Mahaweli Ganga Development Project: System 'C' bench mark survey in 1990 yala and 1990/91 maha (Sri Lanka)

agricultural development credit credito crop yield cultivation cultivo farm income farm inputs insumos agricolas moyen de production agricole oryza oryza sativa plant production pratique culturale production costs rendement des cultures rendimiento de cultivos revenu de l'exploitation sri lanka variedades varieties