• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.1
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• pp.2925-2933
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• 1973

For the efficient utilization of farm machines on the inclined uqland, work performance in plowing, harrowing and terracing and critical workable gradients were tested on three farm machines which are 47 ps-farm tractor, 8 ps-power tiller and 5 ps-power tiller. The results of this study are summarized as follows; 1) The steeper the slope of the upland was the more inefficient the work performance of all machines was. 2) The critical workable gradients of the machines were proved as 14 for 47 ps-farm tractor, 12 for 8 ps-power tiller and 10 for 5ps-power tiller. 3) Plowing in the way of turning the furrow slices against the slope in order to build up terraces, the critical workable gradients were 8 for 47 ps-farm tractor and 8 ps-power tiller and 6 for 5 ps-power tiller. 4) Two-way plow is recommended for plowing with farm tractor on inclined upland, and high lug of tire would be good to prevent the slippage, and side valance-weight should be attached to power tiller for preventing its overturning.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.435-449
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• 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 Korean Society on Water Environment
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• v.25 no.1
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• pp.102-111
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• 2009

Turbid storm runoff from intensive highland agriculture area has emerged as the major problem of water quality deterioration in the upstream region of the Han River. High slope of the upland combined with high rate of fertilization and intensive plowing causes high rate of soil erosion, and subsequently high suspended sediment and phosphorus content in the runoff water. The variations of water quality during rain spells were surveyed for two years (2005 and 2006) in the Jawoon Stream that is one of hot spots of intensive horticulture discharging turbid storm runoff. SS and TP showed large increase according to the increase of flow rate, whereas TN and BOD showed less fluctuations. Mean EMCs of SS and TP measured for nine rain events were as high as $207mgSS{\cdot}L^{-1}$ and $0.27mgP{\cdot}L^{-1}$, respectively. The export coefficient of SS and TP per area of cultivated field were calculated as $11,912kgSS{\cdot}yr^{-1}{\cdot}km^{-2}$ and $785kgP{\cdot}yr^{-1}{\cdot}km^{-2}$, repectively, which are significantly higher than reports of other area. It can be concluded that SS and TP in the runoffs were high enough to impose major threat to aquatic habitats, and the highland agriculture should be the main target of water quality management or habitat conservation in the study area.

• Journal of Biosystems Engineering
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• v.39 no.1
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• pp.1-10
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• 2014

Purpose: This research was conducted to evaluate feasibility of a crank-type walking cultivators for weeding in furrowed upland. Methods: A walking cultivator developed by RDA was selected and evaluated with its working speed (S), cultivation depth (CD) and weeding performance (WP). The evaluation was performed in upland field on July and August, 2012. Also kinematic analysis of the machine was performed to draw out design improvements. Results: S in flat, uphill and downhill were about 0.11 m $s^{-1}$, 0.11 m $s^{-1}$, and 0.13 m $s^{-1}$ respectively. It was found that S had a low relevance with user conditions. The CD was 35 ~ 40 mm which was satisfied with the RDA guide for weeding machine. A wide variation was observed in values of WP depending on the growth stages of weeds and field conditions. The cultivator showed low performance in eliminating the well-grown weeds. Kinematic simulation revealed that high forward speed caused a high ratio of un-weeded area. Conclusions: The weeding performance of the cultivator was satisfactory for weeds in early growth stage but it showed difficulties in handling on up-slope and in entering up-land. Specifically, the weight of the cultivator was judged as overweight for female workers. The crank-hoe type cultivator was judged as unsuitable for small walking type machine due to weight of the four-bar linkage system. Kinematic analysis revealed that the ratio of crank speed to the ground speed must be 850 rpm s $m^{-1}$ (255 rpm based on 0.3 m $s^{-1}$) or greater to avoid uncultivated area. Selection of forward speed is a decisive factor in designing the weeding cultivator.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.9-16
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• 2011

Curve Numbers (CN) for the combination of land use and hydrologic soil group were regionalized at Imha Watershed using Long-term Hydrologic Impact Assessment (L-THIA) coupled with SCE-UA. The L-THIA was calibrated during 1991-2000 and validated during 2001-2007 using monthly observed direct runoff data. The Nash-Sutcliffe (NS) coefficients for calibration and validation were 0.91 and 0.93, respectively, and showed high model efficiency. Based on the criteria of model calibration, both calibration and validation represented 'very good' fit with observe data. The spatial distribution of direct surface runoff by L-THIA represented runoff from Thiessen pologen at Subi and Sukbo rain gage station much higher than other area due to the combination of poor hydrologic condition (hydrologic soil C and D group) and locality heavy rainfall. As a results of hydrologic condition and treatment for land use type based on calibrated CNs, forest is recommended to be hydrologically modelled dived into deciduous, coniferous, and mixed forest due to the hydrological difference. The CNs for forest and upland showed the poor hydrologic condition. The steep slope of forest and alpine agricultural field make high runoff rate which is the poor hydrologic condition because CN method can not consider field slope. L-THIA linded with SCE-UA could generated a regionalized CNs for land use type with minimized time and effort, and maximized model's accuracy.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.3
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• pp.33-43
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• 2022

