Progress 01/01/09 to 09/30/13
Outputs
Target Audience: Our target audience included undergraduate and graduate students, scientific community, and farmers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project provided a unique opportunity for undergrad and graduate students as well as visiting professors to learn about the management strategies to result in optimum forage production while reducing the risk associated with nutrient transport from agricultural areas. How have the results been disseminated to communities of interest? In addition to the peer-reviewed journal articles, our research efforts were presented in scientific meetings, producer’s magazine, extension materials, and a number of educational activities throughout the state. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
This project addressed aspects of nutrient cycling and water quality issues associated with grassland ecosystems. More specifically, this research project was focused on promoting implementation of nutrient management strategies that minimize fertilizer inputs necessary to sustaining adequate forage/animal production while protecting the environment. The project was also focused on developing means to mitigate P transport from nutrient enriched-soils. Although pasture fertilization can play a major role in non-point source pollution, sustainability of productive forage systems depends, to a major extent, on pasture fertilization. The fate of fertilizers applied to grassland systems is extremely complex and is affected by several factors including application rate, timing, fertilizer source and soil and environmental characteristics. The key is to integrate all the factors that affect fertilizer efficiency to achieve sustainable forage production and yet protect the natural resources. The factors that affect nutrient use efficiency take on greater importance in Florida, where unique hydraulic conditions and soil characteristics can favor nutrient losses. Research showed that well-managed forages serve as conservation crops and are likely not major sources of water pollution. This project developed additional tools to better predict P fertilization needs in bahiagrass pastures. Our research showed that tissue analysis in combination with soil testing has potential to be a useful diagnostic tool for developing nutrient management programs that predict when bahiagrass need additional P while avoiding negative impacts on the environment. We proved that a tissue P concentration of 1.5 g kg-1 represents the critical limit below which bahiagrass will respond to P fertilization. As a result of our effort, tissue analysis has been recently incorporated to the revised UF/IFAS fertilization recommendations for established bahiagrass pastures. Our research on bahiagrass P fertilization also indicated that P transport does not represent a major environmental concern when pastures are properly fertilized following the UF/IFAS fertilization recommendations. Alternatives to reduce nutrient transport in P-enriched soils represent a major challenge in sensitive ecosystems in Florida. Our research has shown that chemical amendments such as aluminum water treatment residuals can efficiently reduce P solubility. Our research also demonstrated that forage crops can effectively reduce soil P concentrations in manure-impacted soils. Forage crops used for phytoremediation of P can also represent an important renewable energy source. Our findings on the potential of grasslands for generating synergies between P remediation and C management and sustainable energy source can have significant impacts on pasture management.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
2. Silveira, M.L., and OConnor, G.A. 2013. Temperature effects on phosphorus release from a biosolids-amended soil. Applied and Environmental Soil Science, article ID 81715, 8 pages. doi:10.1155/2013/981715.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2014
Citation:
Silveira, M.L., Vendramini, J.M.B., Seller, B.A., Monteiro, F.A., Artur, A.G., and Dupas, E. 2013. Bahiagrass response and N leaching from various N fertilizer sources. Grass and Forage Science (In Press)
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2014
Citation:
Silveira, M.L., Rouquette, F.M., Smith, G.R., Silva, H.M.S*., and Dubeux, J.C.B. Jr. 2013. Soil fertility principles for warm-season perennial forages and sustainable pasture production. Forage and Grazinglands (In Press)
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Silveira, M.L., F.M. Rouquette, Jr.*, V.A. Haby, and G.R. Smith. 2013. Soil P in bermudagrass pastures during 37 years of stocking Agron. J. 150:999-1004.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
7. Silveira, M.L., J.M.B. Vendramini, X. Sui*, L.E. Sollenberger, and G.A. OConnor. 2013. Use of warm-season grasses managed as bioenergy crops for phytoremediation of P in P-enriched soils. Agron. J. 105:95-100.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Silveira, M.L., J.M.B. Vendramini, X. Sui*, L.E. Sollenberger, and G.A. OConnor. 2013. Screening perennial warm-season bioenergy crops as an alternative for phytoremedication of excess soil P. BioEnergy Research 6:469-475.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
1. Silveira, M.L., Vendramini, J.M.B., and Sollenberger, L.E. 2013. Use of warm-season grasses managed as bioenergy crops for phytoremediation of P in P-enriched soils. ASA-CSSA-SSSA Annual Meeting, Tampa, OH, November 3 - 6, 2013.
