Nitrogen Fixation in Tropical Cropping Systems

Tropical environments: climats, soils and cropping systems; Nitrogen fixing organisms in the tropics; The process of nitrogen fixation; Assesment of the nitrogen fixation; Cereal crops and grasses: free-living and roat associated nitrogen fixing bacteria;Ewtland rice: cyanobacteria, Azolla and green manures cyanabacteria; Grain legumes; Pasture improvement: introduction of legumes; Plantation crops: understorey legumes and shade trees; Legumes in multiple cropping: crop rotations, green manures, leys and intercrops; Agroflorestry: nitrogen fixing trees in integrated agriculture; Environmental constraints to nitrogen fixation; Pat approaches: successes and failures; Future benefits: an ecological approach to agriculture.