The influence of rainfall on growth of rubber trees in marginal area of Northeast Thailand

摘要

Rubber trees grow predominately in the southern and eastern areas of Thailand, where there is the majority of rainfall. However, the rubber tree plantations extend to north and northeastern areas, with lower annual rainfall. The aim of this study was to evaluate the effect of rainfall on growth of rubber tree in northeastern areas of Thailand. The outcome of this work should be helped to indicate the optimum area for rubber tree planting in northeast. The study was undertaken using rubber tree clone RRIM600 by comparing the girth at 150 cm at the soil surface, planted in areas of differing rainfall: in Nongkhai, Chaiyaphum, Khon Kaen, Roiet and Buriram provinces. The sample of 50 trees was selected in 3 plantations per province (150 trees per province). The results found that there was no significant difference in girth of the rubber trees in all areas. However, the rubber trees planted in Nongkhai, where had highest rainfall, had highest growth. Moreover, the relationship between rainfall and growth exhibited a positive correlation, demonstrating that higher rainfall increased the girth of rubber trees.