The multi-function of 18 Bacillus subtilis isolates collected from agricultural extension centers of local government and National Academy of Agricultural Science was investigated by measuring their antifungal activities against five plant pathogens, such as Rhizoctonia solani, Colletotrichum acutatum, Fusarium oxysporum, Magnaporthe oryzae and Phytophthora capsici, phosphorus solubilization ability, production of indole acetic acid (IAA) and siderophore, and nitrogen fixation. The B. subtilis isolates showed antifungal activity against several plant pathogens and nitrogen fixation activity, and produced siderophore and IAA. They could control pepper powdery mildew (Leveillula taurica), but there was no difference in control efficacy among the B. subtilis isolates. In fields, the control efficacy of B. subtilis R2-1 (10 8 cells/ml) was compared with two microbial fungicides, Q-pect and Topsid. In 2009, the control efficacy of B. subtilis R2-1 (37.7%) was lower than that of Topsid (47.6%), but higher than that of Q-pect (25.7%). In 2010, the control efficacy of B. subtilis R2-1 (83.3%) was higher than that of Topsid (67.9%). In order to elucidate mode of action of B. subtilis R2-1 for controlling pepper powdery mildew, spore germination rates of pepper powdery mildew pathogen collected on treated leaves was investigated when suspensions of B. subtilis R2-1 and two microbial fungicides (Q-pect and Topsid) were foliar-sprayed. They highly suppressed spore germination of the pathogen with inhibition values of 84.2% for B. subtilis R2-1, 97.9% for Q-pect and 94.7% for Topsid. Further study on the mass-culturing method and formulation is needed for development of a microbial fungicide.

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Nitrogen added to farmland is used to plants or remains in soil, or is lost to environment. We incorporated 15 N-labeled materials (Chemical fertilizer (CF), green manure (GM), livestock compost (LC), GM+LC, and oil cake (OC) to soil and cultivated Chinese cabbages (Brassica rapa subsp. pekinensis) and analyzed the 15 N recovery of crop and soil to investigate the fate of nitrogen. The results follow. The 15 N crop recovery of chemical fertilizer (CF) was the highest, and that of organic materials differed by type. The 15 N soil recovery of CF was the lowest, and that of organic materials was 3 -6 times higher than CF. The 15 N loss was not significantly difference between CF and organic materials (except GM+LC). As results, despite of the same amount of nitrogen input, there was the difference in plant uptake and soil residue between organic materials and CF. Nitrogen of CF is used to Chinese cabbages more than organic materials, however most of the remaining nitrogen is estimated to be lost to the environment. Therefore, CF might be hard to occur residual effect in the next cropping season. In organic materials, nitrogen is less used to Chinese cabbages than CF, but remains in soil more than CF. Therefore, organic materials might be useful for improving soil fertility and have a residual effect in the next cropping season. We suggest that these properties of organic materials should be taken into account in calculating the amount of applied fertilizer in organic farming where mainly organic materials are used. Moreover, it is necessary to investigate the cumulative and residual effects of continuous input of the same organic materials.

2014) Effects of hairy vetch, rye, and alternating cultivation of rye-vetch cover crops on soil nutrient concentrations and the production of red pepper (Capsicum annuum L.