigated versus dryland soybean production. Progress was made towards evaluating the potential benefits to soil physical, chemical, and biological properties by amending soils with agricultural-crop-processing waste materials, specifically poultry litter added to soils cropped to rice (Objective 3). Poultry litter applied annually at recommended rates has not resulted in a significant positive effect on post-leveling crop yield. Significant continuing progress was made towards characterizing solute leaching and runoff losses from soil with pasture-type vegetation amended with poultry litter (Objective 4). There were no differences in plant nutrient leaching losses among litter rates during either year or cumulatively over the 2-yr period. Flow-weighted mean concentrations of Mn during Spring Year 1 (February through April 2004) and Ni and Cu for the whole year differed among litter treatments, but there were no consistent trends. In Spring Year 2 (February through April 2005), flow-weighted mean concentrations of Cr and Fe differed among litter treatment, but there were no consistent trends. Metal leaching losses did not differ among litter treatment during Year 1. In Year 2, leaching losses of Zn, Fe, and As differed among litter treatments during Summer, Fall, and Winter, respectively, but there were no consistent trends. Results indicate that reducing poultry litter application rate by 50% does not proportionally reduce plant nutrient and heavy metal leaching losses; thus simply reducing application rates in areas with a history of litter application will not necessarily result in improved subsurface water quality.

Impacts
The variety by N study determines the proper N fertilizer rate for all new rice varieties in the state of Arkansas prior to their commercial release. This ensures the new rice varieties obtain their full yield potential when grown commercially in Arkansas. Studies conducted to compare Helena Chemicals two CoRoN liquid N sources, HM9310 and HM0108, to the standard N source, urea, normally used at midseason in rice indicated that they could not be applied at lower rates than urea and produce equivalent grain yield. Neither of the experimental N sources, HM9310 or HM0108, applied at 10 or 20 lb N/acre at midseason produced rice grain yields equivalent to those produced when 45 or 60 lb N/acre as urea was applied at midseason. If the concentration of NH4+-N mineralized after a 14 d anaerobic incubation is a reliable indicator of N uptake in field grown rice, then it can be assumed that the acid oxidation procedure, the ultraviolet absorbance method and the ISNT method for predicting N mineralization should accurately predict N mineralization in the field. Data generated from research is being used to characterize soil fertility and plant nutrition needs of wheat, rice, and soybean when these crops are grown in rotation which should improve our understanding of soil testing and plant nutrition relationships for rotations involving rice. Information is extended to the Cooperative Extension Service for grower use, considered in new fertilizer recommendations when appropriate, and published in various locations for documentation. Research data was used to refine existing soil test-based P and K fertilizer recommendations for rice, soybean, and wheat grown in Arkansas. Additional P and K fertilization trials are needed to build confidence in the preliminary correlation and calibration relationships. These data will also aid in developing nutrient management guidelines for these crops grown in states adjacent to Arkansas that use similar soil-test methods. The profitability of row-crop production will be improved through more accurate nutrient management guidelines. Research findings will improve our ability to predict when significant crop yield responses to fertilization will occur, provide insight on how to manage nutrient deficiencies, increase fertilizer use efficiency, and integrate nutrient and pest management recommendations. The introduction and continuance of intense mechanized agriculture and its associated practices have significantly, and for the most part negatively, impacted soil quality in eastern Arkansas. Current management practices could be refined or new ones developed based on the results of research conducted within this project to lessen the negative impact high-intensity production agriculture has on soil quality. Results or these studies also suggest that 1) prairie preservation, restoration, and management practices should differ depending on climate regimes, 2) wheat-residue management practices other than burning affect the loss of C as carbon dioxide from the soil and that there are additional soil and/or environmental factors, other than those measured in study, that contribute to controlling soil surface carbon dioxide flux during the soybean growing season of a wheat-soybean rotation in the mid-southern United States, 3) land leveling is a severe soil disturbance whose impacts on soil physical, chemical, and biological properties and ultimate effects of post-leveling crop productivity need to be further evaluated on a range of soil textures, and 4) simply reducing poultry litter application rates to area that have received a long history of litter applications may not result in significant decreases in leaching losses on soluble litter constituents.

