• 농업과학연구
• /
• 제37권3호
• /
• pp.435-449
• /
• 2010

Soils in the sloping uplands in Korea are subject to intensive land use with high input of agrochemicals and are vulnerable to soil erosion. Development of the environmentally sound land management strategy is essential for a sustainable production system in the sloping upland. This report addresses the status of upland agriculture and the best management practices for the uplands toward the sustainable agriculture. More than 60% of Korean lands are forest and only 21% are cultivating paddy and upland. Uplands are about 7% of the total lands and about 62% of the uplands are in the slopes higher than 7%. Due to the site-specificity of the upland, many managerial and environmental problems are occurring, such as severe erosion, shallow surface soils with rocky fragments, and loadings of non-point source (NPS) contaminants into the watershed. Based on the field trials, most of the sloping uplands were classified as Suitability Class III-V and the major limiting factor was slope and rock fragments. Due to this, soils were over-applied with N fertilizer, even though N rate was the recommendation. This resulted in decreases in yield, degradation of soil quality and increases in N loading to the leachate. Various case studies drew management practices toward sustainable production systems. The suggested BMP on the managerial, vegetative, and structural options were to practice buffer strips along the edges of fields and streams, winter cover crop, contour and mulching farming, detention weir, diversion drains, grassed waterway, and slope arrangement. With these options, conservation effects such as reductions in raindrop impact, flow velocity, runoff and sediment loss, and rill and gully erosion were observed. The proper management practice is a key element of the conservation of the soil and water in the sloping upland.

• Journal of Applied Biological Chemistry
• /
• 제50권1호
• /
• pp.22-28
• /
• 2007

Most of the uplands in alpine regions during off-season are left as bare soil and thus vulnerable to severe erosion due to the inherent topographical conditions. Appropriate management strategy to cope with this problem is urgently needed, yet few researches have been reported on the effects of winter cover crop and management on soil erosion. We assessed effects of ryegrass (Lolium multiflorum) as cover crop, green manure or mulching residue on soil erosion and quality through field and segment plot lysimeter experiments in alpine uplands. Ryegrass successfully adopted to winter in alpine region based on biomass, nutrient contents, and vigors of top and root systems. Incorporation of ryegrass into soil maintained soil fertility, nutrient uptake, and yield of cabbage exerting potential use as green manure. Cultivation of ryegrass suppressed occurrence of Chinese cabbage pests. Surface coverage by ryegrass as cover crop and mulching residue significantly reduced soil loss up to 96%, when combined with soil conservation management practices. Results revealed maintaining cover crop over winter was beneficial in reducing soil erosion, and sustaining soil quality and Chinese cabbage productivity. This study suggested winter cover crop, followed by green manure and mulching, and conservation tillage system could be one of the best management practices in alpine sloping uplands cultivating Chinese cabbage.

• 대한환경공학회지
• /
• 제32권11호
• /
• pp.1024-1029
• /
• 2010

본 연구에서는 경사도 20%의 강원도 경작지 실험포장(가로 3 m${\times}$세로 18 m)을 대상으로 자연강우 조건하에서 폴리머 기반 토양개량제인 polyacrylamide (PAM) 및 바이오폴리머의 처리가 토양유실 및 작물의 생장에 미치는 영향을 평가하였다. 40 kg/ha PAM 및 바이오폴리머 처리시 토양입단 안정도는 대조구에 비해 최대 11% 증가하였다. 생육조사 결과 폴리머 처리에 따라 무(Raphanus sativus)의 엽장은 증가하였으나 수확량의 경우 유의적인 차이를 나타내지는 않았다(P>0.05). 토양유실의 경우 폴리머 기반 토양개량제 처리시 토양유실량이 최대 41% 감소하였으나 유거수량에는 유의적인 차이가 없었다. 또한 토양유실량은 강우강도의 증가에 따라 대수관계($R^2=0.85$)로 증가함을 확인하였다. 이상의 결과로부터 피복이 완전치 못한 경사지 경작지에 대한 폴리머 기반 토양개량제 시용은 토양유실 저감에 효과적이며 작물생육 촉진 및 토양질 향상에도 기여할 수 있을 것으로 판단된다.

