| This experiment took the reclaimed soil in the coal mining subsidence area near the village of Piancheng in Xiaoyi City Shanxi Province as the object.Indoor incubation experiments were used to study the dynamic characteristics of nitrogen mineralization of different manures(chinken manure,pig manure,cattle manure).At the same time,through field experiments analyzed the nitrogen availability of different doses of chicken manure and its substitution equivalece for chemical nitrogen,the effects of chicken manure and chemical fertilizers application on nitrogen uptake,nitrogen use efficiency,and soil nitrogen index in coal mining subsidence areas,The study aims to provide effective fertilization for the mining area and increase nitrogen use efficiency.The main results are as follows:(1)The nitrogen mineralization characteristics of three kinds of manure(chicken manure,pig manure,cattle manure)were studied through indoor incubation experiments.The results showed that the content of nitrate nitrogen in soil treated with different manures increased rapidly during the period of 56-84 days,and the nitrate accumulation rate reached the maximum during the period of 84-112 days.At the end of incubation,the soil nitrate accumulation amount under different treatments was:chicken manure>pig manure>cattle manure>control check.There was a significantly negative correlation between the ammonium nitrogen content and the incubation time of all treatments before 14 days,and the greatest reduction was observed in the pig manure,and after 14 days the ammonium nitrogen content was basically stable.The application of manure significantly increased the soil mineral nitrogen content and showed:chicken manure>pig manure>cattle manure.(2)Through field experiments,the research has studied the effects of different levels of chicken manure(50,100,150,200 kg N hm-2)and different levels of chemical fertilizer(0,100,150,200,250 kg N hm-2)on maize yield and nitrogen availability.The results showed that applicated of chicken manure and chemical fertilizer can increase maize yield by 33.55%-61.41%and 26.09%-53.08%compared with no nitrogen treatment,respectively.The recovery efficiency of nitrogen decreased with the increase of nitrogen application levle.The recovery efficiency of nitrogen decreased from 44.40%to 20.56%with the increase of chemical fertilizer and decreased from 37.27%to 16.94%with the increase of chicken manure.The average nitrogen relative efficiency of manure was 59.98%.The average relative fertilizer equivalence was 48.15%.(3)Through field experiments,the research has studied the effects of different amounts of nitrogen combined chemical fertilizer with chicken manure on the growth and nitrogen use efficiency of maize in the coal mining subsidence area.The results showed that when the amount of nitrogen applied was 150 kg hm-2,the combination of manure and chemical fertilizer significantly increased the maize grain yield and uptake of nitrogen(P<0.05),while the difference between the combination of manure and chemical fertilizer and the single application of chemical fertilizer was not significant when the nitrogen application was 100 kg hm-2 and 200 kg hm-2(P>0.05).Under the same nitrogen application level,nitrogen uptake efficiency were significantly higher in combination of manure and chemical fertilizer(P<0.05),but there was no significant difference in partial factor productivity of nitrogen(P>0.05).When nitrogen was applied at 150 kg hm-2,the agronomic efficiency of nitrogen was 23.03 kg kg-1 in the treatment of combination chemical fertilizer with chicken manure,which was 49.56%higher than single used of chemical fertilizer(P<0.05).When nitrogen was applied at 100 and 200 kg hm-2,the physiological efficiency of nitrogen showed that the single used of chemical fertilizer was significantly higher than the combination chemical fertilizer with chicken manure(P<0.05).(4)The effects of combined chicken manure with chemical fertilizer on soil nitrogen related indicators were studied in coal mining subsidence area under different nitrogen levels.The results showed that under the tested nitrogen levels,compared with the single application of chemical fertilizer,the total nitrogen in the plough layer had no significant change compared with the combined application of chicken manure and chemical fertilizer(P>0.05),but the soil alkali-hydrolyzed nitrogen was significantly higher than that of the single chemical fertilizer treatment(P<0.05).The increase range was 13.91%-41.42%at the seedling stage,9.35%-25.50%at the jointing stage,5.85%-40.50%at the heading stage,and 8.08%-42.21%at the maturity stage.Soil nitrate nitrogen and ammonium nitrogen content decreased at seedling stage,jointing stage and heading stage with the increase of soil depth,and the maturity stage increased with soil depth.Under the same nitrogen application level,combination chemical fertilizer with chicken manure can significantly increase the content of mineral nitrogen compared with single chemical fertilizer application(P<0.05).When the amount of nitrogen applied was 150 kg hm-2,the combination of chemical fertilizer and chicken manure significantly increased the activity of urease,L-asparaginase and transglutaminase(P<0.05),but the protease activity did not change significantly(P>0.05).In summary,organic nitrogen in chicken manure is easier to mineralize than pig manure and cattle manure.The average nitrogen availability is 59.98%,and the average relative fertilizer equivalence was 48.15%.The combination of chicken manure and chemical fertilizer can significantly promote the absorption of nitrogen by maize,increase the utilization rate of nitrogen fertilizer,and increase the nitrogen content of reclaimed soil in coal mining subsidence area.Especially application level of 150 kg N hm-2 treatment effect is the best. |
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