• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.4
• /
• pp.50-58
• /
• 1989

An approach to irrigation scheduling for chinese caggage is presented, and a crop yield response function to soil moisure is derived from irrigation experiments, based on a root- zone water balance method. The paper concludes that crop yield can be estimated by allowable depletion and actual evapotranspiration in 3 cropping stages, and presents the optimal allowalbe depletion, irriga- tion frequency and the amount of irrigation water to get the maximum crop yield and opti- mal irrigation policy.

• Carbon letters
• /
• v.16 no.4
• /
• pp.265-269
• /
• 2015

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.1
• /
• pp.21-28
• /
• 2009

Detailed information on soil characteristics is of great importance for the use and conservation of soil resources that are essential for human welfare and ecosystem sustainability. This paper introduces soil inventory of Korea focusing on national soil database establishment, information systems, use, and future direction for natural resources management. Different scales of soil maps surveyed and soil test data collected by RDA (Rural Development Administration) were computerized to construct digital soil maps and database. Soil chemical properties and heavy metal concentrations in agricultural soils including vulnerable agricultural soils were investigated regularly at fixed sampling points. Internet-based information systems for soil and agro-environmental resources were developed based on 'National Soil Survey Projects' for managing soil resources and for providing soil information to the public, and 'Agroenvironmental Change Monitoring Project' to monitor spatial and temporal changes of agricultural environment will be opened soon. Soils data has a great potential of further application in estimation of soil carbon storage, water capacity, and soil loss. Digital mapping of soil and environment using state-of-the-art and emerging technologies with a pedometrics concept will lead to future direction.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.4
• /
• pp.292-297
• /
• 2007

Global warming and climate changes have been major issues for decades andvarious researches have reported their impact on our environment. According to recent researches, increased carbon dioxide ($CO_2$) concentration in the atmosphere is considered as a dominant contributor to global climate changes and thus numerous researches were conducted to control $CO_2$ concentration in the atmosphere. Soil management practices, such as reducing tillage intensity, returning plant residues, and enhancing cropping system have recommended for restoring organic carbon into the soils effectively. However, few studies on soil carbon sequestration have reported for Korean paddy soils. Therefore, evaluation of soil organic carbon (SOC) dynamics in the long-term single rice cropping system is essential in order to find out potential capacity of paddy field as a carbon sink source. The objective of this research was to evaluate SOC dynamics on the long-term single rice cropping system. Research was conducted in the research farm at National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon. Long-term phosphorus and potassium fertilization and lime application didn't significantly affect on SOC compared to controls. We found that SOC contents were increased continually at the long-term composting plots with enhanced rate of carbon storage. In conclusion, continuous incorporation of plant residues (i.e., composting) is recommended to effectively sequester soil carbon for Korean paddy soils. This result implies that continuous composting in a paddy field may contributenot only for increasing SOC in the soils but also for mitigating global warming through reducing carbon dioxide emission into atmosphere. Therefore, we recommend that a strategy or policy measures to encourage farmers to return plant residues continuously for mitigation of global warming as well as soil fertility is being developed.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.12 no.2
• /
• pp.82-90
• /
• 2004

This study was conducted to evaluate in situ soil flushing and coagulation for naphtalenes-contaminated soil remediation. Mixed-surfactant of 1% POE12 and 1% SDS (1 : 1 by volume basis) was used as a flushing solution. When 5 pore volumes of mixed -surfactant were added to soil column, the flushing efficiencies of 2-methylnaphtalene and 1,5-dimethylnaphtalene with about 1,500 mg/kg(dry soil) were approximately 80% and 60% respectively. In adding 13 pore volumes of mixed-surfactant, the flushing efficiencies of 2-methylnaphtalene and 1,5-dimethylnaphtalene were 90% and 82%. However, considering in situ soil flushing with distilled water, about 42% and 71% were flushed for 2-methylnaphtalene and 1,5-dimethylnaphtalene by surfactant-only. For about 10,000 mg/kg(dry soil) diesel-contaminated soil, 40% and 70% of TPH were flushed-out in 5 pore volumes and 13 pore volumes addition. However, for naphtalenes in diesel TPH, 90% of flushing efficiency was discovered in adding only 5 pore volumes of flushing solution. There was not discovered significant difference among coagulation efficiencies of 6 kinds of polymers, and the coagulation efficiencies were near 50%.

• Journal of Korea Water Resources Association
• /
• v.41 no.2
• /
• pp.149-162
• /
• 2008

The Soil and Water Assessment Tool (SWAT) developed by the USDA-Agricultural Research Service for the prediction of land management impact on water, sediment, and agricultural chemical yields in a large-scale basin was applied to Daecheong Reservoir basin to estimate the amount of soil losses from different land uses. The research outcomes provide important indications for reservoir managers and policy makers to search alternative watershed management practices for the mitigation of reservoir turbidity flow problems. After calibrations of key model parameters, SWAT showed fairly good performance by adequately simulating observed annual runoff components and replicating the monthly flow regimes in the basin. The specific soil losses from agricultural farm field, forest, urban area, and paddy field were 33.1, $2.3{\sim}5.4$ depending on the tree types, 1.0, and 0.1 tons/ha/yr, respectively in 2004. It was noticed that about 55.3% of the total annual soil loss is caused by agricultural activities although agricultural land occupies only 10% in the basin. Although the soil erosion assessment approach adopted in this study has some extent of uncertainties due to the lack of detailed information on crop types and management activities, the results at least imply that soil erosion control practices for the vulnerable agricultural farm lands can be one of the most effective alternatives to reduce the impact of turbidity flow in the river basin system.

