Abstract
Maize (Zea mays)-cassava (Manihot esculenta) intercrop is a prominent cropping system in Ghana, grown with little or no fertilizer and component crops planted randomly. One approach to ensure sustainable production of the system is to exploit the biological nitrogen fixation capacity of leguminous crops by using maize and cowpea [Vigna unguiculata (L.) Walp] rotation and row planting in the intercrop. The study was conducted at three sites in the forest and forest-savannah transition zones of Ghana from 1997 to 1999. The objective was to develop a stable and highly productive maize-cassava-cowpea intercropping system. There were two cassava varieties (main-plots): Gblemodoade and Ankra, combined with five row arrangements (sub-plots) in a split plot design. The row arrangements were: A1 , 1 row cassava (1 m within row)-1 row maize-1 row cowpea after maize harvest; A2, 1 row cassava (0.5 m within row)-1 row maize-1 row cowpea; A3, 1 row cassava (1 m within row)-2 rows maize-3 rows cowpea; A4, 1 row cassava (0.5 m within row)-2 rows maize-3 rows cowpea; and A5, 1 row cassava-3 rows maize-5 rows cowpea. The A1, A2, A3, and A5 arrangements with Ankra and A1 and A3 arrangements with Gblemodoade were the most productive (Land Equivalent Ratio = 1.25-2.83) and stable. The stability of these cropping systems was apparently due to the high yield stability of Ankra and Gblemodoade in arrangement A5. These five cropping systems are recommended for on-farm verification.
