• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.36-40
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• 2014

Korea's agricultural land is constantly being reduced. The reasons for this are due to the change of agricultural profitability and the policy conditions. The reduction of agricultural land in 2010 showed a decline trend by 14.4 % of paddy fields and 1.2% of uplands compared to areas from 2000. These reductions were mainly due to switch rice paddy fields into upland or greenhouse facility cultivation because of low profitability of rice products compared to farm products. In addition, the permit system of agricultural areas was relaxed in switching paddy fields and this accelerated the reduction of agricultural land. For this reason, more than 1% of agricultural land area has been reduced every year for last five years. Moreover, indiscreet fill and cover materials such as construction wastes were used in agricultural lands and caused land contamination which threatened foundation as sustainable agricultural lands. For these reasons, it is a desperate situation to conserve good agricultural lands. However, the standards of transported soils, filling soils and cutting soils in the Agricultural Land Act are qualitative and have a problem of causing complaints. Therefore, the following criteria (proposals) are proposed in the Agricultural Land Act; (1) Use the proper soils for crops (criterion), (2) Soil components and amounts should be proper as transported soils (range), and (3) Prohibiting usage of improper earth rocks or recycled aggregates in case of filling soils (kinds). The presented criteria (proposals) suggest following; (1) Use physio-chemically proper soils for crops (criterion), (2) In case of transported soils, i, exclude potential acid sulphate soils, ii, gravel content sould be less than 15%, and iii, Heavy metals and other contaminants should be less than the soil contamination warning limit from the Ministry of Environments, (3) In case of filling soils, 13 kinds of recycled wastes specified in the Wastes Control Act should not be used as filling soils, (4) Practice soil conservation technology in case of sloping areas, and (5) Follow proper fertilizer application standards for maturing paddy fields and uplands when cutting soils.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.336-340
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• 2004

The objective of this study was to establish the decision criteria of land suitability for red pepper using soil morphological and physical properties. The investigation was carried out in Jechen, Goesan, Euiseong, Andong, Gochang and Pyongchang district in Korea. The obtained results showed that factors related to the decision criteria of the land suitability for red pepper cultivation were soil texture, soil drainage class, land slope, available soil depth and stone content. The criteria of the best suitable soil for red pepper was coarse loamy, well drainage class, C-slope (7-15%), 10-20% gravel content and available soil depth deeper than 100 cm. Also in the best suitable soil, hardpan was located below 100 cm from the soil surface. Outbreak rate of phytophthora blight occurred well in the soils with high clay content, poor drainage class, low land slope and low gravel content. Database determining the decision criteria of the land suitability for red pepper in Jinchen-gun was established by Arc info GIS tool.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.119-131
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• 2017

This study evaluated the feasibility of recovering and recycling nitrogen (N) and phosphorus (P) from livestock excreta as struvite ($MgNH_4PO_4{\cdot}6H_2O$) in South Korea. Our experimental results showed that struvite precipitation was a very effective way to recover N and P from livestock excreta. Moreover, our study demonstrated that struvite precipitates from livestock excreta (SPL) contain higher concentrations of N, P, and magnesium (Mg) as compared to compost and liquid manure from livestock excreta. In addition, although SPL contain high concentrations of copper (Cu) and zinc (Zn), they meet the fertilizer criteria for concentrations of heavy metals. In South Korea, SPL cannot currently be used as a fertilizer due to legal constraints. Legal permission for SPL use would offer greater choice in livestock excreta management. In conclusion, recovery and recycling of N and P from livestock excreta as struvite can be an effective tool for managing nutrients in livestock excreta.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.4
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• pp.226-232
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• 1982

