Nutrient Uptake and Leaching from Soil Amended with Cattle Manure and Nitrapyrin

We investigated whether nitrification inhibitor nitrapyrin can reduce nutrient leaching and increase nutrient uptake by corn (Zea mays L.) in cattle manure amended soil. Amendments included non-amended check (CK), urea (Urea), REG (manure from cattle fed barley grain), and DDGS (manure from cattle fed 60% dried distillers grains with solubles), co-applied with or without nitrapyrin and leached or unleached with water. Nitrapyrin reduced (P<0.01) leaching of nitrate by 56, 32, and 24% from DDGS, REG, and Urea treatments, respectively, and also reduced (P<0.05) leaching of phosphate (58%), potassium (39%), calcium (39%), and magnesium (39%) from DDGS treatment. While nitrapyrin reduces the rate of ammonium conversion to nitrate, higher magnesium and phosphate levels in DDGS-amended soil favor struvite formation and reduce their leaching. Corn biomass and nutrient uptake were higher (P<0.01) in DDGS and Urea than CK and REG treatments, but remained unaffected by nitrapyrin. The benefits of nitrapyrin should be further investigated under field conditions.Abbreviations: DCD, dicyandiamide; DDGS, dried distillers grains with solubles; NI, nitrification inhibitor; TP, total P; TN, total N.