Effect of Different Irrigation Water and Nitrigen Rate on Transfer and Leach Soil NO_3~--N in Loess Soil

Soil infiltration experiment was carried out to study the effect different irrigation water and nitrogen rate on transfer and leach soil NO-3-N in loess soil.The results indicated that soil water content increased with irrigation water quantity increase.In large irrigation quota,soil moisture downward migration rapidly in nearly saturated soil layer,nitrogen leach seriously.Under conditions of small irrigation quota,soil moisture in 0-35 cm reduced significantly,not occurring nitrogen leaching.When nitrogen rate is certain,NO-3-N content in soil profile decreases with the increasing of irrigation content and have significantly increasing trend with the increased depth of soil.NO-3-N content in soil profile have an increasing trend with increase of the nitrogen rate,and soil moisture is inversely relation with soil NO-3-N content.There have a positive correlation of soil nitrogen accumulation with the nitrogen rate,soil depth and infiltration time,and have a negative correlation with irrigation water good quantity,which can be described with multiple non-linear model.So in order to reduce nitrogen leaching losses,and consider the economic and environmental benefits,the reasonable rate of irrigation and application N were 80 mm and 1.80 mg/cm2 respectively in loess soil.