Agronomic and economic evaluation of methods of establishing alley cropping under a maize/groundnut intercrop system

Agronomic and economic benefits of maize intercropped with groundnut in alleys formed by Leucaena leucocephala were assessed at Matomb, Cameroon, from 1990 to 1992: (a) without fertilizers and (b) with the application of 200 or 400 kg ha(-1) of N-P2O5-K2O (20-10-10). In treeless (control) plots, maize grain yields decreased from 1.2 t ha(-1) in 1990 to 0.8 t ha(-1) in 1992, while groundnut yields declined from 1.1 to 0.5 t ha(-1) during the same period. With the application of Leucaena prunings alone, groundnut yield was maintained around 1 t ha(-1) for 3 years while maize yields stabilized at 2.5 t ha(-1) in the second and the third year; the yields of both crops were greater over the 3 years than in the control. Leucaena prunings applied in combination with 200 and 400 kg ha(-1) of N-2-P2O5-K2O increased maize yield by 1.7 and 2.0 t ha(-1), respectively, but groundnut yield decreased by 13 and 24% over the 3 years. The dominance analysis showed that alley cropping without fertilizer was the only non-dominated alternative, with a marginal rate of return of 447%. It was the best system at this early stage (3 years) of implementing the technology.