滴灌玉米根系生长动态对灌水量响应的试验研究

通过连续2年的盆栽试验,设置100%ET_c,75%ET_c和50%ET_c(作物需水量)3个灌水水平,分析了滴灌不同灌水水平对土壤水分、根系生长动态分布的影响.结果表明,玉米根长密度随土壤深度和距滴头水平距离的增加均逐渐减小;玉米根长密度随着生育期的变化而变化,拔节期根长密度最小,抽穗灌浆期达到峰值,成熟期后期根长密度有所降低.拔节期各处理垂向根长密度差异较小,抽穗灌浆期处理75%ET_c0~40 cm土层根长密度分别比处理50%ET_c和100%ET_c高8%和26%;成熟期处理50%ET_c0~60 cm土层根长密度最大,分别比处理75%ET_c和100%ET_c高51%和40%.拔节期和灌浆期处理50%ET_c和75%ET_c水平方向根长密度均比处理100%ET_c高29%;成熟期处理50%ET_c水平方向根长密度最大,分别比处理75%ET_c和100%ET_c高52%和40%.

Response of maize root growth dynamics to drip irrigation amount

The spatial and temporal dynamics of root growth determines the ability of crop roots water uptake. Two-year continuous pot experiment was conducted to investigate the effect of irrigation amount on the dynamics of soil water content and root growth as well as the distribution in the soil profile. In this pot experiment, three irrigation levels were designed, i.e. 100%, 75% and 50% of crop water requirement ET_c. The results showed that the root length density of maize decreased gradually with the increase of soil depth and horizontal distance from the dripper. The maize root length density varied during the growth stages, the minimum root length density at the jointing stage, the highest in the heading-milk stage, and then decreased in the late mature stage. Less difference of root length density was found among the treatments in the vertical direction in the jointing stage. The root length density of treatment 75%ET_c at the depth of 0-40 cm was greater than that of treatments 50% and 100%ET_c by 8% and 26% in the heading-milk stage, respectively. In the mature stage, the root length density at the depth of 0-60 cm of treatment 50%ET_c was the highest. It was greater than that of trea tments 75% and 100%ET_c by 51% and 40%, respectively. In the horizontal direction, root length density of treatments 50% and 75%ET_cwere higher than that of treatment 100%ET_c by 29% in jointing and heading-milk stages. In the mature stage, the root length density of treatment 50%ET_cin the horizontal direction was the biggest. It was greater than that of 75% and 100%ET_c by 52% and 40%, respectively. 