Source: UNIVERSITY OF FLORIDA submitted to
EFFECTIVENESS OF SILVICULTURE BEST MANAGEMENT PRACTICES FOR FOREST FERTILIZATION IN PINE STRAW PRODUCTION TO PROTECT WATER QUALITY IN FLORIDA
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
REVISED
Funding Source
Reporting Frequency
Annual
Accession No.
0222955
Grant No.
(N/A)
Project No.
FLA-NFC-005053
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jul 1, 2010
Project End Date
Jun 30, 2015
Grant Year
(N/A)
Project Director
Minogue, P.
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
North Florida Research and Education Center, Quincy
Non Technical Summary
In 2009 two large-scale, replicated studies were established in mid-rotation slash pine (Pinus elliottii L.) plantations in North Florida at locations with soils having contrasting leaching potential to evaluate and assess the effectiveness of current forest fertilization BMPs in reducing nonpoint source pollution. The effects of straw removal on soil physical and chemical properties, leaching potential and nutrient budgets are being examined in a long term study, with existing and projected funding until June 2014. A secondary integrated objective is to estimate the magnitude and geographic extent of pine straw production, the amount, type, and rates of fertilizer applied in this practice, and to provide training and education programs for practitioners of forest fertilization.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110101025%
1120210205025%
1230611107025%
1330680106025%
Goals / Objectives
1. Determine the environmental fate of N and P following annual fertilization for four years using a wide range of applied (DAP) through large-scale, replicated research at each of two locations with contrasting leaching and sorption potential to evaluate and assess the effectiveness of current forest fertilization BMP's to reduce nonpoint source pollution, as is consistent with EPA's "iterative process" for long-term BMP development. 2. Compare leaching potential, soil physical properties, and nutrient budgets for fertilization in raked and non-raked stands to refine forest fertilization BMP's and provide new information regarding the efficient use of fertilizers in pine straw production in the Coastal Plain. 3. Determine tree growth and pine needle yield responses following a wide range of N+P fertilization rates to determine cost-effective fertilization practices for sites representing extremes in potential for soil sorption and leaching of applied nutrients. 4. Develop models to explain nutrient leaching as a function of soil physical and chemical properties, soil and atmospheric hydrology, soil and atmospheric temperature, and forest stand level nutrient dynamics (nutrient cycling), through a balance-sheet approach in raked versus un-raked forest stands. 5. Estimate the extent, location and magnitude of pine straw production as well as the amount, rates and timing of fertilization for this practice within the region. 6. Provide pertinent information in support of training and education programs for fertilization practices associated with pine straw production.
Project Methods
Long-term, replicated research plots were established in 2008-2009 at two locations with contrasting nutrient leaching and soil sorption potential, within the region in Florida where pine straw raking is common place. The Calhoun County site is an ultisol having sandy loam surface soils and an underlying clay B and C horizon; thus representing a site where soil sorption is high, internal drainage is limited and, therefore, leaching potential is low. The potential for groundwater contamination is also low since this site is within the confined aquifer (protected by overlying clay soils). The Suwannee County site is an entisol characterized by excessively drained sandy soils typical of the Florida Sand Ridge; representing a worst case scenario with respect to leaching potential. This area also has a high risk for groundwater contamination as it is within an area of unconfined aquifer, and the depth to groundwater is only 60-70 feet. Experimental Design: At each of the two study locations, twenty four 1/2-acre plots were established in twelve year old slash pine (Pinus elliottii) plantations to examine 8 different treatment combinations using a completely randomized design with 3 replications of treatments. The experiment is designed as a 4 x 2 factorial, with four levels of annual (February) fertilization treatment (0, 128, 256, 641 lb DAP per ac) and two levels of raking treatment (annual rake and no-rake). This design facilitates statistical tests on the interaction of fertilization and pine straw raking. The unfertilized plot for raked and un-raked treatments serves as an experimental control with respect to fertilization. Sampling: To ensure adequate buffers, all measurements and sampling (with the exception of monitoring wells) are made within a 0.20 acre "measurement plot" centered in the 0.5 acre treatment plot. Groundwater samples: To assess potential changes in groundwater quality, one well is installed in the fertilized study area and comparisons are made to one or more distant (~1,000 ft) control wells. Groundwater samples will be taken prior to fertilization and monthly throughout the project period and analyzed for NOx, TKN, NH4, and TP. Nutrient Budgets: periodic samples of nutrient content at various depths in the soil profile are analysed for NOx, TKN, NH4, TP, K, Ca, Mg, and OM. Nutrients in pine folage, litterfall and in harvested pine straw are measured periodically to construct nutrient budgets following various rates of DAP fertilization, with and without pine straw raking. Extension Outreach: To provide forest landowners and pine straw producers with pertinent information concerning cost-effective and environmentally sound fertilization practices for pine straw production we will conduct grower meetings, site tours, and produce technology transfer publications, such as web based "edis" materials. Detailed methods are available from the project manager.