Publications

  • Slaton, N.A., J. Branson, C.E. Wilson, Jr., R.J. Norman, and R.E. DeLong. 2005. Zinc fertilization of rice grown on clay soils in Arkansas. p.305-309. In R.J. Norman, J.F. Meullenet, and K.A.K. Moldenhauer (eds.) B.R. Wells Rice Research Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 529. Fayetteville, AR.
  • Slaton, N.A., K.R. Brye, R.K. Bacon, and M. Mozaffari. 2005. Correlation and calibration of Mehlich-3 phosphorus recommendations for winter wheat following rice in Arkansas. Commun. Soil Sci. Plant Anal:36(7/8):993-1004.
  • Slaton, N.A., R.E. DeLong, C. Baquireza, R.J Norman, C.E. Wilson, and B.R. Golden. 2005. Rice response to phosphorus and potassium fertilization in Arkansas. p.310-318. p.319-325. In R.J. Norman, J.F. Meullenet, and K.A.K. Moldenhauer (eds.) B.R. Wells Rice Research Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 529. Fayetteville, AR.
  • Slaton, N.A., R.E. DeLong, and R. Thompson. 2005b. Irrigated soybean response to boron application time and rate. p.91-94. In N.A. Slaton (ed.) Wayne E. Sabbe Arkansas Soil Fertility Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 525. Fayetteville, AR.
  • Slaton, N.A., J. Ross, R. DeLong, S. Clark, and J. Shafer. 2005. Residual nutrition of a single boron application on soybean and rice in Arkansas. In Agronomy Abstracts. [CD-ROM]. Amer. Soc. Agron. Meetings, Nov. 6-10, 2005. Salt Lake City, UT. ASA, Madison, WI.
  • Slaton, N.A., J.R. Ross, R.E. DeLong, S.D. Clark, J. Shafer, and D.L. Boothe. 2005. Evaluation of the residual benefits of boron fertilization on soybean and rice. p.100-104. In N.A. Slaton (ed.) Wayne E. Sabbe Arkansas Soil Fertility Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 525. Fayetteville, AR.
  • Slaton, N.A., T.W. Walker, J. Bond, D. Dunn, P.K. Bollich, and R.E. DeLong. 2005. Rice response to boron application rate and time in Arkansas, Louisiana, Mississippi, and Missouri. p.326-331. In R.J. Norman, J.F. Meullenet, and K.A.K. Moldenhauer (eds.) B.R. Wells Rice Research Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 529. Fayetteville, AR. $$
  • Brye, K.R., and C.P. West. 2005. Grassland management effects on soil quality in the Ozark Highlands. Soil Sci. 170:63-73.
  • Brye, K.R., N.A. Slaton, and R.J. Norman. 2005. Penetration resistance as affected by shallow-cut land leveling and cropping. Soil Till. Res. 81:1-13.
  • Brye, K.R., and A.L. Pirani. 2005. Native soil quality and the effects of tillage in the Grand Prairie region of eastern Arkansas. Am. Midl. Nat. 154:28-41.
  • Brye, K.R. 2005. Short-term impacts of land leveling on soil physical and biological properties in a clayey Aquert. pp. 269-275. In R.J. Norman and J.F. Meullenet (eds.) B.R. Wells Rice Research Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 529. Fayetteville, AR.
  • Pirani, A.L. 2005. Leaching of plant nutrients and heavy metals from poultry-litter amended tall fescue pasture. M.S. thesis, Univ. of Arkansas, Fayetteville.
  • Norman, R.J., J.-F. Meullenet, K.A. K. Moldenhauer (eds.). 2005. B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529. pp 441.
  • Bushong, J.T., R.J. Norman, W.J. Ross, N.A. Slaton, and C.E. Wilson, Jr. 2005. Evaluation of several indices of potentially mineralizable soil nitrogen on Arkansas silt loam soils. p.276-281. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Gibbons, J.W., K.A.K. Moldenhauer, K. Gravois, F.N. Lee, J.L. Bernhardt, J.-F. Meullenet, R. Bryant, R.J. Norman, R. Cartwright, M.M. Anders, K. Taylor, J. M. Bulloch, and M. Blocker. 2005. Cybonnet, a semidwarf long grain rice cultivar. p.38-43. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Gibbons, J.W., K.A.K. Moldenhauer, K. Gravois, F.N. Lee, J.L. Bernhardt, J.-F. Meullenet, R. Bryant, R.J. Norman, R. Cartwright, M.M. Anders, K. Taylor, J. M. Bulloch, and M. Blocker. 2005. Medark, a semidwarf medium grain rice cultivar. p.44-48. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Moldenhauer, K.A.K., J.W. Gibbons, M. Anders, F.N. Lee, J.L. Bernhardt, C.E. Wilson, Jr., R. Cartwright, R.J. Norman, R. Bryant, M.M. Blocker, V. Boyett, K. Taylor, and J. M. Bulloch. 2005. Spring, a very early long grain rice variety. p.49-55. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529. $$
  • DeLong, R.E., D.L. Boothe, N.A. Slaton, R.J. Norman, R.D. Cartwright, C.E. Wilson, Jr., and M.W. Duren. 2005. Seeding date effect on kernel smut and grain yield of rice in Arkansas. In Agronomy Abstracts. [CD-ROM]. Amer. Soc. Agron. Meetings, Nov. 6-10, 2005. Salt Lake City, UT. ASA, Madison, WI.
  • Golden, B.R., N.A. Slaton, R.J. Norman, K.R. Brye, R.E. DeLong. 2005. The urea-nitrogen equivalence of fresh and pelleted poultry litter for flood-irrigated rice. In Agronomy Abstracts. [CD-ROM]. Amer. Soc. Agron. Meetings, Nov. 6-10, 2005. Salt Lake City, UT. ASA, Madison, WI.
  • Slaton, N.A., R.E. DeLong, M. Mozaffari, S.D. Clark, and D.L. Boothe. 2005. Winter wheat response to phosphorus fertilization. p.81-85. In N.A. Slaton (ed.) Wayne E. Sabbe Arkansas Soil Fertility Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 525. Fayetteville, AR.
  • Slaton, N.A., R.E. DeLong, and R. Thompson. 2005a. Full-season, irrigated soybean response to phosphorus and potassium fertilization. p.86-90. In N.A. Slaton (ed.) Wayne E. Sabbe Arkansas Soil Fertility Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 525. Fayetteville, AR.
  • Slaton, N.A., E.E. Gbur, C.E. Wilson, Jr., and R.J. Norman. 2005. Rice Response to Granular Zinc Sources Varying in Water-Soluble Zinc. Soil Sci. Soc. Amer. J. 69:443-453.
  • Slaton, N.A., B.R. Golden, K.R. Brye, R.J. Norman, T.C. Daniel, R.E. DeLong, and J.R. Ross. 2005. The nitrogen fertilizer value of preplant-incorporated poultry litter for flood-irrigated rice. p.319-325. In R.J. Norman, J.F. Meullenet, and K.A.K. Moldenhauer (eds.) B.R. Wells Rice Research Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 529. Fayetteville, AR.
  • Slaton, N.A., M. Mozaffari, R.E. DeLong, R.J. Norman, and W.J. Ross. 2005 Influence of nitrogen fertilizer application rate and time on winter wheat yields. p.95-99. In N.A. Slaton (ed.) Wayne E. Sabbe Arkansas Soil Fertility Studies 2004. Ark. Agric. Exp. Stn. Res. Ser. 525. Fayetteville, AR.
  • Slaton, N.A., R.J. Norman, and C.E. Wilson, Jr. 2005. Effect of zinc source and application time on zinc uptake and grain yield of flood-irrigated rice. Agron. J. 97(1):272-278.
  • Griggs, B.R., R.J. Norman, C.E. Wilson, Jr., and N.A. Slaton. 2005. Ammonia volatilization and grain yield by delayed flood rice utilizing conventional and conservation tillage systems. p.282-289. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Norman, R.J., C.E. Wilson, Jr., and N.A. Slaton. 2005. A comparison of Helena Chemicals two CoRoN liquid N sources to urea for use at midseason in drill-seeded, delayed-flood rice. p.290-294. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Frizzell, M.W. Duren, D.L. Boothe, K.A.K. Moldenhauer, and J.W. Gibbons. 2005. Grain yield response of eight new rice cultivars to nitrogen fertilization. p.295-304. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2004. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 529.
  • Brye, K.R., N.A. Slaton, and R.J. Norman. 2005. Penetration resistance as affected by shallow-cut land leveling and cropping. Soil & Tillage Research 81 (2005) 1-13.
  • Slaton, N.A., Norman, R.J., and C.E. Wilson, Jr. 2005. Effect of zinc source and application time on zinc uptake and grain yield of flood-irrigated rice. Agron. J. 97:272-278.
  • Slaton, N.A., E.E. Gbur, C.E. Wilson, Jr., and R.J. Norman. 2005. Rice Response to granular zinc sources varying in Water-soluble zinc. Soil Sci. Soc. Am. J. 69:443-452.


