黄土丘陵沟壑区县域耕地生产力与粮食自给能力变化差异——以安塞县为例

Change Differences of Arable Land Productivity and Grain Self-Supply Ability at County Level in the Hilly Area of the Loess Plateau of China:A Case Study of Ansai County

水土流失是威胁黄土高原地区农业可持续发展的突出生态问题。为了水土保持的需要,自1979年以来,安塞县的坡耕地被逐渐退了下来,尤其是1999年以来,该区成为全国退耕还林还草工程的重点区域之一,受补贴政策的激励,坡耕地退耕的进度加快。如何实现在水土保持生态建设过程中,提高粮食生产力水平,保障粮食自给,是关系全县生态环境恢复和社会经济发展的关键。该文根据安塞县1979年～2000年的统计资料,采用耕地动态度、耕地粮食生产力相对指数和粮食自给能力相对指数这3个指标,定量分析了安塞县各乡镇在全县粮食生产中的相对重要性。通过分析不同乡镇粮食单产变化、耕地动态度、耕地粮食生产力水平和粮食自给能力变化的特点,为合理制定县域不同水土保持分区内各乡镇退耕还林、还草进度,以及相应的以基本农田建设为主的综合措施的布局提供参考。

The runoff of soil and water is one of the seriously ecological problems in Loess Plateau of China, which influences the agricultural sustainability. In order to conserve soil and water, since 1979, part of the slope arable land has been returned, especially after 1999. Ansai county has been designated as one of the experimental sites of the practice on returning cultivated slope land to woodland or grassland, the return speed of slope arable land has been accelerated at the stimulus of subsidiary. How to improve the arable land grain productivity and ensure the grain self-supply during the ecological building of soil and water conservation is the key, which matters the ecological environment recovery and social as well as economic development of Ansai county. On the basis of statistical data, the change differences of arable land productivity and grain self-supply ability are discussed in this paper. Based on the analysis of chosen index, such as ratio of arable land change, relative index of arable land productivity, and relative index of grain self-supply ability, it is clearly that the differences in the arable land area and the productivity between villages and towns are relatively large. It suggest that in order to ensure the reasonably speed of returning cultivated slope land to woodland or grassland, the progress rate of returning cultivated slope land to woodland or grassland in Gaoqiao village and Huaziping village should step up, while in Yanhewan towns and Zhenwudong towns should ease up, in the others villages and towns the progress rate of returning cultivated slope land to woodland or grassland is relatively reasonable.