灌溉水盐度对玉米出苗、产量、品质及土壤盐分动态的影响

The Effects of Irrigation Water Salinity on Maize Emergence,Yield,Quality and Soil Salt Dynamics

为探究适宜于我国北方干旱半干旱农业区玉米正常出苗、籽粒高产优质、土壤积盐有限的灌溉水盐分浓度,在内蒙古河套灌区开展了为期2年的膜下滴灌玉米大田试验。设置5个灌溉水盐度水平(1、2、3、4、5 g/L),在土壤基质势下限-20 kPa和灌水定额22.5 mm/次条件下,玉米耗水量、植株干物质量和籽粒产量均与灌溉水盐度呈显著二次函数关系(R^(2)>0.84),当灌溉水盐度为2 g/L时植株干物质量和籽粒产量达到极大值,当灌溉水盐度超过3 g/L时,含盐水灌溉对玉米出苗、植株干物质积累和籽粒产量均产生不利影响。灌溉水盐度在1~5 g/L范围内每增加1 g/L,膜下滴灌玉米对应水分利用效率下降0.29 kg/m~3;籽粒蛋白质含量随灌溉水盐度增加而增加,籽粒淀粉含量随灌溉水盐度增加而降低。此外,当灌溉水盐度高于3 g/L时,膜下滴灌对应土壤盐分等值线垂直半径和水平半径均随灌溉水盐度的增加而减小。基于玉米生育期内籽粒高产优质、减少土壤积盐的目标,在试验设计条件下,推荐河套灌区膜下滴灌玉米的灌溉水盐度上限为3 g/L。

To explore the appropriate irrigation water salinity for normal emergence,high yield,good quality of maize,as well as limited soil salt accumulation in arid and semi-arid agricultural areas of northern China,a two-year field experiment of maize mulched drip irrigation was carried out in Hetao Irrigation District of Inner Mongolia.The experiment involved five irrigation water salinity levels(1,2,3,4,and 5 g/L).Under the conditions with soil matric potential lower limit of-20 kPa and irrigation quota of 22.5 mm per application,the water consumption,plant dry matter accumulation and grain yield of maize had significant quadratic function relationship with the irrigation water salinity(R^(2)>0.84).When the irrigation water salt content was 2 g/L,the plant dry matter accumulation and grain yield reached the maximum value.However,as the irrigation water salinity exceeded 3 g/L,saline water irrigation showed adverse effects on the emergence rate,dry matter accumulation and grain yield of maize.When the irrigation water salinity increased by 1 g/L within the range of 1~5 g/L,the water use efficiency decreased by 0.29 kg/m3.The grain protein content increased with the increase of irrigation water salinity,while the grain starch content decreased with the increase of irrigation water salinity.In addition,when the irrigation water salinity exceeded 3 g/L,the vertical radius and horizontal radius of soil salinity contour corresponding to mulched drip irrigation decreased with the increase of irrigation water salinity.Based on the goal of achieving high grain yield,good maize quality and reducing soil salt accumulation during the maize growth period,the upper limit of irrigation water salinity for maize mulched drip irrigation in Hetao Irrigation District is recommended to be 3 g/L considering the conditions of the present experiment design.