11:00 〜 13:00
[AGE30-P04] タイ国天然ラテックスを用いた農地土壌侵食軽減のための基礎研究
キーワード：環境保全、小型降雨シミュレーター、室内実験
Soil erosion is a crucial problem, causing reduction of agricultural land productivity and degradation of the water environment downstream. Especially in Asian monsoon regions such as Thailand, decomposition of organic matters in agricultural soils will be accelerated due to high temperature and strong ultraviolet rays. The decomposed soils have low water holding capacity and low resistance to compression by heavy machinery which causes low permeability. Since the soil is easily washed away during heavy rains, negative impacts are observed in surrounding areas.
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. Thus, we tried to understand the function of the latex for soil erosion mitigation by using newly developed small-scale rainfall simulator with local agricultural 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 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 with total 3 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.
As a result, about 11% reductions of surface flow in both the first time and the second time experiments were observed in sandy loam soil between with and without latex conditions. In addition, about 57% increase in the first time and 108% increase in the second time experiments were observed in infiltration. In red clay soil, surface flow was not observed both with and without latex in the current experimental condition. However, as like sandy loam soil, slight increment of infiltrations was observed. Thus, it is considered that the natural latex can be used for reducing soil erosion with increment of infiltration in agricultural fields. Further experiments are needed to understand functions of the latex for this new usage with mitigation mechanism of soil erosion, suitable conditions of the latex addition to the agricultural soils, and influence to crop production and surrounding environment.
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. Thus, we tried to understand the function of the latex for soil erosion mitigation by using newly developed small-scale rainfall simulator with local agricultural 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 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 with total 3 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.
As a result, about 11% reductions of surface flow in both the first time and the second time experiments were observed in sandy loam soil between with and without latex conditions. In addition, about 57% increase in the first time and 108% increase in the second time experiments were observed in infiltration. In red clay soil, surface flow was not observed both with and without latex in the current experimental condition. However, as like sandy loam soil, slight increment of infiltrations was observed. Thus, it is considered that the natural latex can be used for reducing soil erosion with increment of infiltration in agricultural fields. Further experiments are needed to understand functions of the latex for this new usage with mitigation mechanism of soil erosion, suitable conditions of the latex addition to the agricultural soils, and influence to crop production and surrounding environment.