• Korean Journal of Soil Science and Fertilizer
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• v.12 no.2
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• pp.99-107
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• 1979

The properties, land use and genesis of the Jang-weon series, Planosol-like soils, distributed in Cheong-do area were investigated. Planosol-like soils in Korea have been believed unsuitable for perennial crops but 34.6% (594ha) of the Jang-weon soils in Cheongdo-gun are used for perennial crops such as apples, persimmons, peaches, mulberry etc. With productivity more or less equal to alluvial soils. The reason for high productivity and a working hypothesis for the genesis of the fragipan is suggested with discussion.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.55-58
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• 2004

The objective of this study was to get information about water retention characteristics of horticultural substrates used in Korea determined by European standard method. Water retention curves were prepared at water volume (v/v, %) in relation to -10 cm, -50 cm, -100 cm water pressure head. Water retention curves showed different properties depending upon the type, the place of origin, particle size, and manufacturing processes of substrates. Peat and coir had easily available water content in the range of 30-40% and showed high water holding capacity, water buffering capacity, and aeration for plant growth. However, bark, sawdust and rice hull showed low water holding capacity about below 10%. The easily available water content of perlite and clay ball was low about 0.1-13.8%, whereas that of vermiculite and rockwool granulate was high about 25.9-52.0%. Understanding water retention characteristics of growing substrates is very important in cstablisliing optimum condition for plant growth. Further study on water retention curves for more substrates, mixture and growing media is needed.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1300-1305
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• 2011

The study was conducted to investigate the characteristics of flower quality and yield of gerbera 'Sunny Lemon' by mutrient solution strength and media of nutrient solution. The plant growth of 'Sunny Lemon' showed the highest values in the media of rockwool and perlite 1: peatmoss 2. Especially the yield of cut flowers for a year was more than 60 flowers and the flower longevity was over 10 days irrespective of nutrient solution concentration in the two media. There were no significant differences of plant characteristics in the nutrient concentration of 1/2 and 1 times, and the mineral nutrient contents showed similar values. Therefore, we recommended the media of perlite1: peatmoss2 with the concentration of 1/2 times for economical use. The rockwool media was not appropriate because of the weak buffer capacity like EC and pH.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.103-109
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• 2009

Soils originated from limestone, located at the southern part of Kangwon province and Jecheon, Danyang of Chungbuk province are mainly composed of fine texture, and have different properties from soils originated from granite and granite gneiss, especially for water movement. This study was conducted for classification of hydrologic soil group (HSG) of soils originated from limestone by measuring the infiltration rate of surface soils and percolation rate of sub soils. Soils used for the experiment were 6 soils in total : Gwarim, Mosan, Jangseong, Maji, Anmi and Pyongan series. Infiltration and percolation rate were measured by a disc tension infiltrometer and a Guelph permeameter, respectively. Particle size distribution and organic matter content of the soils were analyzed. HSG, which was made by USDA NRCS(National Resources Conservation Service) for hydrology, of Gwarim series with O horizon of accumulated organic matter was classified as type A which show the properties of low runoff potential, rapid infiltration and percolation rate. HSG of Mosan series, which has high gravel content and very rapid permeability, was classified as type B/D because of the impermaeble base rock layer under 50cm from surface. HSG of Jangseong series with shallow soil depth was classified as type C/D owing to the impermaeble base rock layer under 50cm from surface. HSG of Maji series was type B, and HSG of Anmi series used as paddy land was type D because of slow infiltration and percolation rate caused by the disturbance of surface soil by puddling. HSG of Pyeongan series having a sudden change of layer in soil texture was type D because of the slow percolation rate caused a the layer.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.354-362
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• 2009

This study was performed to develop a suitable nutrient solution for standard rose substrate culture in a closed hydroponic system. 1/4, 1/2, 2/3 and 1 strength of the nutrient solution made by Japan National Institute of Vegetable and Tea Science (JNIVT) were supplied. The photosynthesis rate, quality and growth of cut flower were higher in the 1/2 and 2/3 strength of nutrient solution during high and low temperature period. Based on the above results, optimum nutrient solutions (UOS) were composed by nutrientwater (n/w) absorption ratio with 1/2S ($NO_{3^-}N$ 6.8, $NH_{4^-}N$ 0.7, $PO_{4^-}P$ 2.0, K 3.8, Ca 3.0, Mg 1.2, $SO_{4^-}S$ $1.2me{\cdot}L^{-1}$) at high temperature season and 2/3($NO_{3^-}N$ 9.7, $NH_{4^-}N$ 0.8, $PO_{4^-}P$ 2.2, K 5.0, Ca 3.9, Mg 1.5, $SO_{4^-}S$ $1.5me{\cdot}L^{-1}$) at low temperature season. The results of suitability examination showed that the EC level in newly composed nutrient solution (UOS) was more stable than other nutrient solutions due to its large amount of calcium and potassium. The growth of cut flower cultivated with UOS was higher than those of other nutrient solutions. Especially, the yield of cut flowers in UOS nutrient solution increased 1.4 times than that of other nutrient solution treatments. Consequently, the new nutrient solution investigated in this experiment was suitable for rose cultivation in a closed hydroponic system.