• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.100-106
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• 2014

The present study investigated variations in soil microbial communities by fatty acid methyl ester (FAME) and the chemical properties at 24 sites of upland soils in Gyeongnam Province. The electrical conductivity of the soil under potato cultivation was significantly higher than those of the red pepper and soybean soils (p < 0.05). The gram-negative bacteria community in potato soil was significantly lower than those in the garlic and soybean soils (p < 0.05). The communities of actinomycetes and arbuscular mycorrhizal fungi in the red pepper soil were significantly higher than those in the potato soil (p < 0.05). In addition, the cy17:0 to 16:$1{\omega}7c$ ratio was significantly lower in red pepper, soybean, and garlic soils compared with potato soil, indicating that microbial stress decreased. Consequently, differences in soil microbial community were highly associated with cultivated crop species, and this might be resulted from the difference in soil chemical properties.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.880-885
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• 2010

Importance of climate change and its impact on agriculture and environment has increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere. Nitrous oxide ($N_2O$) emission in upland fields were assessed in terms of emissions and their control at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city. It was evaluated $N_2O$ emissions at different soil water content, soil temperature, and mineral N conditions in a upland cultivating red pepper and soy bean. The results were as follows: 1) There were significant correlation between amount of $N_2O$ emissions and soil temperature, soil water content and mineral N conditions showed $0.528^{**}$, $0.790^{***}$ and $0.937^{***}$ in red pepper field and $0.658^{***}$, $0.710^{***}$ and $0.865^{***}$ in soybean field, respectively. 2) From the contribution rate analysis as to contribution factors for $N_2O$ emission, it appeared that contribution rate was in the order of mineral N (71.9%), soil moisture content (23.6%), and soil temperature (4.5%) in pepper field and mineral N (65.5%), soil moisture contents (19.2%), and soil temperature (15.2%) in soybean field.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.199-208
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• 2015

This study was conducted to provide basic information for weed control by surveying the occurrence of weed species in upland crop fields in Gyeongnam province of Korea. The result of this survey, 55 weed species 21 families in barley fields, 56 weed species 22 families in garlic fields, 47 weed species 19 families in onion fields, 68 weed species 26 families in Chinese cabbage fields, 54 weed species 22 families in potato fields, 62 weed species 25 families in sweet potato fields, 87 weed species 29 families in red pepper fields, 79 weed species 28 families in corn fields, 84 weed species 29 families in soybean fields. The most dominant weed species in upland crop fields of Gyeongnam province were Alopecurus aequalis var. amurensis 20.7% (barley fields), Cardamine flexuosa 12.3% (garlic fields), Chenopodium ficifolium 18.7% (onion fields), Portulaca oleracea 8.1% (Chinese cabbage fields), Chenopodium ficifolium 13% (potato fields), Digitaria ciliaris 12.6% (sweet potato fields and red pepper fields) and Digitaria ciliaris 11.3% (corn fields), 13.2% (soybean fields). This information could be useful for establishment of future weed control methods in Gyeongnam province.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.211-217
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• 2001

Field survey for Orius spp., predacious natural enemies of thrips pests, on several plants by beating or sweeping method revealed that O. sauteri, O. strigicollis, O. minutus, and O. nagaii habituated in open fields or in greenhouses of Korea. Among them, O. sauteri was the most dominant species at all areas (83.0~92.5%), followed by O. strigicollis and O. minutus. Especially, O. sauteri exclusively dominated on the economically important crops such as soybean, red pepper, and watermelon. On the other hand, O. strigicallis and O. nagaii occurred mainly on ornamental plants including chrysanthemum and rose and on rice, respectively, during summer-autumn season. The seasonal occurrence varied depending on the plant. Initial population of Orius spp. was first observed on white clover in late May, followed by on soybean, red pepper, an buck wheat in early June, indcating that movement of Orius spp. relates to the flowering time of the plant. Peak of Orius spp. abundance was found first in July and secondly in August or September. On white clover and buck wheat the first peak of abundance was one week earlier than on soybean and red pepper. Therefore, we suppose that wild plants such as white clover can serve as a reservoir for Orius spp. after overwintering.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.680-686
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• 2018

