Abstract:

Drought is one of the main hazards for affecting winter wheat production in North China. In order to assess the drought impact on wheat yields quantificationally, the evaluation model was set up based on crop water production function. According to the observed wheat growth and development and meteorological data from three agrometeorological stations, i.e., Nangong, Hejian and Bazhou, selected in Hebei province during 1991 to 2007, and Penman-monteith equation for evapotranspiration, FAO method of crop production potential for wheat light-temperature production potential and Jensan model, the impacts assessment model of drought on wheat yield was constructed. The results showed that water sensitive coefficient was close related to irrigation times during the whole growth season of winter wheat. For that wheat was usually irrigated three times in the station of Nangong and Hejian, water sensitivity stage in farming condition was similar to the former research result, which had a variation tendency of small values in earlier and later stages, and large in medium. Also a statistically significant relationship (0.01) existed between estimated and predicted results from drought evaluation model and actual yield output during the whole growth period. The drought evaluation results from drought evaluation model were in accordance with actual results during seeding to elongation, seeding to earing, seeding to grain-filling and seeding to maturity. Another station Bazhou where winter wheat was irrigated five times in the growing season, the results showed that drought stress was not obvious, positive water sensitive coefficient only existed during the period from earing to grain-filling, it was not sensitive to water deficit in other growth stages.