• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.181-188
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• 1993

The effects of paddy-upland rotation and cropping system on the mineralization of soil organic nitrigen, on the change of organic matter and available phosphorus content in the soil, and on the rice yield and nutrients absorption were studied in Seokcheon fine-sandy loam soil. 1. In the incubation test mineralzed soil nitrogen and the nitrogen extracted by pH 7 phosphate buffer solutions were higher in the soils from every and two year rotation systems than continuous rice cultivation. In terms of cropping system potato-chiness cabbage-rice increased them more than soybean-rice system. 2. The change of soil organic matter and available phosphorus contents were not much in continuous rice cultivation, while in rotation system they decreased as the paddy-upland rotation frequency decreased. In terms of cropping system they decresed more in potato-Chinese cabbage-rice system compared with soybean-rice systems. 3. The rice yield was higher in the paddy-upland rotation system than that of continuous rice cultivation. However, the effects were decreased gradually every year, as shown by 26~20, 17~5, and 5~4% yield increase for first, second, and third year, respectively, in potato-Chinese cabbage-rice and soybean-rice system compared with continuous rice cultivation. 4. All the absorbed nutrient contents increased in every and two year rotation system compared with continuous rice cultivation. In terms of cropping system potato-Chiness cabbage-rice system increased them more compared with soybean-rice system.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.1-8
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• 1998

To compare different methods for the determination of available soil P in the relationship between the soil P and plant uptake of P, rice and corn were cultivated in the pot filled with soils of different available P contents. The soils were taken from 20 rice fields and 20 upland soils. The available soil P were determined before the experiment by Olsen, Lancaster, Bray 1, Bray 2, Mehlich II and Calcium lactate methods and the correlations between the available soil P measured by different methods and the amount of P taken up by corn at 10 leaf stage and by rice at maximum tillering stage were investigated. In upland soils, the available P measured by all the methods was linearly regressed with high significance to the amount of P taken up by corn. The coefficients of determination($R^2$) in the regression equations ranged from 0.596(Calcium lactate method) to 0.891(Olsen method). In rice soils, the soil available P did not regressed by first-order to the amount of P taken up by rice plant, while Michaelis-Menten equation better explained the relationship between the two parameters. In the Michaelis-Menten equation the coefficients of determination for each analytical method ranged from 0.607(Mehlich II method) to 0.923(Lancaster method). Based upon these observations it is concluded that for testing of available P for corn soils Olsen, Bray 2 and Lancaster methods are equally superior to other methods. For rice soils Lancaster, Bray 1, and Bray 2 methods are better than others.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.405-411
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• 2007

This study was carried out to measure insoluble phosphorus fractions content fixed in different soil type and isolate a superior phosphate solublizing bacteria(PSB) producing free phosphate in citrus orchard soil. Distribution of insoluble phosphate fraction ordered Al-P>Ca-P>Fe-P in the investigated citrus orchards. Insoluble phosphate fraction such as Al-P, Ca-P, Fe-P were higher in volcanic ash than in non-volcanic ash soil. A PSB with high holo zone in PDA-P medium isolated from citrus orchard soil. This strain identificated by MIDI system as Bacillus sphaericus. The optimum growth of pH and temperature were at 4~5, $30^{\circ}C$, respectively. When Bacillus sphaericus cultured at $25^{\circ}C$, 150 rpm condition in LB broth medium included different phosphate. Bacillus sphaericus produced free phosphate in the culture broth medium from tricalcium-phosphate(207.0 ppm), aluminium phosphate(324.5 ppm) and hydroxyapatite(334.8 ppm) and Phosphatase activity of Bacillus sphaericus was higher at $35^{\circ}C$ culture condition than that of $25^{\circ}C$. Two type preparation inoculated Bacillus sphaericus made with carrier materials such as Bentonite, $CaCO_3$, Sodium alginate. Density of PSB in this preparation conserved at $10^5c.f.u.\;g^{-1}$ level during storage in different temperature condition for 7 month. It also showed that free phosphate produced at PDA-P medium.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.67-77
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• 2011