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Effective options for reducing P losses from P-enriched soils remain a major challenge, particularly in intensive agricultural areas. While different strategies have been shown to control P mobility (e.g., Ca- and Al-based soil amendments, and riparian buffers), they provide no means to reduce in situ soil P concentrations. The objectives of this study were to i) investigate the potential P-removal capacity of four bioenergy crops [(elephantgrass (Pennisetum purpureum Schum.), sugarcane (Saccharum spp.), switchgrass (Panicum virgatum L.), and stargrass (Cynodon nlemfuensis Vanderyst)] grown on a manure-enriched soil, and ii) examine the impacts of crop P uptake on soil P concentrations and surface groundwater quality. Treatments were distributed in a completely randomized design with four replicates. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The greatest dry matter (DM) yields were observed for elephantgrass (average of 46 Mg ha-1 yr-1) followed by sugarcane (average of 40 Mg ha-1 yr-1). Tissue P concentrations were greater for stargrass (~ 4 g kg-1) as compared to elephantgrass (3.2 g kg-1) and sugarcane (1.9 g kg-1). Elephantgrass showed the greatest cumulative P removal (420 kg P ha-1 during the 3-yr period). Soil P concentrations in the Ap horizon decreased over time, while an increase in soil P concentration was observed in the Bh horizon. Elephantgrass resulted in the lowest leachate P concentrations (~0.5 mg P L-1) at 60-cm depth. Crop species had no effect on leachate P at the 90-cm depth. Growth of elephantgrass as a biofuel feedstock appears to be an effective approach for remediation of excess soil P.
Publications
- Silveira, M.L. et al. 2012. Short-term effects of grazing intensity and nitrogen fertilization on soil organic carbon pools under perennial grass pastures in the Southeastern USA. Soil Biol. Biochem.In Press.
- Silveira, M.L. et al. 2012. Use of warm-season grasses managed as bioenergy crops for phytoremediation of P in P-enriched soils. Agron. J.In press.
- Silveira, M.L. et al. 2012. Screening perennial warm-season bioenergy crops as an alternative for phytoremedication of excess soil P. Bioenergy Research.In press.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Repeated applications of P fertilizer and manure have increased soil P concentrations in many agricultural soils. While numerous strategies have been suggested as a means to reduce the mobility and associated risks of P transport, few attempts have been made to remediate in-situ soil P levels. The objective of this study was to identify potential crop species candidates adapted to Florida's environmental conditions that can be used for both remediation of soil P and as a cellulosic fuel-stock for production of renewable energy. Fifteen crop entries were investigated for their potential to remove P from a P-enriched soil. The study was conducted at a commercial dairy farm in South Florida on a Pomona soil (sandy, siliceous, hyperthermic Ultic Alaquods). The study site has been continuously occupied by dairy cows for over 50 yr and fertilized annually with ~ 80 and 10 kg ha-1 of N and P. Initial Mehlich-1 P concentrations in the Ap (0-15 cm), E (15-30 cm), and Bh (30-60 cm ) horizons were ~ 173, 76, and 150 mg kg-1, respectively. These soil P levels are considered very high according to the University of Florida fertilizer recommendations and reflect the long-term history of inorganic fertilizer application and manure deposition. Initial soil pH was ~ 6.2. Treatments consisted of the fifteen cultivars replicated three times in a completely randomized design for a total of 45 plots. Control plots (n=3) were also tested. Forage species used in the study were selected based on the following criteria i. high dry matter production potential, ii. high P uptake rate, iii. seed or planting material widely available, iv. potential to be used as bioenergy crop. PARTICIPANTS: Joao Vendramini (UF, Agronomy), Lynn Sollenberger (UF, Agronomy), John Arthington (UF, Animal Science), James Jawitz (UF, Soil and Water Science), Augustine Obour (Univ. of Wyoming). TARGET AUDIENCES: scientific community, students, clientele groups PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Dry matter (DM) yields varied considerably among crop species with greater yields observed for elephantgrass and sugarcane (43 and 39 Mg ha-1 yr-1, respectively). Similarly, greater P removal rates were observed for elephatgrass (up to 126 kg P ha-1 yr-1 in 2008) followed by sugarcane (62 kg P ha-1 yr-1 in 2008). Both bahiagrass cultivars exhibited the smallest P removal rates (5 to 9 kg P ha-1 yr-1). Although there was no effect (P = 0.45) of crop species on soil P, soil P concentrations decreased linearly during the 3-yr study. Data indicated that elephantgrass exhibited characteristics of a good candidate for remediation of P-enriched soils. Further studies are warranted to examine the long-term impacts of elephantgrass cropping on soil P concentrations and subsequent effects on water quality.
