Land application of manure

The Livestock and Poultry Environmental Learning Center , a National Facilitation Project of the CSREES National Integrated Water Quality Program, and The National Center for Manure & Animal Waste Management , funded by the USDA Fund for Rural America, are important projects helping USDA address this issue.

Land Application of Manure

Historically, manure generated by livestock has been returned to the soil to improve its tilth and fertility. Both the USDA and USEPA recognize that land application is the best method of utilizing animal manures. However, if the manure is not applied properly or if the manure load exceeds the site’s nutrient demand, ground and surface water quality can become impaired. USDA CSREES sponsors research to assess and improve land application of manure to protect and improve water quality.

Effects of Land Applied Manure on Soil Physical, Chemical, and Biological Properties
Soil physical, chemical, and biological properties are affected when manure is applied as fertilizer to land. Researchers assess these effects in order to prevent the transport of nutrients and pathogens into ground and surface waters.

Accomplishments:

Researchers at the University of Arizona (Martin and Tanksley, 2003) found a significant increase in the phosphorus (P) content of the soil due to the manure and compost applications on an irrigated alfalfa production system. The nitrate content varied slightly and was higher in the manure and compost plots than the control plot.

The interaction of nutrients in tropical soils receiving livestock manure application is being explored in Hawaii and the American Pacific (Evensen et al., 2003). About four to five times as much manure-P application was required to reach the same extractable P levels in an Anidisol soil as the Mollisol or Oxisol soils studied.

Researchers in the Heartland Region determined that the annual application of manure reduced runoff volume and soil loss from cropland areas.

Crop Utilization of Manure Nutrients

Understanding crop nutrient use efficiency is a key in preventing water quality degradation as a result of land cattle basking in field applications of manure.

Accomplishments:

Researchers at the University of Vermont evaluated the effect of rate and method of application of liquid dairy manure and nitrogen (N) fertilizer on N utilization, yield, and quality of grass hay . Results of this study have been used to improve extension recommendations for availability of N in manure thereby avoiding excessive application rates that threaten water quality.

Ongoing research at the University of Pennsylvania has found that the N-fixing legume may be less suitable for utilizing manure N than corn, perennial forages, and orchardgrass.

Example:

Another study comparing manure andfertilizer application rates and placement on corn and soybean phosphorus use is being conducted at the University of Minnesota.

Impacts of Tillage Practices and Timing of Manure Application
Tillage practices and the timing of manure application can affect the extent of nutrient and pathogen loss from fields. Researchers are exploring which combinations result in the least water quality impacts.

Accomplishments:

A research project conducted through the University of Nebraska and the USDA-ARS concluded that land receiving manure should be tilled (i.e., manure incorporated into the soil) in order to minimize runoff concentrations of nutrients. A similar project looking at the impact of tillage and timing of manure application on ground and surface water quality is being conducted at the University of Minnesota.

An additional project in the Heartland Region concluded that when estimating nutrient transport from land application areas, the length of time since the last manure application should be considered .

For more information on the current state of knowledge in the area of land application of manure, refer to the Land Application of Manure for Beneficial Reuse White Paper Summary produced by the National Center for Manure and Animal Waste Management funded through a USDA CSREES Fund for Rural America Grant.

Indicates work supported by the USDA-CSREES National Research Initiative Competitive Grants Program .

The intent of this page is not to catalogue all activities but rather to indicate the types of research activities in the Animal Waste Management theme across the U.S.