Under the treaties the state was impelled to play an active role in encour- aging commercialisation by promoting agricultural production and centralising the export economy on Bangkok through transport infrastruc-ture. Through expanding rice production the state aimed to increas domestic food supply as well as expand the base for state revenue through axation. Farm settlement and land-clearing in the central region wer ncouraged by incentives such as exempting newly cultivated land fro taxation(Ingram 1971: 1975-6: Suehiro 1989: 22-4).