Effects of potassium application rate on stem lodging resistance of summer maize under high yield conditions

Abstract

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 17.90%, 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.