咸淡水交替滴灌对滨海盐渍土水盐动态和作物生长的影响

Effects of Alternate Saline and Fresh Water Drip Irrigation on Water and Salt Dynamics and Crop Growth in Coastal Saline Soil

【目的】研究黄河三角洲地区不同咸淡水交替滴灌频率对土壤水盐分布状况和作物生长的影响。【方法】以毛叶苕子-玉米轮作为研究对象,开展两季作物咸、淡水交替滴灌田间试验。试验设置3个咸淡水交替滴灌频率,对应的咸(咸水矿化度4 g/L左右)、淡(淡水矿化度1 g/L左右)水灌溉频率比分别为1:3(T2处理)、1:1(T3处理)、3:1(T4处理),此外,设置仅灌淡水(T1处理)和仅灌咸水(T5处理)作为对照。通过测定作物生育期内的土壤EC值、作物生物量和产量,探究咸淡水交替滴灌频率对黄河三角洲地区土壤水盐运移和玉米产量影响。【结果】(1)在非雨季土壤水分动态主要受灌溉控制,随着咸水灌溉频率的增加,土壤盐分显著增加;雨季土壤水分动态主要受降水影响,各处理土壤盐分逐渐降低。整体来看,0~20cm土层周年盐分维持平衡;从毛叶苕子返青期到玉米成熟期,T1—T4处理20~60cm土层盐分均呈下降趋势,分别下降26.14%、11.61%、13.17%、6.43%,而T5处理则增加21.26%。(2)毛叶苕子鲜草产量和干物质产量随咸水灌溉频率的增加而降低,T2—T4处理与T1处理之间无显著差异,而T5处理的鲜草产量和干物质产量较T1处理分别显著降低15.54%和19.69%。(3)玉米产量随微咸水灌溉频率的增加呈先增加后降低的趋势,T2处理的籽粒产量显著高于T5处理,但与T1、T3、T4处理差异不显著。T3、T4、T5处理籽粒产量较T1处理分别降低了4.33%、4.58%、7.87%。【结论】咸、淡水交替滴灌频率比为3:1(T4处理)可减少淡水灌溉量,维持土壤周年盐分平衡,稳定苕子生物量和玉米产量,可作为黄河三角洲盐渍农田最佳咸淡水交替灌溉方案。

【Objective】The aim was to study the effects of different frequency of alternating saline and fresh water drip irrigation on soil water and salt distribution and crop growth in the Yellow River Delta Region.【Method】A field experiment of alternating saline and fresh water drip irrigation for Vicia villosa(V.villosa)-maize(Zea mays L.)in two seasons was conducted.The experiment was divided into three frequency treatments of alternating saline and fresh water drip irrigation,and the corresponding irrigation frequency ratios of saline water(salinity of about 4 g/L)and fresh water(salinity of about 1 g/L)were 1∶3,1∶1 and 3∶1(T2—T4 treatments),respectively.Additionally,a treatment of fresh water irrigation only(T1 treatment)and a treatment of saline water irrigation only(T5 treatment)were set as the control.The effects of different frequency of alternating saline drip irrigation on soil water and salt transport and maize yield in Yellow River Delta Region were explored by measuring soil EC value,crop biomass and yield during crop growth period.【Result】①Soil water dynamics was mainly controlled by irrigation in non-rainy season,and soil salinity increased significantly with the increase of saline irrigation frequency.During the rainy season,soil water dynamics were mainly affected by rainfall,and the salinity in each treatment decreased gradually.On the whole,annual salinity in the 0-20 cm soil layer was balanced.In T1—T4 treatments,the salinity in the soil layer of 20-60 cm showed a decreasing trend from the regreening stage of V.villosa to the mature stage of maize,decreased by 26.14%,11.61%,13.17%and 6.43%,respectively,while that in T5 treatment increased by 21.26%.②With the increase of saline irrigation frequency,the yield of fresh grass and dry matter yield decreased.There was no significant difference between T2—T4 treatments and T1 treatment,but the fresh grass yield and dry matter yield of T5 treatment were significantly reduced by 15.54%and 19.69%,respectively,compared with T1 treatment.③Maize yield increased first and then decreased with the increase of saline water irrigation frequency.Grain yield for T2 treatment was significantly higher than that of T5 treatment,but there was no significant difference between T2 and T1 treatment,as well as T3 and T4 treatments.The grain yield of T3—T5 treatments was 4.33%,4.58%and 7.87%lower than that of T1 treatment,respectively.【Conclusion】The frequency ratio of saline and fresh water alternating drip irrigation 3∶1(T4 treatment)can reduce the amount of fresh water irrigation,maintain the annual soil salt balance,and stabilize the biomass of the V.villosa and maize yield,which can be used as the best saline and fresh water alternating irrigation scheme for saline farmland in the Yellow River Delta Region.