Impacts of N‐stabilizers and Biochar on Nitrogen Losses, Nitrogen Phytoavailability, and Cotton Yield in Poultry Litter‐Fertilized Soils

Abstract

Core Ideas Effect of nitrogen stabilizers were evaluated on nitrogen uptake and yield of cotton in poultry litter fertilized soils. Nitrogen stabilizers effect on nitrogen losses as NH3 and N2O were evaluated from poultry litter fertilized soils. Effect of pine hardwood biochar on nitrogen uptake, yield of cotton, and nitrogen losses were evaluated from poultry litter fertilized soils. Poultry litter (PL) serves as a multi‐nutrient fertilizer. However, compared to inorganic fertilizers, PL requires high rate of application to meet crop nutrient requirements due to relatively low concentration and easy loss of nutrients. A 4‐yr field experiment was conducted with cotton (Gossypium hirsutum L.) to examine the effect of the N‐stabilizers [N‐(n‐butyl) thiophosphoric triamide (NBPT) and dicyandiamide (DCD)], and pine hardwood biochar (PBC) on minimizing N‐losses through NH3 volatilization and N2O emissions, plant nutrient content and agronomic yield in PL applied soils. Application of NBPT to PL was evaluated at 1, 2, and 4 kg ha−1, and NBPT+DCD at 0.22 kg NBPT+2.72 kg DCD and 0.44 kg NBPT+5.44 kg DCD ha−1 with PL only and untreated control treatments. PBC applied to PL was evaluated at 2 and 4 Mg ha−1 along with PBC only at 4 Mg ha−1. The results showed that N‐stabilizers were useful in mitigating PL N‐losses via reducing NH3 volatilization and N2O emissions by up to 12 and 64%, respectively, compared to PL only treatment. N‐stabilizers also improved plant tissue‐N content by up to 5.5% and cotton yields by about 6% over PL treatment. The application of NBPT at 2 kg ha−1 with PL produced higher cotton yield along with lower N losses. For NBPT+DCD, 0.44 kg NBPT+5.44 kg DCD ha−1 with PL performed better than 0.22 kg NBPT+2.72 kg DCD ha−1. PBC was effective in reducing N‐losses through NH3 volatilization and N2O emissions, compared to PL and the untreated control. However, PBC led to reduced N‐availability to plants, as evidenced by lower tissue N‐content and lower cotton yields.