Importance of Soil Properties on Recommended Biosolids Management for Winter Wheat

Abstract

Core Ideas Coarse soil texture should not restrict fall biosolids application to winter wheat. Grain yield from biosolids is greater than or equal to that from urea. Nitrogen recovery from biosolids is greater than or equal to that from urea. Environmental concerns and regulatory guidelines about winter N leaching limit fall biosolids applications to winter wheat (Triticum aestivum L.) in Virginia to a plant‐available N (PAN) rate of ≤50 kg PAN ha−1. Ten field studies were established in 2012 to 2014 in Virginia to determine the agronomic and environmental feasibility of fall biosolids applications to soft red winter wheat at the agronomic N rate (100 kg PAN ha−1). Anaerobically digested and lime‐stabilized biosolids were fall applied at rates of 100 and 50 kg PAN ha−1. The 50 kg PAN ha−1 biosolids treatments received 50 kg N ha−1 as urea in spring. Urea‐N was split applied at 0, 50, 100, and 150 kg N ha−1, with 1/3 applied in fall and 2/3 in spring. Biosolids increased N use efficiency (NUE) by 0 to 27%, grain yield by 0 to 1.1 Mg ha−1, and N recovery by 0 to 38% compared with agronomic N rate urea in coarse‐textured soils, especially when lime‐stabilized biosolids were used. Biosolids and agronomic rate urea typically resulted in equal NUE, grain yield, and N recovery in fine‐textured soils, regardless of biosolids type or application strategy. Therefore, biosolids can be fall applied at the full agronomic N rate to winter wheat in coarse‐ and fine‐textured soils in Virginia.