| Summary: | 碩士 === 國立屏東科技大學 === 水土保持系所 === 106 === The object of this study is to investigate the effects on infiltration and surface runoff under straw-mat mulch and Carpet grass cover. Field runoff plot was established for each surface treatment; whereas a bare plot was used as the check plot. Soil moisture sensors were used to monitor volumetric soil water content and USDA H flume was used to measure surface runoff hydrograph. Since antecedent soil moisture content affects the soil water responses, therefore, field observations were first divided into groups based upon time lag between storms, where 6-hour interval was used as partition interval.
Results of field observations indicated that straw-mat mulch possesses the unique functions of absorbing rainwater and protecting soil surface from raindrop impact. Similarly, Carpet grass provides additional but limited rainwater storage capacity. When facing no rain for longer period and receiving minimal rainfall afterward, both straw-mat mulch and Carpet grass cover prevents soil water content from immediately reaching peak values with lag time between 10 ~ 30 minutes. In addition, straw-mat mulch helps increase soil water content more than Carpet grass does.
Surface runoff hydrographs from bare check plot show good synchronization with rainfall; however, an apparent time lags as well as less synchronization were found in Carpet-grass treatment’s runoff hydrograph until Carpet grass receives enough precipitation to fulfill its storage capacity. If rainfall continues to fall, surface runoff hydrographs from Carpet grass start synchronize with the rainfall. This synchronization implies that a soft armor layer is formed by Carpet grass, which provides high surface runoff drainage efficiency.
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