畦灌不同液施模式下水氮空间分布特征

【目的】改善土壤水氮分布。【方法】基于夏玉米生长关键期灌溉施肥的试验结果,探究畦灌不同液施模式对土壤水氮空间分布状况及其变化趋势的影响。选取畦宽(1.5、2.3、3.2 m),施肥时机(灌溉到畦长的1/3、1/2施肥和全程施肥)和改水成数(85%、90%、95%)3个因素,每个因素3个水平,设置传统畦灌进行对照,采取正交设计选取最优水平组合,以形成适合作物生长发育的土壤水氮空间分布状况。【结果】畦宽对于土壤水分沿畦长分布的变异系数有显著影响,贡献率达94.36%;改水成数影响水分和氮素沿畦长分布均匀性(DUWH和DUNH、DUNQ),尤其对氮素沿畦长分布均匀性有显著影响,贡献率分别为23.9%、91.74%和71.26%;施肥时机仅对DUWH和DUNQ有显著影响,贡献率为56.09%和27.41%。【结论】液施条件下可以改善土壤水氮空间分布;畦宽为1.5 m、灌溉到畦长1/2时施肥,改水成数为95%的施肥方式可以形成较好的土壤水氮储存效率和水氮沿畦长分布均匀性。

Spatial Distribution of Water and Nitrogen under Different Strip-border Fertigation

【Objective】The purpose of this paper is to estimate the optimal geometrical parameters of strip border fertigation of summer corn, as well as the associated spatial distribution of soil water and nitrogen.【Method】Strip border with three widths-1.5, 2.3 and 3.2 m-were studied. Fertilization ushered in when the surface water front reached 1/2, 1/3 and 100% of the border length respectively with the inflow of the fertigation cutting off when 85%, 90% and 95% of designed irrigation water was deemed to have flown into the border. The conventional border fertigation was used as the control.【Result】Spatial soil moisture distribution along the border length was significantly affected by the border width with a contribution rate of 94.36%. Along the same direction, the timing at which the inflow fertigation was cut off also had a significant effect on the uniformity of soil water and nitrogen distribution(DUWHand DUNH, DUNQ), particularly the nitrogen distribution, with a contribution rate of23.9% and 91.74% respectively. Fertilization timing only significant affected DUWHand DUNQ, with a contribution rate of 56.09% and 27.41% respectively.【Conclusion】The spatial soil water and nitrogen distribution can be improved under strip-border fertigation by setting the border width at 1.5 m, and applying the fertilizer when the surface water front reached 1/2 of the border length, followed by cutting off the inflow when 95% of water was deemed to have flown into the border. The results presented in this paper provide a guidance for water and nitrogen management to improve their use efficiency under strip border irrigation/fertigation.