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: A silvicultural fertilization BMP effectiveness monitoring project is being conducted at two study locations in north Florida having contrasting leaching potential to observe the environmental fate of nitrogen (N) and phosphorus (P) following application of diammonium phosphate (DAP) at various amounts, in the presence or absence of commercial annual pine straw raking. In separate studies at the two locations, a factorial design with three replications is examining the effects of two sequential February-March DAP fertilizations at four levels (providing 0/0, 22/24, 67/72, or 112/120 lb/acre N/P annually), annual raking at two levels (with, without), and the interaction of these factors on a host of soil and plant aspects of nutrient status and tree response. Groundwater monitoring wells are used to measure NOx-N, NH3-N, TKN, and TP concentrations periodically to assess leaching in the fertilized area as compared to a distant control well. An automated monitoring station within the stand is taking 15-minute readings of through-fall (precipitation under the canopy), soil temperatures and moisture contents at 6, 12, 24, 36, 48, and 60 inch depths. An automated weather monitoring station is taking 15-minute readings of precipitation, wind speed, air temperature, relative humidity, and photosynthetic active radiation (PAR) measurements at each study site to support nutrient fate modeling. In March 2013 all monitoring will be completed, which will be three years after the last fertilization event. PARTICIPANTS: (1) Individuals: PI Patrick Minogue, PD Masato Miwa, Co-PD Anna Osiecka, Colaborators - Cheryl Mackowiak, Jeffrey Vowell, Roy Lima; (2) Partner organizations: Florida Department of Environmental Protection, Florida Forest Service, Neil Land and Timber, Burch Family Farms; (3) Training: Daniela Chevasco Ph.D. candidate, School of Natural Resources and Environment, The University of Florida. TARGET AUDIENCES: Pine straw producers (owners of forest land) and State of Florida water quality regulators (BMPs) are the primary target audiences for this research. The research being conducted will also build upon scientific knowledge pertaining to the fate of applied nutrients, effects of pine straw removal on nutrient cycling within pine stands, and quantification of economic benefits and thresholds for fertilization in pine straw production. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Results from this study are supporting refinement of the Florida Silviculture BMPs to refine fertilization recommendations for pine straw production, to better understand the environmental fate of applied N and P, and to protect water quality in Florida and the region. DAP is the most widely used fertilizer in forestry, largely because it conveniently provides both N and P. This study showed that two consecutive annual applications of 128 lb DAP/ac (22 lb/ac N) increased surface soil NOx-N concentration without elevating NOx-N concentration of deeper soils (48-72 in depth), while two consecutive annual applications of 384 lb DAP/ac (67 lb/ac N) slightly increased deeper soil NOx-N concentration, and two consecutive annual applications of 641lb DAP/ac (112 lb/ac N) significantly increased deeper soil NOx-N concentration, particularly after the second annual application. Since NOx-N is a relatively stable and mobile nutrient, any fertilizer rate that significantly increases NOx-N concentration below the primary rooting zone (generally the upper 48 inches) should be avoided to protect groundwater. Nitrate leaching was more pronounced following the second fertilization in both studies. Rather than stipulating limits for a three-year period, BMPs should specify maximum annual amounts to apply, particularly since fertilizer applications in conventional silviculture are typically done every five to ten years. Annual fertilization guidelines would accommodate pine straw production, where annual fertilizations are common. This research suggests that two sequential annual applications of 112 lb N could be a threat to water quality in certain soils. While this level of fertilization is not practiced, it would be permissible under current BMPs. Since DAP fertilizer application rates were determined to provide various N amounts up to the near maximum BMP limit of 250 lb/ac N in three years, two applications of the high DAP rate also provided 120 lb/ac elemental P, which exceeded the BMP limit of 80 lb/ac elemental P in a three year period. Fertilization did not result in movement of P below the primary rooting zone or to groundwater in either study. Phosphorus is not a mobile nutrient, but P fertilization may increase soluble organic phosphorus (SOP), which is more prone to leach. Continued monitoring for several years would be needed to ascertain the fate of applied P in this study.

