民勤沙区退耕地土壤系统演变规律研究

Study on the Evolution Law of Soil System of Abandoned Farmland in Minqin Sandy Area

摘要: 甘肃沙区在我国的生态安全中占有十分重要的地位，特别是石羊河流域下游的民勤地区，近几十年来，由于人为破坏及自然环境的恶化，该区域的农田大面积退(弃)耕，在无人为干预的情况下会逐渐退化，向裸露化和沙漠化发展，这部分土地退耕后的保护与合理利用关系到整个沙区生态系统的安全与稳定。本研究选择民勤沙区不同年代的退耕地为研究对象，运用时空替代法，测定和系统分析其植被组成、土壤物理特性、土壤化学特性、土壤生物学特性和土壤酶活性，阐明民勤沙区退耕地土壤系统动态变化规律、过程，揭示民勤沙区退耕地土壤系统变化的驱动因素及其机制，有利于该地区生态系统的修复、改善，为甘肃沙区及其西北地区退耕地保护与可持续利用提供理论依据。

Abstract: The sand area of Gansu occupies a very important position in China’s ecological security, especially in the lower reaches of the Shiyang River in Minqin area. In recent decades, due to man-made damage and deterioration of the natural environment, farmland in this area has been largely retired. In the absence of intervention, it will gradually degenerate and develop into bareness and desertification, the protection and rational use of this part of the land is related to the safety and stability of the entire sand area ecosystem. The research object selects the cultivated land in different ages in Sand Area in Minqin, the vegetation composition, soil physical properties, soil chemical properties, soil biological properties and soil enzyme activities were determined and systematically analyzed by time-space substitution method, clarifies the dynamic changes and processes of soil systems in abandoned farmland and then reveals the driving factors and mechanisms of soil system changes in abandoned farmland in sand area in Minqin, conducive to the restoration and improvement of the ecosystem in the region, and provides a theoretical basis for the protection and sustainable use of the cultivated land in the sand area of Gansu and northwest part of China.