South Korea's agricultural nitrogen balance and phosphorus balance rank first and second, respectively, among OECD countries, and proper nutrient management is required to preserve the water quality of rivers and lakes. This study evaluates the effects of furrow mulching on the reduction of non-point source pollution (NPS) load from a sloped upland. The study site was Wanju-gun, Jeollabuk-do, and the survey period was from 2018 to 2019. The slope of the testbed was 13%, and the soil type was sandy loam. The cropping system consisted of maize-autumn Chinese cabbage rotation. The testbed was composed of bare soil (bare), control (Cont.), furrow vegetation mulching (FVM), and furrow nonwoven fabric mulching (FFM) plots. Runoff was collected for each rainfall event with a 1/100 sampler, and the NPS load was calculated by measuring the concentrations of SS, T-N, and T-P. The NPS load was then analyzed for the entire monitoring and crop cultivation periods. During the monitoring period, the effect of reducing the NPS load was 1.5%~44.5% for FVM and 13.1%~55.2% for FFM. During the crop cultivation period, it was 1.2%~80.5% for FVM and 27.0%~65.1% for FFM, indicating that FFM was more effective than FVM. As the NPS load was fairly high during the crop conversion period, an appropriate management method needs to be implemented during this period.

• Journal of Environmental Impact Assessment
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• v.15 no.1
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• pp.1-12
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• 2006

Changes in the soil physical property and the topographic condition derived from agricultural activities like as farming activities, land clearance and cutting down resulted in environmental and economic problems including the outflow of nutrient from farms and the water pollution. Several theories on the soil conservation have been developed and reviewed to protect soil erosion in the regions having a high risk of erosion. This study was done using the USLE model developed by Wischmeier and Smith (1978), and model for the slope length and steepness made by Desmet and Govers (1996), and Nearing (1997) to evaluate the potential of the soil erodibility. Therefore, several results were obtained as follows. First, factors affecting the soil erosion based on the USLE could be extracted to examine the erosion potential in farms. Soil erodibility (K), slope length (L), and slope steepness (S) were used as main factors in the USLE in consideration of the soil, not by the land use or land cover. Second, the soil erodibility increased in paddy soils where it is low in soil content, and the very fine sandy loam exists. Analysis of the slope length showed that the value of a flat ground was 1, and the maximum value was 9.17 appearing on the steep mountain. Soil erodibility showed positive relationship to a slope. Third, the potential soil erodibility index (PSEI) showed that it is high in the PSEI of the areas of steep upland and orchard on the slope of mountainous region around Dokjigol mountain, Dunji mountain, and Deummit mountain. And the PSEI in the same land cover was different depending on the slope rather than on the physical properties in soil. Forth, the analysis of land suitability in soil erosion explained that study area had 3,672.35ha showing the suitable land, 390.88ha for the proper land, and 216.54ha for the unsuitable land. For unsuitable land, 8.71ha and 6.29ha were shown in fallow uplands and single cropping uplands, respectively.

• Journal of Biosystems Engineering
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• v.3 no.1
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• pp.1-19
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• 1978

