• Journal of Environmental Science International
• /
• v.23 no.11
• /
• pp.1827-1833
• /
• 2014

This study has been carried out to present the valuation system of soil carbon sequestration potentials of soil in accordance with the new climate change scenarios(RCP). For that, by analyzing variation of soil carbon of the each type of agricultural land use, it aims to develop technology to increase the amount of carbon emissions and sequestration. Among the factors which affects the estimation of determining the soil carbon model and influence power after the measurement on soil organic carbon, under the center of a causal relationship between the explanatory variables this study were investigated. Chemical fertilizers (NPK) decreased with increasing the amount of soil organic carbon and as with the first experimental results, when cultivating rice than pepper, the fact that soil organic carbon content increased has been found out. The higher the carbon dioxide concentration, the higher the amount of organic carbon in the soil and this result is reliable under a 10% significance level. On the other hand, soil organic carbon, humus carbon and hot water extractable carbon has been found out that was not affected the soils depth, sames as the result of the first year. The higher concentration of carbon dioxide, the higher carbon content of humus and hot water extractable carbon content. According to IPCC 2006 Guidelines and the new climate change scenario RCP 4.5 and the measurement results of the total amount of soil organic carbon to the crops due to abnormal climate weather, 1% increase in atmospheric carbon dioxide concentration was found to be small when compared to the growing rate of increasing 0.01058% of organic carbon in the soil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.5
• /
• pp.650-658
• /
• 2010

We used green manure crops such as hairy vetch, crimson clover, rye, sorghum, and sudan grass by mixing with soils to assess the effects of green manure crops on nutrient supply and soil quality improvement. Temporal changes in soil inorganic nitrogen, carbohydrate, microbial biomass, and humus content were determined as soil quality indicators. Inorganic nitrogen content of the control maintained similar level during the whole period, but it had continually increased until 4 weeks after incorporation (WAI) of green manure crops. Especially, inorganic nitrogen content sharply increased in sudan grass. After incorporation of green manure crops, temporal change of soluble sugar in soils was as follows: it had gradually increased in legume green manure crops-incorporated soils until 7 WAI, which was the highest, and then showed the tendency to be reduced. Meanwhile, it in non-legume green manure crops-incorporated soils rapidly increased after the incorporation, and reached the maximum around 4 WAI. Humic acid by the decomposition of crop residues in green manure crops-incorporated soils was greatly enhanced with the elapsed time of 4 WAI, although it was low at the same level as the control until 2 weeks. In addition, there was a difference in fulvic acid by incorporated crops, fulvic acid in hairy vetch, sorghum and sudan grass showed a similar tendency with the change in humic acid. Our results suggest that soluble sugar, microbial activity and humic acid could be available indicators to evaluate the fertility of green manure crops-incorporated soils.

• Korean Journal of Agricultural Science
• /
• v.38 no.1
• /
• pp.25-30
• /
• 2011

This study was conducted to investigate changes on burned areas after a forest fire in Geyjoksan which occurred in April 2000. Both soil physicochemical properties and vegetation present were analyzed in burned and unburned sites of pinus densiflora according to two slope aspects(south and north-facing slopes). The results of the analysis are as follows. The appearance species of vegetation were 21, 15 and 18 for burned site, burned site-1 and burned site-2 of pinus densiflora community respectively, indicating that the occurrence of forest fire and slope aspects affect vegetation appearance. The pH values at 0~10cm soil depth of unburned and burned sites of pinus densiflora community were 5.04 and 5.12 respectively with no significant difference between them. Mean organic matter, total nitrogen and available P also had no significant difference. This results indicate that the forest recover its former pH, total nitrogen, mean organic matter and available P over time after a forest fire. North-facing slope had relatively higher soil water content thus implying that its pH values of soil lower than south-facing slope. On the other hand, south-facing slope had high organic matter and available P content of soil as compared to north-facing slope. With south facing slope having high water contents, humus was accumulated due to slow organic matter decomposition. The pH values also decreased due to organic acids from humus. However, we observed that organic matter and P concentration in soil increased.