Publications

  • Minogue, P.J., D.K. Lauer, M. Miwa, and A. Osiecka. 2012. Preliminary results: Effectiveness of silviculture best management practices for forest fertilization in pine straw production to protect water quality in Florida - Analyses of monitoring well nutrient concentrations to three years after fertilization. Institute of Food and Agricultural Sciences, North Florida Research and Education Center, Quincy, FL, Research Report 2012-02. 15 p.
  • Minogue, P.J., M. Miwa, D.K. Lauer, and A. Osiecka. 2011. Preliminary results: Effectiveness of silviculture best management practices for forest fertilization in pine straw production to protect water quality in Florida. Institute of Food and Agricultural Sciences, North Florida Research and Education Center, Quincy, FL, Research Report 2011-02. 76 p.


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

Outputs
OUTPUTS: Research: A silvicultural fertilization BMP effectiveness monitoring project is being conducted at two study locations having contrasting leaching potential to observe the environmental fate of N and P applied at various amounts relative to BMP guidelines. Two sequential annual diammonium phosphate (DAP) fertilizations, providing 22/24, 67/72, or 112/120 lb/ac N/P, were monitored in stands with and without pine straw raking and compared to unfertilized controls. Two fertilizations using the highest DAP rate examined provided the near BMP maximum amount of N for a three year period and also provided 300% of the three year P maximum. Monitoring occurred for two years following the first fertilization and for one year after the second fertilization, which has provided short term results for a long term study. Periodic monitoring included N and P concentrations in surficial groundwater, soil nutrient concentrations at various depths, foliar nutrient concentrations, amounts and nutrient concentrations of pine straw litter, and amounts and nutrient concentrations for harvested pine straw. Tree growth responses and disease incidence were also measured periodically. Soil physical and chemical properties were assessed initially and after three years. Continuous rainfall and other weather monitoring and soil moisture and temperature monitoring at various depths was done to support modeling of applied nutrient fate. Extension: We conducted 13 workshops regarding forest fertilization in pine straw production with 664 growers attending. Post workshop surveys (7) indicated 100% of respondents learned something new, 53% changed fertilization practices as the result of something they learned. The two most common changes were the use of lower rates and more frequent applications. Multimedia Web-based Educational Materials: (1) Minogue, P.J. 2010. Financial returns for integrated pine straw and timber production. University of Florida, Institute of Food and Agricultural Science. http://nfrec.ifas.ufl.edu/contact/PatMinogue.shtml; (2) Minogue, P.J. 2010. Overview of pine straw production in north Florida. University of Florida, Institute of Food and Agricultural Science. http://nfrec.ifas.ufl.edu/contact/PatMinogue.shtml PARTICIPANTS: (1) Individuals: PI Patrick Minogue, PD Masato Miwa, Co-PD Anna Osiecka, Colaborators - Cheryl Mackowiak, Jeffrey Vowell, Roy Lima; (2) Partner organizations: Florida Dept. Environmental Protection, Florida Forest Service, Neil Land and Timber, Burch Family Farms; (3) Training: Daniela Chevasco, Ph.D. student, School of Natural Resources and Environment, The University of Florida. TARGET AUDIENCES: Pine straw producers (owners of forest land) are the primary target audience for this Research and Extension Program. These include forest industry, the Florida Forest Service, and non-industrial private forest landowners (NIPFL). The research being conducted will also build upon the scientific knowledge regarding fate of applied nutrients, effects of pine straw removal on nutrient cycling, and quantification of economic benefits and thresholds for fertilization in pine straw production. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Results from this study are supporting refinement of Florida Silviculture BMPs to protect groundwater quality. Nitrogen fertilization responses: This study showed that two consecutive annual applications of 128 lb DAP/ac (22 lb/ac N) increased surface soil NOx-N concentration without elevating NOx-N concentration of deeper soils (48-72 in depth), while two consecutive annual applications of 384 lb DAP/ac (67 lb/ac N) slightly increased deeper soil NOx-N concentration, and two consecutive annual applications of 641 lb DAP/ac (112 lb/ac N) significantly increased deeper soil NOx-N concentration, particularly after the second annual application. Since NOx-N is a relatively stable and mobile nutrient, any fertilizer rate that significantly increases NOx-N concentration below the primary rooting zone (generally the upper 48 inches) should be avoided to minimize groundwater N contamination. Nitrate leaching was more pronounced following the second fertilization in both studies. Rather than stipulating limits for a three-year period, BMPs should specify maximum annual amounts to apply, particularly since fertilizer applications in conventional silviculture are typically done every five to ten years. Annual fertilization guidelines would accommodate pine straw production, where annual fertilizations are common. This research suggests that two sequential annual applications of 112 lb N could be a threat to water quality in certain soils. While this level of fertilization is not widely practiced, it would be permissible under current BMPs. Fertilizer application guidelines are typically expressed in N equivalent weight. However, BMPs should address specific fertilizer forms, since the various forms applied undergo different transformations in the soil, affecting their availability for plant uptake, volatile losses and potential for leaching. New slow release fertilizers are being introduced for forestry, and research is needed to ascertain appropriate BMPs for their use. Phosphorus fertilization responses: Since DAP fertilizer application rates were determined to provide various N amounts up to the near maximum BMP limit of 250 lb/ac N in three years, two applications of the high DAP rate provided 120 lb/ac elemental P, which exceeded the BMP limit of 80 lb/ac elemental P in a three year period. Fertilization did not result in movement of P below the primary rooting zone or to groundwater in either study. Phosphorus is not a mobile nutrient, but P fertilization may increase soluble organic phosphorus (SOP), which is prone to leach. Continued monitoring for several years would be needed to ascertain the fate of applied P in this study. Pine growth responses: While the 2-year study period was too short to adequately evaluate tree growth and pine straw yield responses to fertilization, thus far these studies show that two consecutive annual applications of 384 lb DAP/ac significantly increased foliar and pine litter TKN content. Whereas, two consecutive applications of 128 lb DAP/ac were not sufficient to increase foliar and litter TKN content, and are likely below the threshold required to produce a growth response.

