Correlation between grassland hydrothermal conditions and forage yield of pastoral area in Northwest Sichuan

In order to study the relationship between hydrothermal conditions and forage yield, correlation analysis and multiple regression analysis of precipitation, temperature and forage yield were conducted in 12 major pastoral counties in northwestern Sichuan during the period 2006-2013. The results showed that the monthly dry forage yield was significantly positive correlated with the precipitation for each period except with the period of March-May. The positive correlation decreased in the following order: June-September（=0.192,P0.05）, June-August（=0.187,P0.1）, March-September（=0.171,P0.1）. In March-May, temperatures significantly affected forage yield whereas precipitation did not significantly affect forage yield. The monthly dry forage yield increased 17.1 kgha-1 if precipitation increased 1 mm in JuneSeptember and increased 585.1 kgha-1 if temperature increased 1 ℃ in MarchMay.