• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.136-146
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• 2002

Land application of manure compost is considered one of the widely-used animal waste management practices. Many livestock farms adopt composting for their animal waste disposal and apply the compost to crop fields. While standard rates have been established based on researches with respect to land application of manure compost recently, there have been few discussions on water quality impact of the application. Water quality impact should be taken into account in land applications of manure compost. In this study, management practices were proposed based on the investigation of water quality of leachate from manure compost under rainfall simulation, field studies, and monitoring runoff water quality from farm fields after land application of animal waste. The concentrations of major water quality parameters of the leachate were significantly high, whereas those of runoff from soils after tillage for soil incorporation, were not affected by the application based on a series of experiments. Runoff water from farm fields after land application also showed high concentrations of pollutants. Appropriate management practices should be employed to minimize pollutant loading from manure applied fields. Proposed major management practices include 1) application of recommended amounts, 2) proper tillage for complete soil and manure incorporation, 3) field management to prevent excessive soil erosion, 4) complete diversion of inflow into the field from outside, 5) implementation of vegetative buffer strips near boundaries, and 6) prevention of direct discharge of runoff water front fields Into streams.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.129-138
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• 1993

The shortage of agricultural labour due to industrial growth has greatly induced the mechanization in Korean agriculture. However small and scattered land holdings have been the main constraints in the process of mechanization. This paper describes the interrelationships of farm land structure, machinery selection and machinery operation areas. The sandy silt loam irrigated paddy land having single crop a year was selected as a target areas for this study. Machine operation cost is greatly influenced by operation period, plot geometry and operation area. On the improved geometry plots, optimal machine size increases slowly with increase in operation area. Operable area increases due to increased effective machine capacity on better geometry plot. The difference between the effects of operation period and plot geometry is that in the former case, the cost reduction is caused by delay in increase of machine size, whereas in the latter case timeliness cost is reduced by increase ffective capacity. The effect of farmland consolidation is greater on small plots than that on big plots. Increasing wage rates have induced the adoption of more labor saving machinery. Bigger labor saving machines require enlargement of operation area and larger plots through improvement in farm land structure. Machine cost on poor plot geometry increases more rapidly than that on the good plot geometry and as operation area increases machine cost reduces significantly. It is concluded that the development of agricultural mechanization ion Korea will depend on the improvement in farm land structure and enlargement of operation area.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.289-298
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• 1986

This paper aims at identifying the positive economic effects of the tenant system. Increasing numbers of tenant farms is one of the characteristic aspects of Korean agriculture. They have increased 3.7 percent annually since 1960. At the end of 1985, 64.7 percent of the Korean farmers leased partly or entirely the farm land which they managed, and 30.5 percent of the total arable area was cultivated under the tenant system. To find out the difference in performance of management between land owners and tenants, 600 farm households were selected as samples throughout Chungnam province. Among those sampled were 300 land owners and 300 tenants. Tenants defined this paper include not only full tenants but also part tenants. The results of this study are summarized as; First, rice is the main income resource of tenant farms. Due to their rental charges, the marketable surplus of farm products might be lower than that of land owners. Whereas 40 percent of the landowners income is from rice production, the tenants income from rice production is 43 percent. Second, tenants continue to depend on more agricultural wage incoms and more double crop incomes in paddy fields than land owners. Third, like most poor people in the third world, they have maximized their incomes and minimized their expenditures by saving management costs. Finally, there was no interlinking between landlords and tenants especially related to credit supports. Most farmers in the surveyed area have met their credit requirements from agricultural cooperatives.