Heavy metal remediation in shooting range soil is a challenge over the world. The excessive Pb accumulation in the soil can deteriorate soil quality and fertility. The objectives of this research were to evaluate the efficiency of biochar (BC) in improving the physicochemical and biological properties of the soil and to evaluate its effect on Pb availability in a military shooting range soil. Sandy loam soil was collected from shooting range of Gyeonggi Province, South Korea and was incubated for 30 days with different application rates (0-30% w $w^{-1}$) of BC. The results showed that the addition of BC increased aggregate stability, nitrogen (N) and phosphorus (P) contents, and enzyme activities in soil. Sequential extraction showed that residual and organic bound fractions in the soil amended with BC increased by 33.1 and 16.7%, respectively, and the exchangeable fraction decreased by 93.7% in the soil amended with BC, compared to the unamended soil. We concluded that the application of BC could not only improve physicochemical and biological soil qualities but also stabilize Pb in a shooting range soil.

• Korean Journal of Microbiology
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• v.7 no.1
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• pp.29-40
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• 1969

Two kinds of organic materials, powders of Salicornia and Oryza sativa L. wre added as a source of organic matter to the suspensions of saline soils(soil : water = 1:3) to be 4 per cent of dried saline soil grams. And then, the samples were incubated at $28^{\circ}C$ to improve the decomposition of organic materials by soil microflora. Resutls of this experiment are summarized as followings : 1) The pH of soil suspension showed its highest value on the second or third week after the treatments, which were similar to those of the soil microflora. Results of this experiment are summarized as follwings : 1) The pH of soil suspension showed its highest value on the second ot third week after the treatments, which were similar to those of the soil microflora populations. 2) Salinity increased up to the second week and the highest value of it appeared in the samples which were treated with the powder of Salicornia. In general, the salinity of all samples decreased on the third week after the treatment. The fact was assumed the possibilities of desalination from saline soil by the microbial actions. 3) Soil microflora such as bacteria, actinomycetes and fungi, were determined its populations soil microflora is to act as decomposer in soil. Both of the bacteria and actinomycytes population showed in the third weak after the tratment. In general, 30-years old of saline soil contained microbial population much more than those of 5-year old of saline soil. Salicornia powder favored the increase of both the bacteria and fungal population, and Oryza sativa L. seemed to have been a great role in increase of actinomycetes. Especially, fungal population of the untreated soil suspension contained higher microbial populations more than those of the soils treated with both of the organic materials. 4) Sugar contents of soil suspesions decreased remarkably on the first week after the treatments. 5) The amount of nitrate had similar tendency to those of population changes of soil microflora. Total acidity decreased continuously and the amount of potassium showed its highest value on the third week treatment. However, the amount of phosphorus was determined to be insignificant.

• Journal of The Korean Society of Grassland and Forage Science
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• v.1 no.1
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• pp.2-9
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• 1978

A review of factors influencing grass and clover establishment, survival and yield at oversowing was made from the experimental results of home and abroad. The following conclusions are considered: (1) The existing vegetation present at oversowing appeared to be the most critical factor reducing establishment and survival of grass. Therefore, it is essential to check competition from the native vegetation before oversowing. (2) Although lime had comparatively little effect on yield of grassland, the general effect of lime should be more emphasized under our acid soil conditions to promote the availability of all the essential elements and the growth of microorganisms, and to reduce the toxic effects of nutrients. One to two tons of lime per ha at oversowing would be useful. (3) Phosphorus is one of the nutrients most generally deficient in grassland soils of Korea, consequently, this nutrients applied at oversowing is very effective. Application as much as 200kg of phosphorus per ha would be essential. (4) The effect of nitrogen on the establishment and survival of grass depends on the amount and density of the herbage present. The use of nitrogen in dense herbage adversely affected grass establishment and survival, possible because the fertilizer stimulated the growth of the eisting herbage. Around 40kg of nitrogen per ha may be enough at oversowing (5) Potassium is not as universally deficient in soils of native grassland as phosphorus. Therefore, it cannot be over-emphasized at oversowing. Studies determinig the optimum amount of potassium at of oersowing are needed.

