Rubber Agroforestry System (RAS) Practices in Southern Thailand towards Policy Recommendations to Promote the Practices in Cambodia

Abstract

For rubber agroforestry system (RAS) practices in Southern Thailand and Eastern Cambodia, this study aims to investigate techniques of the RAS plot management, measure the RAS plant community structures and crown covers related to soil erosion, examine economic margin of the RAS plots, and evaluate situation of RAS practices and formulate policy for recommendation in Cambodia. The study results, in Eastern Cambodia, 3 RAS plots are planted with rubber trees at 6 × 3 m planting distance. 2 of the 3 plots are rubber-based annual intercrop plots, and the intercrops were planted at 0.5 x 0.5 m planting distance in lower 5 years old rubber plantation in 2018. The rest is rubber-based chicken raising plot, chickens were raised 300 heads in 2018. Then, 11 RAS plots in Southern Thailand have been divided in five systems of RAS. Rubber planting distance was used by 6 x 3 m, 6.5 x 3.5 m, 7 x 3 m, 7 x 3.5 m, 8 x 3 m, and 10 x 2.5 m. 5 plots have been applied with chemical and organic fertilizer, 4 plots have been applied with only organic fertilizer, and 2 plots have not been applied any fertilizer. Furthermore, the economic margin from 2018 to 2024 of 12 RAS plots in this study (excluding the two rubber-based annual intercrop plots of Eastern Cambodia), show that rubber-based stingless bee raising with bamboo (shoot product) plot, rubber-based sala fruit with neem tree plot, rubber-based champadak fruit with phakleang vegetable plot have highest level of ability to overcome low rubber price. Whereas, rubber-based ironwood plot and rubber-based eaglewood plot are low level of ability to overcome low rubber price, but Ironwood and Eaglewood in the RAS plots will provide high income in the future. Therefore, RAS practices are an alternative to improve household livelihood of RAS farmers although rubber price is degreased. Moreover, the plant community structure and crown cover are composed of rubber trees with upper canopies as well as intercrops with lower canopies. The crown covers of rubber trees and intercrops in representative area of RAS plots are about 86% to 99.5% of the area. Therefore, the crown cover in plots have a great potential to prevent soil erosion and moisture in the RAS plots are kept due to multiple levels of vertical stratification and crown cover percentages of plant species. Finally, policy recommendation to promote the RAS practices in Cambodia as the track of strategies by SWOT reveal that the government should associate the RAS knowledge, rubber processing (rubber sheet) knowledge, and good agricultural practice technique into policy of agricultural extension for rubber farmers, encourage rubber farmers to cultivate RAS and participate with farmer group, and create experimental RAS plots at farmers' farm and laboratory field. Also, farmers should follow the policy of government to be successful in RAS practice and to improve houschold income.