Legume survival during the dry season and its effect on the succeeding maize yield in acid savannah tropical soils

The effects of inorganic fertilizers and three green manure legumes (Canava lia brasiliensis, Mucuna aterrima, and Tephrosia candida) sown at the end o f the wet season and subsequently incorporated into the soil, were measured on subsequent wet season maize crops between 1988 and 1992 at the Cerrado Research Center, Brasilia, Brazil. Maize responded significantly (P < 0.05) to fertilizer N over the 4-year study period, the highest yield being obta ined at 150 kg N ha(-1). A significant (P < 0.05) response to leguminous gr een manure (LGM) was also obtained. There was no interaction between fertil izer N and LGM. Canavalia, mucuna, and tephrosia increased the yield of mai ze by 1700, 960, and 1250 kg ha(-1), respectively, when no fertilizer N was added. This was equivalent to 50, 35, and 40 kg ha(-1) of fertilizer N. Ho wever, while canavalia proved to be the most appropriate legume at one loca tion, Planaltina, the choice of LGM may vary depending upon the severity of the dry season at other locations.