Reducing Ammonia Volatilization from Urea Fertilizer Applied in a Waterlogged Tropical Acid Soil via Mixture of Rice Straw and Rice Husk Biochars

Abstract

Nitrogen deficiency frequently occurs in agricultural soil because of ammonia volatilization to the environment, resulting in low urea-N use efficiency by plants. A laboratory incubation experiment was conducted to assess the effect of rice straw and rice husk biochar’s on ammonia volatilization, soil pH, exchangeable ammonium, and available nitrate in comparison to the urea without additives under waterlogged conditions. Application of rice straw and rice husk biochar’s mixture at application rate 5-10 t ha-1 had significantly minimized ammonia volatilization by 30.86% - 38.61% over T1 (175 kg ha-1 urea). T2 (5 t ha-1) and T3 (10 t ha-1) also had significantly increased retention of ammonium by 79% - 95% and nitrate ions by 49% - 51% over control. The treatments amended with biochar had successfully improved soil pH compared to T0 (soil only) and T1. Hence, the findings suggest that urea amended with rice straw and rice husk biochar’s altered the nutrients level in the soil by minimizing ammonia loss to enhance nitrogen availability in waterlogged conditions.

Keywords

• ammonia volatilization
• biochar
• nitrogen
• urea
• ammonium