This study was conducted to investigate the responses of soil properties and microbial communities to different agricultural management and soil types, including organic management in Andisols (Org-A), organic management in Non-andisols (Org-NA), conventional management in Andisols (Con-A) and conventional management in Non-andisols (Con-NA) by using a pyrosequencing approach of 16S rRNA gene amplicon in Radish farms of volcanic ash soil in Jeju island. The results showed that agricultural management systems had a little influence on the soil chemical properties but had significant influence on microbial communities. In addition, soil types had significant influences on both the soil chemical properties and microbial communities. Organic farming increased the microbial density of bacteria and biomass C compared to conventional farming, regardless of soil types. Additionally, Org-NA had the highest dehydrogenase activity among treatments, whereas no difference was found between Org-A, Con-A and Con-NA and had the highest species richness (Chao 1) and diversity (Phyrogenetic diversity). Particularly, Chao 1 and Phyrogenetic diversity were increased in organic plots by 12% and 20%, compared with conventional plots, respectively. Also, regardless of agricultural management and soil types, Proteobacteria was the most abundant bacterial phylum, accounting for 21.9-25.9% of the bacterial 16S rRNAs. The relative abundance of putative copiotroph such as Firmicutes was highest in Org-NA plot by 21.0%, as follows Con-NA (13.1%), Con-A (6.7%) and Org-A (5.1%.), respectively and those of putative oligotrophs such as Acidobacteria and Planctomycetes were higher in Con-A than those in the other plots. Furthermore, LEfSe indicated that organic system enhanced the abundance of Fumicutes, while conventional system increased the abundance of Acidobacteria, especially in Non-andisols. Correlation analysis showed that total organic carbon (TOC) and nutrient levels (e.g. available P and exchangeable K) were significantly correlated to the structure of the microbial community and microbial activity. Overall, our results showed that the continuous organic farming systems without chemical materials, as well as the soil types made by long-term environmental factors might influence on soil properties and increase microbial abundances and diversity.

Termites (Isoptera) are classified into approximately 3,106 species. In Korea, only one species has been identified, which is Reticulitermes speratus kyushuensis Morimoto. The termite, a social insect, is known to play an important role in nutrient cycling of the ecosystem, although some species of termites are well-known pests attacking wooden structures or any plant materials. However, there is a lack of research about termites in Korea, including aspects such the taxonomy, physiology, and ecology of termites. This study was carried out to provide valuable basic data on the ecological role of termites in an ecosystem in Korea for the future studies. For the experiments, soil and termite samples were randomly collected from Mt. Hwajang located in Jikdong-ri, Eonyang-eup, Ulju-gun, Korea between October 5 and 30, 2015. Analysis results showed that there were no significant differences in soil chemical properties between the soil samples just after air-drying and one year elapsed without any treatment. The treated soil with termites showed significantly higher than the soil without termite treatment. Chemical properties of total nitrogen, organic matter, available phosphate, pH, Calcium(Ca), Potassium(K) and Magnesium(Mg) in soil treated with termites were 1.11 ± 0.3 g kg-1, 43.3 ± 12.4 g kg-1, 27.4 ± 2.9 mg kg-1, 4.56 ± 0.2, 0.82 ± 0.2 cmolc kg-1, 3.18 ± 1.4 cmolc kg-1, 1.73 ± 1.1 cmolc kg-1, respectively. The values of soil property of without termite treatment were 0.56 ± 0.1 g kg-1, 30.5 ± 3.1 g kg-1, 24.0 ± 4.7 mg kg-1, 4.09 ± 0.1, 0.71 ± 0.2 cmolc kg-1, 2.88 ± 1.5 cmolc kg-1, 1.30 ± 0.7 cmolc kg-1, respectively. These results suggest that inhabitation of termites could improve soil chemical properties in an ecosystem.

Background : The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot in many ginseng production areas. Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. Methods and Results : Five kinds of rotation crops, sudan grass soybean peanut sweet potato, perilla were grown for one year in ginseng garden harvested 6-year-old ginseng. The ratio of gram-negative bacteria, fungi, bacteria, total microbial biomass, aerobic/anaerobic microbes were increased by rotational crop cultivation, while the ratio of actinomycetes and the ratio of saturated to unsaturated fatty acids were decreased. The increase in the fungal density or the increase in the proportion of fungi to the bacteria tended to increase the incidence of root rot, but there was no significant difference. The yield of ginseng root showed a highly significant negative correlation with actinomycetes. The correlation between the soil chemical properties and the incidence of root rot was analyzed by cultivating 23 kinds of green manure crops for one year in field where cultivated ginseng continuously. The survival rate of ginseng showed a highly significant positive correlation with soil acidity and a highly significant negative correlation with nitrate nitrogen, and a significant negative correlation with soil salt concentration. Conclusion : Rotation crops improved soil microbial communities, lowered the rate of fungi and increased the proportion of bacteria, the survival rate of ginseng was significantly correlated with soil acidity, nitrate nitrogen and soil salinity.

This study was carried out to investigate the cause of leaf discoloration occurring frequently in paddy cultivation. Chemical property of soil and inorganic nutrient component of leaf were analyzed on abnormal fields of 7 regions where leaf discoloration occurred severely and normal fields of 7 regions among ginseng garden. The pH of abnormal fields was strong acidic condition (pH 5.51) compare to normal fields of slightly acid condition (pH 6.42). Calcium and magnesium content in abnormal fields were lower distinctly than that of normal fields, while EC, organic matter, phosphate, and potassium content showed not distinct difference between abnormal and normal fields. Whereas calcium and magnesium content were distinctly high in normal fields, both of potassium and iron content of ginseng leaf were distinctly high in abnormal fields. In particular, iron content of abnormal fields was more 1.94 times in soil, and 3.03 times in leaf than that of normal fields. In soil chemical property, there were significant negative correlation between leaf discoloration ratio and soil pH, and there were also significant positive correlation between leaf discoloration ratio and iron content. In ginseng leaf, there were highly significant negative correlation between leaf discoloration ratio and calcium content, and there were also highly significant positive correlation between leaf discoloration ratio and iron content.

벼에 대한 SCB 액비의 활용방법을 구명하기 위하여 기 추 비 시용량을 달리 처리한 후 쌀 수량 및 토양환경에 미치는 영향 등을 검토한 결과는 다음과 같다. 논토양의 화학성은 규산을 제외한 액비시용구가 무시용구에 비하여 높았으나 시험 전 후 간에는 큰 차이가 없었다. 액비시용 후 토양 중 NH4 -N함량은 2일 이내 균평작업으로 논 전체에 균일한 농도를 유지하였다. 액비분시에 따른 토양 중 NH4 -N와 NO3 -N함량은 이앙 후부터는 초기에는 화학비료 관행시비구와 액비 기비 100%처리에서 높았으나 분얼감수기 이후에는 모든 처리가 유사하였다. 토양침출수중 NO3 -N함량은 액비기비70%+수비30%시용에서 관행시비구보다 약간 낮은 함량을 보였다. 액비 분시에 따른 쌀 수량은 관행시비구보다 액비 기비 100%처리에서 약간 낮았으나 액비 기비70%+수비30%에서 관행시비구와 대등하였으며 나머지 액비 처리구에서도 큰 차이가 없었다. 쌀 품위는 무 시용구와 액비 기비100%에서 완전립율이 높고, 단백질함량이 낮았으나 액비기비70%+수비30%에서 관행시비구와 유사하였다. 따라서 SCB액비를 이용하여 벼 재배할 경우 액비기비70%와 수비30%시용으로 화학비료 사용을 대체 할 수 있을 것으로 판단된다.