膜下滴灌布置方式对土壤水盐运移和产量的影响

以棉花主要根系层各生育期保持适宜土壤含水率为灌水目标,设置一膜单管四行和一膜双管四行两种毛管布置方式,以TRIME-T3管式TDR测定土壤含水率指示灌水,开展膜下滴灌大田试验,研究了干旱区膜下滴灌棉田土壤水盐运移规律及分布特征,并对不同滴灌模式下的棉花产量和灌溉水生产效率进行评价。结果表明:膜下滴灌单、双管布置棉花生育期内灌溉定额分别为390、550 mm;双管布置在10~40 cm棉花主要根系层形成适宜作物生长的淡化脱盐区,生育期内棉花主要根系层土壤含水率处于适宜的范围,灌水均匀度高,控盐效果好,棉花生长不受水盐胁迫;单管布置盐分随水分运移至湿润锋边缘至外行,棉花主要根系层有积盐的趋势,加上滴头流量大,不利于淡化脱盐区的形成。膜下滴灌毛管布置方式决定土壤水盐分布特征,进而影响植株对水分和养分的吸收,单、双管布置棉花产量分别为5 355、6 075 kg·hm~(-2),灌溉水生产效率分别为1.38、1.11 kg·m~(-3),单管布置灌溉水生产效率较高。

Effect of different pipe arrangements on soil water-salt transport and yield of cotton under mulched drip-irrigation

The soil water content for the main root layer of cotton at growth stages was kept constantly favorable in the experiment ,with different treatments including a single pipe (drip-irrigation pipe ) and two pipes on four rows of cot-ton planting . In addition ,TRIME -T3 tubular TDR was employed to measure the soil water content , the water-salt transportation and salt distribution characteristics was studied to evaluate the cotton yield and irrigation water use efficien-cy under different pipe arrangement in arid area .The results indicated that the irrigation quota for single pipe and two pipes treatment under mulched drip-irrigation were 390 mm and 550 mm ,respectively ,during the whole growth period of cotton .Two pipes treatment resulted in desalination areas which fitted for the growing of cotton in the main root layer of 10~40 cm depth ,the soil water content was in appropriate range ,had higher irrigation uniformity and a beneficial effect on the controlling of salt ,and the cotton growth was not affected by water and salt stress .The single pipe treatment showed that the salt transport was followed with water movement to the edge of wetting front ,and the salt accumulation occurred in the main root layer of cotton .The larger dropper flow was not conducive to the formation of the desalination area .The drop-irrigation pipe arrangement influenced the soil water-salt distribution characteristic ,and then affected the water and nutrients absorption of cotton ,with the single pipe and two pipes arrangements having the yield of 6 075 kg·hm-2 and 5 355 kg·hm-2 ,and the irrigation water use efficiency of 1 .11 kg·m-3 and 1 .38 kg·m-3 respectively . The single pipe treatment can obtain higher irrigation water use efficiency .