• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.81-86
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• 2013

For organic farming, green manure crops such as leguminous forages and barley have been broadly used to improve soil fertility and soil physical and chemical properties by repeatedly cutting and mulching them directly as winter crop in the field in the rotation. In this investigation we selected 78 agricultural farm corporations as well as individual organic farmhouses related to crop rotation from greenmanure crops to main crops in order to analyze the relationship of cropping system between main crops and green manure crops. The results showed that the green manure crops were divided into two groups as leguminous and nonleguminous crops, representing that those are limited to specific climate and farming systems of regions. Also the 10 or less green manure crops including sudangrass, hairyvetch, italian ryegrass, sorghun, buckwheat, oat, pea, rye, clover, and canola which belong to leguminous crops which are presently cultivated from the organic farmhouses within the rotational crop system. We also confirmed that the major main crops are sweet potato, soybean, corn, tobacco, spinach from usage frequency analyzed by NetMiner H 2.6 which was used to estimate the rotational cropping system among the green manure crops and main crops.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.544-554
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• 2018

Tomato (Solanum lycopersicum) production in Ghana is limited by the root-knot nematode (Meloidogyne incognita, and yield losses over 70% have been experienced in farmer fields. Major management strategies of the root-knot nematode (RKN), such as rotation and nematicide application, and crop rotation are either little efficient and harmful to environments, with high control cost, respectively. Therefore, this study aims to examine morphometric variations of RKN populations in Ghana, using principal component analysis (PCA), of which the information can be utilized for the development of tomato cultivars resistant to RKN. Ninety (90) second-stage juveniles (J2) and 16 adult males of M. incognita were morphometrically characterized. Six and five morphometric variables were measured for adult males and second-stage juveniles (J2) respectively. Morphological measurements showed differences among the adult males and second-stage juveniles (J2). A plot of PC1 and PC2 for M. incognita male populations showed clustering into three main groups. Populations from Asuosu and Afrancho (Group I) were more closely related compared to populations from Tuobodom and Vea (Group II). There was however a single nematode from Afrancho (AF4) that fell into Group III. Biplots for male populations indicate, body length, DEGO, greatest body width, and gubernaculum length serving as variables distinguishing Group 1 and Group 2 populations. These same groupings from the PCA were reflected in the dendogram generated using Agglomerative Hierarchical Clustering (AHC). This study provides the first report on morphometric characterisation of M. incognita male and juvenile populations in Ghana showing significant morphological variation.

• Research in Plant Disease
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• v.9 no.2
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• pp.57-63
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• 2003

Clubroot disease of curcifer crops caused by Plasmodiophora brassicae had been first reported in 1928 in Korea, and maintained mild occurrence until 1980s. Since 1990s the disease has become severe in alpine areas of Kyonggi and Kangwon, gradually spread to plain fields throughout the country, and remains as the great-est limiting factor for its production. Researches on the disease has begun in late 1990s after experiencing severe epidemics. Survey of occurrence and etiological studies have been carried out, particularly, on the pathogen physiology, race identification, quantification of soil pathogen population, and host spectrum of the pathogen. Ecology of gall formation and its decay, yield loss assessment associated with time of infection, and relationships between crop rotation and the disease incidence was also studied during late 1990s. In studies of its control, more than 200 crucifer cultivars were evaluated for their resistance to the disease. Lime applica-tion to field soil was also attempted to reduce the disease incidence. Resistant radish and welsh onion were recommended as rotation crops with crucifers after 3-year field experiments. However, so for, most studies on clubroot disease in Korea have been focused on chemical control. Two fungicides, fluazinam and flusulfamide, were selected and extensively studied on their application technologies and combination effects with lime application or other soil treatment. To develop environmentally-friendly control methods, solar-disinfection of soil, phosphoric acid as a nontoxic compound, and root-parasiting endophytes as biocontrol agents were examined for their effects on the disease in fields. In the future, more researches are needed to be done on development of resistant varieties effective to several races of the pathogen, establishment of economically-sound crop rotation system, and improvement of soil-disinfection technique applicable to Korean field condi-tion, and development of methodology of pretreatment of fungicides onto seeds and seedbeds.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.1
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• pp.67-76
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• 2007

