黄淮地区涝渍胁迫影响夏玉米生长及产量

在黄淮平原,夏玉米常因降水过多遭受涝渍害而减产,确定其能忍受的涝渍胁迫天数,可为该区减轻涝渍引起的夏玉米产量损失和农业生产防灾减灾管理提供依据。该研究在田间条件下以玉米品种浚单20为试验材料,分别于玉米拔节期和抽雄期设置持续淹水(3和5 d)和渍水(5、7和10 d)处理,旨在研究黄淮地区夏玉米拔节期和抽雄期持续涝渍胁迫对其生长及产量的影响。结果表明:玉米拔节期连续淹水3 d或拔节期、抽雄期连续渍水5 d夏玉米产量开始降低,产量损失率随涝渍时间延长而增加:拔节期淹水3 d、抽雄期淹水5 d,其产量损失率分别为28.4%和42.8%;拔节期或抽雄期渍水5 d的产量损失分别为13.8%和5.5%(2011年)和3.0%和3.4%(2012年);拔节期淹水5 d产量损失是淹水3 d的3.1倍;拔节期或抽雄期渍水10 d产量损失分别为渍水5 d的1.3和3.0倍(2011年)、2.4和3.2倍(2012年)。淹水天数相同时,拔节期淹水产量损失率大于抽雄期淹水。所有淹水处理都会降低每平方米有效株数,而抽雄期淹水5 d还影响秃尖比,拔节期淹水5 d影响所有测定指标如收获指数、果穗性状等。不同于淹水处理,所有渍水处理都不影响每平方米有效株数,但影响果穗长和秃尖比、收获指数(抽雄期渍水5 d除外)。涝渍胁迫的后续影响与胁迫生育期、及涝渍天数有关,如抽雄期淹水3~5 d和抽雄期渍水5 d只影响乳熟期地上部分干质量累积,而抽雄期渍水7 d会影响所有生育期干质量累积。拔节期淹水5 d和渍水10 d使玉米后期(吐丝后25~35 d)灌浆速度降低59.6%和28.9%。因此在玉米实际生产中出现连续强降水天气时,建议尽快采取排涝降渍措施减少以避免玉米拔节期连续淹水3 d或抽雄期连续渍水5 d,从而降低涝渍胁迫对玉米生长及产量的影响。

Effect of waterlogging at jointing and tasseling stages on growth and yield of summer maize

Abstract: Huang-huai Plain of China is featured of heavy rainfall in June-September, which accounts for 60%-70% of total annual precipitation. The heavy rainfall-induced soil waterlogging stress during the summer rainy season (June-September) is one of the major constraints for summer maize (Zea mays L.) production in the region. It is necessary to determine the critical days that crops can tolerate stress for minimizing the adverse effect of stress on crop production. In this study, a field experiment was conducted during the summer maize growing season from 2011 to 2012 at Hefei Agrometeorological Experimental Station in Anhui province in order to investigate the effect of waterlogging stress on the growth and grain yield of summer maize and determine the critical days of waterlogging stress. The Xundan No.20 widely cultivated in Huang-huai Plain was used as tested maize. Surface (3 and 5 days) and subsurface (5, 7 and 10 days) waterlogging duration the jointing and tasseling stages were designed. The surface waterlogging was assumed to be 5 cm depth of water on soil surface and the subsurface waterlogging was considered to be 90% of field capacity. Meanwhile, the control soil (CK) had soil moisture kept at 70%-80% of field capacity. Each waterlogging treatment in a plot about 20 m2 had three replicates The aboveground dry matter and leaf area per plant were measured at the jointing, tasseling, milking and maturity stages, respectively. Yield characteristics of summer maize, such as ear length, ear diameter, length of bare tip, grain number per spike, 100-seed weight and harvest index were determined. The results showed that the effect of waterlogging on the growth and yield varied with types and duration of waterlogging at different developmental stages of summer maize. Compared with CK, the surface waterlogging for 3 days at the jointing and for 5 days at tasseling stages resulted in an average decrease in yield with 28.4% and 42.8%, while the subsurface waterlogging for 5 days at jointing or tasseling stages resulted in an average decrease in yield with 3.0%(2012)-13.8%(2011) and 3.4%(2012)-5.5%(2011), respectively. The damage degree due to waterlogging stress at the jointing stage was greater (P<0.05) than at the tasseling stage under the same waterlogging duration, and the yield loss rates were increased with the prolonged waterlogging days. The yield loss rates of surface waterlogging for 5 days was 3.1 times that of surface waterlogging for 3 days at jointing stages, while the yield loss rates of subsurface waterlogging for 10 days were 1.3-3.0 times (2011) and 2.4-3.2 times (2012) that of subsurface waterlogging for 5 days, respectively. The yield losses were related with 100-grain weight and grains per spike. Waterlogging stress not only reduced the grain yield of maize, but also affected the characters of spike, harvest index, the accumulation and distribution of aboveground dry matter weight, leaf area per plant and the grain filling rates. Leaf areas per plant at the milky stage were decreased by 21.2%-65.7% and 4.0%-8.5% in the surface waterlogging and subsurface waterlogging treatments, respectively. The aboveground dry matter weight were reduced by 43.6% and 6.5% in the treatments of surface waterlogging for 5 days and subsurface waterlogging for 10 days at jointing stages, respectively, and the proportion of dry matter in corncob was reduced by 18.8% and 4.2%. The grain filling rate at 25-35 days after silking in the surface waterlogging for 5 days at the jointing or tasseling stages and subsurface waterlogging for 10 days at the jointing stage was decreased by 59.6%, 50.0% and 28.9%, respectively. Therefore, effective measures should be taken to avoid waterlogging for 3 days at jointing stages or 5 days at tasseling stages, when heavy rainfall occurred in the growing season of summer maize.