1. Afif E, Barrön V, Torrent J (1995) Organic matter delays but does not prevent phosphate sorption by Cerrado soils from Brazil. Soil Sci 159: 207–211
2. Aghinoni I (1989) Época e métodos de aplicaçäo de corretivos nos solos. In: Anais do Seminârio sobre corretivos da acidez do solo, 2. pp 130–150. Santa Maria, RS, Brazil: Universidade Federal de Santa Maria
3. Aina PO (1979) Soil changes resulting from long-term management practices in Western Nigeria. Soil Sci Soc Am J 43: 173–177
4. Akobundu IO & Deutsch AE (1983) No-tillage crop production in the tropics. Corvallis, OR, USA: International Plant Protection Center
5. Ali M & Narciso JH (1996) Farmers’ perception and economic evaluation of green manure use in rice-based farming systems. Trop Agric (Trinidad) 73: 148–154