• Weed & Turfgrass Science
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• v.3 no.4
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• pp.312-317
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• 2014

This study was conducted to obtain basis information for effective weed control by the fact-finding survey of herbicides use at farmer's level and distribution of herbicide resistant weeds in paddy field of Jeonbuk province, Korea. The distributions of major paddy field weeds and frequently used herbicide according to the survey were as follows. The dominant weeds in rice paddy field were Echinochloa crus-galli, Eleocharis kuroguwai, Scirpus juncoides, Monochoria vaginalis, etc.. Preferred herbicides widely used by farmers were ranked in the following order, early and middle treatment (48.0%), treatment before transplanting (36.7%) and foliar treatment (15.3%). The occurrence of herbicide-resistant weeds according to collected paddy soils was as follows. The occurring area of herbicide-resistant weeds was 24,413 ha, approximately 18.4% of rice cultivation area. Herbicide-resistant weeds were occurred in four species. The order of occurrence were Scirpus juncoides (39.0%) > Monochoria vaginalis (27.8%) > Echinochloa crus-galli (16.6%) and Cyperus difformis (16.6%). This information could be useful for estimation of future herbicide-resistant weed and establishment of herbicide-resistant weed control methods in Jeonbuk province, Korea.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.169-178
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• 2021

BACKGROUND: The Ministry of Agriculture, Food and Rural Affairs is promoting agri-environment conservation program to induce farmers to participate in agricultural environment improvement and conservation activities. However, assessment tools based on scientific evidence are needed to determine the effectiveness of the program objectively and quantitatively. Therefore, this study was performed to develop plant indicators in order to efficiently evaluate the effects of the agri-environment conservation program promoted by the Ministry of Agriculture, Food and Rural Affairs. METHODS AND RESULTS: The survey was conducted in five regions (Hampyeong, Boryeong, Mungyeong, Hongseong, and Sangju) participating in the agri-eonvironment conservation program. In each region, twenty paddy fields were investigated (ten paddy fields included in the program and ten paddy fields not included in the program). A total of 231 taxa vascular plants were identified in the paddy fields that were included in the agri-environment conservation program, and a total of 177 taxa were identified in the paddy fields that were not included. The average species number occurred on each field was 55.8 taxa in the fields included in the program, and 35.0 taxa in the fields not included in the program. The difference in occurring plants between two groups was found to be more higher in perennial plants than in annual plants. We selected the six groups as indicator plants through five criteria such as perennial plants and broadly occurring species, etc. to verify the effectiveness of the agri-environment conservation program: Taraxacum spp., Ixeris spp., Viola spp., Platago spp., Calystegia spp., and rare and endagered species. There was a high positive correlation between the score calculated using these indicator plants and the total number of plants species. CONCLUSION: This study suggests that it is possible to evaluate the agro-ecological environment by using indicator plants. The selected indicator plants can be effectively used to verify the effectiveness of projects such as agri-environmental conservation programs in the future.

• Journal of Korean Society of Rural Planning
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• v.28 no.2
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• pp.71-85
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• 2022

The food self-sufficiency rate of agricultural products in Korea, excluding rice, is around 20%, and the government is promoting various policies including a Multiple-Purpose Utilization of Paddy Fields project, to increase the self-sufficiency rate of major grains. The project for Multiple-Purpose Utilization of Paddy Fields is being promoted as a part of a program to create farmland infrastructure to facilitate the cultivation of crops other than rice in rice paddies, and pilot projects were started in four regions in 2020. The purpose of this study is to analyze the economic effects of the pilot project for Multiple-Purpose Utilization of Paddy Fields, and to propose policies to increase the effectiveness of the project. In order to analyze the economic effect, we estimated the change in farm income generated by switching from rice to other crops, and measured the effect of welfare change using the Equilibrium Displacement Model (EDM). As a result of the analysis, social welfare is expected to increase when the pilot project for Multiple-Purpose Utilization of Paddy Fields is implemented, and the income of the beneficiary farmers is also expected to improve compared to that of single-cropping when double-cropping is implemented. However, it was found that the economic feasibility of the project differs depending on the crops converted. Juksan-myeon, Gimje-si, which is an area where soybean production was successful, was analyzed from the viewpoint of increasing the economic feasibility of the pilot project. Their success factors were analyzed into four major factors: infrastructure, farming methods, education, and collaboration with local agricultural organizations. If such a success story can be utilized in the future project implementation process, it can contribute to the improvement of farm household income and national economic welfare.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.1
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• pp.49-54
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• 1995

