摘要：Census of agriculture data were used to estimate manure nutrient production andthe capacity of cropland and pastureland to assimilate nutrients. Most farms (78percent for nitrogen and 69 percent for phosphorus) have adequate land on which itis physically feasible to apply the manure produced onfarm at agronomic rates.(The costs of applying manure at these rates have not been assessed). Even so,manure that is produced on operations that cannot fully apply it to their own land atagronomic rates accounts for 60 percent of the Nation's manure nitrogen and 70percent of the manure phosphorus. In these cases, most counties with farms thatproduce "excess" nutrients have adequate crop acres not associated with animaloperations, but within the county, on which it is feasible to spread the manure atagronomic rates. However, barriers to moving manure to other farms need to bestudied. About 20 percent of the Nation's onfarm excess manure nitrogen isproduced in counties that have insufficient cropland for its application at agronomicrates (23 percent for phosphorus). For areas without adequate land, alternatives tolocal land application—such as energy production—will need to be developed.
