Research On Productivity And Obstacle Factors Of Reclaimed Farmland Filled With Yellow River Sediment In The Coal Mining Area With High Groundwater Level

In the mining area of the high diving level plain in eastern China,the underground coal resources and the surface high-quality cultivated land present a large area of compound area.The high-intensity well mining of coal resources causes a large area of surface subsidence and water accumulation,which makes the farmland lose the cultivation conditions and further aggravates the contradiction between human and land in eastern China.It is the latest technology of land subsidence control in east China to use the Yellow River silt to fill and reclaim the high diving level plain.Taking the reclaimed farmland filled with sediment from the Yellow River in Qiuji coal mine,Dezhou City,Shandong Province as the research object,this study collects the information of soil,crop and farming management measures in the research area,systematically analyses the yield of reclaimed farmland crops and its main obstacles,and puts forward the corresponding control measures,in order to further improve and collect the information.To provide scientific basis for promoting the reclamation technology of sediment filling in the Yellow River.The following conclusions are obtained through the research:1)The thickness of overburden is an important factor affecting the productivity of reclaimed farmland.With the decrease of the thickness of overburden,the growth of wheat is poor and the yield presents a decreasing trend.The wheat yield of the reclaimed farmland with soil covering thickness of 70 cm was 28.57% higher than that of the reclaimed farmland with soil covering thickness of 30 cm.The wheat yield of the reclaimed farmland with soil covering thickness of 30 cm was only 70% of that of the normal farmland.2)There was a significant difference in clay content between reclaimed farmland(SR2,SR3)and normal farmland.The water content in the subsoil of reclaimed farmland was obviously lower than that of normal farmland.There was no significant difference in soil bulk density between the two types of farmland,both of which showed strong alkalinity,no significant difference in EC value,and the organic matter content was generally at a low level.The two types of farmland soil nitrogen content is insufficient,soil available p,available k content difference is not significant.3)Total nitrogen,total phosphorus,organic matter,available phosphorus,CEC value,and alkali-hydrolyzed nitrogen had the greatest influence on the increase of crop yield in the surface soil(0-20 cm)of the two types of farmland,and total potassium promoted the increase of crop yield.PH value,EC value,water content,bulk density and available potassium have an inhibitory effect on the increase of crop yield.4)The investigated yield of wheat and maize in the two types of farmland in the study area was significantly correlated with the irrigation amount at the level of 0.01.It was suggested that farmers should adopt a small number of irrigation methods in the cultivation and management process and at the same time prevent soil salinization.In the process of fertilization,attention should be paid to the balanced application of N,P and K fertilizers,to reduce the amount of nitrogen fertilizer,and pay attention to the mode of fertilization and a small amount of multiple fertilization."Jimai 22" is the wheat variety with the highest yield investigated in the reclamation area with silt filling in the Yellow River."Liangxing 77" and "Liangxing 99" have a yield increase space of 11.41% and 20.36% respectively in the reclamation area."Denghai 605" and "Zhengdan 958" are suitable maize varieties in the study area.5)The reclamation of Yellow River sediment filling is feasible in the study area,but it still needs to improve the technology and improve the quality of reclaimed land.At the same time,farmers should pay attention to returning crop straw to the field,fertilizing the soil,improving soil water and fertilizer retention capacity,reducing soil salinization and surface hardening,and preventing weeds,diseases and insect pests.With the continuous improvement of filling and reclamation technology and the gradual improvement of farmers’ farming management level,the productivity of reclaimed farmland will be greatly improved.