水肥一体化施磷量对玉米抗倒伏能力的影响

Effects of Phosphorus Application Rate on Lodging Resistance of Maize under Integrated Water and Fertilizer

在水肥一体化条件下,探明不同施磷量下玉米茎秆抗折断力、植株形态及基部节间机械强度的差异,明确施磷量对玉米抗倒伏能力的作用。结果表明,在吐丝期,随施磷量的增加茎秆抗折断力先增加后减小,2年内均在P120处理(120kg/hm^(2))最大;成熟期,茎秆抗折断力随着磷肥用量的增加逐渐增加。P120处理的穗位高、茎秆基部节间直径、第3节间穿刺强度(RPS)和单位长度干重(DWUL)均比其他处理高。相关分析表明,茎秆抗折断力与第3节间RPS和DWUL均呈显著正相关,与穗位系数呈显著负相关。综上可知,在密植滴灌水肥一体化条件下,分次施磷主要是通过改变基部节间干物质积累量来影响茎秆机械强度,同时也改变了植株的穗位系数,从茎秆机械强度和形态方面综合影响其抗倒伏能力。

Under the condition of integrated water and fertilizer of drip irrigation,the differences of stalk breakage,plant morphology and internode mechanical strength of maize stalks were investigated among different phosphorus application rates,and the effects of phosphorus application rate on lodging resistance of maize was clarified.The results showed that the breaking resistance of the stems was first increased and then decreased with the increase of phosphorus application at the silking stage,which was the maximum at P120 treatment(120kg/ha)within two years;during the maturation period,the breaking resistance of stems gradually increased with the increase of phosphorus application.The ear height,internode diameter at the base of the stem,the third internode puncture strength(RPS)and dry weight per unit length(DWUL)of P120 treatment were all higher than those of other treatments.The correlation analysis showed that the stem breaking resistance was significantly positively correlated with RPS and DWUL of the third section,and negatively correlated with the ear position coefficient.In summary,under the condition of integrated water and fertilizer of drip irrigation with dense planting,the fractional application of phosphorus mainly affected the mechanical strength of stems by changing the amount of dry matter accumulation between internodes at the base,and also changed the ear position coefficient of plants,which comprehensively affected its lodging resistance from the aspects of mechanical strength and morphology of stems.