Progress 09/01/03 to 08/28/06
Outputs
1) Experiments were conducted to increase rice yields in conservation tillage (RT) production systems for improved rice varieties. Plant densities responded linearly for five cultivars while one, Cocodrie, responded in a quadratic fashion for rice drill-seeded into a stale seedbed system. Optimal rough rice grain yields occurred at a seeding rate of 323 seeds m2. Ammonium sulfate was a more efficient N source than urea when N was applied after flooding in a water-seeded system, but yields were higher when all N was applied prior to planting regardless of source. 2) The frequency of yield-limiting soil and seedling pests in cotton and field corn was consistently lower in RT plots compared to conventional tillage (CT) plots. Insecticides applied to soil or seed, at the time of planting, improved final plant populations and increased yields in the RT plots. The most common insecticides used to treat seed provided control of a limited pest spectrum compared to recommended
granular and liquid products. 3) Residual effect of prior poultry litter fertilization on yields of various pasture grasses was small. Phosphorus (P) uptake was positively related to soil P level and was greatest for double-cropped bermudagrass/ryegrass and switchgrass alone. Residual effects of poultry litter fertilization on loblolly pine growth were significant. Despite P build-up in surface forest soil with long-term poultry litter application, there was little downward movement of P. Phosphorus in runoff water from pasture and forest soils previously amended with poultry litter was more closely related to P release from soil in miscible displacement (flow through) than standard water extraction (batch). 4) Experiments conducted with broilers indicated different formulations of phytase sources are similar in efficacy and addition of phytase to diets reduces total P in the litter, but has no effect on reactive soluble P in the litter. Extraction studies showed that standard
methodologies underestimate soluble P in litter and the short-term loss of reactive soluble P from litter can be described by a modified Landmuir isotherm. 5) Alternative dairy wastewater treatment systems were studied in comparison to the single-stage lagoon currently adopted by NRCS (standard 359, USDA-SCS, 1994). The system of anaerobic-aerobic lagoons efficiently removed a number of potential pollutants as did the aerobic treatment of wastewater. However, many pollutants were significantly lower in the effluent from aerobic lagoons compared to anaerobic lagoons effluents. 6) DNA fingerprinting of E. coli isolated from land-applied dairy manure runoff generated by artificial rainfall on experimental field plots were analyzed with pattern recognition software. There was a loss of DNA fingerprint diversity with time and a distinct subset of the E. coli DNA patterns was still observed after ten days of exposure to environmental conditions.
Impacts
1) Stand termination and replanting is a difficult decision for Gulf coast rice producers. Depending on rice cultivar, uniform plant densities ranging from 50-70 plants m2 may result in grain yields that can offset the cost of termination and replanting. 2) IPM strategies in RT systems for cotton and field corn will require a combination of chemical and cultural practices to manage arthropod pests. 3) Since hay harvest removed about 50mg P/kg of soil annually, depending on double-cropping and grass species, this approach to site remediation seems practicable for soil with intermediate to high levels of P. The benefits of poultry litter fertilization in forestry encourage this alternate use. Limited downward movement of P suggests primary emphasis on P loss should be on surface runoff. The miscible displacement method for estimating P loss potential may be linked with existing P-index risk assessment to improve reliability. 4) Dietary phosphorus can be reduced in
broiler diets supplemented with phytase with no negative effects on growth or carcass yield, but with a reduction in phosphorus lost to the environment. A better understanding of the fate of phosphorus from poultry litter will help efforts to limit loss of phosphorus to surface water. 5) The use of DNA fingerprinting provided direct evidence that some strains of E. coli persist in the environment longer than most. Evidence for the preferential survival of specific strains of E. coli in agricultural runoff offers a new avenue for the assessment of water quality with respect to the source of contamination.
Publications
- Bond, J.A., T.W. Walker, P.K. Bollich, C.H. Koger, and P. Gerard. 2005. Seeding rates for stale seedbed rice production in the Midsouthern United States. Agron. J. 91:1560-1563.
