[A-GE27] Subsurface Mass Transport and Environmental Assessment

[AGE27-P14] Effects of natural latex to the surface flow and infiltration amounts under different rainfall intensity conditions

*Hiroaki Somura¹, Koki Kumamoto¹, Yasushi Mori¹, Jun Kano², Mamoru Matsushima³, Bnaja Junhasavasdikul⁴ (1.Graduate School of Environmental and Life Science, Okayama University, 2.Graduate School of Natural Science and Technology, Okayama University, 3.UEDA BRAKE Co., Ltd., 4.Rubber division of the Polymer Society of Thailand)

Keywords:Environmental conservation, Small scale rainfall simulator, Laboratory scale experiments, Thailand

Thailand is the world's largest producer of natural latex. Although the latex is widely used in the automobile industry, the effective utilization of surplus latex is a current issue leading to unstabilization of local farmer's livelihood. Considering features of the latex with high film forming ability and elasticity, it can be a material for aggregating the soil particles, which may lead to soil erosion mitigation from a land, especially from an agricultural field. In this study, we evaluated the function of the latex for it by using a small-scale rainfall simulator, two types of soils (sandy loam and red clay), and the latex sampled in Thailand. In the experiments, discharge volume of water from surface flow and infiltration were compared under conditions of different rainfall intensities and with- and without-latex in the two soil types. The experimental conditions were designed as: both soils were dried in air and sieved by 2 mm mesh size, rainfall intensity was 20 mm/hour and 50mm/hour with total 2 hours duration, 0.1% volume of latex was mixed with the soils under "with latex" condition, the experiments were repeated one time after 24 hours. In the case of sandy loam and 20mm/hour rainfall intensity, the latex enhanced infiltration and suppressed surface flow. However, in the case of 50mm/hour rainfall intensity, most of input amount of water discharged as surface flow, regardless of with- and without-latex mixture. In the case of red clay, surface flow was not observed both of rainfall intensities and with/without latex, though slight increment of infiltration was observed under with-latex condition in both of rainfall intensities. Although the natural latex can be used for reducing soil erosion with increment of infiltration in agricultural fields, further experiments are needed to improve the functions under high rainfall intensity.