有机肥与种植密度对旱作玉米根系生长及功能的影响

在大田条件下研究了基施有机肥及3种种植密度（60,75,90千株/hm2）对旱作玉米根系生长和功能的影响。结果表明,在大喇叭口期,基施有机肥显著降低了30—100cm土层内的根长与根表面积,但对根干重影响不显著;由于基施有机肥处理地上部生物量更大,因而显著降低了根冠比;种植密度对该时期根系生长的影响较小。在蜡熟期,基施有机肥限制了30—100cm土层及1/4行间、行间与膜下位置的根系分布,但对根冠比的作用不显著。该时期根长、根表面积及根干重均有随密度增加而减少的趋势,该趋势在0—30cm土层和株上位置表现显著;种植密度的增加也降低了根冠比。有机肥延缓根系衰老作用不明显,其根系导水率与不基施有机肥处理无显著差异;而在种植密度增加情况下,单位根系表面积吸水功能的提高弥补了根量减少带来的损失,表现出一定的适应性。

Effect of Organic Fertilizer and Planting Density on Root Growth and Function of Maize in Dryland

This experiment was focused on the effect of organic fertilizer and planting density(60,75 and 90 thousand plants/hm²) on root growth and function of maize in field condition.The result showed that basal organic fertilizer reduced root length and surface area in 30-100 cm soil layer at pre-tasselling stage,but had no significant influence on root dry weight.The rate of root/shoot was significantly decreased because organic fertilizer dramatically increased the biomass of shoot.The influence of planting density on root growth was not significant.At waxen maturity stage,basal organic fertilizer restricted the distribution of root in 30-100 cm soil layer and at the position of 1/4 row space,1/2 row space,under plastic mulch,but had no significant influence on root/shoot.The trends of root length,root surface area and root dry weight were decreased as planting density increasing,especially in 0-30 cm soil layer and at planting position.The increase of planting density also decreased the rate of root/shoot,but increased the root function.Organic fertilizer also didn't show the significant effect on deferring senescence and had no significant difference in hydraulic conductivity of root system compared with the treatments without basal organic fertilizer.Root showed some flexibility by increasing water uptake function per surface area as planting density increasing.