COMPARATIVELY STUDY WATER SENSITIVITY INDEX of the WINTER WHEAT for DIFFERENT GROUNDWATER DEPTH in SHAJIANG BLACK SOIL AREA and YELLOW FLUVO-ACQUIC SOIL AREA

Abstract

Winter wheat which was a typical dry crop in the Huaibei Plain was studied in the paper through the Wudaogou Hydrology and Water Resources Experimental Station, the long sequence of the lysimeter and the uninterrupted special experimental data. The multilevel water table depth was controlled from 0-5m in the experiments. By modeling the crop-water production function (Jensen Model), the tendency and regularity of the moisture sensitivity index variations of winter wheat cultivated was investigated under the above conditions at different plant developmental stages. The results showed that water deficits have greatly impacted winter wheat yield during key reproductive and seed formation periods, which are in the context of this analysis, the heading - maturation stage. Returning to green - jointing periods, the range of sensitivity to water deficits is 46.1% to 61.3%, which is the period towards maturation and 8.5% - 15.3% for the tillering period and overwintering period in maximum. The water sensitivity indexes reaches the maximum at the 1.0m ground water depth in the Shajiang black soil and Yellow fluvo-acquatic soil, which yields a 1.58 - 2.45 times and 1.16 - 2.08 times increase compared to the minimum in the same growth period. The groundwater depth should therefore be maintained between 0.8m and 1.2m in Shajiang black soil and Yellow fluvo-acquic soil. In comparison to other groundwater depths, this can reduce artificial irrigation and the occurrence of either waterlogging events or requisite drainage measures. Therefore, the findings of this study can optimize irrigation and improve water use efficiency.