• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.175-194
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• 1979

The soil organic matter contents in arable land are generally low in Korea. Thus it is generally agreed that the application of organic materials to soils would be much beneficial. Present paper is a review on the effectiveness of organic mat ter application in uplands and lowlands. 1. The effect of organic matter application in uplands are of more clear and simple to explain as compared to that in lowlands. In uplands, appropriate application of organic matters such as compost and various crops residues improves the physical properties of soils leasing to increased water holding capacity, better aeration, and decrease in soil erosion. 2. In lowland, rice soils under water logged conditions the effect of organic matter application on rice yield is not straight borward and demands more refined knowledges for the interpretation of it. 3. It is found that the application of compost in rice soils is more effective when nitrogen fertilizer application is limited it dicating that nitrogen contained in the organic maerials can become available to rice plant and plays an important role for increased yield of rice under the condition where nitrogen fertilizer supply is limited. 4. Application of organic matter does not always bring about the desirable effects. Very often the organic matter application results in more intensive soil reduction leading to the accumulation of harmful substances which would can cancel out the positive effects of organic matter. This is partiunlarly true in poorly drained soils. 5. Rice straw or compost, when applied rice soils, supply sizeable amounts of available silicate to rice plant resulting in yield increase. 6. Although the effectiveness of organic matter application on rice yield in short term experiments is not consistent due to many reasons, the long term effect of organic matter is significant. 7. The term of the $O.M/SiO_2$ ratio in rice soils can serve as a criterion for the judgement of whether organic matter or silicate fertilizer is needed to be applied in a certain soil.

• Korean journal of applied entomology
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• v.38 no.1
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• pp.47-52
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• 1999

Effects of organic matter content in soil on activity. vertical migration. and persistence of two nernaticides. carbofuran and ethoprophos. to root-knot nematode, Mrloitlog!~iei ~lcognita.w ere investigated. As the organic matter content increased. activity of the nernaticides tended to be reduced. Both nematicides exhibited control values of more than 80'k' to M. iix.o,yilit~iln 0-2 cm depth soil layer from the surface. regi~rdless of organic matter content in soil. In 2-4 cm depth soil layer. however. the control value of the neniaticides varied with the organic niatter content in soil. The control value of carbofuran in the soil layer was ranged from I0 to 30'2,. depending on the soil organic niatter content. In contrast. ethoprophos had no control value against M. i/ic.o,ytlitcr in the \oil layer, except that the nematicide had a control value of 30% when the organic matter content was 0.4%. Furthermore. ethoprophos had no effect on controlling M. i/ic.o,gtiitrr in soil layer of below 4cm. whereas control values of carbofuran were approximately from 5 to 20% in all test soils having different organic matter contents. These results indicate that carbofuran has more vertical migration effect than ethoprophos. Persistence of the two neniaticides was also decreased with increasing soil organic matter content. Half life of carbofuran was 2-3 weeks in soil containing 0.4% organic matter, whereas it was found to be I week in soils containning 0.8 ant1 1.6% of organic matter. On the other hand. activity of ethoprophos was reduced to half in 3-3 weeks and in 2-3 weeks in soil containing 0.4 and 0.8%, and 1.6%) of organic matter, respectively. However, no activity of the both nernaticides was found in soil containing 3.2% of organic matter.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.76-82
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• 1986

A laboratory experiment was conducted to find out the denitrification rate upon the levels of nitrogen and source of organic matter in submerged sandy and sandy loam soil. The results obtained were sumarized as follows; 1. Evolution of nitrous oxide was increased at 1st and 10 days after incubation. And dinitrogen was increased at 1st and 30 days after incubation. Applications of green manure was enhanced the evolution of nitrous oxide ($N_2O$) and dinitrogen ($N_2$). 2. The cumulative denitrification rates at 50 days was high in Gyuam sandy loam soil (O-M: 1.52%) than that of Hamchang sandy soil (O-M: 3.81%). On the other hand, the cumulative emission of dinitrogen was high in Gyuam sandy loam soil while nitrous oxide was high in Hamchang sandy soil. The total mount of denitrification rate was high in order of green manure > rice straw > compost > control soil. 3. Increases of fertilizer nitrogen was enhanced the rate of emission of dinitrogen and nitrous oxide during the incubation time. 4. According to Michaelis-Menten kinetic equation, denitrification rates and reaction efficiency were remarkably increased by application of readily decomposable organic matter with in higher organic matter content of soil. 5. The negative relationship was observed between the evolution of dinitrogen and carbon ($CO_2+CH_4$) while the nitrous oxide with carbon was positive. 6. Under the this experiment conditions 1 mg of carbon was required for production of 4 mg N as $N_2O$ and 3 mg of N as $N_2$, respectively.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.76-84
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• 1986

