湖北林业科技

The response relationship between vegetation cover change and river water and sediment was studied, and the influence mechanism of water and sediment effect was clarified, so as to provide scientific support for river water and sediment control. Based on the runoff and sediment data of Changyang station from 1981 to 2002, using the annual average NDVI, annual precipitation, annual runoff and annual sediment discharge from the annual scale, using the monthly average NDVI, monthly precipitation, monthly runoff and monthly sediment discharge from the seasonal scale, the response relationship between vegetation cover change and river water and sediment and the comprehensive response relationship between vegetation cover change and precipitation and river water and sediment were characterized. The results show that: （1）From 1981 to 2002, the vegetation cover increased with a trend of 0.004/a（P<0.01）, and the annual runoff and annual sediment transport decreased by an exponential function of 372 million m3·a?1 and 350400 t·a?1（P<0.01）. （2）On the annual scale, when the average annual NDVI increases by 0.1, the annual runoff decreases by about 177.148 billion m3, and the annual sediment discharge decreases by about 32006800 t. For every 1 mm increase in annual precipitation, the annual runoff increases by about 31 million m3, and the annual sediment transport increases by about 5100 t. The correlation between river flow and sediment and vegetation cover change increased after the variation year（1990）, and the correlation with precipitation began to weaken. However, in general, precipitation still plays a leading role in regulating river flow and sediment. （3）On the seasonal scale, vegetation phenology is sensitive to river water and sediment in winter and rainy season. The correlation between runoff and vegetation cover change and precipitation began to weaken after the variation month（January）, while the correlation between sediment discharge and sediment discharge began to increase after the variation month（May）. However, on the whole, in June, which belongs to the summer and rainy season of vegetation phenology, the response characteristics of river water and sediment are particularly complex and changeable. In the management of water and sediment, special attention should be paid to the precipitation process of vegetation phenology in summer and rainy season.