同步滴灌施肥条件下根际土壤水氮分布试验研究

The Redistribution of Water and Nitrate in Rhizosphere under Drip Fertigation

通过室内土槽试验,探讨了停灌后不同时间,同步施肥滴灌对土壤水分及土壤硝态氮在土壤剖面分布的影响。结果表明:停灌后,各处理土壤水分以滴头为中心沿径向向四周扩散;由于水分在横向及纵向运动,上下层土壤水势梯度随径向距离增加而逐渐减少。停灌后,氮浓度3、2 g/L处理硝态氮的含量与径向距离及土层深度成反比;氮浓度0 g/L处理硝态氮的含量随径向距离及土层深度增加先增大后减小,氮浓度0 g/L处理硝态氮在深度分布表现为"上低中高下稳定"抛物线分布。

Drip fertigation is a promising irrigation method to improve the effective use of water and nutrients by plant roots, and in this paper we investigated the redistribution of water and nitrate after the cease of irrigation. The experiment was conducted in a tank filled with sandy soil, and we measured the change of water content and nitrate concentration under various treatments after the irrigations was stopped. The results indicted that for treatments with nitrate concentrations of 2 g/L and 3 g/L, the nitrate concentration in soil decreases with distance in all the directions from the emitter; while for the treatment of 0 g/L concentration, the nitrate concentration in soil first increases with the distance from the emitter and then decreases after reaching a peak value. For all the treatments, water was found to move radially with preference in the vertical direction.