• 한국환경농학회지
• /
• 제37권3호
• /
• pp.151-159
• /
• 2018

BACKGROUND: In this review paper, the effects of surface cover (SCV), vegetative filter strip (VFS), and vegetated ridge (VRD) on the pollutant runoff from steep-sloping uplands were analyzed to compare the pollutant reduction efficiency in runoff ($PRE_{runoff}$) of the practices and to investigate how slope and rainfall parameters affect the $PRE_{runoff}$. METHODS AND RESULTS: The $PRE_{runoff}$ of SCV, VFS, and VRD for pollutants including suspended solids and biological oxygen demand was compared by analysis of variance. The effect of slope and rainfall parameters on the $PRE_{runoff}$ was explored by either mean comparison or regression analysis. It was found that the $PRE_{runoff}$ differs with the practices due to different pollutant reduction mechanisms of the practices. Though the $PRE_{runoff}$ was likely to be affected by site condition such as slope and rainfall (amount and intensity), more comprehensive understanding was not possible due to the limited data set. CONCLUSION: The $PRE_{runoff}$ of SCV, VFS, and VRD differed due to the distinctive mechanisms of pollutant removal of the practices. It is necessary to accumulate experimental data across a variety of gradient of slope and rainfall for comprehensive understanding of the effects of the practices on pollutant runoff from steep-sloping uplands.

• 한국토양비료학회지
• /
• 제47권1호
• /
• pp.36-40
• /
• 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.

• 한국환경복원기술학회지
• /
• 제18권6호
• /
• pp.73-83
• /
• 2015

The objective of this study is to establish implications for forest restoration planning in North Korea by analyzing spatio-temporal forest changes and detecting bio-physical factors driving forest degraded. We measured the relationship and spatial distribution between shifting cultivation and sparse forest. We also analyzed between degraded forest land and ecological variables by binary logistic regression to find biophysical drivers of forest degradation and deforestation in North Korea. Between the sparse forest and the shifting cultivation, a positive relationship is found (r=0.91) and scattered discontinuously throughout the country (Moran's I = -1, Z score = -13.46 (p=0.000)). The sparse forest showed a negative relationship with the warmest month(bio 9), the coldest month(bio10), and the minimum of soil water contents (swc_min), while the shifting cultivation had a negative relationship with the warmest month(bio 9) and the minimum of soil water contents(swc_min). However, the most critical drivers convert forests into sloping farmland were the three months rainfall in summer(bio8) and the yearly mean of soil water contents. Such results reflect the growth period of crops which overlaps with the rainy season in North Korea and the recent land reclamation of uplands where the soil water contents are maintained with a dense forest. When South Korea aids forest restoration projects in North Korea, in consideration of food shortage due to North Korea's cropland deficiency, terrace farmlands where soil water contents can be maintained should be excluded from the priority restoration area. In addition, an evaluation method for selecting a potential restoration area must be modified and applied based on multiple criteria including altitude and socio-economic factors in the respective regions.

• 한국농공학회지
• /
• 제19권3호
• /
• pp.4449-4461
• /
• 1977

Subsurface Drinage Problems arise from many causes. Flatland tends to be poorly drained, particularly where the subsoil permeability is low. There are many wet areas, however, where there is no evident connection between the area of seepage, or a high water table, and the topography of the site. High water tables may occur where the soil is either slowly or rapidly permeable, where the climate is either humid or arid, and where the land is either sloping or flat. This study is to bring light on subjects relating to increasing yield of crop and possibility of double crops a year in water logging paddy fields. Obtained results are briefly summarized as follows: 1. Effect of crop-yield in the plot A resulted 20.2 percent higher than the ordinary plot with yield of brown rice. 2. Possibility of double-crops a year is investigated. Effect of the barley production of the test plot resulted 168.2 percent higher than the other uplands near test plot with the yield of 1977 production and it is 3.8 percent higher compare with the yearly yields. 3. Decreasing depth of water level was measured 23.9mm per day and 14.3mm per day at the test plot and ordinary plot respectively and the amounts of subsurface drainage measured 30mm to 35mm per day. It is required that the relief well should be controled carefully and adequately. 4. Mean depth of ground water levl was measured 0.4∼0.5m regardless the width of corrugated pipe. It is significantly lowere than the ordinary plot(0.15∼0.20m) 5. The ground temperature of the test plot is higher 1 degree of centigarade or more than the ordinary plot and soil moisture content of the ordinary plot is higher 12.4∼27.8 percent than the plot reversely. There should be a relationship between rising of ground temperature and soil moisture.

