施钾量对高产夏玉米抗倒伏能力的影响

倒伏是玉米高产的重要限制因素之一。本研究旨在探讨施钾量对高产夏玉米抗倒伏能力的影响，为钾肥科学施用提供科学依据。选用登海661 (DH661)和郑单958 (ZD958)，设置6个施钾水平，研究高产条件下施钾量对夏玉米基部茎节穿刺强度、伤流量和产量的影响，并观察基部第3茎节显微结构。结果表明，施钾肥能显著提高茎秆的穿刺强度，DH661和ZD958最大提高幅度分别为17.9%和25.57%，但不同茎节提高幅度不同。伤流液的强度随着施钾量的增大先增加后减小，开花前促进作用大，吐丝期DH661和ZD958施钾180 kg hm^-2时最高，分别比对照提高24.30%和29.68%。单位面积内维管束增加，特别是小维管束增多是提高茎秆穿刺强度的关键。施钾肥可以显著提高玉米产量，随施钾量的增加，籽粒产量呈先增高后降低的趋势，DH661和ZD958分别在施钾180 kg hm^-2和240 kg hm^-2时达到最高产量。

Effects of Potassium Application Rate on Stem Lodging Resistance of Summer Maize under High Yield Conditions

Lodging is an important factor to limit grain yield of summer maize. This study is to investigate the effects of potassium (K) application rate on the lodging resistance of summer maize under high yield cultivation conditions to that providing a reference of reasonable cultivation way. Two cultivars of summer maize (Zea mays L.), Denghai 661 (DH661) and Zhengdan 958 (ZD958), were used and six levels of K application rates were designed. The results showed that the grain yield and bleeding sap were increased at the first, and then gradually decreased with the increment of K application rate. Applied K could enhance rind penetrometer resistance by 17.9%, 25.57% in maximum for DH661 and ZD958. But the increase in different internodes was different. The increased vascular bundles especially the small vascular bundles, per unit area of crease rection of internode, were the key reason to improve stalk puncture strength. DH661 and ZD958 reached the highest yield at the K application rate of 180 kg ha^-1 and 240 kg ha^-1 respectively.