All combinations of oxyfluorfen in 5 dosages and glyphosate in 4 dosages were used to assess the onto-drifting pattern of herbicide inactivation in three different type, such as check soil ($O^-M^-$), organic soil ($O^+M^-$), and micro-organism soil ($O^+M^+$). The plant used for bioassay was rape-hybrid. From the results, it was recognized that the herbicide inactivation is strongly achieved in order of $O^+M^+$ > $O^+M^-$ > $O^-M^-$ soil. Also, the inactivation of oxyfluorfen in soil tended to depend rather on soil microorganisms than organic matter, and to be promoted earlier by paraquat mixture than by that of glyphosate. Average 50 and 95% inactivated time (in days) of herbicides were getting shorten in order of $O^+M^+$, $O^+M^-$, $O^-M^-$, rather prolonged in mixture than in oxyfluorfen single treatment, and rather prolonged in high dose than in low dose, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.3
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• pp.153-167
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• 1979

Proposal on the ways to determine the optimum levels of nutrients application on rice to maximize the yield was made paying attention on the desirable ratios among the major nutrients including N (organic matter) K, $SiO_2$, Ca, Mg. Following are the summary of the discussion. 1. For the higher yields, the balanced nutrients absorption is important. 2. Silica plays an important role in leading the applied N to increased yield. 3. Level of N application should be determined taking account of soil organic matter and abailable silicate contents. The higher the ratio of $SiO_2$/O.M. the more N can be applied for higher yield. 4. Different rice cultivars responds to the ratio of $SiO_2$/O.M. in soils, in different manner, in translating the applied N into yield. 5. By altering the ratio of $SiO_2$/O.M. through the application of silicate fertilizer or organic matter, the requirement of N in accordance with varietal characteristics can be determined. 6. When amount of N determined by above mentioned approaches, level of K application can be determined upon the basis of the ratio of $K/\sqrt{Ca+Mg}$ in soils.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.84-91
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• 2002

If contaminated river water is sprayed over the floodplain, organic matter and nitrogen would be removed by microbial processes in the rhizosphere of vegetation during the filtration through soil. In this study we tested the organic matter and nitrogen removal from contaminated river water by the floodplain filtration. Model system of floodplain was constructed using a PVC pipe (15 cm i.d. ${\times}$ 150 cm L) which was packed with a loamy sand soil collected from a floodplain in Nakdong river. The model system was instrumented with soil solution samplers and gas samplers. A river water collected from Omogcheon in Kyongsan was sprayed from top of the model system at three different rates. The concentration of organic matter, DO, $NO_3^-$, $NO_2^-$, $NH_4^+$, $N_2$ and $N_2O$, and redox potential were measured as a function of soil depth for 24 days after the system reached a steady state. When river water was sprayed at the rates of 40.8 and 68.0 $l/m^2/day$, a significant reductive condition for denitrification was developed at below 5-cm depth of the soil. When the water reached at 90-cm depth of the soil, COD and concentration of inorganic nitrogen were lowered, on an average, from 18.7 to 5 mg/l and from 2.7 to 0.4 mg/l, respectively. $N_2$ comprised most of the N gas evolved from denitrification and $N_2O$ concentrations emitted at the surface of soil were less than 1 {\mu}l/l. The effective removal of organic matter and nitrogen by the filtration in the model system of floodplain demonstrates that the native floodplains, which include rhizosphere of vegetation at the top soil, could be more effective in the treatment of contaminated river waters and other industrial waste waters containing high concentration of organic matter and nitrogen.

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.1-8
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• 1977

