秸秆覆盖和播前灌水量对夏玉米抗倒伏特性的影响

【目的】研究秸秆覆盖和播前灌水量对成熟期夏玉米茎秆抗倒伏特性的影响。【方法】设置2种覆盖处理(秸秆覆盖处理和不覆盖处理,秸秆覆盖处理为小麦秸秆覆盖0.6 kg/m~2)和3种播前灌水量(低灌溉量30 mm、中灌溉量70 mm和高灌溉量110 mm),测定了成熟期夏玉米茎秆主要物理性状参数、倒数第3节间茎秆机械强度、抗倒伏指数和产量等指标。【结果】与不覆盖相比,秸秆覆盖增加了夏玉米穗位高、重心高度和茎秆抗折力,提高了玉米抗倒伏能力和籽粒产量(2017年增产7.6%)。播前灌水量显著影响夏玉米成熟期穗位高系数和倒数第3节间茎长、长粗比和茎秆机械强度,播前灌水量越高籽粒产量越高。秸秆覆盖下播前灌水70 mm玉米抗倒伏能力最优,不覆盖处理播前灌水70 mm玉米抗倒伏能力最差。茎秆长粗比和茎秆抗折力与玉米抗倒伏指数相关系数(r)2016年分别为:-0.458 7、0.434 6,2017年分别为:-0.315 7、0.375,穗位高系数不能作为评价玉米抗倒伏特性的指标。【结论】秸秆覆盖+播前灌水70 mm是实现抗倒高产的最优组合方案。

The Effect of Straw Mulching and Pre-sowing Irrigation on Resistance of Summer Maize Against Lodging

【Objective】Lodging damages crop and leads to yield loss. The purpose of this paper is to investigate experimentally the feasibility of straw mulching and pre-sowing irrigation in improving the resistance of summer maize at mature stage against lodging.【Method】The experiment consisted of two mulching treatments: mulching with wheat straw at 0.6 kg/m~2 and no mulching, and three pre-sowing irrigation amounts: low irrigation at 30 mm,intermediate irrigation at 70 mm and sufficient irrigation at 110 mm. Overall, there were 6 treatments. During each treatment, the physical parameters of the maize stalk, the physical strength of the last third internode, the lodging resistance index at mature stage, and ultimate yield were measured.【Result】Compared with no mulching,mulching increased height of the spike position and the gravitational center, as well as the bending strength of the last third internode; it also improved the lodging resistance and the grain yield by 7.6%. Irrigation had a significant impact on height of the spike position, plant height, the ratio of height to diameter and mechanical strength of the last third internode at the mature stage. The grain yield increased with the irrigation amount. Mulching coupled with 70 mm of irrigation was most effective against lodging, and irrigating 70 mm without mulching was most vulnerable to lodging. The lodging resistance index correlated with the ratio of stalk length to its diameter as well as the bending strength of the last third internode, with their correlation coefficient being-0.458 7 and 0.434 6 respectively in 2016, and-0.315 7 and 0.375 respectively in 2017. The lodging resistance was independent of height of the spike position.【Conclusion】Mulching with wheat straw coupled with 70 mm of irrigation prior to sowing can improve lodging resistance of summer maize.