灌溉量和垄高对次生盐渍地玉米土壤水盐运移变化及产量的影响

Effects of Irrigation Volume and Ridge Height on Water-Salt Transport in Secondary Saline-Alkali Soil and Maize Yield

为探究宁夏扬黄灌区因多年地面灌溉引起的地下水位上升、次生盐渍化突显等难题,本试验以宁夏红寺堡移民区为研究点,选定典型试验区域开展定位试验监测,设置高效滴灌下不同灌溉量(2160、2700 m^(3)·hm^(-2)和3240 m^(3)·hm^(-2))和起垄高度(20、30 cm和40 cm)2个因素3个水平,通过大田试验研究不同组合处理下的次生盐渍地水盐运移变化规律以及其对玉米生长指标、产量和水分利用效率的影响。结果表明,灌水定额一定时,随垄高增加,0~60 cm土层含水率逐渐降低;相同垄高下,随灌水定额增大,各土层含水率逐渐增加,并且深土层明显高于浅土层。垄作滴灌可以有效降低垄上土壤盐分含量,而各处理土壤深层均不同程度积盐,其中T9处理(3240 m^(3)·hm^(-2)和40 cm组合)40~60 cm土层积盐最明显。T6处理(2700 m^(3)·hm^(-2)和40 cm组合)各项生长指标及产量均优于其他各处理,产量达6597.15 kg·hm^(-2),T5(2700 m^(3)·hm^(-2)和30 cm组合)水分利用效率最高,达到1.53 kg·m-3。通过回归分析发现,玉米产量最大值时和水分利用效率(WUE)最大值时的灌水量和垄高值不同,进一步利用空间分析方法得出,灌水量2685~2730 m^(3)·hm^(-2)和垄高36~39 cm时,玉米产量、WUE均达最大值的90%以上。

In order to address the challenges of rising groundwater level and secondary salinization caused by prolonged surface irrigation in Ningxia Yanghuang irrigation district,a designated experimental area-was selected from Hongsibao of Ningxia,and the location test monitoring was carried out.Two factors with three levels were set as irrigation volume at 2160,2700 and 3240 m^(3)·hm^(-2)and ridge height at 20,30 and 40 cm under efficient drip irrigation.The water and salt movement patterns in secondary saline soil under dif-ferent combination processings and their effects on maize growth indicators,yield and water use efficiency(WUE)were studied through field experiment.The results indicated that the moisture content in 0~60-cm soil layer decreased with ridge height increasing at a constant irrigation quota,while it increased with irrigation vol-ume increasing at a constant ridge height,and the deeper the soil layer was,the higher the moisture content was.Ridge drip irrigation could reduce soil salinity on ridges effectively,while varying degrees of salt accumulation oc-curred in deeper soil layers in all treatments,among which,T9 treatment(combination of 3240 m^(3)·hm^(-2)and 40 cm)showed the most obvious in salt accumulation in the 40~60-cm soil layer.In T6 treatment(combination of 2700 m^(3)·hm^(-2)and 40 cm),both the growth indicators and yield were superior to those in the other treat-ments,and the yield was up to 6597.15 kg·hm^(-2).In T5 treatment(combination of 2700 m^(3)·hm^(-2)and 30 cm),the WUE achieved the highest level of 1.53 kg·m^(-3).Regression analysis revealed that the irrigation volume and ridge height were different when the maize yield and WUE at their maximum values.Spatial analysis further indicated that both maize yield and WUE reached 90%of the maximum values when the irrigation vol-ume was 2685~2730 m^(3)·hm^(-2)and the ridge height was 36~39 cm.