淹水历时与排水对夏玉米叶面积和产量的影响

通过防雨棚下测坑试验,研究了不同淹水历时和是否排水对夏玉米叶面积、产量及其性状、生物产量的影响,结果表明:夏玉米植株绿叶数和叶面积指数(LAI)随着淹水历时增加而急剧减少,与CK(无淹水)相比,排水条件下FD4、FD5、FD6、FD7和FD9绿叶数分别减少12.50%、10.71%、19.64%、32.14%和42.86%,无排水条件下FUD4、FUD5、FUD6分别减少21.43%、37.50%和51.79%;各处理LAI变化幅度类似于绿叶数,与CK相比,排水条件下LAI平均减少21.81%,无排水条件下LAI平均减少38.32%;相同淹水历时条件下,不排水处理对玉米叶面积抑制作用明显高于排水处理。夏玉米穗长、穗粒数、百粒重随着淹水历时增加呈减小趋势,秃尖长呈增大趋势,籽粒产量和生物产量减产幅度增加;与CK相比,排水条件下,淹水历时超5d后减产明显增加,淹水历时每增加1d,减产率增加7%左右;无排水的条件下,FUD4、FUD5和FUD6分别减产34.06%、49.64%和58.82%;相同淹水历时4d、5d和6d,排水与否减产率分别相差31.20个百分点、45.57个百分点和40.82个百分点。夏玉米排水指标为:在夏玉米抽雄期排水情况下,淹水历时应低于6d,籽粒产量减幅可控制在5%以内;在没有排水条件下,淹水历时应小于4d,否则减产在30%以上。

Effects of Flooding Duration and Drainage on Leaf Area and Yield of Summer Maize

By imposing different irrigation treatments on summer maize(Zea mays L.) grown under a rain shelter,the effects of different flooding duration and whether drainage or not on leaf area,yield and its components of summer maize were studied.The results showed that the number of green leaves and leaf area index(LAI) of summer maize decreased sharply with the flooding duration increased.Compared with CK(no flooding),under drainage conditions,the number of green leaves of FD4,FD5,FD6,FD7,and FD9 decreased by 12.50%,10.71%,19.64%,32.14% and 42.86%,respectively,and that of FUD4,FUD5,FUD6 decreased by 21.43%,37.50% and 51.79%,respectively,under no drainage conditions.The magnitude of LAI changes of each treatment was similar to the number of green leaves.Compared with CK,the average LAI of treatments with drainage conditions decreased by 21.81%,and that with no drainage conditions decreased by 38.32%.Under the same flooding duration condition,the inhibition effect of no drainage treatments on leaf area was significantly higher than that of the drainage treatments.As the flooding duration was increased,ear length,grains per spike and kernel weight tended to decrease,bald tip tended to increase,and grain yield and biomass production showed increasing degree of reduction.Compared with CK,under the drainage conditions with flooding duration over 5 d,the cut rate significantly increased,with flooding lasting for additional 1 d,the cut rate increasing of 7%.Under no drainage conditions,the grain yield of FUD4,FUD5 and FUD6 reduced by 34.06%,49.64% and 58.82%,respectively.At the same flooding duration of 4,5 and 6 d,the difference of the cut rate between drainage and no drainage was 31.20,45.57 and 40.82 percentage points,respectively.The drainage index of summer maize was proposed in this region.The flooding duration under drainage conditions should be less than 6 days in tasseling stage,and the reduction of yield could be controlled within 5%.In the absence of drainage conditions,the flooding duration should be less than 4 days,otherwise,yield would decrease by more than 30%.