Search

Paddy fields comprise the single largest land use in Korea, occupying nearly 60% of arable land, consuming about 56% of the nation's water supply, and discharging a significant amount of agricultural non-point source (NPS) pollution to public waters. Rural water resources conservation, the improvement of irrigation water productivity (IWP) and the reduction of NPS pollution from paddy fields are important issues in Korea. To quantify the issue, a field-size rice-plot study was conducted for 3 years comparing the treatment of a system of rice intensification (SRI) irrigation management and a conventional practice (CT). The SRI reduced the irrigation requirement at field level by 50% compared to the CT. The IWP of the SRI improved by an average of 94% over that of the CT. The average reductions of the NPS pollutants by SRI was 44.4% (BOD), 38.6% (SS), 35.3% (CODMn), 28.3% (CODCr), 23.8% (TN) and 36.3% (TN). The SRI treatment was concluded to have contributed to healthy rice plant growth, improvement of IWP and reduction of agricultural NPS pollution from paddy fields, which could significantly conserve rural water resources and improve water quality in Korea. Copyright © 2016 John Wiley & Sons, Ltd.

A 2-year runoff plot study was conducted under simulated rainfall to explore the effects of no-till (NT) practice on the runoff ratio and NPS pollution in an intensive farming region of Korea. Eight 5 × 30 m runoff plots, four each on 3 and 8% slopes, were prepared in existing loamy sand fields. Cultivation in two plots on each slope followed conventional practice (CT). Six rainfall simulations were conducted during the study, each of a nominal 1 h duration and 30 mm h-1 intensity. The runoff ratio of the NT plots decreased 64.9% compared with that of the CT plots. The reduction of NPS pollution load by the NT treatment was 88.3% (SS), 79.0% (CODCr), 86.4% (CODMn), 66.4% (BOD), 67.6% (TN) and 73.6% (TP) compared to losses from the CT plots, with no reduction in average crop yield. Runoff reduction was a key factor in the reduction of pollution loads. The study demonstrated that agricultural NPS pollution loads can be significantly reduced by the application of no-till practice without harming crop productivity. Furthermore, NPS pollution loads can be controlled better if management practices are targeted for runoff reduction rather than concentration reduction. Copyright © 2016 John Wiley & Sons, Ltd.

We described the effects of straw mat cover and soil amendments on runoff, agricultural non-point source nNPS) pollution and crop yield on sloping alpine fields in Korea. Two sandy loam field plots were prepared. One was a control plot and the other (SPG) was an experimental plot treated with rice straw, polyacrylamide (PAM) and gypsum (rice straw mat (3,300 kg/ha) + PAM (5 kg/ha) + gypsum (1 ton/ha)). Chinese cabbage was cultivated in the plots and seven rainfall-runoff events were monitored during the growing season in 2012. Less runoff and a lower NPS pollution load were measured from the SPG plot, compared to those from the control plot. The SPG plot had 29.4% less runoff and the pollution load was reduced by 86.6% for suspended solids, 34.7% for total nitrogen and 39.1% for total phosphorus. The Chinese cabbage yield at the SPG plot was 39,600 kg/ha, which was about 40% higher than that at the control plot. These results indicated that the SPG treatment could not only reduce runoff and agricultural NPS pollution but also increase crop yield and be a best management practice for sandy loam sloping fields in Korea. © 2016 The Authors. Irrigation and Drainage Published by John wiley & Sons Ltd.

Sloping fields under intensive farming have been a major source of agricultural nonpoint source (NPS) pollution in Korea. Comprehensive studies to quantify edge-of-field water quality and measure surface mulch effects on NPS pollution discharge have been conducted over the past several years. Edge-of-field water quality was seriously degraded by NPS pollutants. The range of average event mean concentrations (EMCs) was suspended solids (SS) 547 ~ 2600 mg l−1, biochemical oxygen demand (BOD) 8.7 ~ 50.7 mg l−1, total nitrogen (TN) 3.5 ~ 21.8 mg l−1, and total phosphorus (TP) 2.4 ~ 13.1 mg l−1. Experiments treated by a rice straw mat mulch (S), S with gypsum (SG), and SG with PAM (SPG) showed good results as best management practices (BMPs) in controlling NPS pollution from sloping fields. The range of reductions by the treatments was runoff 28.3 ~ 96.7%, SS 71.5 ~ 99.5%, BOD 37.5 ~ 91.9%, TN 32.4 ~ 91.0%, and TP 43.0 ~ 95.7%. The SPG showed the best reduction effect for both runoff and NPS pollution. The S also showed encouraging results as a prospective BMP. Crop yields under the treatments also increased by up to 740% (lettuce) and 6.1 ~ 39.2% (cabbage and radish). The mulch treatments were proven to be effective for the increase of farm productivity and to improve runoff quality as well. Copyright © 2016 John Wiley & Sons, Ltd.

