Biosolids application to no-till dryland crop rotations, 2013 results

Abstract

Biosolids recycling on dryland winter wheat (Triticum aestivum, L.) can supply a reliable, slow-release source of nitrogen (N) (Barbarick et al., 1992). Barbarick and Ippolito (2000, 2007) found that continuous application of biosolids from the Littleton/Englewood, CO wastewater treatment facility to dryland winter wheat-fallow rotation provides about 16 lbs N per dry ton. This research involved tilling the biosolids into the top 8 inches of soil. A question related to soil management in a biosolids beneficial-use program is: How much N would be available if the biosolids were surface-applied in a no-till dryland agroecosystem with winter wheat-fallow (WF) and winter wheat-corn (Zea mays, L.)-fallow (WCF) crop rotations? Our objective was to compare agronomic rates of commercial N fertilizer to an equivalent rate of biosolids in combination with WF and WCF crop rotations. Our hypotheses were that biosolids addition, compared to N fertilizer, would: 1. Produce similar crop yields; 2. Not differ in grain P, Zn, and Cu levels. 3. Not differ in soil P, Zn, and Cu AB-DTPA extractable concentrations, a measure of plant availability (Barbarick and Workman, 1987); and 4. Not affect soil salinity (electrical conductivity of saturated soil-paste extract, EC), pH or soil accumulation of nitrate-N (NO3-N).