agriculturalecology agriculturalextensionworkers agriculturalgeography agriculturalinnovations agriculturalproductivity agriculture agricultureandstate climatechangemitigation computersimulation congresses croppingsystems crops dataprocessing decisionmaking environmentalaspects farmmanagement fieldcrops fieldexperiments foodsupply greatbritain growth history humanecology landuse middleages research rural ruralconditions simulationmethods socialaspects soilconservation southeastasia sustainableagriculture sustainabledevelopment thailand trainingof tropics