| Field experiment of winter wheat has been conducted for three years to investigate the effect of cultivation methods,rate of nitrogen fertilizer and planting density on soil water utilization.The results indicated that different cultivation methods showed the similar trend of fluctuation of water content through the soil profile during the stage of winter wheat growth.Large amount of water stored in the depth of 0～200 cm or even deeper soil before wheat sowing was consumed during the stage of winter wheat growth.Two soil layers(40～80 cm and 120～160 cm) with lower water content through the 0～200 cm soil profile were found after wheat harvest no matter what kinds of cultivation methods was applied.Effect of mulching on water utilization varied in different years,probably due to the water content before wheat sowing and precipitation during the stage of wheat growth.Straw mulch could increase significantly water use efficiency(WUE) in drier year,comparing with no mulch.High WUE could often be found when plastic film mulch was applied.Furrow planting(with plastic film covered on ridge and straw covered on furrow and wheat planted on furrow) was expected to increase wheat yield and WUE comparing with no mulch,straw mulch or plastic film mulch. However,we failed to see it.N fertilizer increased remarkably water consumption through 0～200 cm of soil profile.The effect became more obvious with the time.More water lost in deep soil layer than topsoil,and more water lost in the depth of 40～80 cm and 120～160 cm than any other depth of soil.N fertilizer increased significantly WUE.Appropriate increase of wheat planting density could lead to increase of WUE in dryland as well. |