Study On Application Effect Of Different Modifiers In Damaged Soil In Southern Ganzhou Ion-type Rare Earths Mining Area

The exploitation of ionic rare earth ore causes damage to the ecological environment in the mining area and serious damage to the soil,such as the destruction of soil structure,lack of soil nutrients,soil acidification,and serious soil pollution.This paper selects the damaged soil of Xinfeng County rare earth mine,and pot experiment to investigate the effect of different modifiers.The results show:?1?Compared with the control,the application of biochar,fly ash,and lime alone changed the texture of the soil from tight sandy soil to light loam,sandy loam,and loam soil;adding a single modifier had a certain effect on reducing the bulk density of the soil,C₃ had the best effect on reducing soil bulk density,which was reduced by0.13 g/mL.The pH of the soil with modifier was significantly increased.The overall order of improvement was:lime>fly ash>biochar,pH of C₂ treatment.The value was the highest,significantly increased by 2.89 units compared to the control;the content of alkaline dissolved nitrogen and available potassium in the soil treated with biochar was significantly higher than that in the control,and other treatments were lower than the control;the ammonium nitrogen in the soil treated with B₁ was significantly higher than the control by 2.02 mg/kg,other treatments were significantly lower than the control;B₃ treatment of soil available phosphorus content is greater than the control,other treatments were significantly lower than the control;biochar,fly ash treatment soil organic matter content was significantly higher than the control,and with the modifier With the increase in dosage,the lime treated organic matter was significantly lower than the control.The comprehensive index of soil fertility of all treatments was at level II?general?level,and soil comprehensive fertility without adding B₃ did not increase,while soil A₃ treatment had the highest comprehensive fertility index of 1.72,which was 0.58 units higher than the control.?2?Control and biochar treatment of Chinese cabbage were not grown.Compared with the control,fly ash and lime treatment can improve the biological characteristics of pakchoi,and can also increase the content of nitrogen,phosphorus and potassium in stems and leaves of pakchoi.The biological characteristics of Chinese cabbage treated with B₃ was the best,and it was significantly higher than that of B₁.The content of nutrients was the highest.The effects of fly ash and lime on the total content of rare earth and the reduction of Y,La,and Nd content in Chinese cabbage were as follows:Lime>Fly ash,C₃ reduces best.?3?Compared with the control,the addition of biochar+fly ash,biochar+lime can increase the content of physical clay??0.01 mm%?in soil,and A₃B₃ has the best improvement effect,increasing by 29;adding biochar+Lime reduced soil bulk density more than biochar+fly ash,A₃C₃ reduced the best effect,reducing the 0.30g/mL.The effect of adding biochar and lime on soil pH and ammonium residues was greater than that of adding biochar and fly ash.The effect of adding biochar and fly ash on improving soil alkali-hydrolyzable nitrogen,available phosphorus,available potassium and organic matter was greater than adding biochar and lime.The comprehensive index of soil fertility with the addition of interactive soil improver was at level II?general?level,and biochar+fly ash>biochar+lime.The A₃B₂ treated soil had the highest comprehensive fertility,which was 1.60.The A₁C₁ treated soil had the lowest comprehensive fertility,which was 1.09.?4?Two interactive soil amendments can both improve the biological characteristics and nutrient content of pakchoi,and biochar+fly ash>biochar+lime,of which the biological characteristics of A₂B₃ are the best;the addition of biochar+lime interactive soil The modifiers reduced the total rare earth content of the Chinese cabbage and Y,La,and Nd effects were greater than the biochar+fly ash.The A₃C₃ had the best effect.