暗管排水条件下微咸水灌溉对土壤盐分动态及夏玉米生长的影响

进行暗管排水条件下微咸水灌溉田间试验,设置3种暗管埋深,分别为80 cm(D1)、120 cm(D2)以及无暗管排水(D0),3种微咸水浓度,其电导率分别为0.78 dS/m(S1),3.75 dS/m(S2)和6.25 dS/m(S3),共9个处理,每个处理3组重复.试验结果表明:暗管排水措施可以有效排除微咸水灌溉过程中土壤中累积的盐分;在玉米全生育期内,暗管埋深D1条件下,3种浓度微咸水S1,S2和S3灌溉时根系土壤电导率分别下降了39.00%,31.56%和29.43%,暗管埋深D2条件下,根系土壤电导率则分别下降了31.91%,18.08%和7.44%;夏玉米干物质累积量、穗棒累积量和穗棒质量分配率及最终产量均随着微咸水浓度的升高而降低;在相同微咸水浓度下,不同暗管埋设条件下的夏玉米最终产量从大到小依次为D1,D2,D0;3种暗管埋设条件下的作物需水量从大到小依次为D0,D2,D1的规律;暗管埋深80 cm的处理(D1)下夏玉米水分利用效率最高,而未埋设暗管的处理(D0)水分利用效率最低;当暗管埋设条件一定时,夏玉米水分利用效率随微咸水浓度的升高呈逐渐降低的趋势.

Effects of saline water irrigation on soil salinity movement and summer maize growth under subsurface drainage

A field experimental study was conducted to identify the effect of saline water irrigation on soil salinity movement and summer maize growth under subsurface drainage system. This study was comprised of nine treatments combined with three subsurface drainage depths, namely 0 m-no subsurface drainage(D0), 0.8 m(D1)and 1.2 m(D2)and three water salinity levels, such as 0.78 dS/m(S1), 3.75 dS/m(S2), and 6.25 dS/m(S3). The results indicate that the accumulated salt in the soil is effectively removed under subsurface drainage during the studied period. At the drainage depth of 80cm, the soil electronic conductivity within the root depth is decreased by 39.00%, 31.56% and 29.43% in S1, S2 and S3, respectively. But at the drainage depth of 120 cm, the soil electronic conductivity is decreased by 31.91%, 18.08% and 7.44% in S1, S2 and S3, respectively. The dry matter and yield of summer maize are reduced with increasing irrigation water salinity at the same drainage depth. The water use efficiency of summer maize from large to small is D1,D2 and D0 at the same irrigation water salinity. At the same drainage depth, the water use efficiency is decreased gradually with increasing irrigation water salinity.