Progress 01/01/04 to 12/30/04

Outputs
The cultivar x nitrogen (N) fertilizer interaction study determines the proper N fertilizer rates for the new cultivars across the array of soil and climatic conditions that exist in the Arkansas rice-growing region. The rice cultivars studied in 2004 were Banks, Cheniere, Cybonnet, Medark, RiceTec CLXL-8, RiceTec XP-710, RiceTec XP-716, RiceTec XP723, and the experimental variety from the Arkansas breeding program, RU0101093. Banks, Cheniere, Cybonnet, and RU0101093 produced maximum grain yields when 135 to 150 lb N/A was applied to silt loam soils in a split application of 90-105 lb N/A at preflood followed by 45 lb N/A at midseason. Medark produced maximum grain yields when 120 to 135 lb N/A was applied to silt loam soils in a split application of 75-90 lb N/A at preflood followed by 45 lb N/A at midseason. The RiceTec hybrids, CLXL-8 and XP-710, produced maximum grain yields when 150 to 180 lb N/A was applied to silt loam soils in a split application of 120 lb N/A at preflood followed by 30 to 60 Lb N/A at full boot. The RiceTec hybrids, XP-716 and XP-723, produced maximum grain yields when 120 to 150 lb N/A was applied to silt loam soils in a split application of 90 lb N/A at preflood followed by 30 to 60 Lb N/A at full boot. The boot application to the RiceTec hybrids very seldom results in a grain yield increase, however, it does help minimize lodging. In general, when any of the above cultivars were grown on clay soils an additional 30 lb N/A was required at preflood to maximize grain yields. Every year there are many commercial fields that are not able to apply the preflood urea-N fertilizer to a dry soil because of frequent spring precipitation. Application of the preflood urea-N fertilizer on to wet or muddy soil is discouraged due to: i) an increase in ammonia volatilization loss from saturated soil prior to flooding. Questions have been asked by producers and extension agents if Agrotain treated urea or ammonium sulfate might help N fertilizer uptake efficiency by rice when the preflood N fertilizer application has to made to a muddy, saturated soil. Due to these questions a study was initiated to determine if Agrotain and/or ammonium sulfate are better than urea when applied to a muddy soil. Grain yields reached a maximum of 195 bu/A when urea was applied onto dry soil 1 day prior to establishment of the permanent flood. When urea application was made to dry soil at 3 days prior to flooding there was no significant grain yield decrease. When urea was applied to a muddy soil at 3 days prior to flooding a grain yield of only 149 bu/A was measured. This indicated that ammonia volatilization was proceeding at a rapid rate for the 3 days prior to flooding on this muddy soil. When ammonium sulfate and Agrotain where applied to the muddy soil 3 days prior to flooding, grain yields decreased to about 170 bu/A. This is about 25 bu/A below what was measured when urea, ammonium sulfate and Agrotain were applied to a dry soil at 1 day prior to flooding. Although this is substantial grain yield decrease, it is still much better than when urea was the N source.

