APPLICATION OF FUZZY-LOGIC TO LAND SUITABILITY FOR RUBBER PRODUCTION IN PENINSULAR THAILAND

This paper aims to determine the quantitative impact of land qualities on rubber production, using the theory of fuzzy logic. This theory is applied in a land suitability assessment for rubber production in the northern part of the rubber growing area of peninsular Thailand. The proposed method differs from the usual technical land evaluation proce dures by (1) the use of an explicit weight for the effect of each land quality on crop performance, and (2) the way of combining the evaluat ion of land qualities into a final land suitability class or land suit ability index. The methodology was tested by comparing the estimated y ields and land indices calculated by fuzzy set theory with those obtai ned by conventional procedures: (1) maximum limitation method; (2) par ametric-Storie method, and (3) multiple linear regression. In the last approach the land index is replaced by the predicted relative yield f rom multiple regression on the various land qualities. The considered rubber clone, RRIM 600 is grown on a wide range of soils under differe nt climatic conditions. The best relationship is given by the fuzzy se t approach, which illustrates the potential usefulness of this theory in land evaluation.