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干旱农业区采用覆膜滴灌技术,在无覆膜的膜间裸露区内设置排盐浅沟,探讨不同灌水定额和不同排盐梯度条件下,覆膜滴灌土壤盐分定向运移和盐分上移地表排盐效果。研究结果表明,膜下滴灌定向排盐效果明显,滴头附近形成盐分淡化区域,排盐沟周边形成盐分集中区域。地表以下0~60cm平均土壤盐分普遍呈现膜下的盐分低于膜外,而膜外裸露区积盐作用显著的特点。灌溉用水量愈大,排盐作用愈强烈,相应的积盐数量也愈大。通过农田排盐沟灌水冲洗后的地表排水矿化度随时间呈减小趋势,排盐梯度最小的试验小区冲洗排盐量最大。总体来说,在排盐沟冲洗定额1515m3/hm2条件下,各小区总排盐量达到4521~6351kg/hm2,表明盐分上移地表排的脱盐效果显著。
In the arid agricultural zone, the technique of film drip irrigation was used to set up the salt-draining shallow ditch in the uncovered membrane-free exposed area. The effects of different irrigation quotas and different salt-discharging gradient on the salinity movement and salinity uplift of the soil Drainage effect. The results show that the effect of directional salt discharge under drip irrigation is obvious, salt desalination area is formed in the vicinity of dripper, and salt concentration area is formed around salt discharge ditch. The average soil salinity below 0-60 cm below the surface is generally lower than that under the membrane, while the salinity outside the membrane is significant. The greater the amount of irrigation water, the stronger the role of salt discharge, the corresponding amount of salt is also larger. The salinity of surface drainage after rinsing with salt drainage ditches in farmland tends to decrease with time, and the amount of salinization in the test plot with the lowest salt gradient is the largest. In general, under the condition of 1515m3 / hm2 of flushing ditches, the total amount of discharged salt in each plot reached 4521 ~ 6351kg / hm2, indicating that the desalting effect of the surface row with the upward salinity was remarkable.