Impacts
The variety by nitrogen study determines the proper nitrogen fertilizer rates for all the new rice varieties prior to their commercial release. This ensures that new rice varieties obtain their full yield potential when grown commercially. The nitrogen source, soil moisture and time of application study indicated that if a rice producer has to apply the large, preflood N ferilizer rate to a muddy soil it would be cost effective and environmentally sound to use ammonium sulfate or Agrotain. Since Agrotain is much cheaper than ammonium sulfate, Agrotain would be the N source recommended in Arkansas rice production.

Publications

  • Wilson, Jr., C.E., R.J. Norman, N.A. Slaton, M.W. Duren, D.L. Boothe, K.A.K. Moldenhauer, and J.W. Gibbons,. 2004. Grain yield performance of rice cultivars grown in northeast arkansas as influenced by seeding date. p.327-332. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2003. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 517.
  • Slaton, N.A., K.R. Brye, M.B. Daniels, T.C. Daniel, R.J. Norman, and D.M. Miller. 2004. Nutrient input and removal trends for agricultural soils in nine geographical regions of Arkansas. J. Environ. Qual. 33:1606-1615.
  • Brye, K.R., P. Chen, L.C. Purcell, M. Mozaffari and R.J. Norman. 2004. First-year soybean growth aan production as affected by soil properties following land leveling. Plant Soil 263:323-334.
  • Brye, K.R., N.A. Slaton, R.J. Norman, and M.C. Savin,. 2004. Short-term effects of poultry litter form and rate on soil bulk density and water content. Commun. Soil Plant Anal. 35:2311-2325.
  • Brye, K.R., N.A. Slaton, M. Mozaffari, M.C. Savin, R.J. Norman, and D.M. Miller. 2004. Short-term effects of land leveling on soil chemical properties and their relationships with biological properties. Soil Sci. Soc. Am. J. 68:924-934.
  • Rutger, J.N., K.A.K. Moldenhauer, K.A. Gravois, F.N. Lee, R.J. Norman, A.M. McClung, and R.J. Bryant. 2004. Registration of five induced semidwarf mutants of rice. Crop Sci. 44:1496-1497.
  • Slaton, N.A., E.E. Gbur, R.D. Cartwright, R.E. DeLong, R.J. Norman and K.R. Brye. 2004. Grain yield and kernel smut of rice as affected by preflood and midseason nitrogen fertilization in Arkansas. Agron. J. 96:91-99.
  • Norman, R.J., J.-F. Meullenet, K.A. K. Moldenhauer (eds.). 2004. B.R. Wells rice research studies 2003. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 517. pp 444.
  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Boothe, B.R. Griggs, and J.T. Bushong. 2004. Effect of agrotain, ammonium sulfate, and urea on ammonia volatilization loss and rice grain yield when applied at different times prior to flooding. p.279-285. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2003. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 517.
  • Norman, R.J., C.E. Wilson, Jr., D.L. Boothe, N.A. Slaton, K.A.K. Moldenhauer, J.W. Gibbons, D.L. Frizzell, M.W. Duren and S.D. Clark. 2004. Grain yield response of new rice cultivars to nitrogen fertilization. p.268-378. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2003. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 517.
  • Wilson, Jr., C.E., R.J. Norman, N.A. Slaton, D.L. Boothe, K.A.K. Moldenhauer, and J.W. Gibbons. 2004. Influence of seeding date on the degree-day 50 thermal unit accumulations and grain yields of new rice cultivars. p.317-326. In R.J. Norman et al.(eds.), B.R. Wells rice research studies 2003. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 517.


