• 한국토양비료학회지
• /
• 제44권1호
• /
• pp.127-145
• /
• 2011

Various environmental ecosystems are valuable sources for microbial ecology studies, and their analyses using recently developed molecular ecological approaches have drawn significant attention within the scientific community. Changes in the microbial community structures due to various anthropogenic activities can be evaluated by various culture-independent methods e.g. ARISA, DGGE, SSCP, T-RFLP, clone library, pyrosequencing, etc. Direct amplification of total community DNA and amplification of most conserved region (16S rRNA) are common initial steps, followed by either fingerprinting or sequencing analysis. Fingerprinting methods are relatively quicker than sequencing analysis in evaluating the changes in the microbial community. Being an efficient, sensitive and time- and cost effective method, T-RFLP is regularly used by many researchers to access the microbial diversity. Among various fingerprinting methods T-RFLP became an important tool in studying the microbial community structure because of its sensitivity and reproducibility. In this present review, we will discuss the important developments in T-RFLP methodology to distinguish the total microbial diversity and community composition in the various ecosystems.

• Journal of Microbiology and Biotechnology
• /
• 제32권10호
• /
• pp.1292-1298
• /
• 2022

Soil autotrophic bacterial communities play a significant role in the soil carbon (C) cycle in paddy fields, but little is known about how rhizosphere soil microorganisms respond to different long-term (35 years) fertilization practices under double rice cropping ecosystems in southern China. Here, we investigated the variation characteristics of rhizosphere soil RubisCO gene cbbL in the double rice ecosystems of in southern China where such fertilization practices are used. For this experiment we set up the following fertilizer regime: without any fertilizer input as a control (CK), inorganic fertilizer (MF), straw returning (RF), and organic and inorganic fertilizer (OM). We found that abundances of cbbL, 16S rRNA genes and RubisCO activity in rhizosphere soil with OM, RF and MF treatments were significantly higher than that of CK treatment. The abundances of cbbL and 16S rRNA genes in rhizosphere soil with OM treatment were 5.46 and 3.64 times higher than that of CK treatment, respectively. Rhizosphere soil RubisCO activity with OM and RF treatments increased by 50.56 and 45.22%, compared to CK treatment. Shannon and Chao1 indices for rhizosphere soil cbbL libraries with RF and OM treatments increased by 44.28, 28.56, 29.60, and 23.13% compared to CK treatment. Rhizosphere soil cbbL sequences with MF, RF and OM treatments mainly belonged to Variovorax paradoxus, uncultured proteobacterium, Ralstonia pickettii, Thermononospora curvata, and Azoarcus sp.KH33C. Meanwhile, cbbL-carrying bacterial composition was obviously influenced by soil bulk density, rhizosphere soil dissolved organic C, soil organic C, and microbial biomass C contents. Fertilizer practices were the principal factor influencing rhizosphere soil cbbL-carrying bacterial communities. These results showed that rhizosphere soil autotrophic bacterial communities were significantly changed under conditions of different long-term fertilization practices Therefore, increasing rhizosphere soil autotrophic bacteria community with crop residue and organic manure practices was found to be beneficial for management of double rice ecosystems in southern China.

• 한국토양비료학회지
• /
• 제48권4호
• /
• pp.262-270
• /
• 2015

The scientific information between microbial community and chemical properties of reclaimed tidal soil is not enough to understand the land reclamation process. This study was conducted to investigate the relation between chemical properties and microbial activities of soils from reclaimed tidal lands located at south-western coastal area (42 samples from Goheuong, Samsan, Bojun, Kunnae, Hwaong and Yeongsangang sites). Most of the reclaimed soils showed chemical characteristics as salinity soil based on EC. Only $Na^+$ in exchangeable cation was dependent on EC of reclaimed soil, whereas other cations such as $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were independent on EC. The mesophilic bacteria decreased with an increase in EC of soil. Microbial population increased with soil organic content in the range of $0{\sim}10g\;kg^{-1}$ and dehydrogenase activity less than $100{\mu}g-TPF\;g^{-1}h^{-1}$. Microbial population of soils from reclaimed tidal lands was closely related to the microbial community containing hydrolytic enzyme activities of cellulase, amylase, protease, and lipase.

