• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.23-31
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• 2019

Crop response to weather and internal water pressure changes is more sensitive to crop water stress than soil water content. Recently, its implementation to optimal irrigation scheduling has been receiving much attention. This study was conducted to determine and compare the theoretical crop water stress index (CWSI) using meterological data and canopy temperature collected from three different irrigation treatments, which were Tr-1 plot (rainfed), Tr-2 plot (50% of daily evapotranspiration (ET) irrigated) and Tr-3 plot (75% of daily evapotranspiration (ET) irrigated). The readings of canopy temperature and CWSI were significantly different among irrigation treatment schemes. The average canopy temperatures and CWSIs of Tr-1 and Tr-3 plots were $34.6^{\circ}C$ and $32.6^{\circ}C$, 0.79 and 0.64, respectively. Solar radiation had the biggest correlation with CWSI (R=0.68) which was followed by wind speed, relative humidity and air temperature. Overall, the findings of this study indicated that canopy temperatures and CWSIs could be further used for irrigation scheduling for crop growth.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.206-206
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• 2022

Sustainable agriculture is a potential strategy to enable agricultural cultivation systems to feed the growing population under climate change. Sustainable agriculture consists of environment-friendly farming methods that allow the production of crops with minimal harm to the ecosystem. Early establishment in rice might be helpful to adopt sustainable agriculture with less inputs, such as water and phosphorus fertilizer. Two QTLs conferring tolerance to abiotic stress and low nutrition condition, DTY4.1 and Pup1, respectively, are effective for good establishment in the early growth stage under low water and phosphorus fertilizer application. We developed 'Sechanmi' and 'MSI 1-DTY' harboring Pup1 and DTY4.1 into MS11, a japonica rice variety adaptable to tropical regions, using Marker-Assisted Backcrossing (MABC). MS 11-PD lines were developed to meet the demand for less water and P fertilizer application throughout the growth stage of rice. In the F5 generation, water-saving or rainfed cultivation was performed in different P (phosphorus) content. Irrigation was applied only when severe drought was observed one month after transplanting. There was no significant difference observed between the parents and MS11-PD lines in low P conditions. However, MS11-PD lines had more tillers in P-supplied conditions compared to that of the parents 40 and 50 days after transplanting. Under the same amount of P, MS11-PD lines might have higher phosphorus uptake capacity than the parents, increasing the number of tillers and showing better early establishment. The better vegetative growth stage is one of the factors that can potentially increase production by way of higher number of panicles. Through this breeding strategy, it is possible to attain sustainable agriculture by applying less P and water to address the need of a growing population.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.13-13
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• 2022

Recently, stable crop production is threatened by the effects of climate change. In particular, it is difficult to consistently maintain agricultural policies due to large price fluctuations depending on the difference in total domestic rice production from year to year. For stable rice production amid changes in the crop growing environment, development of varieties with improved disease resistance and abiotic stress stability is becoming more important. In here, drought and cold tolerant trait have been studied. First, for the development of drought tolerant varieties, we analyzed which agricultural traits are mainly affected by domestic drought conditions. As a result, it was observed that drought caused by the lack of water during transplanting season inhibits the development of the number of tiller and reduces the yield. 'Samgang' was selected as a useful genetic resource with strong drought tolerant and stable tiller number development even under drought conditions by phenotype screening. Three of drought tolerant QTLs were identified using doubled haploid (DH) population derived from a cross between Nacdong and Samgang, a drought sensitive and a tolerant, respectively. Among these QTLs, when qVDT2 and qVDTl1 were integrated, it was investigated that the tiller number development was relatively stable in the rainfed paddy field conditions. It is known that the high-yielding Tongil-type cultivars are severely affected by cold stress throughout the entire growth stage. In this study, we established conditions that can test the cold tolerance phenotype with alternate temperature to treat low temperatures in indoor growth conditions similar to those in field conditions at seedling stage. Three cold tolerant QTLs were explored using population derived from a cross between Hanareum2 (cold sensitive variety, Tongil-type) and Unkwang (cold tolerant variety, Japonica). Among these QTLs, qSCT12 showed strong cold tolerant phenotype, and when all of three QTLs were integrated, it was investigated that cold tolerant score was relatively similar to its donor parent, Unkwang, in our experimental conditions. We are performing that development of new variety with improved cold tolerant through the introduction of these QTLs.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.321-321
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• 2017

