Research On Effects Of Fertilization On Soybean-maize Rotation And Microbial Diversity In Reclaimed Soil

Fertilization is one of the effective ways to improve the quality of reclaimed soilin mining area.The improvement of reclaimed soil quality in mining area is of great significance to the stability of soil microbial community and function,the sustainable development of agriculture.Rhizosphere is the main channel for soil nutrients to enter the plant,which determines the nutrients transportion,absorption,transportation and degradation and metabolism.At present,the effects of different fertilization treatments on the microbial community functional diversity,structure and soil enzyme activity about rotation crop rhizosphere and non-rhizosphere soil during different period of the reclamation area of coal gangue landfill have not been reported.Therefore,it is of great academic value and practical significance to study theeffectsof fertilization on soybean-maize rotation and microbial diversity in reclaimed soil.In this paper,we took soybean-maize rhizosphere and non-rhizosphere soil under different fertilization treatments during different period in the coal gangue landfill reclamation area as the research object,analyzedthe effects ofdifferent fertilization treatments on soil microbial community structure and diversity in soybean and maize rhizosphere and non-rhizosphere soil during different period were analyzed,and the mechanism of fertilization on soil microbial community under rotation system was revealed.The main(1)The results showed that the effect of combined application of organic and inorganic fertilizer on increasing plant height,and aboveground biomass of soybean and maize in the reclamation area was better than that of inorganic fertilizer or organic fertilizer.Compared with organic fertilizer and inorganic fertilizer,the yield of soybean increasedrespectively by 2433kg/hm2 and 489 kg/hm2;compared with organic fertilizer,the yield of maize increased by 5558kg/ hm2,but there was no significant difference between organic-inorganic fertilizer and inorganic fertilizer.(2)Under soybean-maize rotation system,rhizosphere nutrient,enzyme activity and microbial quantity in reclaimed soil showed obvious rhizosphere effect,the contents of alkaline nitrogen,catalase and alkaline phosphatase in reclaimed soil in maize season increased significantlycompared with soybean season.In soybean season,the nutrient enrichment rate of rhizosphere was positive under all fertilization treatments,and the organic matter enrichment rate was the highest under organic and inorganic fertilizer,which could increase by 7.14% ~ 20.14% and 1.09 ~ 15.41% respectively compared with inorganic fertilizer and organic fertilizer treatment;the effect of organic and inorganic fertilizer on improving enzyme activities in soybeanrhizosphere and non-rhizosphere soil was better than other treatments;the R/S values of rhizosphere effects of bacteria,actinomycetes and fungi respectively ranged from 0.52 to 121.94,3.04 to18.51 and 11.00 to 21.30.In maize season,the nutrient enrichment rate of rhizosphere was positive in different periods under organic and inorganic fertilizer;except catalase activity,the rhizosphere effect of other enzyme activities was significantly correlated with organic matter enrichment rate;the R/S value of rhizosphere effect of bacteria,actinomycetes and fungi respectively ranged from 5.47 to 20.17,3.05 to27.47 and 2.75 to 90.00.(3)The stable dominant phylum and genus of bacteria in reclaimed soil under different treatments and the significantly different phylum and genus of bacteria were preliminarily identified.The number and structure of bacteria,actinomycetes and fungi in soybeanandmaize rhizosphere and non-rhizosphere soil changed dynamically with periods under different fertilization treatments;however,in the bacterial community structure,proteobacteria and actinomycetes remained relatively stable and are the dominant bacteria phyla with relative abundance more than 20%,and nocardioides is the dominant bacterial genus.There were 10 phyla and 23 genera of bacteria with significant differences under different fertilization treatments in soybean season,while 10 phyla and 34 genera in maize season.(4)Carbon sources and driving factors affecting soil microbial metabolic function in different crop growing seasons were screened out.In soybeanseason,the main carbon sources affecting the metabolic function of soil microorganisms are sugars,acidsand amino acids;and the key soil nutrient factors driving the changes are soil total nitrogen and available nutrients in the fast growing stage of soybean,while organic matter and available phosphorus are mainly in the mature stage.However,carbon sources affecting the metabolic function of soil microbial community are mainly sugars and amino acidsin maize season,organic matter and available phosphorus are the key nutrient factors in maize fast growing stage,but in its mature stage is organic matter.(5)The main nutrient factors affecting the microbial community structure of rhizosphere and non-rhizosphere soil under soybean maize rotation were studied.In soybean season,the dominant nutrient factors of soil microbial community in different growth stages were different;in maize season,available phosphorus was the common dominant nutrient torhizosphere microbial community in different growth stages,while to non-rhizosphere soil microbial community was organic matter.(6)By evaluating the fertility factors of reclaimed soil,we determined that organic and inorganic combined application was the suitablefertilization measures in the reclaimed soil in mining area.