| Mulching cultivation technique is widely used in agricultural production,especially in arid and semi-arid regions,where do not has enough water resource and rainfall.Mulching cultivation technique can improve soil water and temperature condition,thus promote the growth of crop and increase yield,water use efficiency.But in different area it may have different results because the climate,soil type,management method are different.In order to choose a most suitable mulching pattern in our district,we designed experiments in ShaanXi YangLing from 2014 to 2016.We arranged four treatments: ridge-furrow with plastic mulching(RM),straw mulching(SM),ridge covered by plastic and furrow covered by straw(RSM),flat plot without mulching(CK).We focused on the effects of different treatments on soil water,soil temperature,maize height,stem diameter,leaf area index(LAI),dry matter of above ground and yield,so we can evaluate which treatment is most suitable.What's more,in order to understand the influences of mulching on crop water consumption,we simulated the maize transpiration,soil evaporation,bottom flux of water in root zone based on hydrus-2d model.The main conclusions were as follows:(1)The 0~100 cm profile water content of RM,RSM,SM were higher than CK in 3-leaf stage,jointing stage,tasseling stage,maturity stage by 4.0%?4.0%?8.0%;-4.0%?-4.0%?-4.0%;0%?-4.2%?0%;0%,0%,0%.Indicated that RM,RSM,SM could conserve soil water in maize early stage,but had little or no effects in middle and late stage.Among the four treatments,SM had the best effect on conserving water.Mulching treatments had little effects on 0~100 cm water storage,but could increased 0~200 cm water storage,which indicated that mulching on soil surface can promote water infiltrate to deeper soil.what's more,the effect of mulching on water storage ranked by RM>SM>RSM.(2)RM?RSM?SM increased the average soil temperature in 15 cm layer by 0.85,0.45,-0.5?,and increased the average soil temperature in 30 cm layer by 0.65?0.65?-0.35?,respectively.Which indicated that RM could obviously increased soil temperature,but SM had quite opposite effect,RSM could increased soil temperature,but it can also decrease soil temperature at the same time in some period.(3)RSM and SM could increase the plant height and LAI.RSM and SM increased the maximum LAI by 15.4%,8.5%;increased average LAI by 20.4%,14.1% when compared with CK,and increased the above ground dry matter about 26.4%,12.4%.But for RM treatment,in 2014,it had lower plant height and smaller LAI,the maximum and average LAI was 12.6%,12.5% smaller than CK,the above ground dry matter was about 13.4% less than CK.In 2015 and 2016,RM increased the maximum,average LAI and above ground dry matter by 7.7%,11.6%;-0.6%,-1.1%;12.8%,4.6%.(4)Mulching cultivation technique could increased length of kernel,the number of kernels per ear and weight of 100 kernels.As for grain yield and biomass yield,RM?RSM?SM increased by 8.0%,37.9%,29.9% and-3.2%,14.4%,11.0% compared with CK,the harvest index also had been increased under mulching.Above results proved that surface mulching could obviously promoted maize yield,and RSM was the most profitable mulching pattern in this district.(5)Model results showed that HYDRUS-2D could simulated water dynamics very well.The average transpiration and evaporation rate for RM and CK were 1.3,1.1;0.8,1.2 mm/d.the ET rate for both treatments were 2.1,2.3 mm/d,which indicated that RM could increase transpiration rate and decreased evaporation rate.Totally,RM increased 15.6% transpiration water and decreased 29.6% evaporation water,thus decreased the ratio between evaporation and evapotranspiration,made soil water more available for crop. |
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