Soil Water Movement And Evaluation Of Soil Moisture Availability In Winter Wheat Field

Researches on soil water movement and evaluations on soil moisture efficiency for winter wheat in Henan Province are of great importance to alleviate regional freshwater resource shortage,to promote the efficient use of water in wheat field,and to ensure the sustainable development of winter wheat industry.In this study,no-weighing lysimeters experiment,runoff plot experiment,soil column experiment,and field experiment were investigated in two stations in Jiaozuo City and Xinxiang City,Henan Province,from 2012 to 2015.Several different irrigation treatments were designed.Dynamic changes of soil moisture were measured and simulated under different irrigation conditions.The responses of winter wheat growth and water utilization were revealed.Meanwhile evaluations on soil moisture efficiency were made.The main results were as follows:(1)Elaborating the dynamic changes of soil moisture and soil evaporation in winter wheat field under different conditions.Under the condition of test,irrigation obviously improved the soil moisture content of 0-100 cm if single irrigation amount greater than 60 mm.The influence degree of the rainfall to the soil moisture content of each layer depended on the amount of the rainfall.Irrigation could obviously promote the soil evaporation intensity.Using Ritchie model to simulate soil evaporation,Cumulative evaporation in the first stage(U)was closely related with soil properties;The slope of soil cumulative evaporation(?)in the second stage should use different values at different reproductive stages,Under the condition of test,? was 2.5026,2.0477 and 3.425 in reviving stage,jointing stage and filling stage,respectively.(2)Clarifying the effects of different irrigation mode on the growth,yield and water use efficiency of winter wheat.Under the conditions of this test,Irrigation in reviving stage had a significant effect on the growth of plant height at early growth stage,Irrigation in jointing stage and filling stage had no significant effect on the growth of plant height.Irrigation in reviving stage had a significant effect on the growth of leaf area index,and irrigation in jointing stage had smaller promoting effect on the growth of leaf area index.Irrigation in filling stage could effectively slow the rate of leaf area index decrease.The influence of irrigation on spike grain number was more than thousand seed weight.Irrigation at earlier growing stage was good for the increase of production.Adequate water supply in reviving stage was better for the formation of the production and Improving the efficiency of water use than irrigation in late growth stage.(3)Clarifying the response characteristics of layered water control on root morphology index,aboveground growth index,and yield of winter wheat.The moisture content was too low of the surface layer(0-40 cm)could unfavorable affect plant height,dry matter accumulation,spike grain number,thousand seed weight and the grain yield.The low soil moisture content could cause small root indicators,such as the average root length density,root weight density,root diameter and root surface area.By analyzing the response characteristics of winter wheat root growth on soil moisture conditions,it was shown that there was a very significant correlation between the root-shoot ratio of winter wheat and the average soil moisture during the growing stage.(4)Localizing the parameters of SIMDual_Kc Model and identifying the suitable soil and crop parameters.Soil moisture of effective root layer and evaporation during the growth stage of Winter Wheat were better simulated.The consistency index(d)of soil moisture simulation and evaporation simulation reached more than 0.933 and 0.913 respectively.It was found that transpiration and evaporation accounted for about 65% and 35% of evapotranspiration respectively during the whole growth stage of winter wheat.(5)Evaluating the efficiency of soil moisture of different soil layers in each of the winter wheat growth stages.Under the condition of test,from the winter to reviving stage,the availability of soil water in the depth of 0-40 cm was the highest.From reviving stage to jointing stage,the availability of soil water in the depth of 0-40 cm and 40-70 cm were higher.From jointing stage to filling stage,the soil moisture in the depth of 70-100 cm was more efficient.From filling stage to harvest,the efficiency of soil moisture in each soil layer was quite similar.