秸秆隔层及不同灌水上限对土壤水氮分布的影响

【目的】探究秸秆隔层以上适宜的灌水上限及其对土壤水分和氮素分布的影响。【方法】通过室内土柱入渗试验,研究了秸秆隔层埋深25cm时饱和含水率、田间持水率、80%田间持水率3个灌水上限情况下土壤水分入渗及水氮分布情况。【结果】①秸秆隔层能抑制水分入渗,显著增加0~25 cm土层的储水量和储水效率。在无蒸发条件下,当灌水上限不超过田间持水率时,6 d后0~25 cm土壤水的储存效率达89%~91%;②秸秆隔层能抑制硝态氮的深层渗漏,增加0~25cm土体硝态氮量。80%田间持水率灌水上限结合秸秆隔层处理对0~25cm土层硝态氮量高于其他处理。【结论】秸秆隔层以上适宜的灌水上限为80%田间持水率。

Effects of Straw Interlayers and Different Irrigation Limits on Soil Water and Nitrogen Distribution

【Background】At present,water and fertilizer use efficiency is low in many protected cultivation areas in southern China.Studies show that straw interlayers can effectively conserve water and fertilizer.【Objective】In order to investigate the optimal irrigation upper limit above the straw barrier and its effect on soil moisture and nitrogen distribution,【Method】Through the indoor soil column test,the distribution of infiltration soil water and nitrogen under three irrigation upper limits of saturated water content,field water holding capacity,and 80%field water holding capacity at 25 cm depth of straw interlayer were studied.【Result】The result indicated that straw interlayer can inhibit water infiltration and significantly increase the water storage capacity and water storage efficiency of 0~25 cm soil.Under the condition of no evaporation,when the upper limit of irrigation water does not exceed the field water holding capacity,the storage efficiency of 0~25 cm soil water reaches 89%~91%after 6 days.Moreover,straw interlayer can inhibit the deep leakage of nitrate nitrogen.Increase the amount of nitrate nitrogen in 0~25 cm soil.The 80%field water holding capacity irrigation upper limit combined with straw interlayer treatment has a higher nitrate nitrogen content in the 0~25 cm soil layer than other treatments.【Conclusion】The suitable irrigation upper limit above the straw barrier is 80%field water holding rate.