Some issues confronting the rehabilitation of major irrigation schemes in the dry zone [irrigated farming, Sri Lanka]

agricultura de regadio asia asie behaviour clima climat climate climatic zones comportamiento comportement condiciones ambientales condition de milieu cropping systems cultivation cultivo cultivo migratorio decision making environment environmental conditions environnement irrigated farming labranza medio ambiente methode methods motivation pratique culturale shifting cultivation sistemas de cultivo site factors tillage toma de decisiones travail du sol zone climatique zone semi-aride