The purpose of this study was to investigate eco-friendly measures to manage major diseases which cause heavy economic damages to ginseng. Morphological, physicochemical, and molecular biological species identification was carried out after isolating useful antagonistic bacteria from ginseng fields. In addition, optimal conditions for mass culture were established, and he efficacy of the bacteria in the prevention of the diseases was verified in the field. The results showed that about 150 bacteria were extracted from 150 ginseng fields in the whole county. Among them, B. pyrrocinia LA101 was finally selected, which had a strong antagonistic potency against Alternaria panax, Botrytis cinerea, Rhizoctonia solani, and Cylindrocarpon destructans on agar media. The B. pyrrocinia LA101 is a baculiform gram-negative bacterium identified as Burkholderia pyrrocinia according to results from an API(Analytical Profile Index) kit, 16S rRNA, and gyrase gene sequencing analysis. It was donated to the microbe bank of the Agricultural Genetic Resources Center at the National Academy of Agriculture Science under the Rural Development Administration on September 28, 2011 (Donation No. KACC91663P). A patent for the mass culture technology was granted in August 2012 (Patent No. 10-1175532).

This study was carried out to investigate the changes in the amount of 20 free amino acids in PDB (Potato Dextrose Broth) medium during the incubation period while cultivating Lentinula edodes. The total incubation period was 90 days, and the total amount of free amino acids was confirmed every 45 days. Among the 18 kinds of amino acids whose increase and decrease patterns were confirmed, 10 amino acids were increased compared to that in the control, among which cysteine increased from its initial value of 9,889 ± 3 μg/L to 12,909 ± 2 μg/L at 45 days and 29,256 ± 4 μg/L at 90 days. Six amino acids with decreased expression patterns were identified. Arginine decreased to 83,751 ± 2 μg/L after 45 days from its initial value of 161,787 ± 1 μg/L and to 79,055 ± 7 μg/L at 90 days.

This experiment was conducted to assess changes to the chemical properties of soil and applicability in a case of rice cultivation with organic fertilizers. The investigator applied organic fertilizers to rice cultivation for five years to examine changes to the chemical properties of soil and found that the experiment group of organic fertilizers made an ongoing increase in pH, organism content, and available phosphate content annually compared with the control group with no big differences according to the amounts of organic fertilizers used. As for the yield components, there were no statistical differences in the number of spikelets and grain filling rate between the experiment group of organic fertilizers and the control group. The experiment group recorded a higher level in 1,000 seeds weight and yield than the control group. Experiment Group 4 recorded the highest level at 29.11 kg of 1,000 seeds weight. Experiment Groups 3 and 4, which used 222 kg and 267 kg per 10 a, respectively, recorded 576 kg and 572 kg of yield, respectively, which were 4.7% and 4.1% higher than 549 kg of control group, respectively. As for the quality of brown rice, there were no statistical differences in the head rice percentage between the control and experiment group, both of which were in the range of 83.2-85.7%. As for the protein content, Experiment Groups 3 and 4, both of which used a lot of organic fertilizers, were in the range of 6.9-7.1%, which was lower than 7.5% of control group. Those findings indicate that the long-term application of organic fertilizers can improve the chemical properties of soil and increase the yield more than the conventional method of fertilizer application. The findings also suggest that it will be effective to apply 222 kg of organic fertilizers or more per 10 a.