Se-Won Kim

Effect of Mixed Sowing of Hairy Vetch and Rye on Green Manure Yield in Mountainous Highland

Co-incorporation of Leguminosae with Gramineae could reduce the risk of nitrogen starvation phenomena caused by appling green manure of Gramineae alone. The objective of the study was to examine the effect of mixed sowing of hairy vetch and rye seeds on soil quality in mountainous highland. Mixed sowing of hairy vetch and rye increased the yield of green manure and nutrients compared with those for sowing of hairy vetch or rye alone. The yield of green manure from row seeding was compared with for broadcast seeding. Incorporation of the two green manure crops increased yield of red-bean by 58~92% as compared with yield for incorporation of rye alone. The results obtained in the study imply that mixed sowing of hairy vetch and rye can solve the problem of low emergence of hairy vetch in spring and high C/N ratio and rough incorporation of rye, in addition to increase in yield of green manure.

Nitrous Oxide Emission from Livestock Compost applied Arable Land in Gangwon-do

Agriculture activities account for 58% of total anthropogenic emissions of nitrous oxide (N 2 O) with global warming potential of 298 times as compared to carbon dioxide (CO 2 ) on molecule to molecule basis. Quantifying N 2 O from managed soil is essential to develop national inventories of greenhouse gas (GHG) emissions. The objective of the study was to compare N 2 O emission from livestock compost applied arable land with that for fertilizer treatment. The study was conducted for two years by cultivating Chinese cabbage (Brassica campestris L.) in Chuncheon, Gangwon-do. Accumulated N 2 O emission during cultivation of Chinese cabbage after applying livestock compost was slightly greater than that for chemical fertilizer. Slightly greater N 2 O emission factor for livestock compost was observed than that for chemical fertilizer possibly due to lump application of livestock compost before crop cultivation compared with split application of chemical fertilizers and enhanced denitrification activity through increased carbon availability by organic matter in livestock compost.

A Survey on Herbicide Usage for Paddy Rice Cultivation in Gangwon Province, Korea

Youngho Seo*, Sewon Kim, Seungchul Choi, and Byeongchan JeongABSTRACT The occurrence of sulfonylurea-resistant weeds has recently increased in Korea. A survey was performed to investigate major paddy field weeds and frequently used herbicides in Gangwon province, Korea in order to establish a system to efficiently control herbicide-resistant weeds. The dominant paddy field weeds included Monochoria vaginalis (14%), Sagittaria trifolia (14%), Scirpus juncoides (13%), and Echinochloa spp. (13%), and the most widely used herbicides were oxadiazon 12% EC (27%), butachlor 5% GR (20%), oxadiargyl 1.7% EC (16%), and benzobicyclon+imazosulfuron+pyriminobac-methyl 6.1% SC (14%) in Gangwon province, Korea. Many paddy rice growers considered Scirpus juncoides, S. trifolia, Echinochloa spp. and M. vaginalis as herbicide-resistant weeds. An extensive research deserves to be conducted to monitor occurrence of herbicide-resistant paddy weeds in Gangwon province, Korea.Key words: Gangwon province; herbicide; paddy field rice; survey; herbicide-resistant weed.

Effect of Green Manure Crop and Biochar on Nitrous Oxide Emission from Red Pepper Field

Atmospheric nitrous oxide () level has been increasing at a rate of 0.2~0.3% per year. The rise in concentration in atmosphere was mainly due to an increased application of nitrogen fertilizers. The objective of the study was to assess the effect of green manure crop and biochar on emissions from upland crop field. The green manure crop used in the study was hairy vetch and the cultivated crop was red pepper (Capsicum annuum L.). Nitrogen was applied at a rate of , standard N fertilization rate for red pepper. Emissions of from the field were reduced from the plots applied with hairy vetch and biochar by 46.5% and 24.6%, respectively, compared with nitrogen fertilizer treated plots with emission of . The results from the study imply that green manure crop and biochar can be utilized to reduce greenhouse gas emission from the upland crop field.

