Coupling Effects of Water-fertilizer on Soil Water Distribution and Soil Nitrogen under Drip Irrigation

The effects of water-fertilizer coupling on the distribution of soil moisture and soil nitrogen were studied under surface drip irrigation.The results showed that the changes of soil moisture were mainly affected by irrigation scheduling;The absorption and utilization of crop water were promoted by improving fertilizer application rate under proper irrigation scheduling.The distributions of soil nitrate nitrogen and soil ammonia nitrogen were significantly affected by irrigation scheduling,fertilizer application rate and water-fertilizer coupling.The risk of soil nitrate leaching was larger under the treatment of high irrigation quota and high fertilizer application rate,fertilizer use efficiency was higher and the potential leaching risk was the minimum under the treatment of moderate irrigation quota and moderate fertilizer application rate, and the probability of ammonia volatilization as well as leaching loss under the treatment of low irrigation quota and high fertilizer application rate was obviously higher than those under the other treatments.