Effect Of Water Application Control In Combination Of Depth And Amount On Dry Matter Partitioning And Water Use Efficiency Of Winter Wheat

In order to analysis and determine the optimum irrigation methods for controlling water distribution with depths which could adjust effectively root growth and distribution in soil profile, a 3-yr field trial, with 12 treatments under the water control experiment combined with different soil depths and water contents, was carried out from 1999-2001 at Yucheng Comprehensive Experimental Station, Chinese Academy of Sciences, Yucheng County, Shandong Province, China. Under different irrigation conditions, root growth and distribution, dry matter accumulation and distribution of shoot, grain yield and water use efficiency (WUF) were investigated in detail.The results showed that distribution of roots was closely related to irrigation types: under surface irrigation the density of roots declined exponentially downward and over half of them were located within 0-10cm top layers. In the treatment where irrigation was done at the depth of 30cm and 50cm, two peak values for the root distributions appeared. The dry matter accumulation above the ground is 65%>80%>50%FC in the treatment of surface irrigation and 80%>65%>50% in other three treatments of under surface irrigation; the treat of 30cmX80%FC products the highest yield and the lowest yield appears in the treatment of 50cmX50%FC; Water consumption by winter wheat decreased with depth while water use efficiency gradually increases with the depth. Considering the realization of water economy and yield increasing at the same time, the optimum combinations would be 30cm X80%FC , OcmX65%FC and 30cmX65%FC.