Effects of Bio-degradable Mulches on the Yield of Maize and the Density of Soil Microbe

The use of polyethylene film has a problem such as increasing rural environmental contamination, collection costs and farmers’ workload. The objective of this study was to evaluate bio-degradable films in terms of yield of maize and soil environment. Treatments were bio-degradable film A (BDF A), bio-degradable film B (BDF B), high density polyethylene (HDPE), and non-mulched (NM) soil. Daily mean values of soil temperature (10 cm depth) under BDF A, BDF B, and HDPE were higher than in NM soil by 2.2, 2.8, 3.1℃ respectively. In the mulching cultivation of maize, bio-degradable film began to degrade from 50~60days after the planting. The degradation was much progressed in the harvest time and almost decomposed in the following spring. The weight of ear of maize was not shown significantly by mulching treatments. There were little changes of soil chemical properties for the bio-degradable film mulching. After using bio-degradable films, the contents of biomass-C and dehydrogenase activity increased from 92 to 137~147 mg kg -1 , and from 87 to 123~168 mg kg -1 respectively.

Stem Rot on Ligularia fischeri Caused by Sclerotium rolfsii in Korea

Youn-Gi Moon, Se-Won Kim, Jun-Keun Choi, Soon-Bae Kwon, Hong-Sik Shim, Ho-Jong Ju and In-Young Choi* Division of Agricultural Environment Research, Gangwon-do Agricultural Research and Extension Services, Chuncheon 200-150, Korea Speciality Crops Research Institute Wild Vegetable Research Branch, Gangwon-do ARES, Pyeongchang 232-923, Korea Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Wanju 565-851, Korea Department of Agricultural Biology, Chonbuk National University, Jeonju 561-765, Korea Division of Climate Change Response, Jeollabuk-do Agricultural Research and Extension Services, Iksan 570-704, Korea

Influence of Continuous Organic Amendments on Growth and Productivity of Red Pepper and Soil Properties

Organic farming has rapidly increased in Gangwon province, but there is a concern about nutrient accumulation and nutrient imbalance in the soil of organic farming. This study was conducted to investigate the impact of continuous application of organic amendments on growth and yield of red pepper and soil characteristics compared with chemical fertilizers application for four years. Treatments of organic amendments including oil cake, rice straw compost, amino acid compost, rice bran compost, and mushroom media (spent substrate) compost resulted in comparable growth and yield of pepper to chemical fertilizers. Organic amendments improved soil physical and chemical characteristics. Especially, rice bran compost and oil cake significantly increased soil organic matter compared with chemical fertilizer application and mushroom media compost and rice straw compost significantly improved soil aggregate stability. On the other hand, available phosphate level in the soil amended with rice bran compost or mushroom media compost was relatively high compared with the other treatments due to relatively high phosphate levels in the composts. It is not easy to adjust nutrient composition in the organic materials. Therefore, the results obtained from the study imply that nutrient imbalance needs to be carefully considered in organic farming without use of chemical fertilizers.

Three Alternative Crops to Reduce Soil Erosion for Mountain Agriculture

One of the problems for cultivating crops in the mountainous highland is soil erosion and nutrients runoff. Alternative cropping ways were searched to reduce soil erosion and to ensure farm income in the mountainous highland agricultural region. Three edible wild plants including goatsbeard, Korean thistle, and aster, were selected to test as alternative crops to reduce soil erosion in mountain agriculture of highland area. In the first year, the soil losses from the alternative cropping were 26 to 63 percents of the soil loss from summer radish cultivated by conservation tillage with contour and plastic film mulching. The relative soil losses in the second year ranged from 2.8 to 5.5 percents in comparison with radish cultivation. Rapid surface coverage contributed to successive soil loss protection by these alternative crops. Farm net profit of these crops was greater than that of radish. Monitoring of yields of Korean thistle or aster for further experiments, however, might be necessary for economic cultivation due to yield reduction caused by consecutive production.