09:30 〜 09:45
[AGE28-03] Kaolinite application into post-tin-mined soils to restore the soil water-holding capacity
キーワード：Kaolinite, Tin mining, Water holding capacity, Soil restoration
Sandy soils that remained after mining have low water availability. Restoring the soils by adding organic matter is frequently done, but low water retention and soil erosion still exist. The starting phase of the soil's physical restoration is crucial to handle well for a successful measure. We aimed to investigate whether clay particles, in addition to the post-mined sandy soils, are able to rebuild the water-holding capacity. We sampled soil from three areas: 0, 1, and 6 years after mining and an adjacent natural forest as a reference site in Belitung Island, Indonesia. We took 50 cc of the sampled soils into 50 cc core cylinders with three treatments: adding 1% kaolinite, adding 5% kaolinite, and the control cylinder filled the soils without kaolinite. We incubate all the soils at 34°C to mimic the highest air temperatures on site. The soil aggregate distribution, mean weight diameter, soil water retention time, and soil water retention curve were measured in the laboratory. We also captured photographs of the soil using a Scanning Electron Microscope to observe the soil particles. The soil showed an increasing trend of fine particles. Water-holding capacity was significantly increased in the soils with kaolinite addition, with a 5% increment for 0-year and 1-year soils and a 15-20% increment for 6-year soil. Soil water retention time in the 6-year-old soils is ten days longer than in the 0-year and 1-year soils. There is no significant difference in mean weight diameter between soil ages and treatments. Soil fine particle amounts raised in the kaolinite-added soil’s pictures were observed. This experiment examined the more profound changes in the soil physical properties of tropical post-tin-mined land under clay addition. Kaolinite application to the sandy soils can lift the water-holding capacity performance.