The incubation study of the phosphate Fertilizer Index (P.F.I) fertilizer recommandation method combining two factors-retention capacity of phosphate and available soil phosphate was conducted to test the applicability on both upland and paddy soils. The relationship between added P and the square root of the $NH_4OAc-P$ (for upland) or Bray No.1-P (for paddy) was a straight line for most of soils but was not straight for some soils which are low in phosphate absorption coefficient (P.A.C) However, the relationship between the value of the slop (termed as P.F.I) and the phosphate absorption coefficient was not showed a good correlation. The P.F.I was highly correlated with extractable Al on upland soils. The effect of extractable Al on P.F.I is more pronounced on newly reclaimed soil than cultivated upland. In case of paddy soils the P.F.I showed a high correlation with active iron contents. Also, P.F.I method was compared to NPK field trial on paddy soils to eximaine the applicability of the method in determining phosphate fertilizer recommandation.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.3
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• pp.165-181
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• 1976

Fertilizer(N,P,K) demand for crop production in 1980, 1990 and 2000 was estimated according to the two proposed models, one of which is fertilizer use efficiency model expressed in $Fn=(Y/E){\cdot}(1-Cs)Eu$, where Fn:fertilizer demand, Y:Crop production estimated, E:nutrient efficiency, Cs:fraction of natural resource nutrient in plant, Eu:fertilizer use efficiency and the other fertilization efficiency model expressed in Fn=Y(1-Cys)/Fe, where Cys:fraction of yield without fertilizer, Fe:fertilization efficiency. Total crop uptake of nutrient and its noncycling portion were estimated as criteria for fertilizer demand and nutrient maintenance. Total crop uptake of N,P,K was 600,000 M/T in 1965 700,000 M/T in 1974 and estimated to 880,000 M/T in 1980, 1,170,000 M/T in 1990 and 1,410,000 M/T in 2000. Fertilizer demand appeares to be about 90% of total crop uptake according to fertilizer use efficiency model and about 87% according to fertilization efficiency model. The noncycling nutrient was about 29% of total crop uptake. Fertilizer demand was almost same to the uptake amount in nitrogen, 1.5 times of uptake in phosphorus and half of uptake in potassium. Varietal development, improvement of soil fertility and cultivation method and development of fertilizer forms appears to decrease fertilizer demand by increasing efficiency term in two models while environmental stress such as low temperature appears to give reverse effect resulting in higher fertilizer demand. Fertilizer consumption in 1974 seemed to be unreasonably high especially in nitrogen and phosphorus and thus the effective use of fertilizer appeared as an urgent problem considering that large fields are still remained in lower fertility.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.683-693
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• 2014

This study was carried out to investigate the characteristics of the organic liquid fertilizer and find out optimum fermentation conditions of Effective Microorganisms (EM) including ascidian tunic. During the EM fermentation by adding ascidian tunic, electrical conductivity (EC) was increased, contrast to decrease the pH value, on related to the initial dosage molasses rate. Additionally, the total nitrogen quantity was shown to be increased on EM fermentation and the most effective increasing was recorded up to 220% on more than 15% molasses dosage condition. The phosphorus quantity was to be maximum rate on 21th of EM fermentation, and other contents, such to potassium, calcium, magnesium, sodium, had be shown an increasing patten during the fermentation period. After the EM fermentation, the concentration of hazardous material (Zn, As, Cd, Cu, Cr, Hg, Ni, pb) was measured below than the official criteria for commercial fertilizer. As a effective material in fermentated fertilizer, the 29 kinds free amino acids were detected and their total concentration was measured to 7080.94 mg/L.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.81-85
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• 1996

Tentative consolidation criteria, a kind of land suitability classification, was established for cultivated upland soils. The criteria were composed of systematically quantified individual soil properties such as physiography(relief), slope, available soil depth etc., and local features such as soil complexity, mapping unit separation, width/length ratio etc. The criteria was applied to upland soils in granite area, and sedimentary rock area. It was clear that the comparison of local features among candidated areas, and classification of suitability classes for land consolidation of upland soils was satisfactory for selection. The status of the areas classified to "Well suitable" were distributed on alluvial plains or less dissected rollings with lower complexity of soils occurred and extended acreage in each mapping unit. On the other hand, the areas classified as "Unsuitable" were distributed on the elongated narrow valleys with quite divided mapping units by paddy fields on the valley bottom.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.235-245
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• 1979

