Effect of climate change on the forages in natural grassland of Xinghai County in Threeriver headwaters region

Based on the forages and climate data from 1999 to 2007 collected by Xinghai Agricultural Weather Station in Threeriver headwaters region, the relationship between climate and forage growth and the impact of climate change on forage growth period, height and yield were studied. The results indicated that the forage regreening date was as same as the date of the first day of 5 ℃ daily average temperature and the forage withering date fitted with the date of 10 ℃ daily average temperature. The dates of forage regreening and withering were brought forward, and the withering date was brought forward in more extend. The vegetation coverage reduced at a rate of 1.73 percentage units and the forage height increased 1.08 cm per year. Under the global warming background, the temperature in growth season increased and the rainfall in this area increased as well, the forage yield increased because of better matching between water and heat conditions.