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

Outputs
The variety x nitrogen (N) fertilizer interaction study determines the proper N fertilizer rates for the new rice cultivars across the array of soil and climatic conditions that exist in the Arkansas rice growing region. Banks, Cheniere, Clearfield CL161, Medark, RiceTec XL8, and RiceTec Clearfield XL8 were the new rice cultivars studied in 2003. The experimental varieties studied were RU0101093 from Arkansas, RU9803181 and RU9903092 from Texas, and XP710 and XP712 from RiceTec. The N fertilizer recommendations for the new cultivars when grown on silt loam soils will be: i) 135 lb N/acre applied in a split application of 90 lb N/acre at preflood and 45 lb N/acre at midseason for Clearfield CL161 and Medark; ii) 150 lb N/acre applied in a split application of 105 lb N/acre at preflood and 45 lb N/acre at midseason for Banks and Cheniere; and iii) 120 lb N/acre applied in a split application of 90 lb N/acre at preflood and 30 lb N/acre at midseason to late boot for the RiceTec hybrids XL8 and Clearfield XL8. All of the rice cultivars studied usually required more N fertilizer to maximize grain yields on the clay soils compared to the silt loam soils and thus, the preflood N rates for all rice cultivars should be increased by 30 lb N/acre when grown on clay soils. A study was conducted to evaluate the ammonia volatilization loss and impact on rice yield when urea, Agrotain and ammonium sulfate were applied preflood and a flood established at 1, 5 and 10 days after N application. Fifteen to 20% of the urea-N, only 3 to 5% of the ammonium sulfate-N, and only 2 to 3% of the Agrotain-N was lost via ammonia volatilization within 5 days of application. By 10 days after application and time of flooding, the losses from ammonia volatilization where leveling off at about 17 to 25% for the urea, 4 to 10% for the Agrotain and 3 to 5% for the ammonium sulfate. When flooding was delayed for 5 and 10 days after N fertilizer application, Agrotain and ammonium sulfate produced the highest grain yields which were quite similar and were significantly higher than those produced with urea. Rice grain yields did not decline or declined only slightly as N fertilizer application time before flooding increased to 5 and 10 days when Agrotain or ammonium sulfate were applied. If more than 2 to 3 days is required to move the flood water completely across a rice field after the preflood N fertilizer has been applied than an N fertilizer such as Agrotain or ammonium sulfate should be used. A study was conducted to assess the mechanism by which annual bluegrass was affecting N uptake efficiency in winter wheat. There was very little influence of annual bluegrass on ammonia volatilization losses of urea. Wheat that was infested with bluegrass accumulated significantly less fertilizer N than wheat that was bluegrass free. Grain yields of wheat were reduced significantly by the presence of annual bluegrass. Thus, annual bluegrass was influencing N uptake efficiency in winter wheat by competing with the wheat for fertilizer N, not by aggravating NH3 volatilization losses.

Impacts
The variety by nitrogen study determines the proper nitrogen fertilizer rates for all the new rice varieties prior to their commercial release. This ensures that new rice varieties obtain their full yield potential when grown commercially. The nitrogen source and application timing study has found that ammonia volatilization losses are greater than previously though when urea is applied to delayed flood rice and a flood is not established in a few days following urea application. If a rice farmer can not flood a particular rice field in less than 3 days after application of the urea fertilizer then a nitrogen fertilizer less prone to ammonia volatilization loss such as Agrotain or ammonium sulfate should be used. The presence of annual bluegrass in winter wheat reduces wheat yeilds by competing with the wheat for N, not by aggravating ammonia volatilization losses.

