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

Ammonia volatilization causes major nitrogen losses from the soil and applied urea which results in low urea-N usage efficiency. In line to this, laboratory incubation experiment was conducted to assess the effect of rice straw and rice husk biochar on ammonia volatilization, soil pH, exchangeable ammonium, and available nitrate in comparison to the urea without additives under waterlogged conditions. Application of mixture of rice straw and rice husk biochars at application rate 5-10 t ha-1 had significantly minimized ammonia volatilization by 30.86%-38.61% over T1. The biochar mixture also had increased retention of ammonium and nitrate ions with increment of soil pH over control. Hence, the findings suggest that urea amended with rice straw and rice husk biochar altered the nutrients level in soil by minimizing ammonia loss in a way that enhanced nitrogen availability in waterlogged conditions.