Publications
- Obour, A.K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., OConnor, G.A. 2011. Fluctuating water table effect on phosphorus release and availability from a Florida Spodosol. Nutrient Cycling in Agroecosystems 91:207-217. Silveira, M.L., Obour, A.K., Vendramini, J.M., and Sollenberger, L.E. 2011. Using tissue analysis as a tool to predict bahiagrass phosphorus fertilization requirement. Journal of Plant Nutrition 34:2193-2205. Obour, A.K., Silveira, M.L., Vendramini, J.M.B., Jawitz, J.W., OConnor, G.A., and Sollenberger, L.E. 2011. A phosphorus budget for bahiagrass pastures growing on a typical Florida Spodosol. Agronomy Journal 103:611-616. Liu, K., Sollenberger, L.E., Silveira, M.L., Vendramini, J.M.B., and Newman, Y.C. 2011. Distribution of nutrients among soil-plant pools in Tifton 85 bermudagrass pastures grazed at different intensities. Crop Science 51:1800-1807. Castillo, M.S., Sollenberger, L.E., Vendramini, J.M.B., Woodard, K.R., OConnor, G.A., Silveira, M.L., and Sartain, J.B. 2011. Incorporation of municipal biosolids affects organic nitrogen mineralization and elephantgrass biomass production. Agronomy Journal 103:899-905. Silveira, ML, Obour, A.K., Arthington, J., Sollenberger, L.E. 2011. The cow-calf industry and water quality in South Florida, USA- A review. Nutrient Cycling in Agroecosystems 89:439-452. Obour, A. K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., OConnor, G.A., Jawitz, J.W. 2011. Agronomic and environmental impacts of phosphorus fertilization of low input bahiagrass systems in Florida. Nutrient Cycling in Agroecosystems 89:281-290 Obour, A.K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., OConnor, G.A., and Jawitz, J.W. 2011. Phosphorus fertilization responses on bahiagrass pastures. Forage production and water quality. Agronomy Journal 103:324-330. Silveira, M.L., Liu, K., Sollenberger, L.E. and Vendramini, J.M.B. 2011. Short-term effects of grazing intensity and nitrogen fertilization on soil organic carbon under grazed pastures in the Southeastern USA. ASA-CSSA-SSSA Annual Meeting, San Antonio, TX, October 16 - 19, 2011. Speckmann, R.D., Silveira, M.L., Carlisle, B., Kirby, C.L., Gornto, R.W. and Wiggins, L.F. 2011. A survey of soil and plant tissue nutrient status of established bahiagrass pastures in Southwest Florida. American Society of Animal Science, Southern Section, Corpus Christi, TX, February 5-8, 2011
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Research results were disseminated at local, regional, national, and international conferences, peer-reviewed publications, and extension materials. A number of educational activities were conducted in 2010 with the objective to disseminate information relative to nutrient management and environmental issues related to forage and beef cattle production in Florida. PARTICIPANTS: Augustine A. Obour (PhD student, James Jawitz (Associate Professor - Soil and Water Sci. Dep., Univ. of Florida), Joao Vendramini (Assistant Professor - Agronomy Dep., Univ. of Florida), Lynn Sollenberger (Professor - Agronomy Dep., Univ. of Florida). TARGET AUDIENCES: scientific community, students, various clientele groups PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Field and greenhouse studies were conducted to evaluate the role of the Bh horizon on the overall P budget for bahiagrass (Paspalum notatum Flugge) pastures grown on a Spodosol. Treatments consisted of three P rates (0, 5, and 10 kg ha-1) arranged in a completely randomized design with each plot receiving a basal application of 56 kg N ha-1 and 47 kg K ha-1. Phosphorus application had no effect on bahiagrass P uptake or P leaching. Average P mass leached below the 45-cm soil depth was 0.08, 0.08, and 0.09 kg P ha-1 for the 0, 5, and 10 kg P ha-1 treatments, respectively. Results indicate that soil P concentrations were sufficient to maintain bahiagrass production with no additional P fertilization required. The amount of P losses through leaching and surface runoff was small compared to P uptake in the overall mass balance computations. The available soil P in the Ap horizon had no effect on the overall P budget. However, when available soil P within the top 45 cm of the soil was included in the P budget, net P balance was positive for all treatments. Traditionally, soil testing focuses on the top 15 cm of the soil, and using this approach at this study site would lead to the conclusion that the soils were P deficient. However, when P concentration within the top 45 cm of the soil was considered, the soil was considered to be P sufficient and no P fertilization was needed. This is evidenced by no P uptake response of bahiagrass to P fertilization, suggesting that the P held in the Bh horizon is available for bahiagrass uptake. We conclude that P held in the Bh horizon is a significant supply of P to low-input pastures growing on Spodosols in Florida and should be considered in nutrient management programs for perennial grasses.