The conclusion of free Trade Agreement between South Korea and USA can become a serious threat to the Korean agriculture. On the strategic scheme the foodstuffs is the basis for protection of the state sovereignty. The Amur oblast of Russian Federation is region, which can supply South Korea cheap and good qualitative feeds. It means South Korea should create agricultural cooperation with the Amur oblast of Russian Federation with the purpose to begin organic agriculture in this area and it will help South Korea to counteract a quantitative attack on Korea from the side of american agricultural production. In the Amur oblast there are following fodder crops; Alfalfa, Smooth brome grass (gromus adonis L.), Siberian couch grass, Sudan pass, Colza rape (Brassica napus) and Amaranth (Avfranthus). In the same area also exist oatmeal, wheat, corn and barley, which is possible to use for feeds. All these above written cultures are cultivated organically, therefore it is possible to use them as organic forages in South Korea. It is very important to know system of crop rotation in the Amur oblast. There is a scheme of crop rotation, which is connected with increase and preservation of fertility of soil, maintenance of growth of productivity of agricultural cultures and reception of high-quality production. It is necessary to begin organic agriculture in a southern part of Amur oblast, where, in 2001 year, 97% of all sowing areas was concentrated. The acidity degree of soil in this part is not high ($ph5.1{\sim}5.5$), therefore does not require liming.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.66-72
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• 1978

Cultural practices favoring the crops are one of the excellent weed control measures in upland crops. The primary cultural method for weed-management may include planting of weed-competitive cultivars, proper planting time and spacing, optimum rate and placement of fertilizer, crop rotation, mulching, and timely tillage. However, cultural method must be applied as a part of the program along with all other available means for controlling weeds since this method alone is not adequate. The efficient and economical weed control can only be achieved by combinating cultural, mechanical method that supplement each other into a weed management system. Intelligent selection of weed control, however, presuppose knowledge of the life history and growth requirements of the weed and its interaction with the environment.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.94-95
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• 2006

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.17-17
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• 2019

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.124-134
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• 1997

As control of plant diseases, insects and weeds were heavily relied on pesticides, residues of pesticides in environment and food supply were recently focused by environmentalists and consumer groups. The reduction of pesticide use was implemented in Sweden, Denmark, Netherland, England, and United States. Therefore, it is very important to discuss environmentally sound systems of weed management including cultural, mechanical, and integrated weed control. Mechanical methods using tillage, cultivation, mulching, burning, mowing, solarization, and UHF are used as one of most effective environmentally sound weed management systems. Cultural practices favoring the crops are excellent weed management measures. Correct seedbed preparation for the soil and cultural system, and use competitive cultivars contribute to weed management. Increasing crop density by higher seeding rate or by narrowing row width and careful attention to optimum fertility to produce vigorous crop plants increase competitiveness of crops against weeds. Crop rotation breaks life cycles of weeds by alternating the crop it must associate with. Herbicides are efficient and profitable to control weeds, but must be part of a total weed management program with use of minimum rate. The best weed management will be an integrated approach including two or more methods to manage weed problems.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.209-213
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• 2006

This study was carried out to investigate the changes in soil chemical properties and yields of crops by rice-soybean rotation cropping system at silt loam soil. There were 4 rotation cropping systems; continuous rice cultivation, annual, biennial and triennial rotation of soybean and rice. There were little change in pH, organic matter, $Ca^{2+}$ and $K^+$ contents with decrease in available phosphate content in the continuous rice cropping. The cropping system of soybean-rice caused to increase in available $P_2O_5$, $K^+$ and $Ca^{2+}$ in the soil after harvest. Content of $NH_4-N$ in the soil also increased after the rotation of soybean than the continuous rice cropping in the soil during the rice growth period. These chemical change in the soil caused to increase rice growth in number of the panicles and the spikelet per square meter. The yield of rice was increased by the rotation with soybean, and was gradually increased in the triennial rotation of soybean and rice. But the yield of soybean was decreased in continuous cultivation for two or three years in the paddy field. It was recommended for annual rotation to prevent the yield of soybean from decrease.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.269-274
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• 2014

Series of field experiments were conducted to evaluate the long term effect of gypsum and crop residue on crop yield and soil health in rice-wheat crop rotation system in salt affected soil. A saline-sodic field having $EC_e$ (electrical conductivity of the saturation extract) 4.77 ($dSm^{-1}$); pH ($H_2O$) 8.96; SAR 43.78 ($mmol\;L^{-1}$) and gypsum requirement (G.R.) 2.86 (Mg $acre^{-1}$) was selected on Soil Salinity Research Institute Farm. Five treatments consisting of ($T_1$) control, ($T_2$) gypsum at 100% G.R., ($T_3$) gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$, ($T_4$) gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$, ($T_5$) gypsum at 25% G.R.+ rice and wheat straw at $3Mg\;ha^{-1}$ were replicated four times under completely randomized block design. The data indicated that grain and straw yield of rice and wheat was significantly (P<0.05) increased by all the amendments used either single or in combination. $T_2$ (gypsum at 100% G.R.) significantly (P<0.05) increased grain and straw yield of rice and wheat crops followed by $T_3$ (gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$) when compared with control. Soil properties were also improved by used amendments, pronounced decreased in $EC_e$, $pH_s$ and SAR were recorded in $T_2$ followed by $T_3$. The efficiency of the treatments could be arranged in following order gypsum at 100% G.R.> gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice and wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$ > control.