Comprehensive evaluation of throughfall erosion in the banana plantation

Banana is an important cash crop in tropical and subtropical areas; however, the development of banana farming has caused thorny ecological problems, such as water and soil loss. There are few studies on the runoff response to rainfall in banana land to date. In this study, several evaluation indexes, rainfall redistribution, throughfall erosivity, splash kinetic energy, soil splash loss and runoff, respectively, were used to clarify the mechanism of soil erosion in banana land. Results showed that the atmospheric rainfall was significantly redistributed by the banana canopy, with about 81.2% throughfall, 8.3% stemflow and the rest canopy interception. Although the throughfall erosivity evaluated by the model was slightly lower than that of open rainfall, the throughfall kinetic energy and the soil particle splash loss reached 1.5 times and 5 times higher than that of open rainfall, respectively. Consequently, throughfall has an obvious splash erosion effect on the surface soil. In addition, influenced by throughfall and stemflow, surface runoff during the rainy season (May–September) accounts for the annual 91.7%, July and August in particular having the highest incidence of soil erosion in banana land. The above results suggest that the convergence effect of the banana canopy on rainwater is the main inducement for the increase in throughfall volume and surface runoff volume. Therefore, it is necessary to implement soil and water conservation measures on banana fields during the rainy season, such as planting low vegetation under the banana canopy to mitigate splash effects. Throughfall, 81.22% of gross rainfall, has an obvious splash erosion effect on the surface soil. In addition, influenced by throughfall and stemflow, surface runoff during the rainy season (May–September) accounts for the annual 91.7%, July and August in particular having the highest incidence of soil erosion in banana land. The above results suggest that the convergence effect of the banana canopy on rainwater is the main inducement for the increase in throughfall volume and surface runoff volume.