Soil conservation management is necessary for sustainable agriculture, in highland areas, and cover crops are one of the best soil conservation methods for slopes. In this study, we evaluated the effects of alfalfa cultivation on maize production, as well as soil conservation and quality. There was an outstanding soil conservation effect with alfalfa cultivation in the fallow and maize growing seasons. In particular, alfalfa cultivation reduced soil loss by up to 98% compared with bare field. It also increased the activities of soil microorganisms and the supply of organic matter. Maize production with alfalfa cultivation showed no significant differences in yield. In conclusion, alfalfa is an advantageous perennial cover crop in highland agricultural slope areas, which can have positive effects on soil quality and conservation, as well as maize production.

The purpose of this study was to evaluate the mixed treatment of compost tea and amino acid liquid fertilizer as a substitute of oil cake for the organic cultivation of maize in Goesan, Chungbuk province. As a result, nitrogen, phosphoric acid, potassium, calcium and magnesium contents of each organic fertilizer were in the order of oil cake > amino acid fertilizer > compost tea. Each of these organic fertilizers had little influence on the change of soil chemical. Individual treatment of amino acid fertilizer and oil cake for weight of an ear as well as all individual treatments for the fresh weight of 100 kernels showed significant increase, compared to the untreated control. For the corn yield of merchantable quality, each treatment of compost tea, amino acid liquid fertilizer and oil cake increased higher 3.9, 5.4 and 5.9% than untreated control, respectively. On the other hand, as a result of mixed treatment of amino acid fertilizer and compost tea, the change of soil chemical property was insignificant. The mixed treatment, Nonetheless, showed significant increase for stem height to 1st ear, grain setting length in an ear, weight of an ear, and fresh weight of 100 kernels, compared to the oil cake as a control. After all, the corn yield of merchantable quality produced by the mixed treatment was 3.9% higher than the control. Therefore, our study would be considered that the mixed treatment of amino acid and compost tea is one of organic materials that can replace oil-cake in maize.

Background: Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results: The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. After May fumigation, the sowing date of maize was delayed by 15 days and thus its dry weight was decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, NO3, P2O5, and K significantly. Maize cultivation after May fumigation decreased fungi population and the ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different between treatment of May and September, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusions: Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by the amendment of mineral composition and microorganism in fumigated soil.