• Fire Science and Engineering
• /
• v.24 no.6
• /
• pp.1-6
• /
• 2010

A smoldering ground fire can be a probable cause of reignition of surface fire when transmitted from Fermentation layer to Humus layer with temperature higher than that of ignition. Purpose of this paper is to identify experimental methodology on the potential risk of a smoldering ground fire, which is similar to the real surface fuel bed, and its combustion characteristics. The fuel model designed in this study is composed of 3 layers such as Litter layer, Fermentation layer and Humus layer and 8 Thermocouples are set through 3 layer at each boundary and in between to detect the temperature change and duration of smoldering and propagation velocity. As a result, it was observed that ignition conditions in the boundary between L layer and F layer determined transmission and non-transmisstion to F-H layer. In addition, range of critical humidity at which a smoldering ground fire was transmitted in a material layer was 33~44% and when temperature exceeds $350^{\circ}C$, likelihood of transmission of a smoldering ground fire was high. In the research, the experimental model for multi-layer smoldering ground fire is suggested and information about propagation of smoldering fire, possibility of reignition according to moisture content, propagation velocity and temperature change are obtained, Also, the built-up methods were established to help analyze basic characteristics of smoldering ground fire.

• Korean Journal of Soil Science and Fertilizer
• /
• v.19 no.3
• /
• pp.239-244
• /
• 1986

This study was conducted to investigate the characteristics of humic substances and the fractional distribution of organic nitrogen in Korean paddy soils. The results are obtained as follows: 1. The content of humus in soils used was 665-2680 mg/100g and the average contents of humic acid in normal paddy soils and in sandy paddy soils were 1436 mg/100g, 970 mg/100g respectively. 2. The humic acid diagrams classed by Kumada method belong to B type, P type and Rp type. 3. The content of Mineral - N to Total - N was 1.04-2.86% and the average contents of that in sandy paddy soils and in normal paddy soils were 1.72% and 1.75% respectively. 4. The fractionations of acid hydrolysable organic - N in sandy paddy soils were Amino acid - N (31.52%), Humin - N (20.63%), Amino sugar - N (18.70%), and Unknown - N (25.73%).

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.1
• /
• pp.30-36
• /
• 2012

The active fraction of soil organic matter, which includes organic debris and light organic fraction, plays a major role in nutrient cycling. In addition, particulate organic matter is a valuable index of labile soil organic matter and can reflect differences in various soil behaviors. Since soil organic matter bound to soil mineral particles has its density lower than soil minerals, we partitioned soil organic matter into debris ($<1.5g\;cm^{-3}$), light fraction ($1.5-2.0g\;cm^{-3}$), and heavy fraction ($>2.0g\;cm^{-3}$), based on high density $ZnCl_{2-}$ sucrose solutions. Generally, partitioned organic bands were clearly separated, demonstrating that the $ZnCl_{2-}$ sucrose solutions are useful for such a density gradient centrifugation. The available gradient ranges from 1.2 to $2.0g\;cm^{-3}$. Although there was not a statistically meaningful difference in organic debris and organomineral fractions among the examined soils, there was a general trend that a higher content of organic debris resulted in a higher proportion of light organomineral fraction. In addition, high clay content was associated with increased fraction of light organomineals. Partitioning of soil organic carbon revealed that carbon content is reduced in the heavy fraction than in the light fraction, reflecting that the light fraction contains more fresh and abundant carbon than the passive resistant fraction. It was also found that carbon contents in the overall organic matter, debris, light fraction, and heavy fractions may differ considerably in response to different farming practices.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.1
• /
• pp.27-32
• /
• 2003

