旱地小麦降水年型与氮素供应对产量的互作效应与土壤水分动态的研究

本文研究了中国黄土高原同一自然年度下的３个模拟降水，施用氮素的生产效应及互作效应，明确了在４００－６００ｍｍ降水范围内的产量变幅、生产潜力，及土壤水分动态变化进修生。嫌量随着水分的增加报酬递增，水分生产效率提高，耗水系数降低。

Study on the Combined Effects of Simulated Rainfalls and Nitrogen Treatments on the Yield and Soil Moisture Dynamic change of Rain-fed Winter Wheat

Effects of rainfalls, nitrogens and their interactions on wheat were studied in Loess Plateau, China. Three rainfalls were simulated under the same natural growing season. Results showed that with the increasing of rainfall within the range of rainfall 400-600 mm, yield increased directly, efficiency of water increased and index of water expenses decreased. Effects of rainfall and nitrogen are impelled each other obviously. It means increasing rainfall can improve nitrogen efficiency and vice versa. In one word, yield will be increased in a large range under sufficient water and fertilizer; yield will decreased when water is decreased and input of fertilizer increased; under sufficient water and less fertilizer yield can be increased; when water and fertilizer are both insufficient, yield will be the lowest level. Quantitative relationships between rainfall and fertilizer are disclosed, If rainfall is sufficient, wheat yield will be increased obviously through increasing nitrogen appropriately with partly applying in spring. The results provide a view of improving the traditional habit which do not apply fertilizers to dryland winter wheat in spring.