The rubber agroforestry system is an alternative agriculture practice for rubber smallholders to enhance the ecological integrity and crop diversity. The data collection for the study of diversification of smallholding rubber agroforestry system (SRAS) included 300 rubber farms of 21 systems in the south, east, and northeast of Thailand. The project results revealed that there are a multitude of 21 rubber farming systems in Thailand. These systems can be classified into three main types: (1) the intercropping rubber-food crop system, growing short-lived plants, for example, pineapple, chili, banana, rice, sweet potato, long bean and corn, for a rubber period, no longer than 36 months; (2) the rubber-fruit crop system, growing multicrop within the rubber area during the rubber productive period. The most common fruit crops that have been grown in Thailand are guava, gnetum, long kong, salacca, mangosteen, durian, and levistona, etc., and (3) the rubber-timber species system, normally yielding higher income to rubber smallholders since the sales of both rubber and wood products are at the same time and this is coupled with the presently high value of wood. The important timber varieties in the rubber area are neem and teak. As for profitability of Smallholding Rubber Agro forestry System (SRAS), it was noted that pineapple, chili, salacca, and gnetum are highly profitable. However, in the rubber-pineapple system which yields the highest income, the cost of investment is the highest too, when compared to the rubber-gnetum system which requires minimal input and low cost of production and management. The main conditions for decision-making in the rubber intercropping system are as follows: (1) farm household labor requirement, (2) knowledge and experience, (3) extension and policy implication, (4) marketing opportunity, (5) consistent capability of local communities, and (6) land topography and sustainability. For SRAS development strategy in the southern Thailand, improvement should be made on pricing and marketing of agroforestry products, appropriate technology for higher productivity, greater farm efficiency and risk reduction at farm level, and more synchronized co-ordination among stakeholder agencies at the regional level.
