Confined Animal Production And Manure Nutrients

Using data from the Census of Agriculture on animal inventory and sales, we estimate manure nutrient production on farms with confined livestock. Using reported on-farm production of crops on these same farms, we estimate the nutrient uptake for major field crops and pastureland. This enables us to examine the balance between manure nutrient production and nutrient need measured by crop uptake at a farm level. Examination at alternative spatial scales, shows that 75 percent of counties in the U.S. have farms that produce more manure nutrients than can be assimilated on the farm of production (excess nitrogen).The vast majority of the counties that produce excess nitrogen have adequate land in the county to spread the manure at agronomic rates. Thus, proposed policies that focus on land application have the potential to limit manure nutrient movement to waterways in most areas, if properly managed. However, moving manure to crop farms that formerly had not used manure will increase costs. There were about 5 percent of counties where the manure nitrogen production levels from confined animal production exceeded half the nitrogen assimilative capacity of all the cropland and pastureland in the county. These areas have the greatest need for mechanisms to encourage off-farm solutions to utilize manure as a feedstock for commercial enterprises or central processing.