• Journal of Wetlands Research
• /
• v.17 no.2
• /
• pp.163-175
• /
• 2015

In this paper, soil erosion and soil loss management system (SMS) of the City of Calgary in Albert, Canada was reviewed. Regulatory basis supporting this soil management system, permit process and conditions, guidelines and principles for the SMS, and monitoring and repair duties, inspection were discussed. Permit process in the City of Calgary is handled mainly by Urban Development Division, in which special task force called CPAG (Coorporative Planning Application Group) (if necessary circulated through related subdivisions). Inspects all the permit conditions and decides permit or refusal, and LUM (Land Use and Mobility) advertises the approval, if there is no appeals, permit is released to developers. If permit is rejected, applicant can appeals Development Appeal Board, it can approve or reject. In addition to permit, the city has manual for soil management plan, which includes BMP selection, design, monitoring, maintenance, and inspection activities. Perfect SMS policy does not necessarily guarantee relieving the soil-particle related pollution problem, but in Korea, we have to recognize that construction works during development is potentially the most destructive stage of environmental pollution. The central and local governments must make preparations for the effective and tight regulations and ordinance which is appropriate for regional social-economic conditions.

• Journal of Environmental Policy
• /
• v.9 no.2
• /
• pp.41-55
• /
• 2010

This paper analyzes optimal watershed management focusing on reservoir-level sediment removal techniques. Although dams and reservoirs provide several benefits, sedimentation may reduce their storage capacity. As of today, the Aswan High Dam (AHD) in Egypt faces approximately 76% reduced life of the reservoir. Since the AHD is the major fresh water source in Egypt, sustainable use of this resource is extremely important. A model is developed to simultaneously determine optimal sediment removal strategies for upstream soil conservation efforts and reservoir-level sediment control. Two sediment removal techniques are considered: mechanical dredging and hydro-suction sediment removal system (HSRS). Moreover, different levels of upstream soil conservation efforts have introduced to control soil erosion, which is a major contributor of reservoir storage capacity reduction. We compare a baseline case, which implies no management alternative, to non-cooperative and social planners' solution. Our empirical results indicate that the socially optimal sediment removal technique is a mechanical dredging with unconstrained amount with providing a sustainable life of the reservoir. From the empirical results, we find that social welfare can be as high as $151.01 billion, and is sensitive to interest rates and agricultural soil loss.

• Journal of Ecology and Environment
• /
• v.39 no.1
• /
• pp.17-29
• /
• 2016

We conducted the study on the relationship between the distribution of coastal sand dune plants and edaphic factors from the shoreline to inland in sand dune ecosystem. The application of TWINSPAN classification based on 10 species, led to the recognition of three vegetative groups (A-C), which associated with their habitats (foredune, hummuck in semistable zone and stable zone). The associations were separated along soil gradient far from the seashore. The relationships between species composition and environmental gradients were explained by canonical correspondence analysis (CCA). Distance from the shoreline was an important indicator to determine soil properties (pH, total ion contents, sand particle sizes, organic matters and nitrogen contents) from the seaward area to inland area and distribution pattern of coastal sand dune plants. Group A is foredune zone, characterized by Calystegia soldanella; group included typical foredune species such as Elymus mollis, Carex kobomugi, Ixeris repens, C. soldanella and Glehnia littoralis. Group B on semi-stabilized zone was characterized by Vitex rotundifolia, a perennial woody shrub. This group was associated the proportion of fine sand size (100 to 250 μm). The results on the proportion of soil particle size showed a transition in sand composition, particularly with respect to the proportion of fine sand size that occurred from the foredune ridge at 32.5 m to the Vitex rotundifolia community at 57.5 m from the shoreline. Group C on stabilized zone was characterized by Zoysia macrostachya, Lathyrus japonicus and Cynodon dactylon and were associated soil organic matter and nitrogen contents. The spatial distribution of plants in the Goraebul coastal sand dune system may result from the interactions between the plant species and environmental heterogeneity.

• Journal of the Korean earth science society
• /
• v.26 no.7
• /
• pp.661-667
• /
• 2005

It was preliminarily considered that Jangdo wetland was a concave landform formed by the weathering of granite intruding Precambrian silicified metasedimentary rocks. Various granite-weathered topography was observed. The formation scenario of Jangdo wetland is as follows. By flood or slope mass movement of regolith, rock fragments were moved to form a low-relief slope landform. As a result, wetland was formed. By analyzing the slope soil and wetland sediment, we conjectured that Jangdo wetland depended on the influence of peripheral slope soil. In these concavelandform environment, the supply of water and organic materials was sustained for a long time to form a organicnondegradable wetland environment. In addition, the plants appropriate to this wetland environment were settled to thicken the wetland. This is how the present Jangdo wetland was thought to be formed.