Water availability in rainfed lowlands (RFL) is strongly affected by climate change. In RFL, rice plants are exposed to soil moisture fluctuations (SMF) but rarely to simple progressive drought as widely believed. Typical RFL field is characterized by a about 5-cm thick high bulk density hardpan layer underneath the cultivated layer at about 20 cm depth that impedes deep root development. Root system has the ability to develop in response to changes in SMF, known as phenotypic plasticity. We hypothesized that genotypes that can adapt to RFL have root plasticity. The roots can sharply respond to re-wetting after drought period and thus penetrate the hardpan layer when the hardpan is wet and so becomes relatively soft, and thus access water under the hardpan. This study aimed to identify CSSLs derived from a cross between Sasanishiki and Habataki which adapted to such RFL conditions. We used 39 CSSLs together with the parent Sasanishiki, which were grown in hydroponics and pot under transient soil moisture stresses (drought and then rewatering), and compared with continuously well-watered (WW) (control) up to 14 days after sowing (DAS), and 20 DAS, respectively. Based on the results of hydroponics and pot experiments, we selected a few lines, which were grown in the soil-filled rootbox with artificial hardpan layer and without artificial hardpan. For the rootbox without artificial hardpan, plants were grown under WW and transient soil moisture stresses for 49 DAS. While the rootbox with artificial hardpan, the plants were grown under WW (control) and SMF (WW up to 21 DAS, 1st drought (22-36 DAS), rewatering (37-44 DAS), and followed by 2nd drought (45-58 DAS)). Among the 39 CSSLs, only CSSL439 (SL39) consistently showed significantly higher shoot dry weight (SDW) than Sasanishiki under transient soil moisture stress conditions as well as SMF conditions in all the experiments. Furthermore, under WW, SL39 consistently showed no significant differences from Sasanishiki in shoot and root growth in most of traits examined. SL39 showed significantly greater total root length (TRL) than Sasanishiki under transient soil moisture stress, which is considered as phenotypic plasticity in response to rewatering after drought period. Such plastic root development was the key trait that effectively contributed to root elongation and branching during the rewatering period and consequently enhanced the root to penetrate hardpan layer when the soil penetration resistance at hardpan layer reduced. In addition, using the rootbox with artificial hardpan layer ($1.7g\;cm^{-3}$, heavily compacted), SL39 showed greater root system development than Sasanishiki under SMF, which was expressed in its significantly higher TRL, total nodal RL, and total lateral RL at hardpan layer as well as at below the hardpan layer. These results prove that SL39 has plasticity that enables its root systems to penetrate hardpan layer in response to rewatering. Under SMF, such root plasticity contributed to its higher gs and Pn.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.7-7
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• 2017

Unfavorable weather and soil conditions reduce rice yield and land and water productivity, aggravating existing encounters of poverty and food insecurity. These conditions are foreseen to worsen with climate change and with the unceasing irrational human practices that progressively debilitate productivity despite global appeals for more food. Our understanding of plant responses to abiotic stresses is advancing and is complex, involving numerous critical processes - each controlled by several genetic factors. Knowledge of the physiological and molecular mechanisms involved in signaling, response and adaptation, and in some cases the genes involved, is advancing. Moreover, the genetic diversity being unveiled within cultivated rice and its wild relatives is providing ample resources for trait and gene discovery, and this is being scouted for rice improvement using modern genomics and molecular tools. Development of stress tolerant varieties is now being fast-tracked through the use of DNA markers and advanced breeding strategies. Large numbers of drought, submergence and salt tolerant varieties were commercialized over recent years in South and Southeast Asia and more recently in Africa. These varieties are making significant changes in less favorable areas, transforming lives of smallholder farmers - progress considered incredulous in the past. The stress tolerant varieties are providing assurance to farmers to invest in better management of their crops and the ability to adjust their cropping systems for even higher productivity and more income, sparking changes analogous to that of the first green revolution, which previously benefited only favorable irrigated and rainfed areas. New breeding tools using markers for multiple stresses made it possible to develop more resilient, higher yielding varieties to replace the aging and obsolete varieties still dominating these areas. Varieties with multiple stress tolerances are now becoming available, providing even better security for farmers and lessening their production risks even in areas affected by complex and overlapping stresses. The progress made in these less favorable areas triggered numerous favorable changes at the national and regional levels in several countries in Asia, including adjusting breeding and dissemination strategies to accelerate outreach and enabling changes at higher policy levels, creating a positive environment for faster progress. Exploiting the potential of these less productive areas for food production is inevitable, to meet the escalating global needs for more food and sustained production systems, at times when national resources are shrinking while demand for food is mounting. However, the success in these areas requires concerted efforts to make use of existing genetic resources for crop improvement and establishing effective evaluation networks, seed production systems, and seed delivery systems to ensure faster outreach and transformation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.4
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• pp.11-23
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• 2018

