Effect Of Different Nitrogen Application Time On Lodging Resistance Of Summer Maize (Zea Mays L.)

This study was conducted to observe the influences of different nitrogenapplication time on agronomic morphologies, anatomical characteristics andmechanical characteristics with three summer maize varieties of xianyu335, xundan20and jingdan28. It was in order to achieve high yield, stable yield and provide atheoretical basis in Hebei Province. The results were showed as follows:1. The application of nitrogen fertilizer could significantly increase plant height,base internodes and individual stem dry matter accumulation of summer maize.Different nitrogen application time had no effect on ear height, center of gravity andthe ratio of ear height/plant height. Seed fertilizer and seedling fertilizer couldincrease length and diameter of base internodes, especially increased diameter. So theratio of length/diameter had not significantly increased. Jointing fertilizer could makelength of base internodes quickly elongated, and the ratio of length/diametersignificantly increased. V12fertilizer could make base internodes short and thick, andthe ratio of length/diameter was low. VT fertilizer had no effect on the development ofbase Internodes.2. Seed fertilizer, seedling fertilizer and V12fertilizer could significantlyincrease width of outer vascular bundles group (WVB), percentage of vascularbundles area (PVBA) and width of cuticle tissue (WCT), and promoted the toughnessand mechanical strength of stem. Jointing fertilizer and VT fertilizer decreased WVB,PVBA and WCT, so it was maybe the cause of stem weakness of resistance.3. Seed fertilizer and seedling fertilizer significantly increased bending resistance,breaking resistance and hardness, so the lodging rates were low. Jointing fertilizerdecreased bending resistance, breaking resistance and hardness, so the lodging rateswere high. Increasing bending resistance, breaking resistance and hardness had a greatsignificance on promoting the capability of lodging resistance.4. Length of stem had no significant effects on bending resistance, breakingresistance and hardness. Diameter of stem had highly positive correlations withbending resistance, breaking resistance and hardness. With diameter of stemthickening, bending resistance, breaking resistance and hardness could increase. Andthe capability of lodging resistance of stem was high. WVB, PVBA and WCT had positive correlations with the capability of lodging resistance, so anatomicalcharacteristics could be influence factors on stem lodging resistant ability.