会宁县退耕还林还草工程实施后植被状况调查

通过对MODIS NDVI数据的解译,结合研究区野外调查资料,对甘肃省会宁县退耕还林还草工程实施后的植被状况进行了分析和研究。结果表明,该区植被生长状况得到了明显改善,主要体现在以下4个方面:(1)通过退耕还林、封山禁牧等措施,该区植被盖度明显提高,2000-2011年植被NDVI指数增加的面积占全县总面积的77.74%,约4404.75 km²; (2)退耕还林还草区植被群落趋于稳定,且呈现出良好的生长势头;(3)严重水土流失的现象得到了遏制,山洪暴发次数明显降低,50个排洪沟暴发山洪的年均值比实施前减少了1/2多,而且山洪的流量和破坏力也明显降低; (4)广大农户对退耕还林还草工程取得的水土保持效益广泛认同,而且大多数农户的家庭经济收入呈现增加趋势。

Vegetation Conditions After Implementation of Returning Farmland to Forest/Grassland Project in Huining County of Gansu Province

Vegetation condition after implementation of the returning farmland to forest/grassland project in Huining County of Gansu Province was analyzed based on the analysis of MODIS NDVI data and field investigation in the study area. The vegetation conditions have been improved in recent years, with four facts as below:(1) Vegetation coverage has increased significantly due to the implementation of the project, closing hillsides for livestock grazing and other measures, and the area for increased NDVI index was 4404.75 km² in 2011 in comparison with the year of 2000, accounting for 77.74% of the total area of Huining County. (2) Vegetation type showed a stable and increasing tendency in the region after implementation of the project. (3) Soil erosion has been curbed, and the number of mountain torrents obviously decreased from 2000 to 2011, with the corresponding decline of discharge and destructive power. The average value for mountain torrents was 3 times for 50 drainage ditches in 2011, which declined by nearly half as compared with the case before the implementation of the project. (4) The majority of farmers have approved of soil and water conservation benefits after implementation of the project, and their economic income also showed an increasing trend.