Publications

  • Norman, R.J., and J.-F. Meullenet (eds.). 2003. B.R. Wells rice research studies 2002. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 504.
  • Slaton, N.A., S.D. Linscombe, R.J. Norman, and E.E. Gbur, Jr. 2003. Seeding Date Effect on Rice Yields in Arkansas and Louisiana. Agron J. 95: 218-223.
  • Brye, K.R., N.A. Slaton, M.C. Savin, R.J. Norman, and D.M. Miller. 2003. Short-term effects of land leveling on soil physical properties and microbial biomass. Soil Sci. Soc. Am. J. 67:1405-1417.
  • Slaton, N.A., R.D. Cartwright, J. Meng, E.E. Gbur, and R.J. Norman. 2003. Sheath blight severity and rice yield as affected by nitrogen fertilizer rate, application method, and fungicide. Agron. J. 95:1489-1496.
  • Gibbons, J.W., K.A.K. Moldenhauer, F.N. Lee, J.L. Bernhardt, M.M. Anders, N.A. Slaton, R.J. Norman, J.N. Rutger, J. M. Bulloch, K. Taylor, M.M. Blocker, and A.C. Tolbert. 2003. Development of semi-dwarf long- and medium-grain cultivars. p.47-52. B.R. Wells rice research studies 2002. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 504.
  • Moldenhauer, K.A.K., J.W. Gibbons, F.N. Lee, R.J. Norman, J.L. Bernhardt, M.M. Anders, C.E. Wilson, Jr., J.N. Rutger, T.Tai, R. Bryant, M.M. Blocker, and A.C. Tolbert. 2003. Breeding and evaluation for improved rice varieties - The Arkansas rice breeding and development program. p.93-98. B.R. Wells rice research studies 2002. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 504.
  • Mattice, J.D., B.W. Skulman, and R.J. Norman. 2003. Environmental implications of pesticides in rice production. p. 135-141., B.R. Wells rice research studies 2002. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 504.
  • Norman, R.J., C.E. Wilson, Jr., D.L. Boothe, N.A. Slaton, K.A.K. Moldenhauer, and J.W. Gibbons. 2003. Influence of seeding date on the degree-day 50 thermal unit accumulations and grain yields of new rice cultivars. p.280-287. B.R. Wells Rice Research Studies 2002. Ark. Agric. Exp. Stn. Res. Ser. 504.
  • Norman, R.J., C.E. Wilson, Jr., D.L. Boothe, and N.A. Slaton. 2003. Grain yield performance of rice cultivars grown in northeast arkansas as influenced by seeding date. p.288-291. B.R. Wells Rice Research Studies 2002. Ark. Agric. Exp. Stn. Res. Ser. 504.
  • Norman, R.J., C.E. Wilson, Jr., D.L. Boothe, and N.A. Slaton. 2003. Evaluation of Agro-cultures high nrg-n and xn as preemergence and preflood nitrogen fertilizers in drill-seeded, delayed-flood rice. p.292-297. B.R. Wells Rice Research Studies 2002. Ark. Agric. Exp. Stn. Res. Ser. 504.
  • Norman, R.J., C.E. Wilson, Jr., D.L. Boothe, N.A. Slaton, K.A.K. Moldenhauer, J.W. Gibbons, D.L. Frizzell, and S.D. Clark. 2003. Grain yield response of new rice cultivars to nitrogen fertilization. p.298-308. B.R. Wells Rice Research Studies 2002. Ark. Agric. Exp. Stn. Res. Ser. 504.


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

Outputs
The 2002 DD50 study was conducted over four seeding dates (i.e., 3/29, 4/25, 5/16 and 6/12/2002) and evaluated fifteen rice cultivars and experimental varieties. The days and DD50 thermal units required to reach one-half inch internode elongation (panicle differentiation) decreased as seeding date was delayed for all of the cultivars in the study. In general, the days and DD50 thermal units required for the rice cultivars to reach 50 percent heading decreased as seeding date was delayed from 3/29 to 5/16 and then stayed relatively constant as seeding date was further delayed until 6/12. Most rice cultivars/experimental varieties produced their highest yield when seeded on either 3/29 and/or 4/25 and then decreased as seeding was delayed until 5/16 and 6/12. In general, milling yields for each of the rice cultivars and experimental varieties were similar across the first three seeding dates. The best millers were Francis, CL161 and RU0001151, and the worst millers were the RiceTec hybrids, RU0101093 and Ahrent. The cultivar x nitrogen (N) fertilizer interaction study determines the proper N fertilizer rates for the new cultivars across the array of soil and climatic conditions which exist in the Arkansas rice growing region. Ahrent produced maximum grain yields when around 150 lb N/A was applied to silt loams and 180 lb N/A was applied to clay soils. Francis produced maximum grain yields when around 150 to 180 lb N/A was applied to silt loams and 210 lb N/A was applied to clay soils. The three Clearfield varieties performed the best when 120 to 150 lb N/A was applied to the silt loams and when 150 to 180 lb lb N/A was applied to the clay soils. The RiceTec hybrids did well when only 90 lb N/A was applied in a single preflood application, but they also did well when 90 lb N/A was applied preflood followed by 30 or 60 lb N/A applied at midseason or at booting. Many farmers cannot get the flood water across their fields within 3 to 5 days following urea-N fertilizer application as recommended. Some take 7 to 10 days and others as much as 2 weeks. Urea is the primary N fertilizer used in the delayed flood rice cultural, because of its high N analysis and low cost relative to other N sources, but it is prone to ammonia volatilization losses if not soil incorporated within a < 5 days of surface application, especially if the soil pH is >7. In a situation where a farmer cannot flood in < 5 days it has been questioned if ammonium sulfate or Agrotain (i.e., urea with a urease inhibitor) should be used in place of urea. Results in 2002 determined that ammonium sulfate as well as Agrotain were superior to urea if it required 5 to 10 days to establish the flood. Greater than 20 percent of the urea was lost via ammonia volatilization in 5 days, were as only 5 percent or less of the ammonium sulfate and Agrotain were lost within 5 days following application. Ammonium sulfate and Agrotain applied 5 to 10 days prior to flooding produced grain yields of rice similar to urea applied the day before flooding. Rice grain yields dropped drastically when urea was applied 5 to 10 days prior to flooding.

