Soil Fertility And Microbial Community Structure Under Different Land Use Types

More attention would be paid to the effects of different land use types and managements on soil microorganism with better understanding of soil carbon pools’status in global carbon cycle. Soil fertility and microorganism are important components of farmland and forest system, and indicators for assessing soil quality, plant growth and health, and sustainable development and status of soil fertility. Therefore, systematic study of soil ferlity and microorganism of different land use types would forecast the degradation of soil productivity, and contribute to take restoration measures early which could be important significance in theory and practice. In this study, we compared the soil fertility and microbial community structure of two different land use types and analyzed the differences between human disturbance and natural state, using soil samples collected from the reclaimed minesoils of the aluminum mining wasteland in Xiaoyi County and Lingkong Mountain Nature Reserve in Changzhi city, Shanxi Province, North China, which could provide scientific basis for a better understanding of the appropriate management and conservation of ecological environment, anil would be convenient for the further research. The results are summarized as follows:1. Effects of different reclamation patterns on soil fertily and microbial community structure were studied, using soil samples collected from abandoned aluminum mining land in Xiaoyi County, Shanxi Province, North China. The conclusion is as follows:(1) Fertilization significantly increased the soil N, P, K, and soil microbial biomass (P<0.05), and manure with chemical fertilizer was the best fertilization pattern. Under different preceding treatments, the amount of soil available N increased by 7.6,7.9,46.9,16.1,8.8 mg kg-1, the amount of soil available P increased by 37.65,17.39,67.25,7.99,9.98 mg kg-1, the amount of soil readily available K increased by 44.85,38.70,235.23,44.63,23.73 mg kg"1, and the amount of soil microorganisms increased by 5.70,8.03, 31.27,15.65 and 5.22 nmol g-1.(2) Soybean could significantly increase the soil available N, soil available P, and soil readily available K among the three preceding crops (soybean, Vicia sativa, Vicia villosa). In addition, both corn straw returning and whole corn stalk mulch could increase the soil available N, soil available P, and soil readily available K, and whole corn stalk mulch showed better results than corn straw returning(P<0.05). However, Vicia villosa could significantly increase the soil microbial biomass among the 3 preceding crops. Corn straw returning showed better results than whole corn stalk mulch (P<0.05).(3) Application of fertilizers, crop rotation, and corn straw to soil could significantly increased soil N, P, K, and soil microbial biomass. The study of the soil fertility and microbial community structure in reclaimed minesoils of aluminum mining wasteland could provide scientific basis for a better understanding of the appropriate agricultural practice and restoration of mining wasteland, and would be convenient for the further research.2. Effects of different vegetation types on soil fertily and microbial community structure,and correlations between soil microbial community structure and soil basic properties were studied, using soil samples collected from Lingkong Mountain Nature Reserve, a natural mixed forest on Loess Plateau in North China. The conclusion is as follows:(1) Effects of storage conditions of soil samples on soil microbial community were studied, and the results showed that the effects of cold storage were smaller than those of freezing (P=0.031).(2) Correlations among different forms of soil K were significantly different. There were significant relationships among bacteria, fungi, actinomycetes, total microbial biomass and microbial biomass carbon of soil. There were also significant positive correlations between soil total microbial biomass and soil N and K, which indicated that soil N and K had higher influences on soil microorganism.(3) PLFA analysis showed that fatty acids C 16:0, C16:1, C18:1ω9c, C18:1ω9t, C18:2ω6c, C18:2ω6t, i15:0, a15:0, i16:0, cy17:0, cy19:0were relative abundance. Principal component analysis (PCA) of PLFA patterns revealed significant difference of plant diversity on microbial community structure. The vegetation type of Pinus tabulaeformis, Carex lanceolata Boott and rosa xanthina and the vegetation type of Pinus tabulaeformis and Carex lanceolata Boott were different from the other vegetation types, and the distributions of PLFAs were similar among the there vegetation types which was characterized by Quercus liaotungensis.3. In the reclaimed minesoils of the aluminum mining wasteland, the contents of soil total N ranged from 0.09 to 0.27 g kg-1, soil available P ranged from 1.96 to 71.43 mg kg-1, soil available K ranged from 68.47 to 303.70 mg kg-1, and soil total microbial biomass ranged from 0.05 to 31.58 nmol g-1, while soil total N was 0.07 g kg-1, available P was 1.74 mg kg-1,3 available K was 63.96 mg kg-1, and total microbial biomass was 0.03nmol g-1 before reclamation. In the Lingkong Mountain Nature Reserve, soil total N ranged from 0.30 to 3.95 g kg-1, soil available P ranged from 0.12 to 26.13 mg kg-1, soil available K ranged from 66.00 to 538.42 mg kg-1, and soil total microbial biomass ranged from 7.65 to 102.37 nmol g-1. This could mean that soil quality in reclaimed minesoils of the aluminum mining wasteland was significantly lower than that in the Lingkong Mountain Nature Reserve, and human disturbance had a significant impact on soil microbial biomass. Moreover, different reclamation patterns could significantly improve soil fertily of aluminum mining wasteland.