Resource management in high altitude agroecosystems. A study of plantations and smallholdings in the Upper Uma Oya watershed in Sri Lanka

agriculteur agricultores agriculture de montagne agroecosistemas agroecosystems altitud altitude conservation des ressources conservation des sols costos costs environmental degradation facteur de production farm inputs farmers highlands insumos agricolas mejora de suelos motivation mountain farming moyen de production agricole petite exploitation agricole plant production plantaciones plantations production factors resource conservation small farms soil conservation soil improvement sostenibilidad sri lanka sustainability te tea