大豆调节坡耕地径流和泥沙作用研究

黄土高原地区坡耕地面积占该区总耕地面积的75%,产生严重的水土流失,治理坡耕地水土流失对该地农业生产和生态环境建设具有重大意义。大豆是黄土高原坡耕地的重要作物,然而,目前对于大豆在该地区调节径流和泥沙的能力还缺乏深入了解。以种植大豆的坡耕地为研究对象,研究在不同坡度和不同降雨强度下大豆调节径流和泥沙能力。试验设计包括大豆的5个生育期(幼苗期、始花期、盛花期、结荚期和始粒期),5个坡度(3°,5°,10°,15°,20°)和2个降雨强度(40,80 mm/h)。将大豆调节径流和泥沙的作用分为2部分:减少产流和减少产沙。采用产流时间、降雨初损量、径流量、产沙量、减流效益(RRB)和减沙效益(SRB)6个指标进行综合对比分析。结果表明:大豆在调节径流和泥沙方面作用显著。与裸地相比,大豆从幼苗期到始粒期,坡面径流量减少10.75%~64.94%,产沙量减少15.38%~84.24%。大豆的RRB和SRB值从整个生育期来看整体均呈增大趋势,且均与坡度成反比。同样,随着降雨强度增加,大豆的RRB和SRB略有降低且差异不显著,并且SRB值始终大于RRB值,因此发现大豆在减少泥沙方面比减少径流更有效。综上,黄土高原坡耕地上种植大豆对坡耕地土壤侵蚀具有积极的作用,并且对泥沙的拦截作用强于对径流的拦蓄作用。

Regulation Effect of Soybean on Runoff and Sedimenton Sloping Farmland

The sloping farmland in the Loess Plateau accounts for 75% of the total cultivated land area in the region, resulting in serious soil erosion. It is of great significance for agricultural production and ecological environment construction to control the soil erosion of sloping farmland. Soybean is an important crop on sloping farmland in the Loess Plateau. However, at present,the ability of soybean to regulate runoff and sediment in this area needs further study. Taking the sloping farmland with soybean as the research object, and the ability of soybean to regulate runoff and sediment under different slopes and rainfall intensities were studied. The experimental design included five growth stages of soybean (seedling stage, initial flowering stage, full flowering stage, pod-forming stage and granulation stage), five slope gradients (3°, 5°, 10°, 15° and 20°), and two rainfall intensities(40 and 80 mm/h). The effect of soybean on regulating runoff and sediment was divided into two parts, which were reducing runoff and reducing sediment yield. Comprehensive comparative analysis was carried out using six indicators, which were runoff time, initial rainfall loss, runoff, sediment yield, reduced flow benefit (RRB) and sediment reduction benefit (SRB). The results showed that soybe an played an important role in regulating runoff and sediment. Compared with bare land, the runoff of the slope decreased by 10.75%~64.94% and the sediment yield decreased by 15.38%~84.24% from the seedling stage to the granulation stage. The RRB and SRB of soybean showed an overall increasing trend from the whole growth period, and they were inversely proportional to the slope. Similarly, with the increasing of rainfall intensity, the RRB and SRB of soybean decreased slightly and the difference was not significant, and the SRB value was always greater than RRB value, so it was found that soybean was more effective in reducing sediment than in reducing runoff. In summary, planting soybean on sloping farmland in the Loess Plateau had a positive effect on control soil erosion of sloping farmland, and the interception effect on sediment was stronger than the interception of runoff.