The purpose of this study is to identify the ecological characteristics and biological interactions between species of the abandoned rice paddy field in mountainous areas and to suggest a management strategy for stable food chain formation and biodiversity enhancement. The study site is located in Uldae wetland of Songchu district Bukhansan National Park, site characteristics and biological habitat characteristics were identified through site survey and literature survey. With regard to physical environment, among geographical features, the Uldae Wetland and the neighborhood inside the basin was a gently sloping area($5{\sim}15^{\circ}$). And 64.0% of basin faced the north. With regard to water environment, the Uldae Wetland was wetland of rainfed paddy field depending on precipitation and the system of stream flowing into the wetland from valley. According to the results of examining flora in plant ecology, in general, they were herbaceous wetland species. 88.6% of existing plants inside the Uldae Wetland basin was a forest in the mountain. And Quercus spp. community and Pinus densiflora community accounted for 64.6% of that, and was dominant. Except for that, Salix koreensis community was distributed. The existing vegetation of Uldae Wetland inhabited wetland species and terrestrialization indicator species, and it was thought that partial terrestrialization inside the Uldae Wetland was in progress after the discontinuation of paddy cultivation, such as the expansion of Salix koreensis distribution area. In the status of appearing faunae in the Uldae Wetland with regard to wildbirds of appearing principal species, The Uldae wetland was based on a abandoned rice paddy field various wildlife, and was a wildlife feeding, spawning, and resting place. The water environment was an important factor in maintaining the wetland living creatures function, habitat of waterbirds and benthic macroinvertebrates, amphibians and odonate are spawning ground and habitat, it was affecting the vegetation ecosystem based on wetlands. In order to maintain the diversity of wildlife, it was important to maintain smooth water supply and water level. A stable food chain will be formed and the Uldae wetland biodiversity will be abundant by establishing the relationship between the species of Uldae wetland, which is abandoned rice paddy field, and the habitat environment favored by species belonging to the ecosystem stepwise linkage. The ecological characteristics of the Uldae wetlands and the relation between the species were analyzed and the environmental conditions were reflected in the planning and management plan of Uldae wetland ecology.

• Agribusiness and Information Management
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• v.11 no.1
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• pp.27-39
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• 2019

Agricultural risks are exacerbated by a variety of factors ranging from climatevariability and change, frequent natural disasters, uncertainties in yields and prices, weakrural infrastructure, imperfect markets and lack of financial services including limited spanand design of risk mitigation instruments such as credit and insurance. Indian agriculture has little more than half (53%) of its area still rainfed and this makes it highly sensitive to vagaries of climate causing unstable output. Besides adverse climatic factors, there are man-made disasters such as fire, sale of spurious seeds, adulteration of pesticides and fertilizers etc., and all these severely affect farmers through loss in production and farm income, and are beyond the control of farmers. Hence, crop insurance' is considered to be the promising tool to insulate the farmers from risks faced by them and to sustain them in the agri-business. This paper critically evaluates the performance of recent crop insurance scheme viz., Pradhan Mantri Fasal Bhima Yojana (PMFBY) and its comparative performance with earlier agricultural insurance schemes implemented in the country. It is heartening that, the comparative performance of PMFBY with earlier schemes revealed that, the Government has definitely taken a leap forward in covering more number of farmers and bringing more area under crop insurance with the execution of this new scheme and on this front, it deserves the appreciation in fulfilling the objective for bringing more number of farmers under insurance cover. The use of mobile based technology, reduced number of Crop Cutting Experiments (CCEs) and smart CCEs, digitization of land record and linking them to farmers' account for faster assessment/settlement of claims are some of the steps that contributed for effective implementation of this new crop insurance scheme. However, inadequate claim payments, errors in loss/yield assessment, delayed claim payment, no direct linkage between insurance companies and farmers are the major shortcomings of this scheme. This calls for revamping the crop insurance program in India from time to time in tune with the dynamic changes in climatic factors on one hand and to provide a safety-net for farmers to mitigate losses arising from climatic shocks on the other. The future research avenues include: insuring the revenue of the farmer (Price × Yield) as in USA and more and more tenant farmers should be brought under insurance by doling out discounts for group coverage of farmers like in Philippines where 20 per cent discount in premium is given for a group of 5-10 farmers, 30 per cent for a group of 10-20 and 40 per cent for a group of >20 farmers.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.139-152
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• 1985

