Study On The Soil Fertility Improvement Of Mining Wasteland By Plants Under Different Fertilizations

Although mining industry bring huge economic benefits to China,It also cause environmental pollution to the mining area,therefore,it is need to ecological restoration of the mining wasteland urgently.The soil structure of the mining wasteland is poorer,and lack of organic matter and the essential nutrients which is needed to plants,is not conducive to the growth of plants,Thus,take appropriate measures to improve the soil of the mining wasteland quickly become a serious problem.We constructed the experimental filed to simulation the gangue dump mining wasteland in the loess plateau agriculture ecological experimental station in this study.and selected five different Leguminous and Gramineous plants to conduct single and intercropping planting experiment under organic fertilizer, straw manure and without fertilization.Measured soil moisture content of 0 to 120 cm soil layer and soil nutrient indices(organic matter,total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus,available potassium) of 0 to20 cm soil layer and plant biological indexes(height,coverage,ground diameter).to study the soil fertility improvement of mining wasteland by Leguminous and Gramineous plants under different fertilizations.Obtained the following main conclusions:(1)The improvement of the water-holding capacity of soil by plants is mainly embody in 0 to 40 cm soil layer,plants can improve the water-holding capacity of soil under organic fertilizer and straw manure.The effect under organic manure fertilizer is more remarkable.The change trend of soil moisture content with soil depth has obvious differences in coal gangue filled and coal gangue unfilled planting districts.in coal gangue filled planting district,plant roots consume more soil moisture through transpiration in 0 to 35 cm soil layer.lead to its soil moisture content is inferior to coal gangue unfilled planting district.The structure of coal gangue layer is poor,and has a lot of non-capillary porosity,so it has poorer water-holding capacity and higher permeability.result in the soil moisture content decreases with the depth in 35 to 85 cm soil layer meanwhile the value is far less than coal gangue unfilled planting district.because osmotic water of coal gangue layer moves downwards,so the soil moisture content increases with the depth in 80 to 100 cm soil layer meanwhile the value is higher than coal gangue unfilled planting district in110~150cm soil layer.110~150cm soil layer is less affected by the environment,so the changing amplitude of soil moisture content decreases,and its value is tends to be stable.( 2) The average content of soil organic matter,total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus and available potassium is 5.3 percent,4.4 percent,4.3 percent,28.4 percent,28.0 percent and14.5 percent lower than the control respectively in coal gangue filled planting district.Theyears of plants is shorter,the growth of plant is a process of absorbing nutrient.The average content of soil organic matter,total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus and available potassium of 0 to 10 cm soil layer is 25.0 percent,16.9 percent,82.7 percent,10.5 percent,10.3 percent and23.9 percent higher than10 to 20 soil layer respectively under different fertilizations in coal gangue filled and coal gangue unfilled planting districts.the soil fertility improvement by the growth of plant is more remarkable on the surface.( 3) The average content of soil nutrition(organic matter,total nitrogen,ammonium nitrogen,available phosphorus and available potassium) and the height and coverage of plant show the same trend thant organic fertilizer>green manure>without fertilization in coal gangue filled and unfilled planting districts.The promotion of plants growing by fertilization and the soil fertility improvement by plants have remarkable synergetic relationship.The content of soil nutrition average and the average height of plants of single planting plots are higher than intercropping planting plots.the soil fertility improvement of single planting is more remarkable.so the status of plant growth in single planting plots is better than intercropping planting plots. soil fertility and plant growth have remarkable synergetic relationship.but intercropping planting plots can make full use of space and enhance the coverage of plants.(4)In coal gangue filled planting districts,under organic manure fertilizer,Melilotus suaveolens Ledeb,Astragalus adsurgens Pall,Lolium perenne Land Amorpha fruticosa Linn+Coronilla varia L have better soil fertility improvement.under straw manure,they are Melilotus suaveolens Ledeb,Lolium perenne L,Amorpha fruticosa Linn+Lolium perenne Land Amorpha fruticosa Linn.without fertilization,they are Astragalus adsurgens Pall,Melilotus suaveolens Ledeb,Lolium perenne L and Melilotus suaveolens Ledeb+Lolium perenne L.(5)In coal gangue filled planting districts,the hight of Lolium perenne L is mainly affected by soil available potassium(R=0.828).the hight of Melilotus suaveolens Ledeb is mainly affected by soil moisture content(R=0.9920) and nitrate nitrogen(R=0.9862),the hight of Astragalus adsurgens Pall is mainly affected by soil ammonium nitrogen(R=0.9906) and available phosphorus(R=0.9942),the hight of Coronilla varia L is mainly affected by soil available potassium(R=0.9950) and available phosphorus(R=0.9650),the hight of Amorpha fruticosa Linn is mainly affected by soil moisture content(R=0.9977).The average soil fertility value of coal gangue filled planting district is 4.3 percent higher than coal gangue unfilled planting district.but the height,coverage and ground diameter of plants is 17.8percent,63.4percent and 29.3 percent inferior than coal gangue unfilled planting district respectively.The main reason of the status of plant growth is worse than coal gangue unfilled planting district is its soil ammonium nitrogen and available phosphorus content is lower.