Three types of floating-type automatic inlet were developed for the purpose of reduc- ing farmer's working hours required for water management and saving irrigation water. The point of automation is to use a float within the inlet which is floated and sinked by the ponding depth of paddy field, Thus opens and closes the control gate of irrigation. Suitability of each inlet may depend on production cost, applicability to paddy field condi- tions, and feasibility to farmers, etc. The first model was composed of three parts : chamber for irrigation control gate, chamber for float controlled by ponding depth, and connection bar between the two parts. It was designed to open and close the control gate gradually as the ponding depth drops and rises to a certain level. The second model was designed to improve the weak point of the first model which is the imperfect-closing of gate when it approaches to the end of ir- rigation. A switch-spring was equipped above the connection bar for perfect opening and closing of gate when the ponding depth reaches to a certain level. The third model was designed by combining the two chambers, that is, cut in halves the inlet volume of the above two models. Magnets were equipped above the float for perfect opening and closing gate. The functional experiment for three developed inlets was successfully carried out and the rating curves were derived.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.36-36
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• 2012

Drainage water in lowland paddy fields is quantitatively influenced recycle and/or repeated irrigation by irrigation facilities, i.e. pumps, check gates, small reservoirs and so on. In those drainage channels, nutrients accumulation and increasing organic matters are considered to be occurred, and water quality would be degraded not only environmental aspect but irrigation purpose. In general, Total Nitrogen (T-N) is interested water quality index in irrigation water, because high nitrogen concentration sometimes caused decreasing rice production by excess growth and fallen or degrading quality of taste, then, farmers would like to clear water less than 1mg/L of T-N concentration. In drainage channel, it is known that the nitrogen concentration change is influenced by physical, chemical and biological properties, i.e, stream or river bed condition, water temperature, other water quality index, and plant cover condition. In this study, discharge data (velocity and level) in a drainage channel was monitored by an Acoustic Doppler system and water quality was sampled at same time in 2011. So those data was analyzed by multi regression model to realize hydrological and environmental factors to influence with nitrogen concentration. The results showed the difference tendency between irrigation and non-irrigation period, and those influenced factors would be considered in water quality model developing in future.

• Korean Journal of Agricultural Science
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• v.24 no.1
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• pp.94-107
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• 1997

Producing organic farm products is one of the high-payoff farming practices considering the rapid increase of consumer's purchasing power. The purpose of this study is to identify the optimal organic farming system in relation to farm income. To cope with the above objectives, present farming conditions and profitability of 15 farmers producing organic products including rice and leaf vegetables as lettuse and cabbage were surveyed in Hongsung and Ahsan Gun, Chungnam Province. Based on the surveyed data, maximization of organic farm income were analyzed under the constrained conditions such as limited monthly labour inputs and competitive use of land by Linear Programming Model. The results of this study can be summarized as follows. 1. In the profitability analysis of 15 farmers producing organic products, rice farmers could earn their farm income more than that of conventional farmers by 50%. On the other hand, the controlled lettuce farmers could get more about 100% than that of it. But the controlled cabbage farm could get more about 40% of it. These organic farm products were saled at high prices comparing with the prices of conventional farm products by 170% ~ 230% even though the crop yields produced by organic materials had decreased. 2. According to the labor requirement of the organically produced crops, rice cultivation was needed more labour inputs than the conventional farming method by 130%. On the other hand lettuce and cabbage could saved labour requirement by 40% and 80% of those respectively. Especially for the rice cultivation concern, higher labor requirement was due to the activities as organic fertilization, soil preparation and pest and weed controll, etc. 3. With the surveyed data from farmers who produced farm commodities, L.P. analysis was implemented to find out the optimul farming system and the maximum income. According to the results of L.P. analysis, 58% of total farm income could get more than the conventional farming system In the case of rice cultivation, one ha of paddy was recommendable to save more labour inputs than the controlled leaf vegetables such as lettuse and cabbage. However, in the controlled leaf vegatables, only 73% of total upland equivalent to 0.3 ha should be cultivated under the condition of labor shortage as the restricted 4 workers. And increasing the size of hogs raising should be recommened to achieve self-sufficiency of organic fertilizer. As pointed out the possibility of organic farming, present farmers producing organic farm products could be able to maximize their income by expanding organic farm size with regard to all conditions of our organic industry. Of course, there are many difficulties in the course of developing organic agriculture. So Government should effort to support the development of our organic agriculture considering the various aspects of production, marketing, Quality certification of organic produces.

• Korean Journal of Organic Agriculture
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• v.6 no.2
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• pp.127-140
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• 1998

Organic farming excludes any use of the herbicide. The present paper reviews what can be done for effective weed control with existing weed control technology by farmers crop-ping paddy rice, field crops, vegetables, and fruit trees. If condition of the crop-land-al-lows diversified rotational use of the paddy land as paddy and upland field would minimize weed problem. Practising this is limited in acreage due to extremely limited governmental investment to the land for the purpose. Secondly, rotation of crops in the upland field breaking life cycles of various weeds adapted to each crop should reduce the weed problem. This is also limited as only a few crops are making the farmer profitable. In addition climate and tolerance of crops to high and low temperature. Monsoon rains and poor drainage restrict the freedom of choice. For any crop land year-round multiple cropping in denser planting shall lessen the weed problem, this multiple cropping practiced by 1960s has been abandoned due to laborshortage and increased production cost. Deep flooding the rice is impractical at present in Korean. Mulching crop with transparent, black , or combinated polyethylene sheet, hs been in-creasingly used. Progresses in development and use of mulch with allelopathic crop residues. inexpensive paper mulch, allelopathic crop residues, inexpensive paper mulch, allelopathic crop cultivar development, recently developed ex-perimental weeding machinaries, flamers, microbial herbicides, biological control organisms, soil sterilization techniques have been critically reviewed for their adoption into existing in-tegrated weeding system. Unfortunately, information on cost-benifit, and labor-benefit, for the various methods above mentioned are lacking. Urgent need for the research on rational weeding in organic farming, and herbicide low-input farming is emphasized.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.183-188
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• 2006