Publications

  • Minogue, P.J., M. Miwa, D.K. Lauer, and A. Osiecka. 2011. Preliminary results: Effectiveness of Silviculture Best Management Practices for Forest Fertilization in Pine Straw Production to Protect Water Quality in Florida. Institute of Food and Agricultural Sciences, Agricultural Experiment Station, North Florida Research and Education Center, Quincy, FL, Research Report 2011-02. 76 pp.
  • Osiecka, A., P.J. Minogue, and J.T. Wright. 2010. Effect of pine straw removal on pine straw yield and quality, wood volume, and nutrient budgets in fertilized loblolly pine (Pinus taeda), slash pine (Pinus elliottii) and longleaf pine (Pinus palustris) plantations in the Florida Sand Ridge Region. Institute of Food and Agricultural Sciences, Agricultural Experiment Station, North Florida Research and Education Center, Quincy, FL, Research Report 2010-02. 19 pp.


Progress 07/01/10 to 09/30/10

Outputs
OUTPUTS: Activities: (1) Two large-scale (12 acre) replicated studies were established in mid-rotation slash pine (Pinus elliottii L.) plantations in North Florida at locations with soils having contrasting leaching potential to evaluate and assess the effectiveness of current forest fertilization BMP's in reducing non-point source pollution for forest fertilization in pine straw production. (2) A a survey of 63 FL Division of Forestry County Foresters was completed to obtain general information regarding trends in fertilization for pine straw production, to ascertain educational needs, and also to obtain a list of significant pine straw producers (landowners)for a planned subsequent needs survey. Events: A six hour Pine Straw Production Workshop was conducted to disseminate information about sustainable management practices for pine straw production, including appropriate use of of forest fertilizers. PARTICIPANTS: (1)Individuals: PI Patrick Minogue, PD Masato Miwa, Co-PD Anna Osiecka, Colaborator: Cheryl Macowiak, (2) Partner Organizaions: Florida Dept. Environmental Protection, FL Division of Forestry, Neil Land and Timber, Burch Family Farms, (3) Training: Daniela Chevasco, Ph.D. student, School of Natural Resources and Environment, University of Florida TARGET AUDIENCES: Pine straw producers (owners of forest land) are the primary target audience for this research. These include forest industry, the Florida Division of Forestry, and non-industrial private forest landowners (NIPFL). The research will also build upon the scientific knowledge regarding fate of applied fertilizers in stands where straw is removed, thus interrupting nutrient cycling, which will be of interest to forest systems researchers worldwide. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
(1) This new study is providing cornerstone scientific information regarding nutrient fate for fertilization in pine straw production, which is widely practiced by growers who are likely to over-fertilize because of potential yield increases and economic incentives. (2) The 37 participants of our Pine Straw Production Workshop (representing 621,000 acres owned)were surveyed following the meeting and 100% indicated that they had learned something new, 66% said they would change behavior.

Publications

  • Osiecka, A. and P.J. Minogue. 2010. Developing herbicide prescriptions for forest vegetation management. Univ. of Florida Cooperative Extension Service Circular FOR125/FR. 11 pp. http://edis.ifas.ufl.edu/
  • Demers, C., A. Long, and P.J. Minogue. 2010. Longleaf pine regeneration. Univ. of Florida Cooperative Extension Service Circular SS-FOR-13/FR064. 9 pp. http://edis.ifas.ufl.edu/fr064
  • Minogue, P.J. 2010. Control understory vegetation to enhance pine straw yield. North Florida Research and Education Center Newsletter. September, 2010.