Effects Of Manure Application On Phosphorus Mineralization And It’s Availability In A Coal Mining Subsidence Reclamation Soil

Coal mining has caused a large area of land to collapse,resulting in soil structure damage and nutrient deficiencies,especially the availability of phosphorus was extremely low.In order to effectively fertilize reclaimed soil of coal mining subsidence area,enhance soil phosphorus content,increase phosphorus utilization rate,so understanding the characteristics of organic fertilizer phosphorus mineralization and bioavailability of phosphorus in reclaimed soil of coal mining subsidence area was urgently needed,which was also one of the solving problems in coal mining subsidence area.Therefore this experiment used an indoor culture method to study effects of the different organic fertilizers（chicken manure,pig manure,cattle manure）on phosphorus mineralization characteristics in the reclaimed soil of coal mining subsidence,and in this basis,the field experiment was conducted to study the effects of applying different manures（chicken manure,pig manure,and cattle manure）for consecutive years on maize growth,phosphorus availability（Olsen-P）and Hedley phosphorus form in reclaimed soil of coal mining subsidence area,in order to clarify the bioavailability of phosphorus in different organic fertilizers,moreover providing a theoretical basis for organic fertilizers to efficiently fertilize reclaimed soil in coal mining subsidence area.The results were as follows:1.The indoor mineralization test（105 days）was used to study the effects of different organic fertilizers（chicken manure,pig manure,cattle manure）and chemical fertilizers on phosphorus mineralization characteristics in coal mining subsidence soil.The results showed: the available phosphorus content of each fertilization treatment showed a downward trend with the increase of the cultivation time.The available phosphorus content in different cultivation periods varied with different treatments,with a sequence of chicken manure > pig manure ≥ cattle manure > chemical fertilizer >blank treatment.At the end of the cultivation（105 days）,organic fertilizer treatments（chicken manure,pig manure,cattle manure）significantly increased soil available phosphorus content（18.56%-37.09%）compared with chemical fertilizer treatment;and compared with pig manure treatment and cattle manure treatment,the available phosphorus content of chicken manure treatment significantly increased by11.93%-15.62%,but there was no signific ant difference between pig manure and cattle manure treatment.the pseudo-second-order kinetic model（R²=0.995-0.997）could better respond to the process of fast-acting phosphorus release from each fertilization treatment,followed by the Elovich model and the power function model,but the intraparticle diffusion model had a poor fitting effect.During the whole cultivation per iod,the phosphatase activity of organic fertilizer treatments was significantly higher than that of chemical fertilizer treatment,and the increased range was 39.14%-120.70%.There was no signif icant difference on inorganic phosphorus conversion intensity among fertilizer treatments,but fertilizer treatments had an effect on organic phosphorus conversion intensity.In the early cultu re period（0-14 days）,the organic phosphorus conversion intensity of pig manure treatment significantly increased by 41.51% and 86.52% respectively,compared with the treatment of cattle manure and chicken manure;but there was no significant difference in the organic phosphorus conversion intensity among fertilizer treatments in the middle and late period of culture（42-105 days）.2.Field exper iment was conducted to study the effects of different manures（chicken manure,pig manure,and cattle manure）and chemic al fertilizers on corn growth,phosphorus availability（Olsen-P）,and phosphorus fertilizer use efficiency in coal mining subsided soil for three consecutive years.The results showed: the fertilizer treatments significantly increased maize grain yield and above-ground biomass for three consecutive years.Among them,maize grain yield of chicken manure and chemical fertilizer treatment were the highest yield in the f irst year,and there was no significant difference between both（average 13.40 t/hm²）.However,the chicken manure treatment and chemical fertilizer treatment signif icantly increased corn yield（8.40%-21.80%）compared with pig manure and cattle manure treatment;there was no signif icant difference on the maize yield between organic fertilizer treatment and chemical fertilizer treatment in the second years and third years（average 12.21 t/hm2 and 8.50 t/hm²）.According to the yield composition,it was found that fertilizer treatments mainly increased the 100-grain weight of corn and thus increased the grain yield for three consecutive years,but which had no effects on the number of ear rows,ear grains and row grains.As the fertilization years increased,the amount of the phosphorus absorption of corn increased by 35.19%-66.94%（first year of fertilization）,45.57%-49.11%（second years of fertilization）,and 61.44%-103.90%（third years of fertilization）.For three consecutive years,the Olsen-p content of different fertilizer treatments showed a decreasing trend with the increase of soil depth in 0-60 cm soil profile.The regression analysis of cumulative phosphorus application and soil Olsen-P content found that the Olsen-P content of four kinds of fertilizer treatments（chicken manure,pig manure,cattle manure and chemical fertilizer）and cumulative phosphorus application were signif icantly positively correlated in 0-20 cm soil layer（P < 0.01）,the cumulative phosphorus application and the Olsen-P content of chicken manure,pig manure and chemical fertilizer were signif icantly positively correlated in 20-40 cm soil layer（P < 0.05）.Although the phosphate fertilizer recovery rate of chicken manure treatment for three consecutive years was significantly higher than that of pig manure,cattle manure,and chemical fertilizer treatment,there was no significant difference between pig manure application,cattle manure and chemical fertilizer treatment.The agronomic phosphorus coefficients（1.42,1.47 and 1.40）of chicken manure treatment were higher than that of pig manure（0.96,1.00 and 1.21）and cattle manure treatment（0.96,0.89 and 0.91）for three consecutive years.3.Field experiment was conducted to study the effects of applying different organic fertilizers（chicken manure,pig manure,and cattle manure）and chemical fertilizers on the Hedley phosphorus form of coal mining subsidence reclamation soil for three consecutive years.The results showed: the application of organic fertilizer treatment increased the proportion of active phosphorus（H₂O-Pt and NaHCO₃-Pt）in total phosphorus in 0-60 cm soil layer,but there was no significant difference between the organic fertilizers treatments.Compared with cattle manure treatment,chicken manure treatment and pig manure treatment signif icantly increased the proportion of potential active phos phorus（NaOH-Pt）in total phosphorus by 39.28% and 34.28% in 0-20 cm soil layer respectively,but there was no signif icant difference between organic fertilizers treatments on the proportion of potential active phosphorus（NaOH-Pt）in total phosphorus in 20-40 cm and 40-60 cm soil layer.The organic fertilizers treatments reduced the proportion of 0-60 cm soil stable phosphorus（HCl-Pt and Residual-P）in total phosphorus,there was no significant difference between organic fertilizers treatments.Through the correlation analys is between soil Olsen-P and soil Hedley phosphorus forms,it was found that NaHCO₃-Pi could be used as a form of phosphorus easily absorbed by plants in 0-60 cm soil layer.Although organic fertilizer application had increased the content of active phosphorus（H₂O-Pt and NaHCO₃-Pt）and potential active phosphorus（NaOH-Pt）compared with chemical fertilizer treatment,but the above-mentioned phosphorus forms were easy to be lost on the surface runoff,so need to be alert potential phosphorus loss risk caused by applying organic fertilizers to coal mining subsidence reclamation soil.