Task 1   - Methods to reduce nutrient movement from land application sites into surface and groundwater.
Task 2  - Quantify gaseous emissions into the air from land application sites.
Task 3  - Reduce movement of zoonotic pathogens from land application sites.
Task 4  - Improve accuracy of manure land application in accordance with best management practices for nutrient planning.

Scientists working on this task will use phosphorus indices and other shared modeling tools to evaluate the impacts of a variety of innovative practices on nutrient pollution of water.  Phosphorus mass balances and runoff models will be compared across a several different cropping and pasture systems, in different soil types and climates, and with manure from different species.  Intermediate results will be shared across the project and will be used to help formulate better general nutrient management planning strategies.

Scientists will study soils on highly erodible steep slopes under forage production, where high rates of animal manure have been applied for many years.  Such soils already have elevated levels of phosphorus.  Tillage and forage systems will be tested and evaluated to ameliorate areas of phosphorus overload.  Plant uptake measurements and soil analyses will be used to evaluate effectiveness of tillage and different forage production management methods in reducing phosphorus levels at the soil surface.  Concomitant changes in nitrate leaching from the sites to groundwater will also be monitored (AL).  Various approaches to comprehensive nutrient management planning for pasture/broiler litter systems will be evaluated in AR.

Year-around forage production systems will be employed to test the feasibility of combining commercial nitrogen fertilizer with animal manure to provide a more balanced N-P-K ratio that is in line with forage nutrient requirements that enhance phosphorus uptake and reduce phosphorus soil tests.  Annual ryegrass (the cool season grass crop) and warm season bermuda grass will be used in the first two years of the study.  The following three years will test the effectiveness of substituting a legume crop (clover) in place of the commercial nitrogen to provide the nitrogen needed for the warm season bermuda grass crop.  A two-year study of consecutive crops of forage sorghum, winter wheat, and forage sorghum followed by winter wheat with level border irrigation of collected feedlot runoff will be completed.  Soil accumulation of P along with N, K, and salinity constituents as a function of application rate (0, 6and 12 in./yr , plus ground water to equal 12 in. per year moisture additions), soil profile depth, and crop removal will be evaluated for the converted rangeland site at TAES/USDA-ARS,  Bushland, TX.  Effects of cattle ration with lowered P vs. conventional P content in the diet of finishing cattle on runoff quality will be determined from 18 feedpens equipped with runoff monitors and samplers. Runoff studies will encompass comparisons of runoff quantity and quality with emphasis on P mass removals from conventional soil-surfaced feedpens vs. fly ash-surfaced pens. Experiments examining the feasibility of using buried vs. surface drip irrigation for feedlot runoff distribution as a feedlot effluent nutrient management method on the Southern High Plains will be established.

To provide more data and a balanced evaluation of phosphorus movement that includes other climates and cropping systems, scientists in WI and MN will study ways to reduce soluble phosphorus runoff from row cropped land, especially corn fields that have had manure applications.  A combination of tillage systems (conservation tillage and conventional chisel plowing) with addition of low cost chemical amendments (alum, water treatment residuals, and fly ash) will be evaluated for their abilities to immobilize soluble phosphorus.

Multi-state collaboration among scientists will be an important component of this task, to validate the measurement methods and the models being developed.  A variety of cropping systems and types of manure applications will be evaluated and compared, with the resulting data being used to increase reliability and broaden the applicability of the emission models.

Gas emissions from land-applied manure on pasture (AL and GA), sorghum and small grains crops (AL and MD), and no-tilled, deep-subsoil tilled and conventional tilled soybean row crops (GA) will be compared.  Types of manures will include broiler litter, dairy slurry, swine lagoon effluent, and pasture grazed cattle manure.  Emissions of ammonia, nitrous oxide, and methane will be studied and the results used to formulate generalized and localized emissions models.

The water quality impacts of grazing dairy cattle on pasture will be studied in regard to fecal coliform content in runoff water (LA).  As part of an ongoing study, pasture plots will be artificially dosed with dairy cow manure in a manner similar to natural deposition during grazing.  Rainfall simulators will provide various levels of runoff, and the impact of repeated rainfalls on fecal coliform counts in the runoff water will be measured.  This segment of the project will address concerns about the dynamics of fecal bacteria in pasture situations during repeated rainfall events.  Intermediate results of the study will be compared with those from the TN dairy experiments (objective 4) and the filter strip study (objective 2, IL, KS and VA).

A variable rate technology manure slurry applicator will be developed (IL) to enable the swine industry to meet nutrient management plan compliance.  This project will incorporate application rate controls at progressively more sophisticated levels, to parallel the development of commercial fertilizer application equipment that is coupled with GPS software and hardware.  The rate control algorithms and applicator results will be shared with scientists in WI and IN where work is being done on variable rate box- and tank-type manure spreaders.

Scientists will study how changes in livestock systems impact the overall farm nutrient management plan.  In AR, strategies for in-building management of poultry litter and the effects of such strategies on the nutrient compositions and bulk properties of the litter will be examined.  Litter treatments, building cleanout protocols and schedules, and litter storage options will be evaluated for their effects on farm comprehensive nutrient management plans. Interactions of the litter management strategies with the use of a phosphorus index on surface water quality will also be studied.  In VA different nutrient management strategies for feeding stocker cattle will be compared, to determine the effects on soil fertility and surface water quality.  On a fescue pasture system, broiler litter will be used as either a cattle feed supplement or as a soil fertilizer.  Inorganic fertilizer application to the pasture and unsupplemented cattle feeding will be control treatments.  The resulting changes in soil fertility levels (N, P, K, Ca, Mg, S, Cu and Zn) and runoff water quality will be assessed.  Results from these experiments will be shared as the project group formulates recommendations for revising nutrient management plans to meet constraints on water quality and soil fertility.