• 한국환경농학회지
• /
• 제36권4호
• /
• pp.223-229
• /
• 2017

BACKGROUND: Tillage systems and fertilization play an important role in crop growth and soil improvement. This study was conducted to determine the effects of tillage and fertilization on the microbial biomass C and dehydrogenase activity of soils in a field under cultivation of soybean. METHODS AND RESULTS: An experimental plot, located in the temperate climate zone, was composed of two main sectors that were no-tillage (NT) and conventional tillage (CT), and they were subdivided into four plots, respectively, in accordance with types of fertilizers (non fertilizer, chemical fertilizer, hairy vetch, and liquid pig manure). Microbial biomass C and dehydrogenase activity were evaluated from May to July in 2016. The microbial biomass C and dehydrogenase activity of NT soils were significantly higher than those of CT in all fertilizer treatments, and they were further increased in hairy vetch treatment than the other fertilizer treatments in both NT and CT. The dehydrogenase activity was closely related to microbial biomass C. CONCLUSION: It is concluded that application of green manure combined with no-tillage can provide viable management practices for enhancing microbial properties of soil.

• 한국토양비료학회지
• /
• 제49권2호
• /
• pp.144-156
• /
• 2016

Soil is a dynamic biological system, in which it is difficult to determine the composition of microbial communities. Knowledge of microbial diversity and function in soils are limited because of the taxonomic and methodological limitations associated with studying the organisms. In this review, approaches to measure microbial diversity in soil were discussed. Research on soil microbes can be categorized as structural diversity, functional diversity and genetic diversity studies, and these include cultivation based and cultivation independent methods. Cultivation independent technique to evaluate soil structural diversity include different techniques such as Phospholipid Fatty Acids (PLFA) and Fatty Acid Methyl Ester (FAME) analysis. Carbon source utilization pattern of soil microorganisms by Community Level Physiological Profiling (CLPP), catabolic responses by Substrate Induced Respiration technique (SIR) and soil microbial enzyme activities are discussed. Genetic diversity of soil microorganisms using molecular techniques such as 16S rDNA analysis Denaturing Gradient Gel Electrophoresis (DGGE) / Temperature Gradient Gel Electrophoresis (TGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP), Single Strand Conformation Polymorphism (SSCP), Restriction Fragment Length Polymorphism (RFLP) / Amplified Ribosomal DNA Restriction Analysis (ARDRA) and Ribosomal Intergenic Spacer Analysis (RISA) are also discussed. The chapter ends with a final conclusion on the advantages and disadvantages of different techniques and advances in molecular techniques to study the soil microbial diversity.

• 한국토양비료학회지
• /
• 제47권1호
• /
• pp.28-35
• /
• 2014

Due to recent interest of the consumers on safe farm products and the government's political support for eco-friendly agriculture, organic fruit production has been growing continuously. This research was conducted in order to study the effect of cover plants on soil microbial community on cover plants and establish an organic fruit cultivation method through choosing optimal cover plant. As a result of investigating soil microbial population density, the bacterial density in soil showed an increasing trend in June compared to April, and there was a decreasing trend in bacterial density of the soil in August compared to June. The density of actinomycetes in soil increased around 1.6 times in June compared to April when the soil was covered with hairy vetch. The increase of filamentous fungus in crimson clover group was 6.1 times higher in June compared to April and in hairy vetch group, the increase was 4.9 times higher in June compared to April. As a result of analyzing DNA extracted from the soil categorized by different types of cover plants using DGGE method, soil collected from April had higher number of bands detected from different locations according to different types of cover plants. Diversity of the bands from the soil collected from August showed higher range of reduction. As a result of analyzing soil microbial community by different period and the types of cover plants using Pyrosequencing method, microbes were detected in the order of Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, and Firmicutes. Distribution rate of Firmicutes increased in the soil collected in August compared to June and this was shown in all types of cover plants by twice the amount.

