Antonio P. Mallarino, Faculty, Agronomy Department
Nitrogen and phosphorus application to soil is necessary to maintain profitable crop and animal production. However, excess manure N and P inputs and inappropriate manure application methods increase nutrient losses from fields, which are wasteful uses of non-renewable resources and pollutes water resources. The concentration of animal production and manure application in many areas together with already high soil-test P levels and widespread N fertilization have resulted in reduced water quality in many Iowa watersheds. Poultry production (mainly eggs), has increased dramatically in the state, poultry manure is a good source of nutrients, and is being applied to many Iowa soils. Extension should lead efforts at educating farmers and the public about the need for improved manure nutrients management, to improve use of this resource and water quality in Iowa.
This project demonstrated best management practices to improve utilization of poultry manure N and P for corn. It involved campus applied research and extension personnel, farmers, and certified manure applicators.
Demonstrations were conducted at 18 fields across Iowa. The project team collected field management information, soil-test P values, and applied various manure rates to supply various amounts of N and P for corn production using farmers or certified applicators equipment. To demonstrate the value of manure N and P for crops, N and P fertilizer was applied to some sections of manure strips, crop yield was measured, and soil-test values were measured after harvest. The farmers were involved in crop harvest operations. Approximately 300 one-to-one contact meetings were conducted during a three-year period with the cooperating farmers and manure applicators. Project personnel explained the demonstrations, reasons for developing them, and several issues of manure management and its implications for crop production and water quality. In addition, the issues were discussed at 34 field days or winter meetings involving more than 1300 attendees, some of which were specifically developed for the project and others were integrated with other Extension meetings and programs.
The project has had a very positive impact on farmers' perspectives concerning manure management. Without exception, farmers expressed that they gained trust on the value of manure nutrients because of project results and their direct participation on it. All farmers said they changed the way they would look at manure management in their fields, with the only exception of a few who already were using best manure management practices. An important outcome of the project was that all farmers cooperators expressed that this type of project was more useful to them than traditional efforts based only on field days or winter meetings. The project results are providing very useful data to support other extension efforts related to manure management. Extension stand-alone publications or articles are being written at this time, including an update of the publication Pm-1811 (Managing Manure Nutrients for Crop Production). Use of crop yields, manure application rates, and other information from this on-farm project helps stimulating interest and trust of farmers attending conventional field days and meetings. Better farmers understanding of the value of N and P in manure and of the value of careful manure management is having a significant impact on efforts to improve use of this valuable resource and both farm profitability and water quality in the state.
June 30, 2007
160 Natural Resources and Stewardship
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August 2, 2007
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