新疆膜下滴灌棉田土壤有效态氮空间分布特征

棉花膜下滴灌条件下的棉田土壤碱解氮、铵态氮含量变化是,0~10 cm土层与滴灌带垂直水平方向0~75 cm变化波动最大,其次是10~20 cm土层,20~60 cm变化比较小。硝态氮含量的水平变化有所不同,0~60 cm各层土壤变化均较大;棉花各生育时期土壤垂直向下0~60 cm土层碱解氮含量和盛花期铵态氮含量,由上向下呈比较均匀的直线递减变化,硝态氮含量是0~10 cm土层比10 cm以下高出1倍多,呈陡减变化趋势;膜下滴灌棉田土壤碱解氮含量随棉花生育进程逐渐下降,但在棉花生长发育的整个过程中始终保持在63~81 mg/kg较高水平,这是新疆获得大面积棉花高产的重要原因之一。

Space Distribution Characteristic of Soil Available Nitrogen Under Film Trickle Irrigation in Cotton Field in Xiniang

Variance of the content of cotton field soil alkalized nitrogen and ammonium nitrogen of cotton field soil is: soil layers of 0～10 cm and 0～75 cm horizontal direction being perpendicular to trickle irrigation belt fluctuating is maximum;next,the variable motion of soil layers of 10～20 cm and 20～60 is small.The horizontal variance of the content of nitrate nitrogen is different;The variable motion of every soil layer in 0～60 cm is all greater.The content of alkalized nitrogen of soil layer of 0～60 cm beirg perpendicular to down at different growth stages of cotton and the content of ammonium nitrogen at full bloom stage change from up to down;The content of nitrate nitrogen in 0～10 cm soil layer is more than twice higher than that under 10 cm.The content of alkalized nitrogen under film trickle irrigation in cotton field was decreased with the growth progress of cotton,but remain 63～81 mg/kg throughout all cotton growth process;This is one of the important reasons of reaping a bumper harvest over large areas.