• 한국농공학회논문집
• /
• 제50권2호
• /
• pp.11-16
• /
• 2008

The effects of water and pesticide management practices on ponded water pesticide concentrations in a paddy plot were analysed using the RICEWQ model. The molinate which is a herbicide widely used in rice culture, and frequently detected in paddy environment was selected. In a previous study, the RICEWQ model was successfully calibrated with field data obtained from a paddy plot in Daegu. The calibrated model was run using water and pesticide management scenarios with a set of measured meteorological data for 1997-2006 in Daegu. For all three ponded water depths with the label rate application, the amount of molinate dissipated in ponded water and volatilized accounted for more than 70%, and the runoff losses were less than 9%. The molinate losses through drainage in the very shallow ponded depth showed 40% less than that in deep ponded depth. Comparing with the deep and shallow ponded depth, the very shallow depth was the best with regards to the reduction of molinate runoff losses. Simulations with different pesticide application rates, label rate and double label rate, showed molinate concentrations in the ponded water increased linearly with the application rate increase.

• 한국농공학회논문집
• /
• 제57권5호
• /
• pp.129-137
• /
• 2015

The objective of this study was to test the non-point source pollution (NPS) control by the vegetated ridge and silt fence through field monitoring. The experiment plots were established with three sizes which are 5 m width by 22 m length with 8 %, 3 % slope and 15m width by 15 m length with 6 % slope. Flumes with the floating type stage gages were installed at the outlet of each plot to monitor the runoff. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Water quality samples were monitored during the heavy rainfall occurred. The amount of rainfall from 4 monitored events ranged from 27.6 mm to 130 mm. The runoff reduction rate could vary depending on slope, soil, crop growth condition, rainfall amount, rainfall intensity, antecedent moisture condition, and many other factors. The runoff from vegetated ridge and silt fence treatment plots was 24.05 % and -8.28 % lower than that from control plot, respectively. The monitoring results showed that the average pollution loads reduced by vegetated ridge compared to control were BOD 36.62~53.60 %, SS 40.41~73.71 %, COD 39.34~56.41 %, DOC 49.08~53.67 %, TN 26.74~67.23 %, and TP 52.72~91.80 %; by silt fence compared to control were SS 41.73 %, COD 1.93 %, and TN 2.38 %. The paired t-test result indicated that the vegetated ridge and silt fence were statistically significant effect in SS load reduction, with a 5 % significant level. Monitored results indicated that vegetated ridge and silt fence were both effective to reduce the pollutant from the field surface runoff.

• 한국토양비료학회지
• /
• 제43권1호
• /
• pp.36-43
• /
• 2010

충남 공주 팔봉산 남쪽 측면에 위치한 3년간 배나무가 식재된 구릉성 침식포장에서 유거와 침식의 변화를 (1)Glyphosate 처리 (2) paraquat 처리의 두 가지 서로 다른 제초관리 형태하에서 조사하였다. 조사지의 경사도는 5.5% ~ 10.2%, 고도 125 m이며 조사면적은 896 $m^2$ ($28m{\times}32m$)였다. 2006년에서 2008년 사이 총강우사상은 각각 47, 52, 52회였다. 전체 강우사상 중 일 강우량이 20 mm보다 적은 날은 전체 강우일수의 약 65%를 차지하였다. 평형상태에서 침투율은 지표면의 잡초가 모두 제거된 나지에서 일반적으로 증가하였으며, 제초제처리구와 대조구에서는 감소하였다. 모든 대조구에서 유거는 제초제처리구와 나지구보다 항시 낮았다. 동일 강우강도에서 유거는 대조구, glyposate 처리구, paraquat 처리구 glyposate-처리 나지구 순으로 증가하였다. 높은 강우강도하에서 처리구가간 유거의 차이는 1년차에서 가장 높았다. 조사 기간 3년간 토양손실은 각각 달랐다. 미세입자 손실이 조립질보다 높았으나 토양손실은 유거나 총강우량과 상관성은 없는 것으로 조사되었다. 동일 강우강도하에서 토양침식율은 대조구, glyposate 처리구, paraquat 처리구 glyposate-처리 나지구 순으로 증가하였다. 상대적으로 30 mm 이하의 강우강도하에서는 조사구간 제초제 처리 여부 상관성이 거의 없었다. 이는 토양침식은 강우강도에 의존한다는 것을 의미한다.