Forest soil fertility was evaluated through the approach of numerical method. In this study, the soil chemical properties analyzed for 35 different soil series as table 2 were cited in numerical analysis. Minimum contents of essential nutrients in the surface soil for a satisfactory growth of tree in the plantation were evaluated by comparing with Wild's standard as table 1. Demanding level of fertilization were evaluated by using the formula 1 as table 5. Similar relation of soil chemical properties between soil series were calculated through formula 2, and then classified into 5 groups in soil chemical properties. 1. General chemical properties of surface soil in case of 35 soil series. About 40 percent of 35 different soil series are less than 2 percent in organic matter, 10 ppm in available phosphorus, 1.25m.e/l00g in exchangeable calcium and 0.5m.e/l00g in exchangeable magnesium. Generally, shortage of exchangeable potash are not found. CEC less than 10m.e/l00g are in two thirds and strong acid soil less than PH 5.5 are in about four fifths. 2. Soil series requested or not the fertilization are indirectly evaluated from the formula 1 using the relative figure of chemical components of CEC, OM and MgO. Through this analysis, 8 different soil series have very poor quality in soil chemical capacity so that demands highly the fertilization. On the other hand, other 13 different soil series group have not been thought to need the fertilization according to chemical guality. 3. By the results comparing the similarity of chemical properties of forest soil, it is thought to be suitable that the forest soil fertility are divided into 5 groups as follows: 1. Low CEC soil 1-1 Low organic matter soil less than 2 percent 1-2 Medium organic matter soil less than 4 percent 2. High CEC and organic matter soil 2-1 Low magnesium soil 2-2 High magnesium soil 3. High magnesium and calcium soil as lime stone.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.107-113
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• 1998

We investigated the effects of a long term application of soil amendments such as lime, silicate, compost, or combinations of these materials on the contents of Cu and Zn in paddy soil and brown rice. The results obtained from a sequential extraction of Cu and Zn in paddy soils and brown rice, using $H_2O$, $KNO_3$, $Na_2$-EDTA and $HNO_3$ and showed that the most of Cu and Zn were NaOH-extractable (organically bound form) and $HNO_3$-extractable (sulfide and residual form). Cu contents of NaOH and EDTA extractable increased with the long term application of compost while the contents of Zn extracted by $KNO_3$ was decreased even though $HNO_3$ extractable-Zn was prominent chemical form in paddy soils. The percentage and contents of Zn, extracted by $KNO_3$ for each combination treatment of soil amendments, was decreased but the contents of Cu was not affected. The content of NaOH extractable-Cu was proportionally increased with increase in organic matter content irrespective of the extractants used in this experiment. The contents of Zn and exchangeable K were also increased with increase in organic matter content. However, we could not find any relationship between the extractable forms of Cu and Zn, and CEC, OM. while increase in CEC, contents of cations, and organic matter decreased the content of Cu in brown rice.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.195-204
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• 2002

Mineralogy and the exposed surface area are two of the most important factors controlling dissolution and weathering rates of soils. The mixture of inorganic and organic materials of various size distributions and structures that constitute soils makes the calculation of weathering rates difficult. The surface area of soil minerals plays an important role in most of programs for calculating the weathering rates and critical loads. The Brunauer-Emmett-Teller (BET) measurement is recommended for the measurement of specific surface area. However, BET values measured without organic matter removal are in fact those far all the N2-adsorbed surface areas, including the surfaces covered and aggregated with organisms. Surfaces occupied by organisms are assumed to be more reactive to weathering by organic activities. Therefore, the BET surface area difference before and after organic removal depicts the area occupied by organisms. The present study shows that the BET values after organic matter removal using $H_2$O$_2$ are larger than those without removal by 1.68~4.87 $m^2$/g. This implies that BET measurement without organic removal excludes the reactive area occupied by organisms and that the area occupied by organisms in soils is much larger than expected. It is suggested that specific surface area measurement for calculating weathering rates of mineral soils should be made before and after organic matter removal. The results of a column experiment are presented to demonstrate the potential retarding influence that this organic matter may have on mineral dissolution and weathering.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.26-33
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• 2008

Soil nutrient status in an organic apple farm was evaluated in relation to a conventional farm to better understand the effects of organic farming system on soil fertility. Soil organic matter, total and mineral N, available P, exchangeable cations, and available micronutrients were monitored at depth of 5-20 cm from May to October in 2006. Average soil organic matter content was 63.3 and $31.0g\;kg^{-1}$ in organic and conventional farm, respectively. Total N content was 3.3 and $1.7g\;kg^{-1}$ in average for organic and conventional farm, respectively. Ammonium and nitrate N in organic farming were maintained at relatively stable levels, but in the conventional farm the levels were very high in early season due to the chemical fertilizer application. In the organic apple farm, available P content in May was lower than that found in the conventional farm, but during the growing season available P content was continuously increased and in August the content was more than $1000mg\;P_2O_5\;kg^{-1}$. The organic farm maintained relatively greater exchangeable K, Ca, and Mg levels than the conventional farm. Available Cu, Fe, and Mn contents in the conventional farm were relatively greater than those found in the organic farm. However, available Zn extracted in 0.1 M HCl was much greater in the organic farm. Nutrient levels above crop needs were observed in both conventional and organic apple farm suggesting a more appropriate management of soil nutrients in organic farming to secure its fundamental functions for the sustainable agriculture.