Response of maize root growth dynamics to drip irrigation amount
WANG Jun, LI Jiusheng*, LI Yanfeng, HAO Fengzhen, QIU Zhenjie
State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100048, China
Abstract: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 ETc. 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%ETc at the depth of 0-40 cm was greater than that of treatments 50% and 100%ETc 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%ETc was the highest. It was greater than that of trea tments 75% and 100%ETc by 51% and 40%, respectively. In the horizontal direction, root length density of treatments 50% and 75%ETcwere higher than that of treatment 100%ETc by 29% in jointing and heading-milk stages. In the mature stage, the root length density of treatment 50%ETcin the horizontal direction was the biggest. It was greater than that of 75% and 100%ETc by 52% and 40%, respectively.
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