• 한국토양비료학회지
• /
• 제34권3호
• /
• pp.158-164
• /
• 2001

밭토양에 돈분이 시용되었을 때 토양에서 유실되는 유거수에 의한 질산태질소의 유거손실을 구명하기 위하여 본 연구를 실시하였다. 경사가 4% 정도 되는 밭토양에 나지와 옥수수 재배조건 하에서 돈분을 무처리, 50, $100ton\;ha^{-1}$ 수준으로 처리하고 유거수 중에 질산태질소 유거량을 조사한 결과는 다음과 같다. 유거수량은 강우량이 많을수록 증가하였으나 돈분시용량이 증가할수록 유거수량은 감소하였다. 유거수 중에 질산태질소의 농도는 옥수수 재배조건에서 높았는데 같은 처리 조건에서 나지에서의 유거수 중에 질산태질소 농도에 비하여 86.9, 42.9,33.6% 가 높았다. 질산태질소의 총유거 손실량은 나지구에서 높았으며 처리 수준별 유거량은 $1.34{\sim}3.15kg\;NO_3-N\;ha^{-1}$ 였다. 유거수 중에 양이온들의 농도는 K> Mg> Na> Ca 순이었다.

• 한국농공학회논문집
• /
• 제54권4호
• /
• pp.65-71
• /
• 2012

The objective of this study was to estimate surface runoff from rice paddy plots using an artificial neural network (ANN). A field experiment with three treatment levels was conducted in the NICS saemangum experimental field located in Iksan, Korea. The ANN model with the optimal network architectures, named Paddy1901 with 19 input nodes, 1 hidden layer with 16 neurons nodes, and 1 output node, was adopted to predict surface runoff from the plots. The model consisted of 7 parameters of precipitation, irrigation rate, ponding depth, average temperature, relative humidity, wind speed, and solar radiation on the daily basis. Daily runoff, as the target simulation value, was computed using a water balance equation. The field data collected in 2011 were used for training and validation of the model. The model was trained based on the error back propagation algorithm with sigmoid activation function. Simulation results for the independent training and testing data series showed that the model can perform well in simulating surface runoff from the study plots. The developed model has a main advantage that there is no requirement for any prior assumptions regarding the processes involved. ANN model thus can be a good tool to predict surface runoff from rice paddy fields.

• 한국농공학회논문집
• /
• 제46권2호
• /
• pp.107-114
• /
• 2004

NPS pollutant loads from sandy clayey and clayey loam runoff plots were measured. Runoff plots were 2$\times$10 m in size and 8~10% in slope and paddy area was 4,620 $m^2$. Soybean, corn, tobacco and control (natural weed) were cultured. Precipitation during the growing season of June to October, 2002 was 869.5 mm. Runoff and water quality were measured more than 10 times during the measurements depending on the growing stage. Pollutants loads were estimated by using respective concentration and runoff volume. Runoff occurred when daily rainfall exceeded about 30 mm. The largest runoff was observed from the paddy but pollutant loads were larger from upland crops than those from paddy. SS loads from paddy and upland were 1.4 ton/ha/yr and 3.1~4.3 ton/ha/yr, respectively. COD loads 30 kg/ha/yr and 66~90 kg/ha/yr, T-N loads 13 kg/ha/yr and 14~23 kg/ha/yr, T-P loads 1 kg/ha/yr와 4 kg/ha/yr, nitrate nitrogen loads 1 kg/ha/yr and 4~8 kg/ha/yr, and phosphate phosphorus loads 0 kg/ha/yr and 4~6 kg/ha/yr, respectively. It was concluded that NPS pollutant loads from upland crop culture have greater impact on the quality of the receiving water body than those from paddy culture.

• 한국토양비료학회지
• /
• 제43권3호
• /
• pp.260-267
• /
• 2010

As sloped farmland is subject to runoff and soil erosion and consequently require appropriate vegetative coverage to conserve soil and water, a field study was carried out to evaluate the impact of crop canopy coverage on soil loss and runoff from the experimental plot with three different textural types (clay loam, loam, and sandy loam). The runoff and soil loss were examined at lysimeters with 15% slope, 5 m in length, and 2 m in width for five months from May to September 2009 in Suwon ($37^{\circ}$ 16' 42.67" N, $126^{\circ}$ 59' 0.11" E). Red pepper (Capsicum annum L. cv. Daechon) seedlings were transplanted on three different dates, May 4 (RP1), 15 (RP2), and 25 (RP3) to check vegetation coverage. During the experimental period, the vegetation coverage and plant height were measured at 7 day-intervals and then the 'canopy cover subfactor' (an inverse of vegetation cover) was subsequently calculated. After each rainfall ceased, the amounts of soil loss and runoff were measured from each plot. Under rainfall events >100 mm, both soil loss and runoff ratio increased with increasing canopy cover subfactor ($R^2$=0.35, p<0.01, $R^2$=0.09, p<0.1), indicating that as vegetation cover increases, the amount of soil loss and runoff reduces. However, the soil loss and runoff were depending on the soil texture and rainfall intensity (i. e., $EI_{30}$). The red pepper canopy cover subfactor was more highly correlated with soil loss in clay loam ($R^2$=0.83, p<0.001) than in sandy loam ($R^2$=0.48, p<0.05) and loam ($R^2$=0.43, p<0.1) plots. However, the runoff ratio was effectively mitigated by the canopy coverage under the rainfall only with $EI_{30}$<1000 MJ mm $ha^{-1}hr^{-1}$ ($R^2$=0.34, p<0.05). Therefore, this result suggested that soil loss from the red pepper field could be reduced by adjusting seedling transplanting dates, but it was also affected by the various soil textures and $EI_{30}$.