Impacts
The data from the DD-50 study will be used to update the DD-50 Computer Program and make predictions more accurate on the timing of 28 management decisions. The nitrogen fertilizer application timing/flooding study will indicate to farmers how importqant it is to flood a field in a timely manner. In addition, the study will help farmers that can not flood a field timely with alternative nitrogen fertilizers to urea.

Publications

  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Boothe, K.A.K. Moldenhauer, J.W. Gibbons, D.L. Frizzell, and S.D. Clark. 2002. Grain yield response of new rice cultivars to nitrogen fertilization. p.187-201. In R.J. Norman and J.F. Meullenet (eds.) B.R. Wells Rice Research Studies 2001. Ark. Agric. Exp. Stn. Res. Ser. 495.
  • Boothe, D.L., R.J. Norman, N.A. Slaton, C.E. Wilson, Jr., P.K. Bollich, S.D. Clark. 2002. Comparison of nitrogen fertilizer, application timing, and rate on rice yield. In Rice Technical Working Group Abstracts. [CD-ROM]. 29th Meeting, University of Arkansas, Little Rock, AR.
  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, P.K. Bollich, and D.L. Boothe. 2002. An evaluation of some old and new nitrogen fertilizers for delayed flood rice. In Rice Technical Working Group Abstracts. [CD-ROM]. 29th Meeting, University of Arkansas, Little Rock, AR.
  • Tucker, C.L., N.A. Slaton, R.J. Norman, C.E. Wilson, Jr., S. Ntamatungiro, and D.L. Boothe. 2002. Preflood and midseason nitrogen rate effect on nitrogen concentration of rice flood water. In Agronomy Abstracts. [CD-ROM]. 94nd Annual Mtg. Indianapolis, IN. Nov. 10-14, 2002. ASA, Madison, WI. (Poster Presentation)
  • Norman, R.J., C.E. Wilson, Jr., and N.A. Slaton. 2002. Soil fertilization and rice nutrition in mechanized rice culture. pp. 331-411. In C.W. Smith and R.H. Dilday (eds.). Rice: Origin, History, Technology, and Production. Wiley Sciences.
  • Norman, R.J., C.E. Wilson, Jr., N.A. Slaton, D.L. Boothe, K.A.K. Moldenhauer, and J.W. Gibbons. 2002. Influence of seeding date on the degree-day 50 thermal unit accumulations and grain yields of new rice cultivars. p.179-186. In R.J. Norman and J.F. Meullenet (eds.) B.R. Wells Rice Research Studies 2001. Ark. Agric. Exp. Stn. Res. Ser. 495.


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

Outputs
The DD50 study was conducted over four seeding dates and evaluated 14 rice cultivars and experimental varieties. The DD50 thermal units required for each of the rice cultivars to reach panicle differentiation increased as seeding date was delayed from 4/4/01 to 4/26/01 and then decreased as seeding date was further delayed to 6/11/01. In general, the DD50 thermal units required for the rice cultivars to reach heading increased as seeding date was delayed from 4/4/01 to 4/26/01, then increased slightly as seeding was delayed from 4/26/01 to 5/17/01, and finally increased slightly as seeding was further delayed until 6/11/01. Most rice cultivars/experimental varieties produced their highest yield when seeded on either 4/4/01 or 4/26/01 and then decreased as seeding was delayed until June. Milling yields increased for most cultivars as seeding date was delayed from 4/4/01 to 4/26/01 and then had a tendency to decrease as seeding date was delayed until 5/17/01. The cultivar x nitrogen fertilizer interaction study determines the proper N fertilizer rates for the new cultivars across the array of soil and climatic conditions which exist in the Arkansas rice growing region. The rice cultivars studied in 2001 were Ahrent, Clearfield CFX18, Clearfield 121, Clearfield 141, Earl, Francis, RiceTec XP 1003, RiceTec XP 1015 and Saber. All cultivars studied responded better or achieved similar yields with less N fertilizer when it was applied in a single preflood application compared to split applications, except the RiceTec cultivars. Studies on the influence of N fertilizer on the rice diseases sheath blight and kernel smut have shown that the N fertilizer applied at preflood which has such a profound impact on rice grain yields also has a substantial influence on the rice diseases sheath blight and kernel smut. When the preflood N fertilizer rate that maximizes grain yield is exceeded, the degree and severity of the rice diseases sheath blight and kernel smut increase significantly. The N fertilizer applied at midseason did not have much influence on these two diseases, but it also did not have much influence on rice grain yields either. Many farmers cannot get the flood water across their fields within 3 to 5 days following urea-N fertilizer application as recommended. In a situation where a farmer cannot flood in less than 7 days and the soil pH greater than 7 it has been questioned if ammonium sulfate should be used in place of urea and if the N fertilizer rate should be increased. A two year study on a high pH silt loam (pH 7.5) determined that ammonium sulfate is superior to urea if a field has a high pH soil and it requires 7 to 14 days to establish a flood. The best rice grain yields were found for the following treatments: i) field flooded the same day urea or ammonium sulfate was applied; ii) the field was flooded in 7 to 10 days and the urea fertilizer rate was increased by 34 to 67 kg N/ha or ammonium sulfate was used in place of urea and the N rate was the same or increased by no more than 34 kg N/ha; and iii) the field was flooded in 14 days and ammonium sulfate was used in place of urea and the N rate was increased by 34 to 67 kg N/ha.