본 NEWASA 지역의 접수관정관개 개발에 따른 정제성분석 연구는 IBRD-EDI와 INDIA RESERVE BANK의 College of Banking이 공동주최한 Trainers Trining for Rural Finance (1985. 1.19-3.1)의 일환으로 1985. 2. 14-19 까지 NEWASA BLOCK에 대한 정수정관개의 경제적 효율성을 평가하기 위하여 농가조사를 실시하였고, 그 분석결과를 정리한 것으로 농지는 넓으나 농업용수가 부족한 본 지역은 빈곤과 저생산성 농촌잠재 실업을 특징으로 하고 있다. 농촌소득의 제고와 농촌실업의 고용확대는 전 인구의 80% 이상이 농민인 본지역뿐만 아니라 선언도 경제개발의 중심과제이다. 호당 6 acres 규모의 관개가 가능한 Dug-well Irrigation Development는 연평균 강우량이 650m/m에 불과한 인도의 Plateau 지역에서는 농촌빈곤과 실업문제의 해결, 토지 이용율제고를 통한 토지생산성 향상등 농촌경제개발의 중심과제로서 인도정부가 추진하는 핵심적인 농업정책이다. 본 지역의 농가호당 평균 소유농지연적은 8.67 acres(3.5ha)로써 모두가 Rainfed farming으로 현재 본 지역의 관개율은 17.5%에 불과하다. 농작물은 Jowar라고 하는 내한성 작물이 재배되며, 관개 조건하에서는 Jowar, Wheat, Sugarcane이 재배된다. With and Without Dug-Well Irrigation 조건하에서 각 작물별 ha당 생산성을 보면 Jowar는 0.86 ton/ha에서 2.22 ton/ha으로 증산되고 Wheat는 2.96 ton/ha, Sugarcane는 98.8 ton/ha이 생산된다. 한편 Dug-well Irrigation 전후의 농가소득의 변화를 보면 시행전의 4,275Rs가 되어 4배의 농가소득이 증가된다. 이와 같은 농업소득을 획득하기 위해서는 Dug-well에 대한 Initial Investment로서 33,400Rs(2,137,600원)이 투자되어야 하는데 종류별 융자 기간을 보면 Dug-well 15년(95%융자) Pump Set 9년(95%융자), Woriking capital 1년이며 인도의 Union Bank에서 융자하고 있다. 결론적으로 이러한 Dug-well Irrigation Development에 따른 IRR는 Before Financing시에는 29%이며 After Financing 시에는 24%이고 B/C ratio는 두경우에 있어 1.89, 1.24를 각각 나타냈다. 따라서, 본 사업은 재무적인 측면 즉 농가소득증대와 농촌고용증대 및 토지이용면에서 타당성이 크며 Dug-well Irrigation은 인도의 농업성장 및 경제개발의 관건으로 생각된다. 한국의 수리개발 기술 및 농업기술(Bio-chemical, Mechanical & Hydrological Technology)이 이전된다면 보다 괄목할 만한 농업발전이 이룩될 것을 생각된다.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.285-299
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• 1987

Timing and placement of fertilizer applications are two managerial means to improve the fertilizer use efficiency. The relative importance of these two means is determined by the application rate. With the realistic rate of N application recommended to the small farmers in the tropics, at present and in the near future, basal application in right manner, seems to be more important than split application at different times. In wetland rice soils, deep placement by whatever available means is desirable. But in the situations where perfect deep placement is very difficult to implement, the whole-layer application may be worth trying, until better methods become available. In rainfed uplands, N fertilizer application plans should be contingent upon the amount and distribution of rainfall: apply a less risky rate as subsurface banding near the crop rows to start with; then, depending upon the rainfall prospects in the season, apply or omit the additional dose. Because the patterns of crop response to N fertilizer can be significantly different between the research farms and farmers' fields, it seems imperative to have information on the patterns of crop response to N under farmers' management conditions, for the development of realistic fertilizer application recommendations. To enable the farmers to adopt improved fertilizer application technologies, it is essential to develop and make available to farmers convenient fertilizer applicators. Past experience with the improved fertilizer use technologies indicates that, in the long run, the development of fertilizers that are not only effective and convenient for farmers to use but also easy to produce without major modifications of existing fertilizer production systems is the ultimate solution to the problem of low N fertilizer use efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.17-24
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• 2016

Drought caused by global climate change is one of serious problems for rice cultivation. However, it was little reported the impact of drought on rice cultivation in Korea. In here, to assess impact of drought on rice varieties in Korean climate condition, growth characteristics and yield components of rice were compared on irrigated and partially irrigated rice paddy field. First, we have chosen 11 rice varieties including 'Saeilmi' and 'Shindongjin' which are widely cultivated in Korea. For partially irrigated rice paddy treatment, we have withheld irrigation from 25 days after transplanting and water supply was totally dependent on rainfall for rice cultivation. When we examined early plant height and tiller number of these varieties on partially irrigated rice paddy were reduced 1.6% to 18.4% and 10.4% to 33.1%, respectively, and these reduction rate were highly correlated with yield loss in our experimental conditions. Among rice yield components, panicle number was decreased 10.5% to 30.1% according to rice varieties and reduced panicle number was highly correlated with yield loss. Grain number per panicle, grain filling rate and 1,000 seeds weight did not have correlation with yield loss of rice varieties. These result means that growth stage, especially the tillering stage, is seriously affected by drought on rice cultivation in Korea. And we suggest that 'Saeilmi', 'Ilmi' and 'Ilpum' are good for rice cultivation on drought prone rice field in Korea.