To understand the chemical structure of sewer sludge in comparison with commercial compost and charcoal used as a soil improver, it was carried out to analyse their ash contents and metal ions, and to elucidate the chemical structure of their residuals after a sequential treatment of alcohol-benzene(1:2) extraction in Soxhlet, 3% HCl reflux and 79% H₂SO₄ hydrolysis, using CHNS analyzer and solid C-13 NMR spectrometer. The results obtained were as follows: 1. Ash content of sludge was about 46% that is higher than those of compost (17%) and charcoal (4%). 2. The residual of sludge after a sequential treatment of HCl and H₂SO₄ hydrolyses had high ash content about 23%, too. 3. The sludge seems to be suitable to the soil improver because the content of heavy metal ions in sludge was near the compost and below the organic fertilizer standard. 4. Elemental composition of sludge residual after HCl-H₂SO₄ hydrolyes was C/sub 56/H/sub 91/O/sub 12/N₂S = (C/sub 6/H/sub 10/O/sub 5/)/sub 7/(C/sub 6/H₄)/sub 7/C₂H/sub 43/O₂N₂S, similar to C/sub 103/H/sub 122/O/sub 33/N/sub 6/S = (C/sub 6/H/sub 10/O/sub 5/)/sub 6/(C/sub 6/H₄)/sub 10/C/sub 7/H/sub 22/O₃N/sub 6/S of compost. 5. The sludge residual had proved to have both considerable aliphatic and aromatic groups, but the compost residual to have mainly aliphatic groups and the charcoal to have mainly aromatic groups, through the peak analysis of solid C-13 NMR charts. 6. So, the sewer sludge is proved to have a considerable amount of aromaticity like in woody biomass containing lignin.

• Journal of Plant Biology
• /
• v.13 no.3
• /
• pp.25-31
• /
• 1970

The ratio of occurrence of azalea (Rhododendron mucromultum T.) was determined on the north and south facing slopes on a mountain in Koyang county, Kyungi Province. Data was actually recorded at the eight aspects facing N, NE, E, SE, S, SW, W and NW on the mountain. In each of the eight aspects, six 10m transect tapes were placed in parallel directly down the slope, each 1m apart, and fifty 1$m^2$ quadrats were constructed between them. Frequency of the azalea in each of these quadrats was determined by counting the central stumps of the bushes Soil samples were also taken from pits dug in each plot to use for determination of the following: Soil pH, soil moisture loss on ignition, total nitrogen, and available phosphorus. The occurrence rate of azalea on the northern slop e was found to be for higher on the northern slope than on the southern slope. The abundance of azalea on the northern slope was found to be partially correlated with soil moisture(r=0.93; 0.01>p) and the amount of humus in the soil (r=0.04;0.01>p). The content of total nitrogen, soil PH, and available phosphorus in the soil, however, were found to have no evident relationship with the abundance of azalea. The conditions for growth in the species of azalea Rhododendron mucronulatum T'. were generally found to be more favorable on the northern slope.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.11 no.3
• /
• pp.35-41
• /
• 2003

The on-site sewage sludge vermicomposting equipment was designed and evaluated on the batch and continuous tests. The vermicomposting equipment was designed to consider the mechanization as well as automation. Especially, the automatic controls of water content and temperature and the mechanization of the sludge feeding and cast separating were the important factors. In terms of changes in chemical characteristics when the equipments for experiments are operated continuously, the ORP, EC, $NH_3-N$ and $NO_3-N$ were found to be higher before and after treatment. In addition, it was found that changes in properties were low. Furthermore, the $NO_3-N$ concentration of the humus produced after treatment was found to be higher than the $NH_3-N$ concentration showing that it was appropriate based on the recycling criteria.

• Applied Biological Chemistry
• /
• v.9
• /
• pp.149-152
• /
• 1968

In order to establish a effective application method of compost and phosphorus fertilizer for rice plant, a field experiment has been conducted and the variation of the organic matter content in soils has been observed. The results may be summarized as follows. 1. It was more effective to split the application time into basic and in 2 weeks before the young premodia formation for the yield increase of rice grain than to applicate once basic, and it was apparent that the lesser amount of organic matter during the growing period of rice was consumed, the higher yield of rice grain was resulted. 2. The combined application of compost and phosphorus fertilizer showed a tendency to raise higher the grain yield than the separated application. 3. It was suggested that the split application of compost bring yield increase of rice grain.