Development of an Environmentally Safe and Economically Sustainable Year-Round Minimum Tillage Forage Production System Using Farm Animal Manure as the Only Fertilizer

Development of an Environmentally Safe and Economically Sustainable Year-Round Minimum Tillage Forage Production System Using Farm Animal Manure as the Only Fertilizer

Summary

This project proposes to identify, develop and demonstrate some techniques, methods, and systems which can be used to recycle manure to animals through production and consumption of forage crops without negatively impacting the environment. Liquid manure resulting from flush cleaning of dairy cow facilities will be irrigated at four rates each at intervals of 7 to 14 days onto crops grown on land typical of a new dairy site. The crops will include corn and rye seeded into a bermuda grass sod in order to have an actively growing plant cover year-round. Sensitive monitoring and analytical instrumentation will be used to determine the fate of manure nutrients (N, P, K, Ca, Mg and Na) in soil and groundwater when different amounts are applied onto crops. Nutrient utilization efficiencies will be determined for each crop and the total system. Changes in soil nutrient content and soil invertebrate populations will be related to manure application rates and examined for any cumulative effects on sustainability of crop production. Data from all segments of the proposed research will be evaluated and results used to identify manure utilization procedures and crop production systems which have economical soundness, low-input sustainability, and are environmentally safe.

Most research, demonstration and dissemination of information will be carried out at the Coastal Plain Experiment Station; however, important contributions to the project will be made at Anthony's Dairy, Americus, GA, and Masstock Diary, Montezuma, GA. Participants in this project include both University and USDA research scientists, Cooperative Extension Service specialists from a broad array of disciplines, and farmers from two successful dairies.

Using manure application rates to provide a range of 200 to 800 kg N/ha/yr., confirmed that the use of 600 to 800 kg N application rate with the triple crop system (rye-corn-bermudagrass) should be economically attractive to dairy farmers because total dry matter productions are about double that farmers generally obtain from their usual single crop of corn silage per year grown with purchased commercial fertilizer. Initial data do not show any trend for nematode populations to become a problem with this system. Nitrate N concentrations are increasing due to the manure application at the high rates and the relationship to ground water through deep wells. Water analysis is being conducted.

Objectives

(1) Determine nutrient (N, P, K, Ca, Mg) use efficiency and forage production from various rates of manure application and determine the nutritional value and quality of resultant crops.

(2) Determine nutrient (N, P, K, Ca, Mg, Na) fate in soil and groundwater, and the relationship of the water wetting front to nutrient movement associated with various rates of liquid manure application.

(3) Determine the response of soil invertebrates to application rates of manure and to management practices required in the minimum tillage system.

(4) Determine rates of liquid manure applications which are economically and environmentally sustainable in a year-round system of crop production, develop benefit-cost analyses for the system, and make economic comparisons with alternative methods of producing forage crops.