Processed manures sustain silage corn yield with amendment‐specific soil and forage response

Abstract

In semiarid western US dairy systems, field evidence remains limited on whether processed manure products can sustain silage corn ( Zea mays L.) productivity and improve soil health. A field experiment conducted in Logan, UT, during 2021–2022 compared compost, vermicompost, Sedron (a thermally and mechanically processed dairy manure), dissolved air flotation, mineral fertilizer, and unfertilized control for their effects on soil chemical properties, silage corn yield, forage quality, and soil health indicators. Amendments effects on soil pH and total carbon were limited, but the compost + vermicompost mixture produced the highest surface‐soil phosphorus and potassium concentrations of 35.6 and 241 mg kg ⁻¹ , respectively. Silage corn yield ranged from 21.5 to 27.8 Mg ha ⁻¹ in 2021 and 17.0 to 25.8 Mg ha ⁻¹ in 2022. The compost + vermicompost produced the highest yield of 25.8 Mg ha ⁻¹ in 2022 compared with 17.0 Mg ha ⁻¹ in the control. Sedron produced the highest crude protein and total digestible nutrients and the lowest acid detergent fiber (ADF), at 8.40%, 73.0%, and 21.1%, respectively. Compost increased soil infiltration to 1.83 cm h ⁻¹ compared with 0.62 cm h ⁻¹ in the control. Sedron maintained higher potentially mineralizable nitrogen (N) in the second year. Processed manure products did not consistently outperform compost or mineral fertilizer, but individual products improved specific responses. These materials may therefore be useful in silage corn systems for recycling manure nutrients while improving forage quality, infiltration, or N mineralization. Longer‐term studies are needed to determine whether these effects persist and lead to broader gains in soil health and nutrient‐use efficiency.