Effects Of Drip Irrigation On Root System Growth Distribution, Yield And Water Use Efficiency Of Spring Maize

In order to reveal the water demand law and optimal irrigation amount under the dense planting condition of spring maize in northern irrigation area,the root system growth and distribution of spring maize under different drip irrigation,and provide theoretical basis for the improvement of water-saving,yield and efficiency of spring maize under close planting in the northern irrigation area China,with Guangde 5 as the material,effects of five irrigation volumes on soil moisture,agronomic traits,root distribution characteristics,yield and water use efficiency were analyzed.The results were as follows:（1）Under different drip irrigation treatments,the soil water content increases with the soil depth,and varies sharply at the range of 0-40 cm.（2）Except for the significant effect on mature stage by W4,there was no impact on plant height at either stage.Furthermore,the leaf area and dry matter accumulation were significantly higher under W3 than that of W1 treatment except in the silking stage,and no difference among the rest period.（3）The roots of spring maize are mainly grown in the 0-40 cm soil,and less distributed below 40 cm soil.In the silking and filling stages,the high drip irrigation（W4,W5）significantly increased the average root length density of 0-60cm soil layer than the lower one（W1）.（4）There was little effect on the ear traits and yield components by the trip irrigation treatments.With the increasing amount of trip irrigation,the length of the bald tip can be effectively reduced,thereby increasing the number of kernels.The100-grain weight also shows a gradually increasing trend in some way.The highest grain yield of Guangde 5 was 18109.23 kg hm^-22 under W4 treatment,which was8.67%,5.42%,11.08%and 6.49%higher than that of W1,W2,W3 and W5,respectively.With the increase of drip irrigation,there was no significant effect on grain yield water use efficiency（WUE_g）and biological yield water use efficiency（WUE_b）,but significantly decreased grain yield irrigation utilization efficiency（IWUE_g）and biological yield irrigation utilization efficiency（IWUE_b）.The amount of irrigation was significantly negatively correlated with IWUE_g and IWUE_b.In conclusion,when the planting density was 5000 plants/mu and the drip irrigation amount was 1440(m³ ha^-1),the spring maize has the better agronomic traits than the other treatments.The highest grain yield production(18109.23 Kg ha^-1)and biomass(45.50 t ha^-1)were obtained at the irrigation of 1440(m³ ha^-1).Thereby,this water irrigation amount in drought/semi-arid areas can effectively improve water-saving efficiency and farmers’economic income.