Analysis of culturable and unculturable microbial community in bensulfuron-methyl contaminated paddy soils

To investigate the influence of bensulfuron-methyl(BSM)on culturable microbial quantities and unculturable microbial community structures,conventional and molecular biological methods were employed in five BSM treated soils with three replications,respectively. The results obtained with traditional culture-dependent methods showed that a low-level of BSM had slight and transient effects on culturable microorganisms;nevertheless,high concentration of BSM resulted in a dramatic decrease in bacterial colony fo...

Effect of different machinery and rolling times on the microbial activity of reclamation soil in coal area

Mechanical construction will put influence on the biological characters of reclaimed soils,as well as the soil quality.In order to explore the changing rule of soil microbial quantity and respiratory capacity under different construction machineries and rolling times,and find the optimal processing conditions,an experiment was set up and a simulation experimental area was chosen,in which we simulated the main types of reclamation in coal mine area.After 2 years’natural aging,we collected surface soil samples(0-20 cm)that can be used for experimental analysis.The result shows that changing rules of soil biological factors are different with different construction machineries,and soil properties are closest to the normal soil when adopting the combination of“crawler dozer×5 compaction times”and“dump truck×3 compaction times”,which shows that the soil quality is better under this condition.

Effects of Cadmium Contamination on Sugarcane Growth, Soil Microorganism and Soil Enzyme Activity

[Objective] To provide a reference for exploring the relationship between Cd contamination and sugarcane growth and between Cd contamination and micro- bial properties of soil, the effects of adding different concentrations of exogenous cadmium （Cd） on the growth of sugarcane, the quantities of soil microorganisms and the activity of soil enzymes were studied. [Method] The plant height, stem di- ameter and cane yield of sugarcane, the soil microbial quantities and enzyme activi- ties were determined by using sugarcane as a material treated with different Cd concentrations （0, 25, 50, 100, 250 and 500 mg/kg） under potted conditions. IRe- suit] The results showed that the plant height, stem diameter and the yield of sug- arcane decreased with the increase of Cd concentration in the soil, and the higher the Cd concentration, the more obvious the inhibitory effect. The Cd contamination changed the enzyme activity, and the activities of urease and acid phosphatase sig- nificantly decreased with the increase of Cd concentration, especially when the Cd concentration reached 100 mg/kg. The sensitivity of the two soil enzymes to Cd ranked as urease〉acid phosphatase. Cd contamination also changed soil microbial quantities. Fungi, bacteria and actinomycetes significantly decreased at the Cd con- centration level of 100 mg/kg. There were significant and highly significant correla- tions between Cd contamination concentration and fungi, bacteria and actinomycetes, the activities of urease and acid phosphatase, plant height, stem diameter as well as cane yield. [Conclusion] Under the conditions of potted planted sugarcane, ex- ogenous Cd contamination affected the growth of sugarcane, the quantities of soil microorclanisms and soil enzyme activities to different degrees.

Effects of surface cracks on the rhizospheric microhabitat of Artemisia ordosica in subsidence area caused by coal mining

The effects of surface cracks caused by underground coal mining on microhabitat in the rhizosphere of Artem＆ia ordosias were studied based on field investigation and sample analysis. The results show that the amounts of microorganisms, enzyme activity and water content in soil vary with the biomass ofA. ordosias, and that the account exhibits in an order of large A. ordosias〉medium A. ordosias〉small A. ordosias. Surface cracks apparently decrease microbial quantities and enzymatic ac- tivities, and change the composition and structure of microbial community in the rhizosphere of A. ordosias. Surface cracks reduce water content and electrical conductivity, enhance the R/S （ratio of root and soil） of water content, electrical conductivity and pH value, and raise the content of Na and Pb in rhizosphere soil ofA. ordosicas, It can be concluded that the disturbance of underground coal mining on the microhabitat in the rhizosphere ofA. ordosica is obvious in the early days.

Effects of different C/N ratios on the maturity and microbial quantity of composting with sesame meal and rice straw biochar

The purpose of this paper was to study the effects of different C/N ratios on the maturity and microbial quantity of com-posting with sesame meal and rice straw biochar.Rice straw was calcined into biochar as raw materials composting with sesame meal for 30 days,referring to Chenfu Agricultural Book in Sōuthern Song Dynasty(1127-1279 A.D.).Sesame meal was used to adjust the C/N ratio of compost,and three treatments were designed in the experiment,which were C/N ratios of 15,20 and 30,respectively.The results showed that C/N ratio of 20 was beneficial for promoting the temperature rise,the removal of water,the degradation of organic carbon,and the decrease of microbial quantity.The C/N ratio of 20 was beneficial to the compost maturity(T value was 0.47,final GI was 99.67%).The results of Pearson correlation analysis showed that C/N ratio was positively correlated with moisture content,total organic carbon and negatively correlated with germination index,indicating that high C/N ratio was beneficial to water removal and total organic carbon degradation.Therefore,we suggest that the suitable C/N ratio of rice straw biochar and sesame meal is 20.At the same time,we have proved that the composting method in Southern Song Dynasty is feasible,which is of great significance to understand the development of composting in China.