• 한국농공학회지
• /
• 제11권3호
• /
• pp.1719-1723
• /
• 1969

In this country, farmers lay out furrows in the direction which is considered by their own judgement to be convenient for cultivation without paying much attention for soil erosion. The direction of furrow has considerable effects on soil and water losses. In this experiment, it is intedned to observe the differences of soil and water losses in different directions of furrows of sloped fields so that the results thus obtained could be informed to farmers who should be careful in determining furrow direction for soil erosion control. Some the major experimental results are summarized as follows: The direction of furrows did not affect so much on the runoffs in a gentle slope, as the runoff is 509 ton/10a in the contouring plot, $51^{\circ}$/ton/10a in the 45-degree plot, and 560 ton/10a in the up-and-down hill plot. The contouring plot among the three plots had best effect on soil conservation, as the soil losses are 5.8 ton/10a in the contouring plot, 9.3 ton/10a in the 45 degree plot, and 10.2 ton/10a in the up-and-down hill plot.

• 한국환경복원기술학회지
• /
• 제18권3호
• /
• pp.13-22
• /
• 2015

Unpaved forest roads are common accessways in mountain areas being used for forestry purposes. The presence of forest roads produces large volumes of surface runoff and sediment yield due to changes in soil properties and hillslope profile. Rainfall simulation experiments were conducted to estimate the impacts of above-ground vegetation and antecedent soil water condition on hydrology and sediment processes. A total of 9 small plots($1m{\times}0.5m$) were installed to represent different road surface conditions: no-vegetation(3 plots), vegetated surface(3 plots), and cleared vegetation surface(3 plots). Experiments were carried out on dry, wet, and very wet soil moisture conditions for each plot. Above ground parts of vegetation on road surface influenced significantly on surface runoff. Runoff from no-vegetation roads(39.24L) was greater than that from vegetated(25.05L), while cleared-vegetation condition is similar to no-vegetation roads(39.72L). Runoff rate responded in a similar way to runoff volume. Soil erosion was also controlled by land cover, but the magnitude is little than that of surface runoff. Even though slight differences among antecedent soil moisture conditions were found on both runoff and soil erosion, runoff rate and soil losses were increased in very wet condition, followed by wet condition. The experiments suggest that vegetation cover on forest road surface seems most effective way to reduce surface runoff and soil erosion during storm periods.

• 한국산림과학회지
• /
• 제31권1호
• /
• pp.43-47
• /
• 1976

본시험(本試驗)은 저사저수구(貯砂貯水溝)의 유토저지효과(流土沮止効果)를 구명(究明)키 위하여 실시(實施)되었다. 10개(個)의 저사저수구(貯砂貯水溝)가 $50m^2$크기의 시험구내(試驗區內)에 등고선(等高線) 방향(方向)으로 설치(設置)되었다. 저사저수구(貯砂貯水溝)의 크기는 2종류(種類)로서 하나는 폭(幅)$30cm{\times}$장(長)$100cm{\times}$심(深)30cm이고 다른 것은 폭(幅$30cm{\times}$장(長)$100cm{\times}$심(深)20cm였다. 1. 저사저수구(貯砂貯水溝)는 유토저지효과(流土沮止効果)가 매우 높아서 대조구(對照區)는 저사저수구설치구(貯砂貯水溝設置區)보다 2.3~2.6배(倍)의 높은 유토량(流土量)을 나타내었다. 2. 30cm깊이 저사저수구(貯砂貯水溝)와 20cm깊이 저사저수구간(貯砂貯水溝間)에는 차이(差異)가 없었다. 3. 저사저수구(貯砂貯水溝)는 식생(植生)의 피복도(被覆度), 생립본수(生立本數) 및 생장(生長)에는 아무런 영향(影響)을 주지 못했다. 4. 경사여지(傾斜餘地)가 중경사지(中傾斜地)와 완경사지(緩傾斜地)에 비(比)해 식생(植生)의 피복도(被覆度), 생장(生長) 및 생장량(生長量)에 있어서 저조(低調)한 결과(結果)를 보여 주었다.