- LeBlanc, B.D. and V.R. Moreira. 2006. Early Results From Evaluation of Two-Stage Lagoons and Constructed Wetlands Treatment of Dairy Waste Effluent. USDA-CSREES National Water Conference. February 5-9, 2006. San Antonio, TX. Abstract in Conference Proceedings.
- LeBlanc, B.D. and V.R. Moreira. 2006. Early Results from Evaluation of Two-Stage Lagoons and Constructed Wetlands Treatment of Dairy Waste Effluent. USDA-CSREES Southern Region Water Quality Conference. October 23-26, 2005. Lexington, KY. Abstract in Conference Proceedings.
- Moreira, V.R., LeBlanc, B.D., and Ward, J., 2005. Research and Outreach on Pollution Reduction Methods for Dairies in Louisiana and Mississippi. 2005 USDA National Water Quality Conference, San Diego, CA. February 6-9, 2005. Abstract in Conference Proceedings.
- Saichuk, J., P.K. Bollich, et al. 2003. Rice Varieties and Management Tips 2003. Louisiana Cooperative Extension Service Pub. 2270. 23 pp.
- Seibert, J.D., A.M. Stewart, and B.R. Leonard. 2006. Comparative Growth and Yield of Cotton (Gossypium hirsutum L.) at Various Plant Densities and Configurations. Agron. J. 98:563-568.
- Ward, J.D., B.D. LeBlanc, C.M. Drapcho and M.A. Poirrier. 2004. Implementation and Testing of Two Dairy Waste Treatment Systems. Proceedings of the 7th Biennial Basics of the Basin Research Symposium at the University of New Orleans, May 20-21, 2004.
- Gable, R.H., K.D. Emfinger, B.R. Leonard, and J. Temple. 2005. Evaluation of selected insecticides against sugarcane beetle and cutworms in field corn, 2004. Arthropod Management Tests Vol. 30, In http://entsoc.org/Protected/AMT/AMT30/Text/amt30.asp?report=F21.
- Bollich, P.K. 2003. Changes in rice cultural practices. Southern Weed Science Society Proceedings. 56:365.
|
Progress 01/01/05 to 12/31/05
Outputs
Geostatistical characterization of spatial patterns of P retention was conducted on a Ruston soil site with a prior history of poultry litter application. Langmuir isotherms parameters (sorption and slope maxima) were best related to concentration of oxalate-extractable (amorphous) Fe. Concentration of P in surface runoff under simulated rainfall from (0.75 x 2.00 m) plots on shoulder, backslope and footslope landscape positions at this pasture site ranged from 7 to 4 ppm, with nearly all as dissolved P. Effectiveness of poultry litter P mitigation strategies was examined. Addition of phytase coupled with reduced P supplement reduced total P in litter but, contrary to earlier findings, not dissolved inorganic P, the most bioavailable form. Significant differences in pine tree growth due to earlier poultry litter applications (six, ending 2001) persisted in 2005. The effects of feeding different nonphytate P (nPP) levels with and without phytase (PHY) supplementation
on broiler growth performance and phosphorus (P) excretion was determined. In a 4-phase feeding program, broilers were fed a control diet, a low Ca and P (LCaP) diet with a 0.05% reduction in nPP (Ca:P maintained), and these two diets supplemented with 600 PHY units/kg (nPP was reduced by 0.10% in diets with PHY). Total P (TP), soluble P (SP), and reactive soluble P (RSP) were decreased (P<0.04) in litter of broilers fed the LCaP diet. Total P was decreased (P<0.01) in litter of broilers fed PHY, but SP and RSP were not affected (P>.1) by PHY. RAPD PCR was used to explore the survival of E. coli strains, as defined by DNA fingerprints, in the environment. E. coli were isolated from runoff water from land-applied dairy manure as a function of time. The runoff was experimentally controlled. Over a sixteen-day period, not only did the numbers of fecal coliforms decrease, but also the diversity of E. coli strains decreased as judged by the DNA fingerprint patterns. These strains of E.