The land utilization of Korea composed about 22.7% of arable land, 66.9% of forest land and 10.4% for the rest like a house site, road, and lake etc. The ratio of arable land is too small as compared with forest land which is occuping two-thirds of Korea. The expansion of arable land by the reclamation will solve the food problems for increasing populations. First, we have to know the exact extents and distribution of reclaimable land but the reported total extent of reclaimable land in Korea is variable according to the authority which carried out the soil survey. The different reported data of reclaimable land is owing to the method and criteria of soil survey. 840,522ha in Land Capability Survey of the Farm Land Improvement Association and 321,203ha in the Forest Land Survey by the Office of Forest was reported but the Office of Rural Development said that total reclaimable land was 1,400,540ha including grazing and fruit land. To assume the extent of reclaimable land, the soil survey method and criteria of soil survey should be considered. It can be considered that the main reasons of less in extent of reclaimable land in the other authorities than the Office of Rural Development is due to the following. The grazing land and the fruits land are not included by the Farm Land Improvement Association and only relative forest is considered by the Office of Forest. The main purpose of soil survey carried out by the Office of Rural Development is to utilize land of Korea at most. The soil characteristics and potential productivity are considered in soil survey and the reported data was based on reconnaissance soil survey. The more accurate data will be find out by the end of 1979 when the detailed soil survey will be done. In selection of cropping system and management, the soil condition should be considered, because the soil characteristics of reslaimed land is less fertile than the arable lands.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.160-166
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• 2009

We estimated site productivity for unstocked land based on the relationship between site index (i.e., average height of dominant trees at fixed age) and soil physico-chemical properties of Pinus densiflora stands. Site index relates to a direct method of determining a tree's response to a specific environment such as forest soil and climate conditions. We selected 78 sites in 22 P. densiflora stands of central temperate forest zone, and sampled soils for physicochemical analyzing. And 13 properties of soils were statistically treated by stepwise regression. In the degree of contribution of the variables to site index, the highly effective variables in A horizon were OM, clay content, sand content, available $P_2O_5$, and Exch. $Ca^{{+}{+}}$ inorder, and in B horizon T.N., O.M., Soil pH, cation exchange capacity(C.E.C.), and sand content in order. In both A and B horizon of the soil for P. densiflora stands, the variables commonly contributed to the site index were sand content and OM. These results may be useful to provide not only important criteria for establishment of Pinus densiflora stand sespecially in unstocked land but also aguidance for reforestation.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.542-548
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• 2013

Soil properties and yields of liriopis platyphylla were investigated to establish soil suitability of Korean liriopis platyphylla at 116 farms in Korea. Morphological and physical properties of the soils were investigated along with the average yield of 2~3 years. The impact factors of soil properties to the yield of liriopis platyphylla were selected based on standard error of each factor. The yields of liriopis platyphylla showed the greatest values when the morphology was alluvial plains, when the drainage was well or moderately well, when the slope was 0-2%, the texture was coarse loamy, when the gravel content was less than 15% and when the available soil depth was more than 100 cm. Contribution factors of soil properties to the yields were 0.15 by morphology, 0.15 by drainage level, 0.13 by slope, 0.18 by texture, 0.16 by gravel content and 0.23 by available soil depth, respectively. Soil suitability classes were set as follows; the best suitable land if score was greater than 92, suitable land if score ranged from 91 to 86, the possible land if the score ranged from 85 to 83, and low productive land if score was less than 82. According to the criteria, 17.8% of the production area was the best suitable land, 43.1% was suitable land, 17.3% was possible land, and 21.8% was low productive land. The sum of both the best and suitable lands were 60.9% of the farm area of Miryang in Gyeongsangnam-do.