Effects Of Management Measures On Soil Physicochemical Properties And Crop Yield On The Loess Plateau,China

The Loess Plateau is an important food production area in northwestern China.The area is located in arid or semi-arid regions and belongs to the rain-fed agricultural region.Without irrigation conditions,water is the main factor limiting the development of local agriculture.Moreover,the spatial and temporal distribution of rainfall in this area is uneven,and high potential evapotranspiration could severely limit agricultural sustainable development in the region.Therefore,improving water use efficiency,promoting crop growth,and increasing grain production are crucial for accelerating the development of agricultural production under the condition of limited water resources.In order to study the effect of different field management measures on the physical and chemical properties of soil water,heat and crop yield in agricultural production in the area.A located field experiment was conducted at the Changwu Agro-ecological Experimental Station on the Loess Plateau of Northwest A&F University?35°14'N,107°40'E?.Some soil physicochemical properties and agronomic traits had been tested,the main physical parameters included soil bulk density??_b?,total soil porosity???,soil compaction?SC?,soil temperature?T?,soil water content??_m,?_v?,and soil saturated hydraulic conductivity?K_S?.Soil chemical indicators were choosed soil organic matter?SOM?total nitrogen?TN?,nitrate nitrogen?NO₃^--N?,ammonium nitrogen?NH₄⁺-N?,total phosphorus?TP?,available phosphorus?AP?,available potassium?AK?,pH.The agronomic traits of winter wheat included plant height?H?,leaf area index?LAI?,biomass?B?,grain yield?Y?,and yield components.Some related indicators were calculated,included evapotranspiration?ET?,economic benefits?EB?,Best index?BI?,Rainfall harvest?RH?,soil water storage?SWS?,water use efficiency?WUE?,Precipitation utilization efficiency?PUE?.Research indicates,1.Conventional tillage?nitrogen and phosphate fertilizers?treatment?NP?Compared with the long-term non-fertilization control treatment?CK?,SC was significantly decreased,which value was 1074.9±28.6 kPa cm^-2,and K_S(0.026 cm min^-1)was higher than CK(0.016 cm min^-1)increased by 62.5%.The soil nutrients content was changed significantly,and SOM,TN,NO₃^--N,NH₄⁺-N,TP,and AP were increased significantly,and they were 16.9%,11.1%,114.4%,55.1%,and 141.2%higher than CK,respectively.The AK content was significantly reduced at 112.9±9.6 g kg^-1.The H and LAI of winter wheat were also significantly increased,WUE and PUE were significantly increased,Y increased by more than 1 time finally.2.Plastic-film mulching group treatments?based on nitrogen and phosphate fertilizers?Compared with conventional tillage?NP?treatments,different plastic-film mulching patterns had different effects on soil physicochemical properties and agronomic traits of winter wheat.The effects of growth period mulching?GM?and summer fallow period mulching?SM?on?_b and?did not reach significant levels,but N&P total plastic film mulching in the whole year treatment?NPFWT?in the annual coverage group?WM?will significantly increase the?_b and reduce?.All plastic-film mulching treatments have reduced the K_S.The K_S of NPFGT in the growth period was0.013±0.001 cm min^-1,which was the most affected and was reduced by 50%.The mulching treatment in different periods was divided into two kinds of mulching modes,namely half-mulching group?HM?and total-mulching group?TM?.The nutrient contents under two modes basically showed the trend,HM>FM.Only NPFFH can significantly reduce soil pH in all plastic-film mulching treatments.In 2013,all mulching treatments had a positive effect on Y,and NPFWT,NPFGH and NPFFH increased significantly?P<0.05?.In 2014,the impact of natural disasters on hail during the grain filling period caused a significant reduction in Y,especially NPFGH and NPFWH.In 2015,the Y of all treatments increased,and the average NPFWH(5270.3 kg ha^-1)increased by 43.0%?P<0.05?compared with NP(3684.6 kg ha^-1).Except for NPFWT treatment,the content of SWS in the 0-300 cm soil layer was increased,and NPFGT and NPFWH increased significantly?P<0.05?.ET was significantly affected by mulching patterns?P<0.05?.Compared with NP?458.3 mm?,NPFGT?574.6 mm?and NPFWH?517.3 mm?increased by 25.4%,12.9%,respectively.WUE was also affected by mulching patterns,but only for NPFGH,NPFWH,and NPFWT arrived significant level?P<0.05?.With the exception of NPFFH,all treatment PUE increased significantly?P<0.05?.3.Biochar treatment?based on nitrogen and phosphate fertilizers??NPB?Compared with conventional tillage?NP?,NPB significantly increased SC(1362.2±175.4 kPa cm^-2)?26.7%?and significantly increased K_S(0.049 cm min^-1).?88.5%?,significantly increased??56.23%?,and decreased?_b(1.16±0.06 g cm^-3).In addition to AK,other soil nutrients content increased significantly.Both WUE and PUE increased significantly,with Y increased 13.6%,9.8%,and 12.0%for three consecutive years.4.The dynamic changes of soil water,heat under different treatmentsThe 0-10 cm soil water content(?_{V 0-10 cm})under different treatments has a significant relationship with rainfall,but the NPFWT treatment has a greater sensitive to rainfall and can respond to smaller rainfall.The general tendency for?_{V 0-10 cm} is NPFWT>NPFFH>NP>NPB.The water consumption and recharge depth in the 300 cm soil profile are significantly different.NPFWT could increase the depth of soil water consumption and increase deeper layer soil desiccation.NPFFH could increase the depth of water recharge.The soil temperature(T_{5 cm})at 5 cm showed a significant correlation with temperature air and topsoil.The plastic-film mulching would regulate the temperature,reduce the temperature difference between day and night.NPB would increase the maximum and minimum temperatures of the soil and increases the temperature difference between day and night.