coli that displayed superior survival in the farm environment would be expected to make a significant contribution to fecal coliform counts in agricultural runoff. Seven rice varieties and eight hybrids were tested in nitrogen (N) rate and application timing experiments. While varieties responded differently to N, 150 lb N/A as a preflood application generally produced the highest grain yields for each variety. Varieties were also evaluated for response to N applications of 0, 30, or 60 lb/A applied at panicle differentiation. The response to midseason N was extremely inconsistent. Data from 2005 demonstrates that grain yield potential is still dependant on preflood N applications.
Impacts
General patterns of P retention, particularly correlations with easily measured soil properties such as oxalate-extractable Fe, could provide a basis for spatially variable P application (as with poultry litter) so as to limit potential off-site losses. Even though there was no difference in concentration of soluble inorganic P due to diet modification, some longer term benefit may accrue since total P is reduced in phytase-supplemented poultry diets. Continued demonstration of the benefit of poultry litter on pine growth should encourage its use, increasing the land area for its application. Bacterial source tracking using DNA fingerprinting provided a viable means to identify the sources of fecal contamination that threaten the health of residents and the recreational use of the abundant water resources in Louisiana. Variety and hybrid by N rate experiments are essential in determining the rate of N required for optimizing grain yield, minimizing environmental
concerns, and increasing economic returns. Efficiency of fertilizer N is greatly affected by application timing and placement.
Publications
- Payne, R.L., T.K. Lavergne and L.L. Southern. 2005. A comparison of two sources of phytase in liquid and dry forms in broilers, Poultry Sci. 84:265-272.
- Bond, J.A. 2005. Rice response to preflood and late-season nitrogen applications. p. 76 In C. Crozier (ed.) Proc. South. Plant Nutr. Manage. Conf., Olive Branch, MS 3-5 Oct. 2005. The Samuel Roberts Noble Foundation, Ardmore, OK.
- Bond, J.A., Wlaker, T.W., Bollich, P.K., Koger, C.H., and Gerard, P. 2005. Seeding rates for stale seedbed rice production in the midsouthern United States. Agron J. 97:1560-1563.
|
Progress 01/01/04 to 12/31/04
Outputs
1) Soil and seeding pests of cotton and field corn were observed more frequently at yield limiting levels in reduced tillage (RT) plots compared to conventional tillage (CT) plots. An uncommon pest, the sugarcane beetle, Euetheola humilis rigiceps (LeConte), was observed in higher densities and produced more seedling injury in RT plots than in CT plots. Several insecticide use strategies applied to the soil or seed, at the time of planting, improved plant densities and increased yields in the presence of insect pests. Novel seed treatments (clothianidin, imidacloprid, thiamethoxam) demonstrated satisfactory control of several pests on seedlings, but their efficacy was restricted to a limited pest spectrum compared to recommended granular and liquid products. Fall cultural practices (disking, re-bedding, and mowing [rotary and flail]) reduced overwintering survival of southwestern corn borer, Diatrea grandiosella Dyar, and sugarcane borer, Diatrea saccharalis (F.), in
corn and grain sorghum stubble. Significant insect pest problems occurred in RT plots of cotton following a crop of winter wheat harvested for grain. A complex of Lepidopteran larvae and Hemipteran bugs reduced yields by 40% due to the late maturity of the double-cropped cotton. Effective integrated pest management (IPM) strategies included a combination of transgenic Bollgard cultivars and foliar insecticides. 2) Large scale studies were initiated that will compare diets with or without phytase and with conventional or high levels of calcium and phosphorus. Broilers will be carried for 0 to 49 day studies to generate litter for the phosphorus solubility and runoff studies. Research was initiated that compared phytase sources and an antibiotic that may increase phosphorus utilization. Long-term benefits of the phytase-amended diet on water quality can best be assessed in larger field experiments. Sites have been selected and will be instrumented. Data from these will be used in
conjunction with GIS-based water quality modeling for model calibration validation and demonstration training purposes. 3) Despite previous results that showed only numerical but non-significant growth responses of pine in plantation and agroforestry systems to poultry litter, 2003 data established these as significant. Demonstrated benefit of poultry litter on pine growth provides a rationale for use of poultry litter fertilizer with pine, thereby greatly increasing the potential land area for its application. Data for use of poultry litter in a pine straw harvest study showed that poultry litter was effective in off-setting nutrient removal from forest soil A horizon. A follow-up assessment of P leaching in the agroforestry system showed little potential for loss with percolating water. A modification of a laboratory method to predict P loss in runoff was found to be more accurate than conventional extraction methods. The phytoremediation study with Bermuda- and ryegrasses was
expanded to also compare crab- and switchgrasses in small plots. Results for bermudagrass and ryegrass substantiated previous results. Also, switchgrass, due to high biomass production, may show promise.
