基于无限制水分区间的南疆膜下滴灌棉田土壤水分调控机理研究

The southern Xinjiang is located in extreme arid area of China.Water resources shortage and soil salinity are major impedements of agricultural sustainblity. Mulched drip irrigation is a pioneering work and an inevitable choice. However, salt accumulation and physical properties deterioration of soil are major problems in cotton field under mulched drip irrigation. In this work,effects of nonlimiting water range (NLWR)on cotton growth, yield, quality, and water use efficiency will be studied under different irrigation quota; the variation of leaching fraction (LF) with irrigation quota will be investigated; relationshipes between NLWR, LF and irrigation quota will be analyzed. Then, selcetion of index will be modified so that the NLWR will be able to explain relations of soil physical properties-alt and water situation-crops growth.Then,theoretical model of soil water regulation can be established based on the modified NLWR, and optimal irrigation pattern for effective water use and high-quality of cotton under mulched dirp irrigation also can be formulated. All of these results promote the development of water-saving agriculture in southern Xinjiang.

南疆位于我国极端干旱地区，水资源匮乏，土壤盐渍化程度高、面积大。膜下滴灌是该区农业可持续发展的重大创举与必然选择。针对目前该区膜下滴灌棉田普遍存在的土壤积盐和物理性质恶化现象，本研究以南疆膜下滴灌棉花与土壤为研究对象，分析不同灌水定额条件下土壤无限制水分区间(NLWR)对棉花生长发育、产量、品质及水分利用效率的影响，探讨不同灌水定额处理下淋洗份额(LF)理论中相关参数的变化规律，明确NLWR参数指标、LF相关参数、灌水定额三者之间的关系，修正NLWR的参数取值，使其可以定量反映土壤物理性质-水盐状况-作物生长发育的相互关系，进而构建基于NLWR的土壤水分调控理论模型并验证其可行性与准确性，制定南疆膜下滴灌棉花优质高效灌溉制度，为南疆节水灌溉农田土壤水分管理提供理论依据和技术支撑，为新疆节水农业的可持续发展做出有益的探索。

针对目前南疆膜下滴灌棉田普遍存在的土壤积盐和物理性质恶化现象，本研究以南疆膜下滴灌棉花与土壤为研究对象，基于土壤无限制水分区间（NLWR）的观点，对NLWR的参数取值进行了修正，获得了土壤毛管断裂含水量的计算公式，证明土壤毛管断裂含水量为NLWR的唯一下限，对NLWR与土壤物理质量参数S的定量关系进行了分析，明确了S分级阈值的物理意义，使NLWR定量反映土壤物理性质-作物生长发育的相互关系，明确了NLWR参数指标、LF相关参数、灌水定额三者之间的关系，使NLWR定量反映土壤物理性质-水盐状况-作物生长发育的相互关系，构建基于NLWR的土壤水分调控理论模型并验证了其可行性与准确性，制定了南疆膜下滴灌棉花优质高效灌溉制度，为南疆节水灌溉农田土壤水分管理提供理论了依据和技术支撑，为新疆节水农业的可持续发展做出了有益的探索。