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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 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 5×30 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.

The objective of this research was to experimentally test the effect of rice straw mats on the reduction of runoff, sediment discharge and turbidity under a laboratory scale. We used the small runoff plots of 1 m × 1 m × 0.65 m (L × W × H) in size filled with loamy sand. Experimental treatments were bare (control), rice straw mat cover of straw mats＋PAM＋Gypsum (SPG), rice straw mats＋ Chaff＋PAM＋Gypsum (SCPG) and rice straw mats＋Sawdust＋PAM＋Gypsum (SSPG); slope of 10 % or 20 %; and rainfall intensity of 30 mm/hr. Runoff volume and rate of covered plots were significantly lower than those of control plot. Average runoff rate of covered plots, slope of 10 % and 20 %, decreased 85.6 % and 72 % in respectively. Sediment reduction ratio was more than 99 % regardless of slope. The differences runoff and sediment discharge among different cover materials were not significant. It was also shown that even if runoff reduction by surface cover were low, sediment discharge reduction could be very significant and contribute to improve the water quality of streams in sloping agricultural regions. It was concluded that the use of straw mat and soil amendments (PAM and Gypsum) on sloping agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem in receiving waters. But mixing effect of PAM and Gypsum was minimal.