A nation-wide monitoring survey was performed to look into pesticide use pattern and amount on farmers' field after the national registration of pesticides from 2003 to 2004. Tow hundred ninety two leading farmers involved in the survey were chosen from main cultivating regions of targeted crops in consideration with area. Most farmers involved in the survey follow the safe use guideline of pesticides, while their information to select and making-decision for purchasing pesticides were done according to the recommendation of mainly pesticide market dealers or agricultural cooperative dealers. Used amount of pesticide per unit cropping area was surveyed as 5.51 on paddy, 3.91 on field cabbage, 2.93 on greenhouse cabbage, 0.76 on lettuce, 0.55 on spinach, 1.34 on perilla leaf, 4.89 on leek and 0.42 kg $ha^{-1}$ on young radish. As compound with those surveyed from 1999 to 2000, the pesticide amounts used for rice, lettuce and perilla leaf were reduced while that for cabbage was increased.

• 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.

• Korean Journal of Agricultural Science
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• v.31 no.1
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• pp.53-75
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• 2004

This study is aimed at identifying the national economic value of the irrigation facilities by reviewing the existing papers on economic values of the irrigation facilities and presenting current status of dual O & M problems of the irrigation facilities. This study suggested the unified O & M system rather than continuing the existing dual O & M system of irrigation facilities based on the surveyed results of the activities of irrigation fraternities in Chungnam Province. The findings and proposals for the successful unified and mono O & M system of the irrigation facilities are as follows: (1) Total number of irrigation facilities in the nation accounts for 67,582, while the total length of irrigation and drainage canals amounted to about 174,259km. On account of the total length of structural canals was estimated at 31%, much losses of water and much O & M costs have been inevitable for the full irrigation rice culture. In spite of the past heavy investment for irrigation facilities, the ratio of rain-fed and partially irrigated paddy fields accounts for 23% in 2003. Both Korea Agricultural and Rural Infrastructure Corporation (KARICO) and the city and Gun Governments have managed the irrigation facilities separately by irrigation fraternities. The KARICO have commanded 59% of irrigation paddy area with 18% of the total irrigation facilities, while the city and Gun governments covered 41% of irrigation paddy area with 82% of the existing number of irrigation facilities representing small and medium scale. (2) The 1999 demand prices of irrigation water per ton expressed in 2000 constant market price was estimated at 388 won, the supply price was amounted to 184 won per ton. Considering the supply and demand curve of the irrigation water, the existing irrigation facilities could not satisfy the demand of irrigation water. (3) In 1999, total present added value of the irrigation facilities during the economic life accounted for 48 trillion won, while total supply cost was 44.7 trillion won. The marginal benefit and cost ratio of irrigation water was 1.08. (4) The total O & M cost per year amounting to 681.1 billion won have been required to maintain and repair the existing irrigation facilities in Korea. For the successful unified O & M of irrigation facilities covering whole irrigated paddy field in Korea, 950 billion won of O & M costs are required to keep up the marginal benefit of irrigation water as 2,800 billion won per year. The total O & M cost as 950 billion won should be allocated 40%, 380 billion won for O & M costs of irrigation facilities and 60%, 570 billion won for improvement of irrigation facilities. (5) The study investigated and reviewed the present O & M status of the irrigation facilities by small and medium irrigation fraternities. Most of the farmers belong to the irrigation fraternities preferred not only unified O & M but also KARICO take-over of the whole O & M activities of the irrigation facilities. The prevailing O & M cost per 10a expended by the Corporation was amounted to 104,890 won, while that of city and Gun governments was only amounted to 4,600 won per 10a. regarding the small amount of O & M cost expended by city and Gun governments, it is evident that the existing irrigation system have been managed ineffectively and deteriorated the facilities comparing that of KARICO. In conclusion, the Government could not satisfied the demand of irrigation water by suppling water with existing irrigation facilities. Therefore new additional investment and financial support for irrigation water development should be made to convert rain-fed and partially irrigated paddy fields into fully irrigated ones. The operation and maintenance cost should be supported to keep the marginal values of rice production of existing irrigation facilities in the national economy and to modernize the obsolete irrigation facilities. By unifying the existing dual O & M systems, all the farmers belong to the irrigated paddy fields have to be equally benefited and could be increased their farm income and be stabilized their rural lives.