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Effect Of Different Crops Grown On Soil Microbial Characteristics Change

Posted on:2015-03-18Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2370330488498349Subject:Soil science
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Soil microbes play an important role in the agricultural ecosystem is an important part of the agricultural ecosystem.Microbial formation of humus in the soil,nutrient transformation,maintaining soil fertility,transformation and cycling of nutrients,organic matter decomposition and played an important role,and the role of microbial properties are subject to microbial abundance and population structure of the decision.Microbial population structure and abundance of external conditions are nutrients,heat,gas,and water,and heat,gas,water and nutrients they decided on a different farm management practices such as fertilizer,planting crops directly or indirectly affect the soil changes in microbial community structure and function.In this study,based on long-term experiment platform,using plate culture method,PCR and BIOLOG technology,research and cultivation of different crops on soil microbial effects of changes in characteristics.The main findings are as follows:Characteristics under different land use change soil microbial findings showed that:from the microbial composition,the composition of the three categories the number of microorganisms proportion is slightly different,but generally consistent,which accounts for the total number of bacteria in the microbial of 79.83%-90.46%,the total number of fungi0.15%-0.04%,the total number of actinomycetes 9.36%-20.71%,we can see that the number of bacteria occupy an absolutely dominant position in the microbial composition.Changes under different land use patterns of the total microbial grassland>farmland(soybeans,corn,wheat)>bare land,there are differences between the three,while the farmland soil soybeans,corn,wheat,the total number of microorganisms difference was not significant.Soil microbial biomass highest number reached 1.09108? g-1 dry soil,the bare minimum number of soil microorganisms,is 4.50107 ? g-1 dry soil,less 6.40107 ? g-1 dry soil compared to grass soil.The total number of bare soil microbial soil microbes accounts for about 49.45%of the total number,the total number of soil microbial biomass accounted for 119.77%of the total number of soil microbes.Lawn treatment Crenarchaeota 16S rRNA gene and ammonia oxidizing archaea amoA gene abundance was significantly higher than other treatments.Grassland soil Crenarchaeota abundance than the bare ground,soybeans,corn and wheat soil Crenarchaeota abundance increased by 34.4%,30.7%,37.6%and 33.7%.Grassland soil ammonia-oxidizing archaea abundance than bare land,abundance of soybean,corn and wheat soil ammonia-oxidizing archaea were increased by 28.6%,42.6%,44.4%and 53.6%.Due to the long fallow and grassland soil tillage,soil nutrients accumulate more,resulting in grassland ecosystems,organic carbon content and bacteria,Crenarchaeota and ammonia oxidizing archaea abundance.Grassland ecosystems relative to higher farmland and bare land ecosystems organic carbon and nitrogen content,is conducive to microbial proliferation.Therefore,the long-term natural recovery is crucial for solving the problem of black soil degradation plays a role.Effect of different fertilizer application on soil microbial community structure roots showed:under three different crop conditions without fertilization between the total number of root rhizosphere soil microbes exist differences(P<0.05),the total number of ranges is soybeans>wheat>com,different crops there are differences between the root soil microbial populations,the three crops(soybeans,wheat and corn)in the same number of changes in soil fungi and actinomycetes,the performance of soybean>corn>wheat,and bacteria expressed as the number of soybean>wheat>corn,three crops(soybeans,wheat and corn)number of soil bacteria and actinomycetes were there are significant differences.Soil bacteria accounted for about 87.4%to 94.5%of total microorganisms,fungi accounted for 0.06%to 0.22%of total microorganisms,actinomycetes accounted for 2.41%?10.9%of the total number of microorganisms,we can see the bacteria in the rhizosphere soil microbial composition and the number of absolute dominance.In addition,we also found that the total number of soybean rhizosphere microorganisms significantly higher quantities of wheat and maize rhizosphere microorganisms,namely an increase of 40.4%and 343%.Three different crops under conditions of fertilization,soybean rhizosphere microbial bacteria,actinomycetes,and rhizosphere microbial population increased,while reducing the number of fungi;wheat rhizosphere microbial fungi,bacteria,actinomycetes and totals are have increased,and bacteria,actinomycetes,total fat,compared with no difference reached a significant level(P<0.01).Total maize rhizosphere microbial variation as:NPK>NK>PK>CK,and applied NPK,the total number of NK rhizosphere microorganisms compared with no fertilizer,the difference reached a significant level(P<0.05).Effect of soy,corn and wheat crop root differences in the three soil ammonia oxidizing bacteria and ammonia-oxidizing archaea abundance is different.Same fertilization between different crops(wheat,soy,corn)NPK and NK processing wheat,soybeans and corn gene copy number of soil ammonia oxidizing bacteria behave significantly different(P<0.05),PK and CK handle different crops between gene copy number differences(wheat,soy,corn)soil ammonia oxidizing bacteria were not significant(P>0.05).Therefore,to increase the abundance of nitrogen ammonia oxidizing bacteria in soil,fertilizer ammonia oxidizing bacteria for no obvious effect.Same fertilization(NPK,NK,PK and CK treatment)abundance differences(wheat,soy,corn)soil ammonia oxidizing archaea between different crops were not significant(P>0.05).And for the same crop in different fertilization treatments,gene copy number CK handling ammonia oxidizing archaea than NK,PK and NPK gene copy number handling of ammonia oxidizing archaea have increased to some extent.In addition,we can also find the ancient phosphate treatment for ammonia oxidizing bacteria influence is not obvious.Thus,application of nitrogen fertilizer and ammonia for ammonia oxidizing bacteria oxidizing archaea abundance has some influence soil.Different planting patterns on soil microbial functional diversity influence the results showed that:the average rate of change of color under different rotations hole in the soil bacterial communities throughout the training process are the highest rotation handle,handle bare minimum,and alternate cropping and cropping treatment the average rate of change of the color of the hole in the middle.Therefore,the ability of the soil bacterium rotation strongest carbon substrates,bare worst.We chose 96h optical density values of microbial diversity indices.Which results Shannon index and Simpson index showed a different process dominance rotation of soil microbial community richness,species than other treatment.The results showed that the highest index McIntosh evenness in the different treatment of bare ground handling,followed by continuous cropping treatment,and alternate cropping and rotation processing evenness lowest respectively.Therefore,different treatment of different microbial diversity.Biolog principal component analysis is a very effective means to reflect the characteristics of soil microbial community structure.Different treatment in PC-axis there is a clear difference in the distribution of the various processing PCI axis dispersion,bare land deal mainly in the PC1 axis positive direction,and cropping,crop rotation,crop processing greet mainly in the negative direction of PC1 axis;PC2 axis of rotation is mainly distributed in the positive direction,and cropping,stubble and bare welcome in positive and negative directions PC2 axes are distributed.Description crop rotation led to changes in microbial metabolic functions.On the whole a greater differentiation of different treatments,showing the instability of soil microbial communities.In short,planting different crops on soil microbial variation has different degrees of impact,changes in land use patterns,different fertilization methods and cropping patterns may be different degrees of change in soil microorganisms.
Keywords/Search Tags:Black soil, Microorganisms, Ammonia oxidizing bacteria, Ammonia oxidizing archaea
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