Publications
- 1. Obour, A. K., Silveira, M.L., Vendramini, J.M.B., Adjei, M.B., and Sollenberger, L.E. 2010. Evaluating cattle manure application strategies on phosphorus and nitrogen losses from a Florida Spodosol. Agronomy Journal 102:1511-1521. 2. Obour, A.K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., O Connor, G.A., and Jawitz, J.W. 2010. Phosphorus fertilization responses on bahiagrass pastures - Forage production and water quality. Agronomy Journal (In Press). 3. Silveira, ML, Obour, A.K., Arthington, J., Sollenberger LE. 2010. The cow-calf industry and water quality in South Florida, USA- A review. Nutrient Cycling in Agroecosystems (In press). 4. Obour, A. K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., O Connor, G.A., Jawitz, J.W. 2010. Agronomic and environmental impacts of phosphorus fertilization of low input bahiagrass systems in Florida. Nutrient Cycling in Agroecosystems (In press). 5. Silveira, M.L., Vendramini, J.M.B., and Sollenberger, L.E. 2010. Phosphorus management and water quality problems in grazingland ecosystems. International Journal of Agronomy (In press). 6. Obour, A. K., Silveira, M.L., Vendramini, J.M.B., Adjei, M.B., and Sollenberger, L.E. 2010. Evaluating cattle manure application strategies on phosphorus and nitrogen losses from a Florida Spodosol. Agronomy Journal 102:1511-1521. 7. Silveira, M.L., Obour, A.K., Vendramini, J.M., and Sollenberger, L.E. 2010. Using tissue analysis as a tool to predict bahiagrass phosphorus fertilization requirement. Journal of Plant Nutrition (In press). 8. Silveira, M.L., Bateman, R., Walter, J., Sartain, J., Kirby, C.L., and Deal, P. 2009. Phosphorus removal rates from sod production systems. 2009. Florida Cooperative Extension Service, IFAS, University of Florida. SL 309. 9. Silveira, M.L. 2010. Agronomic and environmental impacts of phosphorus fertilization to low input bahiagrass systems in Florida. The Florida Cattlemen and Livestock Journal, vol. 74, n.6. 10. Silveira, M.L. 2010. Phosphorus removal in sod production systems in Florida. UF/IFAS South Florida Beef and Forage Program. "Article of the Month". February, 2010. Available at http://sfbfp.ifas.ufl.edu/ 11. Silveira, M.L., Sui, X., Vendramini, J.M., Sollenberger, L.E., and O Connor, G.A. 2010. Evaluating the impacts on bioenergy crops on soil and water resources. ASA-CSSA-SSSA Annual Meeting, Long Beach, CA, October 31 - November 4, 2010. 12. Silveira, M.L., Sui, X., Vendramini, J.M., Sollenberger, L.E., and O Connor, G.A. Biomass cropping effects on water quality in a manure-impacted spodosol. American Society of Agronomy - Southern Regional Branch Annual Meeting, Orlando, FL, February 6-8, 2010. 13. Silva, H.M.S., Dubeux, J.C.B. Jr., Silveira, M.L., Freitas, E.V., Lira, M.A., Cabral, F.A. 2010. Root decomposition of Brachiaria decumbens Stapf. pastures managed at different grazing intensities and N fertilization regimens. In: 6th Northeastern Congress of Animal Production - SNPA, Mossoro, Rio Grande do Norte, Brazil, November 29- December 2, 2010. 14. Silva, H.M.S., Dubeux, J.C.B. Jr., Freitas, E.V., Silveira, M.L., Lira, M.A., Cabral, F.A. 2010. Litter decomposition in Pennisetum purpureum Shum. pastures managed under different grazing intensities. In: 47th Annual Meeting of the Brazilian Society of Animal Science, Salvador, Brazil, July 27-30, 2010. 15. Silva, H.M.S., Dubeux, J.C.B. Jr., Freitas, E.V., Silveira, M.L., Santos, M.V.F., Ferraz, L. V. 2010. Litter decomposition in Brachiaria decumbens Stapf. pastures, Itambe, Brazil. In: 47th Annual Meeting of the Brazilian Society of Animal Science, Salvador, Brazil, July 27-30, 2010
