Importance of Soil Properties on Recommended Biosolids Management for Winter Wheat

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.