• Journal of Ginseng Research
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• v.2 no.1
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• pp.59-66
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• 1977

Mineral contents of sail in two-year-old ginseng plantation. of the top-dressings for ginseng and of the green grasses (Chung-Cho) were analyzed in order to clarify budget of inorganic nutrients of ginseng Plant. The amount of mineral nutrients contained in soil of two-year-old ginseng plantation had 56 times of nitrogen, 1.2 times of phosphorus and 20 times of potassium as compared with the requisition of two to sin-year-old ginseng plants per $\textrm{m}^2$. In consideration of the lack of phosphorus, it is recommendable to use bone mill as top dressing, which contains higher content of Phosphorus than ether top-dressings.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.265-269
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• 2007

The loss of nitrogen and phosphorus from sediments in two watersheds, one naturally regenerating and one artificially planted, in Sacheon-myun, Gangneung-si, Gangwon Province, were measured two years after a forest fire in 2000. Sediment losses occurred five times in the course of the year. In the artificially planted watershed, $50{\sim}140$ times more nitrogen and $54{\sim}139$ times more phosphorus were lost with sediments during heavy rains, from July to August, than in the naturally regenerating watershed. When the typhoon Rusa struck the country, 1,389 times more nitrogen and 1,647 times more phosphorus were lost from the artificial watershed. In spite of the limited scope of this study, these results suggest that artificially planted watersheds are extremely vulnerable to catastrophic natural disasters such as typhoons. Elevated loss of nutrients in the artificially planted watershed might have resulted from the mechanized silvicultural practices employed immediately after the fire. To maximize soil preservation, the timing and necessity of plantation practices should be reconsidered, and rapidly regenerating vegetation should be protected to promote nutrient uptake and to mitigate nutrient loss from burned forests.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.14-14
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• 2022

Greenhouse gas emissions are one of the critical factors that drive change in rice cropping systems. Within this changing system, less water irrigation and chemical fertilizer are seriously considered, as well combining precision farming technologies with irrigation control. Water and phosphorus (P) fertilizer are two of the most critical inputs in rice cultivation. Due to the lack of water availability in the system, P fertilizer is not available, especially in acidic soil conditions. Moreover, the various types of abiotic stresses, such as drought, high temperature, salinity, submergence, and limited fertilizer result in significant yield loss in the system. Even in the late stage of growth, the waves caused by diseases and insects make the field more unfruitful. Therefore, agronomists and breeders need to identify the secondary phenotypes to estimate the yield loss of when stress appears. The prediction will be clearer if we have a set of markers tagging the causal variation and the associated precise phenotype indices. Although there have been various studies for abiotic stress tolerance, we still lack functional molecular markers and phenotype indices. This is due to the underlying challenges caused by environmental factors in highly unpredictable regional and yearly environmental conditions in the field system. Pupl (phosphorus uptake 1) is still known as the first QTL associated with phosphorus uptake and have been validated in different field crops. Interestingly, some pyramiding lines of Pupl and other QTLs for other stress tolerances showed preferable phenotypes in the yield. Precise physiological studies with the help of genomics are on-going and some results will be discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.39-44
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• 1969

Discussions on the adequacy of present level of supply of fertilizers on the basis of the results obtained from experiments conducted on farmers' fields. 1. No differences have been found between present supply and optimum doses of nitrogen and phosphorus for rice except potash of which present amount of supply is 2.26kg/10a which is lower than the optimum dose by 1.90kg/10a. About 1.2% increase in the yield of paddy may be expected by increasing the level of potash to 4.2kg/10a. 2. Increasing the present supply of nitrogen, phosphorus and potash by 3.4, 4.7 and 3.3kg/10a, respectively for barley is required in order to increase its yield by 8.6%. 3. About 17% increase in the yield of wheat may be expected by increasing the supply of nitrogen, phosphorus and potash by 3.4, 3.9 and 6.4kg/10a. 4. An additional quantity of 7.5kg/10a of nitrogen, 6.4kg/10a of phosphorus and 7.5kg of potash on corn may incrase its yield by 45% 5. 8% increase in the yield of sweet-potato is expected when 3.8, 1.8 and 15.1kg/10a of additional nitrogen, phosphorus and potash, respecitvely is applied to the crop. 6. 21% increase in the yield of potato may arise with 0.6, 3.3 and 3.6kg/10a additional nitrogen, phosphorus and potash, respectively. 7. 15% increase in the yield of soybean may result with the application of 2.8, 1.9 and 2.9kg/10a additional nitrogen, phosphorus and potash, respectively. 8. The present quantity of fertilizer supply, it is necessary hereafter to supply fertilizer with attentions on such crops as corn, sweet-potato and white-potato etc. Needs to be revised in view of such crops as corn, sweet-potato and white-potato.