Ⅲ. 연구개발의 내용 및 범위 훈증제인 다조멧이 토양에 서식하는 인삼 병원균인 Cylindrocarpon 과 Fusarium 등에 미치는 효과와 병원균을 억제할 수 있는 이로운 토양생물의 밀도변화에 대한 영향을 조사하였다. 또한...
Ⅲ. 연구개발의 내용 및 범위 훈증제인 다조멧이 토양에 서식하는 인삼 병원균인 Cylindrocarpon 과 Fusarium 등에 미치는 효과와 병원균을 억제할 수 있는 이로운 토양생물의 밀도변화에 대한 영향을 조사하였다. 또한, 훈증 후에 토양생태계의 회복과정과 유기물시용에 대한 토양생물의 반응을 살펴보았다. 병억제를 위한 토양관리 기준을 설정하기 위해 토양이화학성과 인삼 근부병과의 상관관계를 검정하였고, 유기물 시용에 따른 근부병 관련 병원균의 변화에 대하여 조사하였다.
Abstract ▼
The purpose of this study was to investigate the effects of dazomet on soil biota, including microorganisms, nematodes, and microa...
The purpose of this study was to investigate the effects of dazomet on soil biota, including microorganisms, nematodes, and microarthropods. Bacteria were the most resistant group and some survived following treatment with 2000 mg kg-1 dazomet. Some soil fungi survived 100 mg kg-1 dazomet, although they were mainly Trichoderma. The fungi pathogenic to ginseng were all killed at 100 mg g-1, and showed both inter- and intra-species variation with respect to dazomet susceptibility. Among the nematodes, Aphelenchus was relatively resistant. The results suggested that susceptibility of soil organisms to dazomet differs between species, and tolerant organisms may engage in recolonisation. In microcosm experiments, recolonisation of soil organisms was controlled by the mesh size, and the microbial biomass and community were assessed using phospholipid fatty acid (PLFA) analysis. The bacterial PLFA levels were slightly altered after fumigation, whereas the fungal PLFA levels gradually increased after fumigation. Principal analysis of the PLFA levels and the ratio of gram-negative to gram-positive bacteria showed that fumigation altered the microbial community. The number of nematodes was not recovered even at 12 weeks after fumigation. The increased Collembolan numbers suggested that fumigated soil could be recolonized by specific organisms that have adapted to the conditions. In field experiments, we tested the ability of organic materials to manipulate the recolonisation of fumigated soil by soil organisms. Bean powder and rice bran increased the microbial PLFA levels and nematode numbers at 6 weeks and 12 weeks after treatment, and the abundance of nematodes continued to increase 42 weeks after fumigation. The abundance of microarthropods was only slightly affected by the presence of the organic materials. We suggest that treating fumigated soils with organic materials is an effective technique to promote soil organism numbers. In addition, Trichoderma was observed to be relatively resistant to fumigation, and therefore, we suggest that the fumigation effect can be improved by using a combination of resistant Trichoderma and dazomet. Some saprophytic fungi are pathogenic to ginseng, and input of organic materials may promote these pathogens. The purpose of this study was to investigate the application effects of manure composts on soil-borne pathogenic fungi and the responses of soil organisms in relation to root rot disease. Manure composts from 3 different organisms, namely, chicken, cow, and pig, were applied at 20 t ha-1. We compared these effects between paddy-converted fields and upland fields. Despite the input of manure composts, the root yield did not increase because of root loss and growth disorder caused by root rot disease. We isolated Cylindrocarpon destructans and Fusarium solani from the diseased roots, which suggested that these 2 fungi were the main causal pathogens. Hyphal growth of the 2 fungi increased in soils of both fields treated with manure composts, but the promoting effect was high in paddy-converted fields. These findings suggest that the application of manure composts may accelerate root rot disease by promoting pathogenic fungi. Microflora was estimated by analysing phospholipid fatty acids, and principal component analysis showed that the responses of microflora were different between the 2 fields. Aerobic bacterial PLFAs were greatly increased in the upland field, which indicated that influences of manure compost might differ according to soil type. Fungal PLFAs showed correlations with fungivorous nematodes but not with abundance of Collembola and Oribatida. It seemed that the suppressive effect of fungivorous fauna promoted by manure compost is minor and restricted to some organisms. Our study suggests the use of manure compost might accompany the risk of root rot disease incidence and suppression of soil-borne pathogenic fungi is necessary for safe use of manure compost.
