The Investigation of Grassland Degradation and Analysis about Degradation Reason in Dari County of Qinghai Province
|School||Gansu Agricultural University|
|Keywords||Dari County Vegetation Index Degraded grassland Stocking rate Global Change|
Grassland degradation is a worldwide problem. In this study, remote sensing survey of Dari County, Qinghai Province grass conditions and the degradation causes were analyzed. In this study, the 3S technology, remote sensing, geographic information system and global positioning system GPS. U.S. meteorological satellite NOAA / AVHRR normalized difference vegetation index NDVI and Landsat TM images for grassland monitoring, many domestic and foreign scholars have done a lot of research to prove this method to investigate the speed of grassland vegetation, high-precision, low-cost. Degraded grassland survey in Dari County-based remote sensing technology, remote sensing technology and geographic information technology and ground-field sampling techniques combined; historical data (1985 the animal husbandry zoning report, grassland type diagram the grass level diagram, seasonal pasture Figure , topographic maps, etc.) combined with 1997 data (NOAA data, TM data, field measured production data) after image processing and comprehensive evaluation to split the form to the Township, Dari County land use (total area of dense shrub, grass, grass, black beach, rock and), the grass level, grass yield, stocking rate (the theoretical stocking as well as the winter and spring field and the summer and fall field stocking rates), grass yield seasonal changes information and maps. In this study, the use of the fortnightly 1 to October 15, 2011 April 15, 1997, NOAA data, seeking NDVI values ??calculated image points of the same name, and then measured with the same time on the ground forage yield between statistical calculations The established logarithmic relationship vegetation index as independent variables X yields as the dependent variable Y: Y = 249.137 * LgX-347.213, the correlation coefficient r is 0.823. The survey showed that in 1997 Dari County grassland area 10 793.36km ~ 2, five grass 5 203.379km ~ 2,6 level grass 590.283km to 2, respectively, of the available grassland 48.30% and 51.70% ; theory grass yield edible forage and feed the total of 345.4537 ten thousand tons, of 278.7811 million t and 139.3906 million tons; of theoretical stocking stocking rate in winter and spring, and summer and fall stocking rates were 100.24,87.25 and 1,252,000 sheep units. Of grassland animal husbandry resources survey comparing 1985 and 1997, twice the results, the following conclusions can be drawn: available grassland area to reduce, black beach area increases; can be used to reduce the proportion of high-grade grass in the meadow, and increased the proportion of low-grade grass ; grassland yields and stocking rates decline. The grassland degradation someone and natural conditions two reasons. Dari County of theoretical stocking rate from 1985, 1,724,300 sheep, declining to 1997, 1,002,400 sheep, the actual stocking rates by 1985, 1,257,600 sheep (52.of ten thousand only) fluctuations to 1997, 1,209,000 sheep unit (only about 500,000), so the Dari County grassland overgrazing. This study also shows the profound impact of the Asian hinterland of the extremely dry desert climate of Dari County grass. Over-grazing is the main up to date county grassland degradation; desertification caused global temperatures, but also in Dari County, half of the semi-arid-humid areas of grassland degradation, the blockbuster Black disabilities Beach important reason. Reasonable grazing system, delay and prevent the desertification process (formation) of Black Beach is huge.