交替根区灌溉具有较大的节水、稳产、调质效应；滴灌也具有很大的节水增产作用。两种技术结合形成交替根区滴灌，理论上应该更加具有节水效果。但目前对于交替根区滴灌缺乏系统深入的研究，对这种具有较大节水潜力的灌溉方式下如何进行水肥耦合（形成交替根区滴灌施肥）及其耦合效应与机理缺乏报道。氮肥是农业生产中施用量最大的肥料之一。本项目研究滴灌下根区交替灌溉进行的土壤水分控制条件、交替根区滴灌施肥水氮耦合效应与作用机理，以及利用15N标记、通过多茬种植的方法研究交替根区滴灌施肥下蔬菜对肥料氮、土壤剖面中不同层次累积硝态氮的累积吸收利用率以及标记氮在土壤剖面中长期迁移行为的影响，以期明确交替根区滴灌施肥的控制条件，探讨交替根区滴灌施肥的节水节肥效果，阐明其增产调质作用机制，为农业水肥资源高效利用及降低环境风险提供理论指导和新的灌溉施肥模式。

Both alternate partial rootzone irrigation and drip irrigation has great potential in saving irrigation water, stabilizing yield and improving quality of vegetable. Alternate partial rootzone drip irrigation (APRDI), combined by the two water-saving irrigation technologies should be theoretically more efficient in saving water than anyone of these two technologies independently. However, there lack systematic researches on the APRDI. Furthermore, little information is available about how to apply fertilizer simultaneously with irrigation, forming alternate partial rootzone drip fertigation (APRDF). The coupling effects of different water and fertilizer supply under APRDF is also absent. Nitrogen fertilizer is one of the most frequently applied fertilizers in agriculture production. In this research, the suitable soil water conditions for the alteration of irrigation event under the APRDI will be examined, the coupling effects of water and fertilizer (nitrogen fertilizer) supply under APRDF and its mechanisms will be explored. The utilization, movement and distribution in soil profile of fertilized nitrogen or residual nitrate accumulated in different soil layers under APRDF will be observed by 15N label technology under three successive cultivations. The outcome of this research will reveal the soil water condition for controlling the alteration of fertigation under APRDF, explore the water- and fertilizer-saving effects, and elucidate the mechanisms for improvement of yield and quality under APRDF. All these results will provide theoretical support and new fertigation model for efficient use of irrigation water and fertilizer and thus reducing environmental risks in agricultural practice.