Increasing Nitrogen Fertilizer Efficiency in Wetland Rice

Abstract

Increasing rice yields in the main objective, so using nitrogen fertilizers in paddy fields in proportional increase. Nevertheless the effciency of nitrogen fertilizers in paddy fields in still low due to flooding soil condition, nitrogen is alwasys changeable and loss. Available data from most rice-growing countries indicated that to lower losses and increase efficiency, modern rice varieties that have more abilities to uptake nitrogen give more rice yields than local varieties even no fiertlizer application. Conventional nitrogen fertilizers should be applied in two to three times, with one time applied at the panicle intiation stage. Placement of fertilizer nitrogen as urea supergranules at 10 cm below soil surface also increases the fertilizer nitrogen efficiency. Use of slow-release nitrogen fertilizers as sulfur-coated usea (SCU) appears promising in a number of rice-growing countries. But using nitrification inhibtors and urease inhibitors in paddy fields are still uncertain and should have further study.