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| Effects of straw mulch on surface runoff hydraulic characteristics of dried and wetted red soil |
| Liu Liusong1,2,Shi Xuezheng1,2,Yu Dongsheng1,2,Wang Hongjie1,Ren Hongyan1,Sun Weixia1,Zhang Liming1,3 |
| 1.State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,210008,Nanjing;2.Graduate School of the Chinese Academy of Sciences,100049,Beijing;3.College of Resources and Environmental Sciences,Nanjing Agricultural University,210095,Nanjing: China |
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Abstract Mulching soil surface with a layer of plant residue is an effective method for conserving water and soil.A laboratory experiment was conducted to evaluate the effects of antecedent moisture content(AMC) and straw mulch on surface runoff hydraulic characteristics using rainfall simulator.The rainfall simulator was used to create rainfall intensity of 60 mm/h for 1 h.The study site was located at the Ecological Experimental Research Station of Red Soil,Chinese Academy of Sciences,in Yujiang County,Jiangxi Province of China.The soil used in this study was red soil derived from quaternary red clay.The runoff plot was 12 m in length and 3 m in width with a slope of 14%.Antecedent moisture content levels(dried,wetted) and percentage of straw mulch(0,15%,30%,60% and 90%) were considered as two independent variables in this experiment design.The results showed that straw mulch affected the velocity and Manning coefficient significantly.The velocity decreased quickly with increasing the mulch in the range of 0 and 30%,and decreased slowly with increasing the mulch in the range of 30% and 90%.The runoff velocity of wet soil was larger than that of dry soil under the same mulch rate,especially with the mulch rate of 0,15% and 30%.The Manning coefficient increased quickly with increasing the mulch in the range from 0 to 30%,and changed slowly with increasing the mulch in the range from 30% to 90%. The Manning coefficient of the dried soil were larger than that of wetted soils between the mulch rate of 0 and 30%,and were smaller between the mulch rate of 30% and 90%.By reduced the velocity and increased the Manning coefficient,the straw mulch could protect the soil and water from erosion.The mulch rate of 30% could have the best effect of soil and water conservation from the view of the economy.
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Received: 26 February 2009
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