Water News Archive

Nitrogen Dynamics

Nutrients in manure are potentially valuable resources for the management of soil fertility, but these nutrients are potential pollutants as well. Only 10 to 40 percent of the nutrients consumed by animals may end up in the marketed product; the rest is excreted in feces and urine. Manure contains all nutrients needed by plants, but nitrogen and phosphate generally have the most agronomic significance in Nebraska.

Pathogens, typically microbes (e.g., bacteria, viruses, protozoa, fungi) or parasitic worms, are organisms capable of causing infection or disease in other organisms, including humans, wild and domestic animals, and plants. Several pathogens naturally occur in livestock and poultry manure and under certain circumstances may pose a risk to human health.

Water quality can be degraded by contaminants contained in manure, from water used at milking centers, from silage leachate, and from open lot runoff. These potential pollutants typically follow one or more possible pathways to water.

Understanding Water Quality Issues

Manure contains four primary contaminants that impact water quality: nitrogen, phosphorus, bacteria and other pathogens, and organic matter.

Large animal feeding operations (AFO's) must follow regulations to protect water quality and preserve the environment. Smaller operations can help the environment as well. Livestock Producer Environmental Assistance Project (LPEAP) works with small farms to implement appropriate technologies and best management practices designed to protect water resources and our environment.

Soil health is defined as the continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals, and humans. Typically, soil health includes three types of soil characteristics: biological, physical, and chemical. Although sometimes used interchangeably, soil quality generally refers to soil chemical and physical properties.

Aerial view of evident manure application error

Manure is often an under-valued resource. When well-managed and properly applied, it reaps many benefits. The benefits can be seen in the photo to the left, but are not captured in much of the field because of errors in application.

While tillage has been used to prepare a seedbed, it also destroys the existing root structures in the soil and some of the soil's biological life. Without this biological life, soil structure suffers and many of the nutrients are not as available for crop uptake.

Example: Estimating Manure Phosphorus Application Rates

The Nebraska P-Index developed by the University of Nebraska (2006) will be used for analysis. The P Index risk value is the sum of the erosion and runoff components. The interpretation of risk and recommended manure application risk fall into one of four levels: low, medium, high, and very high.

Estimating Manure P App Rates

Manure phosphorus application rates should be estimated. These estimates should be based upon the most recently available information for manure nutrient concentration (manure sample) and the estimate of crop nutrient needs. Since this information is not typically available at the time of a permit application, estimating manure phosphorus application rates as part of a permit is, at best, an educated guess made without essential information.

Water News Archive

Nitrogen Dynamics

Pathogens and Organic Matter

Contaminant Pathways

Understanding Water Quality Issues

Environmental Planning

Evaluating Soil Health

Manure Value

Soil Biological Life

Example: Estimating Manure Phosphorus Application Rates

Estimating Manure P App Rates