The objective of this paper was to quantit atively analyze the effect of concentrated animal feeding operations (CAFO) NPS pollu tion on a small watershe dwater quality. Monitoring was conducted from March to October, 2013. Monthly flow rate and selected water quality at each monitoring site were measured during dry days. Rainy day monitori ng also was conducted. Modeli ng was conducted to evaluate the effect of CAFO NPS po llution on the wate rquality at the watershed outlet. The highest and mean concentration of se lected water quality indices during rainy days were hi gher than those in dry daysin general. The highest TN concentration measured at the CAFP pollution discharge point was 237.831 mg/L. The results revealed that the CAFO NPSpollution sources could be equally blamed for the water quality degradation of the stream. However, the effect of the NPS pollut ion from CAFOs seeme dnot to be very influential to the watershed water quality at the outlet. SWAT modeling revealed that the TN load was reduced by 18.95 %, 23.39 % and30.53 % at the watershed outlet if the TN load at the CAFO NPS pollution discharge point reduced by 20 %, 40 % and 60 %, respec tively. It was though tthat the natural attenuation processes play ed an important role. The modeling was based only on the assumption of the load redu ction and not verified bythe monitored data. Therefore, it was suggested that a long term monitoring studies for the evaluation of the impact of CAFO NPS pollution on the watershed water quality be conducted.Keywords:Livestock; NPS Pollution; Pollution Load; SWAT*

Four actual cultivations were prepared and a variety of soybean was cultivated. A H-flume, an automatic water level gauge and an automatic water sampler were installed at the outlet of each plot equipped for the measurement of flow rate and its water quality. The amount of rainfall of the study area in 2013 was measured as 975.6 mm which was much lower than the annual average rainfall of 1,271.8 mm, resulting in less occurrences in rainfall-runoff events. Rainfall-runoff events were occurred three times during the rainfall event of 4~5 July, 23 and 24 August. The characteristics of NPS pollution discharge of the plots and the reduction effect of the selected BMPs were analyzed during these events. The reduction effect of straw mat and soil amendments (Polyacrylamide (PAM) and Gypsum) on runoff ratio ranged between 38.2 and 92.9% (average 71.6%). The NPS pollution load reduced between 27.7 and 95.1% (average 70.0%) by the application of rice straw mat and soil conditioner when compared with that of control plot. Soybean yield (2,133.3 kg/ha) of the straw mat covered plots increased by 14.3% when compared with control (1,866.7 kg/ha). The effect of straw mat on the yield was not economically viable if the material and accompanying labor costs were considered. The data collected and analyzed on different soil textures and crops in this study are expected to be a fundamental reference for the expansion of the results to the application nationwide and the development of NPS pollution management policies.

We investigated the effect of straw mat cover and soil amendments on the reduction of runoff, non-point source pollution load and yield of a Chinese cabbage from alpine fields. Two plots on sandy loam soil were prepared. Experimental treatments were control and rice straw mat cover (3,300 kg/ha)+Polyacrylamide (PAM) (5 kg/ha)+Gypsum (1 ton/ha) (SPG). A variety of Chinese cabbage was cultivated and runoff was monitored during a growing season in 2012. Monitoring was conducted to seven times. Runoff rate of SPG plot was lower than those of control plot. The reduction rate of runoff from SPG plot was 29.4 % compared to control plot. The reduction rate of suspended solids (SS), total nitrogen (TN) and total phosphorus (TP) load of SPG plot was 86.5 %, 34.7 % and 39.1 %, respectively. Yield of a Chinese cabbage from SPG plot (39,646 kg/ha) was greater than that of control plots (28,482 kg/ha). It was concluded that the use of SPG on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

This study was conducted to predict greenhouse gas (GHG) emission from paddy by future climate change scenario in Korea. Chuncheon city in Kangwon province were selected as study area. A1B Special Report on Emission Scenario (SRES) of the IPCC (Intergovernmental panel on climate change) was used to assess the future potential climate change. The rainfall and temperature was projected to increase by 8.4 % and 1.9 % (2040s), 35.9 % and 27.0 % (2060s), 19.2 % and 30.8 % (2090s), respectively, compare to the 2010s value. Under the climate change, Denitrification-Decomposition (DNDC) predicted an increase in , and emissions from paddy. The simulations resulted in annual net emissions of 0.4~2.4, 500.5~734.5 and 29.4~160.4 kg/ha/year of , and , respectively, with a cumulated global warming potential (GWP) of were affected by rainfall, temperature, manure amendment and fertilizer amount. The simulation results suggested that implementation of manure amendment or reduction of water consumption instead of increased fertilizer application rates would more efficiently mitigate GHG emissions.

