玉米生长后期的根系分布研究

为了研究玉米生长后期根系的生长发育规律,利用中国气象局固城农业气象试验站大型根剖面系统,采用微根管观测系统及方形整段标本法和地下根系室玻璃窗,对‘屯玉46号’玉米根系的生长状况进行了试验研究。结果表明:垂直方向上,方形整段标本法和微根管法测得的根长密度占整层总根长密度比例的变化趋势一致,相关系数分别为0.987和0.717,且两种方法在0~20 cm土层的根长密度比例均为最大。0~60 cm土层为玉米根系生长活跃区,方形整段标本法测得根长密度生长量为其余层的4倍。两种方法测得的根长密度无显著差异,相关系数为0.830,均匀性水平较好。玉米成熟期根系的水平幅度较乳熟期窄,下层根系仍处于生长中,垂直深度增加。玻璃窗与方形整段标本法观测的根深测定结果存在差异,这可能与观测环境条件不一致有关。

Spatial distribution and temporal variation of maize root in the soil under field conditions

In order to study the growth rhythm of maize root, a large root monitoring system was used in an experimental filed to analyze maize ('NO. 46 Tunyu') root. The minirhizotron observation method and the quadrate monolith method were used to monitor the main parameters such as maize root length, root length density and root length ratio at milky and maturity stage. Meanwhile, underground glass windows were used to measure root length and width. The results showed that root length density ratios measured by the minirhizotron observation method and the quadrate monolith method were consistent with the increase in soil depth at milky and maturity stage, with correlation coefficients of 0.987 and 0.717, respectively. Root length density ratios estimated by the two methods were highest in 0 20 cm soil layers. The 0 60 cm soil layers were the primary growth zone of fine roots, with average net root length density 4 times that in the 70 220 cm soil layer measured by the quadrate monolith method. Root length densities from the two methods were not significantly different, with a correlation coefficient of 0.830. The horizontal width of roots in the upper soil layer became narrower with increasing vertical depth from milky stage to maturity stage. This suggested that roots still grew during late developmental stage. Differences were noted in root depth between the quadrate monolith method and the underground glass window method, probably due to inconsistent environmental conditions.