• 한국토양비료학회지
• /
• 제44권4호
• /
• pp.565-574
• /
• 2011

The development of satisfactory alternatives for supplying the nutrients needed by crops could decrease the problems associated with conventional NPK chemical fertilizers. In this study, the effects of bacterial and fungal effective microorganisms (EM) on the growth of Chinese cabbage (Brassica rapa) were evaluated. This investigation was carried out parrallel with conventional NPK chemical fertilizer and a commercial sold microbial fertilizer to compare between each of their effect. Sterile water and molasses were served as controls. Azotobacter chroococcum effect also was studied either alone or in combination with the effective microorganisms on the growth parameters. In contrast to the bacterial EM, the fungal EM alone without A. chroococcum had a more stimulating effect than fungal EM combined with A. chroococcum. Results showed that seedling inoculation significantly enhanced B. rapa growth. Shoot dry and fresh weight, and leaf length and width significantly were increased by both bacterial and fungal inoculation. The results indicated that the NPK chemical fertilizer deteriorates the microflora inhabiting the soil, while the effective microorganisms either fungal or bacterial ones increased the microbial density significantly. This study implies that both of fungal and bacterial EM are effective for the improvement of the Chinese cabbage growth and enhance the microorganisms in soil. The results showed antagonism occurred between A. chroococcum and each of Penicillium sp and Trichoderma sp in both agar and plant assays. The data were statistically analyzed by ANOVA and Dunnett test.

• 한국토양비료학회지
• /
• 제49권2호
• /
• pp.125-131
• /
• 2016

The biodegradable film application can escape from plastic environmental pollution. This experiments studied the effect of biodegradable mulch film on the soil microbial community using fatty acid methyl ester method in soybean production field. The soil $NO_3$-N content in polyethylene mulch film (PE) soil was significantly higher than biodegradable mulch film soil (p < 0.05). The soil microbial community of Gram negative bacteria showed significantly higher in biodegradable mulch film soil than PE mulch film soil (p < 0.05). In addition, biodegradable mulch film soil had significantly low ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ compared with those of PE mulch film soil (p < 0.05), indicating that microbial stress decreased. The ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ should be considered as a potential responsible factor for the obvious differentiation that was observed between the biodegradable mulch film soil and PE mulch film soil in a upland field. The results of this experimentation show the potential of using biodegradable mulch film in place of PE.

• 한국토양비료학회지
• /
• 제47권2호
• /
• pp.100-106
• /
• 2014

The present study investigated variations in soil microbial communities by fatty acid methyl ester (FAME) and the chemical properties at 24 sites of upland soils in Gyeongnam Province. The electrical conductivity of the soil under potato cultivation was significantly higher than those of the red pepper and soybean soils (p < 0.05). The gram-negative bacteria community in potato soil was significantly lower than those in the garlic and soybean soils (p < 0.05). The communities of actinomycetes and arbuscular mycorrhizal fungi in the red pepper soil were significantly higher than those in the potato soil (p < 0.05). In addition, the cy17:0 to 16:$1{\omega}7c$ ratio was significantly lower in red pepper, soybean, and garlic soils compared with potato soil, indicating that microbial stress decreased. Consequently, differences in soil microbial community were highly associated with cultivated crop species, and this might be resulted from the difference in soil chemical properties.

• 한국토양비료학회지
• /
• 제42권5호
• /
• pp.341-347
• /
• 2009

본 연구는 밀기울과 쌀겨를 이용한 토양 혐기발효 처리가 토양 미생물상 변화에 미치는 영향을 구명하고자 수행하였다. 희석 평판법을 이용하여 토양 미생물상을 분석한 결과 쌀겨를 처리한 토양은 사상균이 크게 증가한 반면, 효모의 생장은 확인할 수 없었다. 반면 밀기울을 처리한 토양은 사상균의 생장이 크게 억제되었으며, 효모는 높은 밀도를 보였다. 인지질 지방산을 이용하여 토양 미생물상을 분석한 결과, 처리가 진행되는 20일 까지는 밀기울과 쌀겨를 처리구 모두 그람 음성균과 양성균의 변동이 미미하였으나, 처리가 종료되어 비닐을 제거한 이후에는 크게 상승하는 경향을 보였다. 각 처리별 미생물 군집구조를 분석한 결과, 밀기울과 쌀겨 처리는 미생물상에 큰 변화를 보였으며, 각각의 군집구조는 크게 달랐다.