• Journal of Wetlands Research
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• v.7 no.1
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• pp.107-117
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• 2005

Soil erosion is influenced from a variety of factors such as rainfall distribution, soil type, land use, etc. This paper is aimed at analyzing the soil erosion hazard zone in cropland. RUSLE was used for an analysis of soil erosion amount, and for the spatial data of basin, soil erosion amount was calculated by extracting the respect topography space related factors of RUSLE using DEM, Landuse, Soil map as base map. This paper is targeting at the watershed of Gyeongan stream in Gyeonggi-do The result of an analysis of soil erosion amount showed that soil erosion occurred in the order of crop field(1210) planting area, orchard(1220), non-adjusted paddy fields(1120), and adjusted paddy fields(1110), and also the average soil erosion in these planting areas has the most amount in crop field planting area. As a result of analysis on soil erosion hazard zone of farm land by classifying it into 5 classes using the result of that result of analysis on the amount of soil erosion, in case of Class 5 in which the hazard of soil erosion is the highest, approximately 72.5ha that corresponds to 2.4% of the total farm land was decided as erosion hazard zone. For this erosion hazard zone, it was analyzed that dry field crop planting area was 72.4ha and orchard was 0.1ha, and Class 5 hazard zone did not appear in other farming areas. Also, it showed that Class II(1~50ton/ha/yr) area had the most ratio of the entire farm land, i.e., 70.2%, regardless of land use state. According to the result of analysis on soil erosion hazard zone of farm land by classifying it into 5 classes, the Class V has the highest soil erosion hazard, approximately 72.5ha that corresponds to 2.4% of the total farm land was estimated as an erosion hazard zone. This erosion hazard shows 72.4ha in dry field crop planting area, 0.1ha in an orchard, but the highest hazard zone, the Class V was not shown in other farming areas. Also, it showed that Class II area had the most ratio of the entire farm land, i.e., 70.2%, regardless of land use state.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.132-139
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• 2010

To manage the effluent nutrients amounts from rice paddy fields using free range ducks or rice bran, we evaluated the effects of a purifying paddy field which is no fertilizer, no pesticides, and dense rice seedling having a concept of constructed wetland. The experimental paddy field was located at downstream in the watershed of ducks using rice culture area in Milyang. The purifying paddy of land design were treated with seeding method, and vegetation type. As land design, direct seeding on plane, and direct seeding on high-ridge field in 2007. Planting rice only, and planting rice with water hyacinth were treated as vegetation type in purifying paddy in 2008. The purifying paddy fields were effective to reduce amount of T-N and T-P contents in effluent to 33.2~45.3%, and 53.1~55.4%, respectively. The direct seeding on high-ridge treatment, having long residence time of effluent water was more effective than plane plot as T-N 0.29 $g^{-1}m^{-2}d^{-1}$, and T-P 0.031 $g^{-1}m^{-2}d^{-1}$. The planting rice with water hyacinth treatment was effective than planting rice only as T-N 0.23 $g^{-1}m^{-2}d^{-1}$, and T-P 0.049 $g^{-1}m^{-2}d^{-1}$. The optimum area of purifying paddy field to treats all effluent were found out 3.2~4.7% of rice culture area using free range ducks, and rice bran at upper stream.

• Mycobiology
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• v.45 no.3
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• pp.129-138
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• 2017

In this study, we aimed to characterize fungal samples from necrotic lesions on collar regions observed in different sweetpotato growing regions during 2015 and 2016 in Korea. Sclerotia appeared on the root zone soil surface, and white dense mycelia were observed. At the later stages of infection, mother roots quickly rotted, and large areas of the plants were destroyed. The disease occurrence was monitored at 45 and 84 farms, and 11.8% and 6.8% of the land areas were found to be infected in 2015 and 2016, respectively. Fungi were isolated from disease samples, and 36 strains were preserved. Based on the cultural and morphological characteristics of colonies, the isolates resembled the reference strain of Sclerotium rolfsii. Representative strains were identified as S. rolfsii (teleomorph: Athelia rolfsii) based on phylogenetic analysis of the internal transcribed spacer and large subunit genes along with morphological observations. To test the pathogenicity, sweetpotato storage roots were inoculated with different S. rolfsii strains. 'Yulmi' variety displayed the highest disease incidence, whereas 'Pungwonmi' resulted in the least. These findings suggested that morphological characteristics and molecular phylogenetic analysis were useful for identification of S. rolfsii.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.144-145
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.56-57
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.216-217
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.11a
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• pp.116-117
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• 2000