Impacts
Data from the DD50 research is placed into the DD-50 computer program to predict for the farmers the dates to perform 28 management practices on rice. The nitrogen fertilizer research provides the farmers with the proper nitrogen fertilizer rate for each cultivar and the ammonium sulfate research gives the farmers that can not flood rice timely an alternative nitrogen fertilizer to use.

Publications

  • Slaton, N.A., Norman, R.J., and Gilmour, J.T. 2001. Oxidation rates of commercial elemental sulfur products applied to an alkaline silt loam. Soil Sci. Soc. Am. J. 65: 239-243.
  • Slaton, N.A., Wilson, Jr., C.E., Ntamatungiro, S., Norman, R.J., and Boothe, D.L. 2001. Evaluation of Zinc Seed Treatments for Rice. Agronomy J. 93: 152-157.
  • Norman, R.J., Slaton, N.A., Moldenhauer, K.A.K., Wilson, Jr., C.E., and Boothe, D.L. 2001. Influence of seeding date on the degree-day 50 thermal-unit accumulations and grain yields of new rice cultivars. p. 189-196. In Norman and Meullenet (eds.), B.R. Wells rice research studies 2000. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 485.
  • Clark, S.D., Norman, R.J., Slaton, N.A., and Wilson, Jr., C.E. 2001. Influence of nitrogen fertilizer source, application timing, and rate on grain yields of rice. p.352-357. In Norman and Meullenet (eds.), B.R. Wells rice research studies 2000. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 485.


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

Outputs
The DD50 study determined the degree-day thermal unit accumulations required to reach critical growth stages for all of the commercial rice cultivars released over the last three years in the southern rice belt. This data has been used by the extension services in the south to develop management reports that assist rice farmers in precisely timing over 25 management decisions including herbicides, fertilizers, insecticides, fungicides, draining and flooding, and harvesting. The rice cultivars studied over the last three years have usually responded better when the N fertilizer was applied in a single preflood application compared to split applications. In addition, the cultivars that had marginal milling quality, had improved milling quality when the N fertilizer was applied in a single preflood application compared to split applications. Rice has been shown to require about 30 lbs N/A more on clay soils compared to on silt loam soils to produce maximum yields and the recommendation was changed this year to apply and extra 30 lbs N/A when rice is grown on a clay soil. Wider windows of application for the preflood and midseason N applications have been defined to give rice producers more flexibility in N application. In addition, the N applied at midseason can be applied in a single application instead of two without any effect on grain yield and thus, save an aerial application cost.

Impacts
Data from the DD50 research is placed into the DD-50 computer program to predict for the farmers the dates to perform 28 management practices on rice and the nitrogen research has given the farmer flexibility in applying N fertilizer to rice.

Publications

  • Grigg, B.C., Beyrouty, C.A., Norman, R.J., Gbur, E.E., Hanson, M.G., and Wells, B.R. 2000. Rice response to changes in floodgate and nitrogen timing in the southern USA. Field Crops Res. 66: 73-79.
  • Liscano, J.F., Wilson, C.E., Jr., Norman, R.J., and Slaton, N.A. 2000. Zinc availability to rice from seven granular fertilizers. Ark. Agric. Exp. Sta. Res. Bull. 963.
  • Norman, R.J., Wilson, C.E., Jr., Slaton, N.A., Moldenhauer, K.A.K., Boothe, D.L., Clark, S.D., and Cox, A.D. 2000. Grain yield response of new rice cultivars to nitrogen fertilization. p. 267-277. In Norman and Beyrouty (eds.), B.R. Wells rice research studies 1999. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 476.
  • Norman, R.J., Slaton, N.A., Moldenhauer, K.A.K., and Boothe. D.L. 2000. Influence of seeding date on the degree day 50 thermal unit accumulations and grain yield of new rice cultivars. p. 261-266. In Norman and Beyrouty (eds.), B.R. Wells rice research studies 1999. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 476.
  • Norman, R.J., Slaton, N.A., Cox, A.D., and Boothe, D.L. 2000. Grain yield performance of rice cultivars grown in northeast Arkansas as influenced by seeding date. p. 256-260. In Norman and Beyrouty (eds.), B.R. Wells rice research studies 1999. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 476.
  • Pulley, H.J., Beyrouty, C.A., Norman, R.J., and Slaton, N.A. 2000. Influence of nitrogen fertilization timing and rate on rice growth. p.278-282. In Norman and Beyrouty (eds.), B.R. Wells rice research studies 1999. Univ. of Ark., Agr. Exp. Stn. Res. Ser. 476.