Power tiller is a major unit of agricultural machinery being used on farms in Korea. About 180.000 units are introduced by 1977 and the demand for power tiller is continuously increasing as the farm mechanization progress. Major farming operations done by power tiller are the tillage, pumping, spraying, threshing, and hauling by exchanging the corresponding implements. In addition to their use on a relatively mild slope ground at present, it is also expected that many of power tillers could be operated on much inclined land to be developed by upland enlargement programmed. Therefore, research should be undertaken to solve many problems related to an effective untilization of power tillers on slope ground. The major objective of this study was to find out the travelling and tractive characteristics of power tillers being operated on general slope ground.In order to find out the critical travelling velocity and stability limit of slope ground for the side sliding and the dynamic side overturn of the tiller and tiller-trailer system, the mathematical model was developed based on a simplified physical model. The results analyzed through the model may be summarized as follows; (1) In case of no collision with an obstacle on ground, the equation of the dynamic side overturn developed was: $$\sum_n^{i=1}W_ia_s(cos\alpha cos\phi-{\frac {C_1V^2sin\phi}{gRcos\beta})-I_{AB}\frac {v^2}{Rr}}=0$$ In case of collision with an obstacle on ground, the equation was: $$\sum_n^{i=1}W_ia_s\{cos\alpha(1-sin\phi_1)-{\frac {C_1V^2sin\phi}{gRcos\beta}\}-\frac {1}{2}I_{TP} \( {\frac {2kV_2} {d_1+d_2}\)-I_{AB}{\frac{V^2}{Rr}} \( \frac {\pi}{2}-\frac {\pi}{180}\phi_2 \} = 0 $$ (2) As the angle of steering direction was increased, the critical travelling veloc\ulcornerities of side sliding and dynamic side overturn were decreased. (3) The critical travelling velocity was influenced by both the side slope angle .and the direct angle. In case of no collision with an obstacle, the critical velocity $V_c$ was 2.76-4.83m/sec at $\alpha=0^\circ$, $\beta=20^\circ$ ; and in case of collision with an obstacle, the critical velocity $V_{cc}$ was 1.39-1.5m/sec at $\alpha=0^\circ$, $\beta=20^\circ$ (4) In case of no collision with an obstacle, the dynamic side overturn was stimu\ulcornerlated by the carrying load but in case of collision with an obstacle, the danger of the dynamic side overturn was decreased by the carrying load. (5) When the system travels downward with the first set of high speed the limit {)f slope angle of side sliding was $\beta=5^\circ-10^\circ$ and when travels upward with the first set of high speed, the limit of angle of side sliding was $\beta=10^\circ-17.4^\circ$ (6) In case of running downward with the first set of high speed and collision with an obstacle, the limit of slope angle of the dynamic side overturn was = $12^\circ-17^\circ$ and in case of running upward with the first set of high speed and collision <>f upper wheels with an obstacle, the limit of slope angle of dynamic side overturn collision of upper wheels against an obstacle was $\beta=22^\circ-33^\circ$ at $\alpha=0^\circ -17.4^\circ$, respectively. (7) In case of running up and downward with the first set of high speed and no collision with an obstacle, the limit of slope angle of dynamic side overturn was $\beta=30^\circ-35^\circ$ (8) When the power tiller without implement attached travels up and down on the general slope ground with first set of high speed, the limit of slope angle of dynamic side overturn was $\beta=32^\circ-39^\circ$ in case of no collision with an obstacle, and $\beta=11^\circ-22^\circ$ in case of collision with an obstacle, respectively.

• Journal of Environmental Impact Assessment
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• v.15 no.1
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• pp.53-65
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• 2006

Topographic condition is one of the most important things in farming activities. The topographic condition didn't matter for farming in the past because agricultural products had competitive power in the market. So farmers tried to extend their farms without any concern of topographic condition. We need less labor-consuming farming as industrial structure has been changed and the competitive power of the farming has been getting weak. This study analyzed the fallow potential in agricultural area by topographic condition so that we have got results as follows. Maps of elevation, slope, distance from roads and water resources were made for getting a fallow probability model in farms, and these 4 factors were used as independent variables while a variable on whether it is fallow or not is a dependent variable in logistic regression model. In an analysis of the fallow potential depending on farm land types, the fallow probability in fallow orchard showed the highest value of farm lands, 0.973. Cultivated orchard had 0.730 and upland had 0.616 of the fallow probability. The fields having high fallow potential had high elevation, steep slope, and long distance from water resources and roads. Especially, fields having a probability over 0.99 appeared in orchards, fallow uplands and single cropping uplands, which were recognized to have several disadvantages related to the fallow like as high elevation, steep slope, and long distance from water resources and roads. With the logistic analysis, the suitable farm lands appeared at 16.45m of the mean elevation, 1.89 degree of the mean slope, 39.91m of the average distance from water resources, and 32.39m of the average distance from roads. On the contrary, non-suitable land appeared at 114.7m of the mean elevation, 24.9 degree of the mean slope. The distance from roads was more important variable than the distance from water resources for analyzing suitable farm land.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.17-21
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• 1974

This study was performed to find out the organic matter content, and what is more, the relation between its content and major morphological properties of cultivated upland soils in Korea. The results were as follows. 1. The average organic matter content of cultivated upland soils was 1.73 percent, mostly ranging from 0.6 to 2.5 percent. 2. Examining the organic matter content by subgroup of cultivated upland soils. It was found 13 percent in volcanic ash yellowish brown Cambisols and 6.3 percent in Humic yellowish brown Entisols, Fluventic yellowish brown Entisols was found 1.0 percent, lowest one. The average organic matter content of Entisols, Cambisols, and Argillisols was 1.1, 2.1, and 1.8 percent respectively. 3. According to organic matter content by texture of profile, the average content of sandy soils was 1.0 percent; 1.5 percent in coarse loamy soils; and 1.8 percent in fine loamy soils. The organic matter content increased with an increased clay content in coarse texture group, but there was no significant difference between fine loamy and clayey soil group. This tendency was also observed in surface soil texture. 4. In the relation between slope and organic matter content, its content in flat area was 1.3 percent that is rather low compared to 1.6 percent of sloping area. Especially, cultivated upland soils ranging brown 15 to 30 percent in slope were 1.8 percent which is relatively high. 5. The organic matter content have nothing to do with suitability groups. Itss ontent of I, II, III, IV and V class was 1.3, 1.6, 1.7, 1.2 and 2.0 percent respectively.