Experimental study on soil erosion characteristics in flooded terraced paddy fields

摘要

This experimental study assesses the effects of event rainfall on soil erosion characteristics in terraced rice paddy fields. A 0.75-ha terraced paddy field located in Northern Taiwan was used to investigate the soil erosion under the regular cultivation of rice during two crop seasons. The environmental changes were investigated in the neighboring areas in which terraced paddy fields have been converted to other land usages. The annual rate of soil erosion calculated from the observed rainfall runoff and suspended solid contained was 0.77 ton/ha, which is significantly less than the erosion rate associated with upland crop cultivation reported by other research conducted in Taiwan. Experimental results also showed that the terraced paddy field retained the highest percentages of clay, silt, and organic matter's content, as compared to those of other upland crops, indicating that the topsoil was less susceptible to rainfall erosion under flooded conditions of rice-cultivation. The results of this study show that the rice-planted terraced paddy offers the highest level of soil conservation. The function of soil and water conservation in terraced paddy fields could be further increased by effective maintenance of embankment and to raise the height of the bund. Poor management, abandoned cultivation, and converse to other upland crops of terraced paddy fields are regarded as major contributors to increased soil erosion in mountainous areas. The government in Taiwan should formulate effective measures and maintain sustainable rice cultivation in the terraced paddies.