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Research results were disseminated at regional and national conferences, peer-reviewed publications, and extension materials. A number of extension activities were conducted in 2009 to disseminate information relative to soil fertility and environmental issues affecting the beef cattle industry in Florida. PARTICIPANTS: Augustine A. Obour (PhD student, James Jawitz (Associate Professor - Soil and Water Sci. Dep., Univ. of Florida), Joao Vendramini (Assistant Professor - Agronomy Dep., Univ. of Florida), Lynn Sollenberger(Professor - Agronomy Dep., Univ. of Florida). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Field and greenhouse studies were conducted at the UF/IFAS Range Cattle REC, in Ona to evaluate the agronomic and environmental impacts of phosphorus (P) fertilization in established bahiagrass pastures. Treatments consisted of factorial combination of three nitrogen (N) rates (0, 56 and 112 kg ha-1) and four P rates (0, 5 and 10 and 20 kg ha-1) arranged in a completely randomized design with each plot receiving a basal K application of 47 kg K ha-1. As part of the objectives of the study, we investigated the use of tissue analysis as a tool in predicting bahiagrass phosphorus fertilization requirements. Our results showed the critical bahiagrass tissue P concentration below which bahiagrass dry matter yields were negatively impacted was 1.4 g kg-1. Above this critical value bahiagrass did not respond to P fertilization. We also determined the minimum P application rates to improve bahiagrass yields in low input systems. Our results indicate that bahiagrass P fertilization is dependent on the amount of N applied. Bahiagrass shown no yield response to P fertilization when N was applied at 56 kg N ha-1, however, when N rate was increased to 112 kg N ha-1 bahiagrass responded to P application, and that P application of 5 kg ha-1 was adequate to sustain bahiagrass yields. Also, at this low P application rates, there is no negative impacts of P application to the environment. Another interesting finding of the study was the effect of fluctuating water table on P release and availability in Florida spodosols. Our results showed that rising water table depth increase P release from the Bh horizon which can be transported to the upper layers of the soil. Also high water table conditions experienced in the summer months in Florida affects P bioavailability. Efforts were also made to determine the P mass balance of low input bahiagrass pastures growing on Florida spodosols. Preliminary results from the study showed that P held in the Bh horizon is a major component of P input to established bahiagrass pastures. This implies that bahiagrass nutrient management programs should consider phosphorus held in the Bh horizon, especially when the rooting zone is within the Bh.
Publications
- Obour, A.K., Silveira, M.L., Adjei, M.B., Vendramini, J.M.B., Rechcigl, J.E. 2009. Effect of cattle manure application strategies on bahiagrass yield, nutritive value and phosphorus uptake. Agronomy Journal, 101:1099 1107.
- Silveira, M.L.,Vendramini, J., Rechcigl, J.E., and Adjei, M.B. 2009. Soil pH and liming issues affecting bahaigrass pasture. Florida Cooperative Extension Service, IFAS, University of Florida. SL 292.
- Silveira, M.L. 2009. Changes in bahiagrass fertilization recommendations. Field Day UF IFAS Range Cattle Research and Education Center. April 16, 2009.
- Vendramini, J.M. and Silveira, M.L. 2009. Pasture aeration. UF IFAS South Florida Beef and Forage Program. Article of the Month. May, 2009.
- Silveira, M.L. 2009. Carbon sequestration in forage systems. UF IFAS South Florida Beef and Forage Program. Article of the Month. February, 2009.
- Silveira, M.L., Sui, X., Vendramini, J.M., Sollenberger, L.E., and OConnor, G.A. Utilization of biomass and forage crops to remediate P impacted soils in Florida. ASA CSSA SSSA Annual Meeting, Pittsburgh, PA, November 1-5, 2009.
- Obour, A. K., Silveira, M.L., Vendramini, J.M.B., Sollenberger, L.E., OConnor, G.A., and Jawitz, J. Fluctuating water table effects on phosphorus release and losses from a Florida spodosol. ASA CSSA SSSA Annual Meeting, Pittsburgh, PA, November 1-5, 2009.
- Obour, A. K., Silveira, M.L., Vendramini, J.M., Sollenberger, L.E. and OConnor, G.A. Predicting bahiagrass response to phosphorus fertilization using tissue phosphorus concentration. Soil Crop and Science Society Florida Annual Meeting, Jacksonville, FL, June 7-9, 2009.
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