Impacts
Producer adoption of conservation tillage practices, cover crops and double-cropping practices can increase yield-limiting arthropod pest problems in field corn and cotton. Novel IPM strategies are being developed that will reduce the impact of these pests and be compatible with best management practices (BMPs). A holistic system of agronomic and plant protection strategies are necessary to obtain the maximum benefits of conservation tillage on the environment and farm productivity. Formulating diets for broilers that result in increased phosphorus utilization by the animal will reduce nutrient loads from land application of poultry litter and should protect water quality in area water bodies. Demonstrated benefit of poultry litter on pine tree growth provides rationale for its use as a fertilizer on pine plantations. Switchgrass may serve as an alternative forage species for phytoremediation of high phosphorus soils because of its high biomass production.
Publications
- Gaston, L.A., C.M. Drapcho, S. Tapadar, and J.L. Kovar. 2003. Phosphorus runoff relationships for Louisiana coastal plain soils amended with poultry litter. J. Environ. Qual. 32:1422-1429.
- Gaston, L.A., T.L. Eilers, J.L. Kovar, D. Cooper, and D.L. Robinson. 2003. Greenhouse and field studies on hay harvest to remediate high phosphorus soil. Comm. Soil Sci. Plant Anal. 34:2085-2097.
- Boquet, D.J., R.L. Hutchinson and G.A. Breitenbeck. 2004. Long-term tillage, cover crop and nitrogen rate effects on cotton: yield and fiber properties. Agron., J. 6: 1436- 1442.
- Cook, D.R., B.R. Leonard, and R. Gable. 2004. Residual toxicity of seed treatments and soil applied insecticides to tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) in cotton. J. Agric. Urban Entomol. 4: 197- 192.
- Gable, R.H., K.D. Emfinger, B.R. Leonard, and J. Temple. 2005. Evaluation of selected insecticides against sugarcane beetle and cutworms in field corn, 2004. Arthropod Management Tests Vol. 30, (In http://www.entsoc.org/_Protected/AMT/AMT30> Text/amt30.asp?Report=F??). (In Press).
- Gaston, L., T. Clason and D. Cooper. 2003. Benefits of poultry litter fertilizer on pasture, silvopasture and forest soils. Louisiana Agriculture. Vol. 45(3)
- Gaston, L.A., J.L. Kovar, and T.J. Sauer. 2003. Predicting phosphorus loss in runoff using a displacement technique. ASA-CSSA-SSA Annual Meetings Abstracts [CD-ROM]. ASA, Madison, WI.
- Leonard, B.R., K. Emfinger, and R. Gable 2004. Insect pest management strategies in conservation tillage cotton, pp. 15-16. In Proceedings, 2004 National Conservation Tillage Cotton and Rice Conferences. National Conservation Tillage Digest, Perryville, MO.
|
|