A field experiment with a locally-bred Japonica rice cultivar was conducted in 2011 to measure the effect of paddy irrigation management in Korea on rice yield, water use, NPS pollution discharge, and greenhouse gas (GHG) emissions. Experimental treatments were conventional paddy cultivation (CT), CT with SRI water management (CS), CT with two forced mid-season drainages (CD), and SRI methods with two different transplant spacing (SRI-30, SRI-40). Each treatment was replicated. The rice yields, selected water quality indices of the irrigation and drainage water, and GHG emissions were measured and analyzed. Irrigation water was reduced by 49.4 and 47.6 % in the SRI and CS treatments, respectively, compared with the CT treatment. Reductions in non-point source (NPS) pollution load with SRI water management ranged from 16.5 to 53.9 % in the CS plots and from 27.1 to 46.0 % in the SRI plots, depending on the water quality indices measured. The GHG emissions from the CD and CS plots when converted to CO2 equivalents were reduced by 65.5 and 72.8 %, respectively, compared with emissions from the CT plots because CH4 reduction far exceeded the N2O increase from the CD and CS plots. The two highest polished rice yields were 6.47 and 6.34 ton/ha from the SRI-30 and CS plots, respectively; these represented 20 and 17 % increase over yields from the CT plots. Trial results indicate that SRI water management in Korean paddy farming could significantly decrease the paddy irrigation requirements and also discharges of NPS pollution and GHG emissions.

A feasibility study on the system of rice intensification (SRI) methods with respect to irrigation requirements, non-point source (NPS) pollution discharge, greenhouse gas (GHG) emissions and rice yields was conducted for either 2 or 3 years depending on the treatment in Korea. Large-size runoff plots were prepared, and the necessary measuring systems installed. The SRI methods were carried out with a Japonica variety of rice, Odaebyeo (Oryza sativa L.), and the results were compared with those for control plots. The data indicated the high potentiality of adoption of the SRI methods for paddy farming in Korea. The SRI methods (i.e. SRI and conventional practice with SRI water management (CS)) reduced the irrigation requirement by 50.2 and 46.0%, respectively. For the SRI and CS plots, averaged concentration reductions of typical NPS pollutants, relative to conventional practice (CT) plots, ranged between 15.3 and 42.6%. The GHG emissions from the conventional practice with two forced drainages (CD) and the CS plots, in terms of their CO2 equivalents, were reduced by 65.5 and 72.8%, respectively, compared with those from the CT plots. The rice yields from the SRI and the CS plots were not greater than those from the CT plots. Application of SRI water management methods could help to improve Korea's water resources and water quality management, and could thus contribute to mitigation of the negative effects of global warming. Copyright © 2014 John Wiley & Sons, Ltd.

The dilapidated windows in old buildings lead to not only energy loss but also condensation, which can cause damages to finish materials and structures, which can adversely affect the residential environment of residents. In the research, in order to prevent the occurrence of condensation, the airtightness performance improvement technology of window(Windbreak) and the thermal insulation performance improvement technology of window(Attached glazing) were selected. Then, these two technologies were applied to real old apartment houses for performance verification. TDR (Temperature Differential Ratio) was calculated by measuring the surface temperature of the window before and after the application of the two technologies, and the quantitative evaluation was performed by comparing the measured values. As a result, the condensation prevention performance was enhanced by about 17.69% result for the installation of the attached glazing and the windbreak. Especially, it was more effective in the lower part of the glazing where condensations mainly occurs.

The objective of the research was to describe the effect of straw mat cover and soil amendments on the reduction of runoff and non-point source load from steep sloped highland agricultural fields. Four m plots on sandy loam soil with 28 % slope were prepared. Experimental treatments were bare (control), rice straw mat cover (3,000 kg/ha) (S), PAM (5 kg/ha)+Gypsum (1 ton/ha) (PG) and rice straw mat cover+PAM+Gypsum (SPG). A variety of lettuce was cultivated and runoff was monitored during a growing season in 2011. Natural monitoring was conducted to three times. Runoff rate of S, PG and SPG plots were significantly lower than those of control plot. Especially, the runoff rate is zero in SPG plot at a first rainfall events. The reduction rate of runoff from the S, PG and SPG plots was 30.8 %, 29.0 % and 81.8 % compared to control plots, respectively. The reduction rate of NPS pollution load of S, PG and SPG was ranged of 50~90 %, 30~70 % and 90~100 %, respectively. Yield of lettuce from S, PG and SPG plots was respectively 400 (567 kg/ha), 320 (453 kg/ha) and 760 (1,067 kg/ha) that of compared to control plots greater than that from control plots (140 kg/ha). We speculated that the experimental treated plots could hold more nutrients and moisture than the control and helped the crop grow healthier. When analyzing the above results, in terms of reduction of runoff and NPS pollution load and crop yields, SPG experimental treatment had the best effect. It was concluded that the use of rice straw mats cover and soil amendments on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.