Nitrogen fertilizers, hairy vetch, and slow-release complex fertilizers were applied to the soil during the cultivation of crops. The impact of these factors on $N_2O$ emission was quantitatively assessed and the GHGs reduction effect comprehensively evaluated. Among the three factors, the significant factors affecting $N_2O$ emission were mineral nitrogen>soil moisture>temperature. Yield and fertilizer utilization efficiency were highest in the slow-release complex fertilizer treatment. There was no significant difference in $N_2O$ emissions between the slow-release complex fertilizer treatments and the NPK+hairy vetch treatments. Comprehensive results showed that slow-release complex fertilizers treatment has high yield and fertilizer utilization efficiency but low $N_2O$ emission.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.209-218
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• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.147-152
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• 2010

The investigations were conducted to improve the fertilizer use in upland soil on the different topographies, and crops at 163 upland fields located in the parts of Gyengsangbuk-do area. The soil distribution was based on crops, and topographiese. Soils from these fields were analyzed for pH, organic mater, available phosphorus ($P_2O_5$), exchangeable potassium, calcium and magnesium, and found to have pH5.9, organic mater 23.2 g $kg^{-1}$, $P_2O_5$ 549 mg $kg^{-1}$, exchangeable potassium, calcium and magnesium were 0.9, 5.6, and 2.3 $cmol^+\;kg^{-1}$, respectively. The excessive distribution percent of soil samples for crops were higher than the optimum range in $P_2O_5$, and exchangeable potassium. The content of organic matter, $P_2O_5$, exchangeable potassium, calcium, and magnesium were increased with the decreasing slope. The major chemical components in fans topographies were 28.4 g $kg^{-1}$ for organic matter, 700 mg $kg^{-1}$ for $P_2O_5$, and 1.0 $cmol_c\;kg^{-1}$ for exchangeable potassium relatively higher in comparison with other topographies. The content of $P_2O_5$ were lower in diluvium, and hilly areas than other topographies. The soil of red pepper was more influenced by the amount of applied fertility than the slope, and topographies, On the other hand the crops like soybean and sesame, were more affected by the slope, and topographies.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.238-246
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• 1994

Rate of conventional allpication of chemical fertilizer and farm manure were surveyed for 23 crops and 13,259 farms on paddy and upland fields in 1992. 1. Farmers have applied fertilizers more than optimum levels on vagetable crops. Based on the optimum levels of N, P and K, the excess ratios of N, P, K fertilization were 40%, 138%, and 53% in vagetable crops and 38%, 7%, and 0% in field crops, respectively. 2. Among provinces, the fertilizer application for paddy rice was higher in Chung-nam and Jeon-buk, which have had higher yield compared to other provinces. And that for red pepper was higher in Kang-won, Jeon-nam, Jeon-buk, Kyeong-nam, Kyeong-buk, and for chinese cabbage in Kang-won and Chung-nam. 3. The fertilizers rates at a chief producing districts of crops(CPD) were higher in vagetable crops than in field crops. 4. Compared with total fertilizer levels of open culture, excess fertilizers in plastic house were 5.9kg/10a(21%) of nitrogen, 8.7kg/10a(52%) of phosphorus and 7.1kg/10a(34%) of potasium. In chemical fertilizer application, fertilizer levels of sweet corn, red papper, tomato and lettuce were higher in plastic house, while those of cucumber, strawberry, radish, chinese cabbage were higher in open culture. 5. Ratio of farmers who applied farm manures was below 60 % on field crops and 69~100% on vagetable crops. 6. The compound fertilizer for paddy rice(21-17-17) was applied on all the crops and its application rate was the highest in all the crops except for paddy rice(single cropping), malting barley, soybean, sesame.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.103-134
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• 1977

The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.