Coupled Simulation And Optimized Management Of Soil Water Transport And Crop Growth Under Different Reconstruction Modes

The emission of fly ash in China is increasing year by year.Long-term stacking of fly ash will occupy a large amount of land,and dust will pollute the surrounding ecological environment and endanger human health.The use of fly ash as a filling substrate for land reclamation can effectively solve the environmental problems caused by fly ash stacking and increase the land area.However,the reconstituted soil filled with fly ash is different from normal soil.The soil properties,profile distribution characteristics,crop yield and quality are different from normal soil,and the different reconstruction modes are different.Therefore,strengthening the basic research of fly ash filling and reclaiming soil is of great significance for improving soil quality,guiding agricultural production,and improving crop yield and quality.This paper takes the reclaimed area of the fly ash yard of Huai'nan PingWei Power Plant as the study area.Through the combination of field experiment,field sampling survey and indoor laboratory test,soil physical and chemical properties such as soil bulk density,water content,organic matter and particle composition under different reconstruction modes were obtained.Based on the WHCNS model,Based on the WHCNS model,a joint simulation model of soil water transport and crop growth under different reconstruction models was established to simulate soil moisture transport and crop growth.Set different management levels and combinations of methods,and optimize the soil management mode of fly ash filling and reconstruction based on the simulation results.The results show that:Under each reconstruction mode,the soil volume of overlying soil layer is larger than that of fly ash filling layer,and the soil moisture content is generally lower than that of fly ash filling layer.There is a phenomenon of soil moisture accumulation at the interface of soil and ash.Soil compactness increases first and then stabilizes with the increase of soil depth.With the increase of soil depth,soil nitrate nitrogen decreased first and then increased,and soil ammonium nitrogen and soil organic matter decreased gradually.The change of soil water characteristic curve shows that under the same soil water content,the soil matrix potential of fly ash filling layer and transition layer is obviously higher than that of overlying layer under different reconstruction modes,but there is no obvious rule between fly ash filling layer and transition layer under different modes.Based on the WHCNS model,a joint simulation model for soil water transport and crop growth under different reconstruction models was established and validated.Both soil moisture transport and crop growth simulation results have small root mean square error(RMSE)and high consistency index(d).The model can simulate soil water migration and crop growth in different reconstruction models.The soil moisture content of different remodeling models was larger than that of the bottom layer.The thicker the soil layer,the smaller the variation of soil water content in each layer,and the smaller the difference between soil layers.The corn yield and water use efficiency of each reconstitution model were very low.With the increase of the thickness of the soil,the dry weight of corn kernels increased gradually,and the water use efficiency increased.The combination of management levels and methods has a certain role in promoting corn yield and water use efficiency.Irrigation + double application of nitrogen fertilizer + application of organic fertilizer combined yield and water use efficiency was the best,followed by irrigation + double application of nitrogen fertilizer combination,the combined yield increase of these two combinations was about 50%,and the water use efficiency increased by about 45%.Considering the effect of yield and water utilization efficiency and the ratio of input to output,it is considered that the combination of irrigation and double nitrogen application in the reconstituted soil of fly ash is the best.Figure [24] table [13] reference [115]...