小麦／玉米和蚕豆／玉米间作对土壤硝态氮累积和氮素利用效率的影响

Effect of wheat/maize and faba bean/maize intercropping on soil nitrate nitrogen concentration and accumulation

提高氮肥利用效率，减少氮肥过量施用对环境造成的污染，是保障国家粮食生产和生态环境安全的关键。文章以甘肃河西灌区为试验地点，在0、300、450kg．hm^-2氮水平下，探讨了小麦（Triticum aestivum L．），玉米（Zea mays L．）和蚕豆（Hcia faba L．），玉米间作对土壤硝态氮累积和分布的影响。结果表明：随氮肥用量增加，0-60cm土层土壤硝态氮相对累积量增加，100～200cm土层降低。在3个氮水平下，蚕豆间作土壤硝态氮含量和累积量都低于单作。小麦间作在300kg·hm^-2氮水平下土壤硝态氮累积量都低于单作，但在0和450kg·hm^-2氮水平下，小麦收获后间作与单作近似，玉米收获后小麦间作土壤硝态氮累积量都低于单作。与小麦和蚕豆间作的玉米在300kg·hm^-2氮水平下土壤硝态氮累积量都低于单作玉米，在0和450kg·hm^-2氮水平下则表现不同。在300kg·hm^-2氮水平下，两种间作氮肥当季利用率都明显高于相应的单作，施氮量增加到450kg·hm^-2时，则表现不一样。

Increasing nitrogen use efficiency and reducing environment pollution resulted from excessive nitrogen fertilizer application were the key factor for ensuring the safety of food production and environment. Therefore, effect of wheat（Triticum aestivum L.）/maize （Zea mays L.） and faba bean （Vicia faba L.） /maize intercropping on soil nitrate nitrogen content and accumulation were researched in Hexi corridor of Gansu province with 0, 300 and 450 kg·hm^-2 nitrogen rate. The results showed that with the enhancement of nitrogen fertilizer application, 0-60 cm relative soil nitrate nitrogen accumulation increased, and 100-200 cm soil layer decreased. Soil NO3^--N concentration and accumulation of intereropped faba bean were lower than that of solecropped faba bean at three nitrogen rate. At 300 kg·hm^-2 nitrogen application, soil NO3^--N accumulation of intereropped wheat were lower than that of solecropped, yet with 0 and 450 kg·hm^-2 nitrogen application, wheat intereropped and solecropped were the same after wheat harvest, and intercropped wheat were lower than that of solecropped after maize harvest. Soil NO3^_-N accumulation of maize intercropped with wheat and faba bean were lower than that of solecroped maize at 300 kg·hm^-2 nitrogen application, but its different with 0 and 450 nitrogen application. At 300 kg·hm^-2 nitrogen application, the nitrogen use efficiency of wheat/maize and faba bean/maize intereropping were high than that of solecropping, but when nitrogen rate were increased to 450 kg·hm^-2,it appeared different.