| According to the observation data and weather data in typical grassland in Xilinguole of Inner Mongolia
from 2004~2005, crop water requirement was calculated directly by water balance method. Also, crop water require-
ment was calculated indirectly by crop coefficient Kc and Penman- Monteith equation, Modified Penman, Blaney-Criddle, Hargreaves, Priestley-Taylor and Markkink. Applying several methods to calculate crop water requirement, the results of
every ten days were evaluated by correlation analysis, the results of six kinds method of forage crop water requirement were evaluated by Penman-Monteith method and mutual conversion was carried out by Penman-Monteith method and other six methods according to the regression equation, and the accuracy of the results of regression equation was proved high with the data measured in 2006. |