|Halbach, T - UNIVERSITY OF MINNESOTA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 1999
Publication Date: N/A
Technical Abstract: Beneficial use of biosolids as an N source for crop production often leads to excessive P loadings, increasing greatly the potential for P runoff in storm waters. The resulting elevated P concentrations in surface waters promote undesirable algal blooms and possible anoxic conditions in freshwater bodies and near shore salt water environments. The objective of fthis study was to determine if biosolids applications at N utilization rates for continuous corn production would result in higher P concentrations in runoff. Over a 20-y period, annual applications of biosolids resulted in the addition of 5100 kg ha**-1 of P to a silt loam Typic Hapludoll in a 16 ha terraced watershed containing slopes of up to 12 percent. Biosolids additions resulted in Bray-1 P levels of up to 460 kg ha**-1 in surface soil. Early spring runoff from treated areas contained as much as 2 mg kg**-1 dissolved P during peak flow, 5-y post biosolids application. Runoff from the control area receiving fertilizer P had <0.2 mgL**-1 of dissolved P.