• 한국토양비료학회지
• /
• 제38권3호
• /
• pp.119-126
• /
• 2005

강원도 홍천군에 위치한 내린천 상류의 자운리는 석비레 성토지에서 대다수 영농활동을 하고 있어 강우에 의한 토양유실이 심각하게 발생하고 있다. 자운 2리와 4리의 농경지에 대해 필지별로 지료를 구축한 후 토양유실량을 RUSLE를 기준으로 평가하였으며, 허용토양유실량을 $11MT\;ha^{-1}\;yr^{-1}$로 보고, 그 이하로 낮추기 위한 최적영농관리방안을 살펴보았다. 조사결과, 토양관리가 불량하여 40% 이상의 경작지에 토양보전을 위한 적정관리가 필요한 것으로 나타났다. 관리방안의 적용이 없을 경우 발생하는 토양유실량은 자운 2리에서 평균 $15.6MT\;ha^{-1}\;yr^{-1}$, 자운 4리에서 평균 $9.0MT\;ha^{-1}\;yr^{-1}$ 이었으며, 석비레 성토지는 대부분 토양유실허용 수준을 초과하였다. 이 지역에 필요한 적정관리방안은 완충식생대, 등고선 및 부초, 승수로 및 배수로, 초생수로, 승수로, 우회수로, 사면정비, 그러고 피복작물 등이 제시되었으며, 이 지역에서 토양유실량을 허용수준 이하로 낮추기 위해 필지별로 필요한 영농관리방안의 필요량은 완충식생대 7,680 m, 등고선 및 부초 123 ha (35%), 승수로 및 배수로 201 ha (58%), 초생수로 13,880 m, 우회수로 3,860 m, 사변정비 8,365 m, 그리고 피복작물 3,492 ha (100%)인 것으로 평가되었다. 경사지 농경지의 적정관리방안의 도입은 우리나라와 같이 수계에 직접 연결된 밭이 많고 상류권에 위치하여 상수원에 영향이 우려되는 지역에서 특히 시급한 과제로 최적영농관리방안에 대한 깊은 연구와 작용이 이루어져야 하며 이러한 프로그램을 교육하고 지속적으로 감시하며 더 나은 관리방안을 찾아서 보완해 나가는 연구가 요구된다.

• 한국농공학회지
• /
• 제17권3호
• /
• pp.3860-3871
• /
• 1975

This experiment was carried out to establish the mechanized methods in stumping and root-clearing, which were the most important works in the reclamation of sloping uplands. The determination of optimum teeth interval of rake blades and its operation methods to reduce the quantity of transported topsoil during the works, are the aims of this investigation. A newly designed rake blade, whose net teeth intervals could be regulated by three stages as 15cm, 25cm, and 35cm, was manufactured to attach to the bulldozer of 13ton. The experiments were carried out at Kilsang-Myon, Kwangwha-Gun, from Aug. 9 to Aug. 23, 1975. For each interval, 36 test plots of 50${\times}$10mn in size, which were regulated under three levels of land slopes of 10, 20, and 30% and two different tree stand density of high or medium values, were randomly chosen and arranged by two-replicated split-split plot design. Each stump classified by its diameter was stumped and cleared by the rake dozer to be related between diameter and stumping time. The results obtained in this experiment can be summarized as follows: 1. Stumping times for the diameters ranging from 6 to 18cm of stumps are almost the same and they are not varied by the difference of teeth intervals of rake dozer. 2. By back-ward stumping method, the number of stumps which can be stumped per hour ranges almost from 100 to 170, showing significant difference with respect to the teeth intervals. The working area is sharply varied with not only the stand density of stumps but the teeth intervals. 3. Optimum stumping distance for each teeth interval of rake dozer to minimize the quantity of transported topsoil are varied with such the rates as it is 15m or 20m for 15cm of teeth interval, but 25m for 25cm or 35cm, respectively. The clearing distance could be chosen almost double as long as the operating distance. 4. The working areas per hour of the simultaneous stumping and clearing methods are no significant difference among the various treatments of working conditions, but they are affected by the operating techniques. However, the influencing factors of the working conditions as classified before and the working directions are ranged from 10 to 15 per cent of total working area, respectively. 5. The residual rates of stumps which are not stumped by the rake dozer in each test plot are generally reduced as the teeth interval gets narrower, but there are no significant difference among them. The mean residual rates average to be about 4% for the simultaneous stumping and clearing method. The back-ward stumping method are recommended to be supervised and directed by more than one man, to show the operator where the stumps are located. 6. The results according to the stumping and clearing methods are summarized as Table IV-2. And the selection of working methods is recommended to follow as shown in Fig. IV-9 with respect to the stand density of the field. 7. Generally speaking, the narrower the teeth interval, the better become the working results, but the more the quantity of transported topsoil is increased. Therefore, it is recommended that the teeth interval should be reduced from the present distance of more than 30cm to 25cm or 15cm, by developing suitable working methods through more field works and experiments.