Effect of Autumn Irrigation on Evaporation from Seasonal Frozen Soils

摘要

To study the effects of autumn irrigation on evaporation from seasonal frozen soils, field experiments were carried out in the Hetao Irrigation District, Inner Mongolia. The results show that the evaporation rate from irrigated soils was more than 100% higher comparing to non-irrigated condition; irrigation water applied to sand soils was almost evaporated, resulting in extremely low efficiency of irrigated water use. Water contents in top layer in spring, which was important for wheat sowing, did not differ much no matter it was autumn irrigated or not. However, the water storage in layer 0-150 cm was much higher when irrigation was applied. This indicates that autumn irrigation could help to store water for spring sowing and following crop growth but efforts should be made to reduce the water loss from evaporation during freezing-thawing.