Effect of straw mulch on runoffand NPS pollution reduction from experimental plots under a climate change scenario in Korea

This study attempted to quantify the effects of rice straw mulches on runoffand nonpoint source (NPS) pollution under a future climate change scenario. For this, regression equations between the observed rainfall and runoffcurve number (CN) were developed to estimate NPS pollution from radish fields. Rainfall data from the special report on emissions scenarios (SRES) A1B were applied to the regression equations in order to predict future runoffand NPS pollution by surface covers. The results show that future rainfall was estimated to increase by 0.8% in the 2020s, 14.4% in the 2050s, and 15.1% in the 2080s. Under the projected rainfall conditions, the loose straw and the straw mat mulches were estimated to reduce runoffby 65.7 to 66.8% and 95.8 to 96.9%, respectively, while the selected pollutants were reduced by 44.1 to 98.8% and 58.9 to 94.9%, respectively. Both types of straw mulch were effective in controlling both runoffand NPS pollution, and thus offer a very promising means to cope with the effect of climate change such as flood, drought, and water quality conservation. Similar studies should be conducted on a wide range of crops, soils, and rainfall conditions to better estimate the effectiveness of mulches more broadly and to assist in the development of national NPS pollution management strategies with respect to expected changes in climate.