Plant spatial configurations and their influences on phenological traits of cereal and legume crops under maize-based intercropping systems

IntroductionIntercropping systems have a great potential for crop diversification thus increasing smallholder systems' resilience to climate change while improving soil health. However, optimal benefits associated with intercropping systems are rarely realised because of the interspecific competition for growth resources among the intercropped species.MethodologySix trials were established in the high and low rainfall agroecological zones of Babati district in Tanzania to assess how promising cropping systems with different plant spatial configurations would influence the phenological development of intercropped maize, bean and pigeonpea. Cropping systems under study included a sole maize system rotated with a pigeonpea-bean intercrop dubbed Doubled-up legume (DUL), maize-pigeonpea system both with and without de-topping, an innovation comprising double maize rows alternated with pigeonpea and beans (Mbili-Mbili), maize-pigeonpea system with two maize seeds sown within a 50 cm intra-row space, a vertical-architecture Meru H513-pigeonpea system and a farmer practice.ResultsBranch formation was significantly higher in DUL than in maize-based systems (p <= 0.05). Seasonal weather had upto 30% influence on pigeonpea flowering, with DUL having highest (p <= 0.05) flower production. The rate of pigeonpea branch and flower production in Mbili-Mbili was stable across seasons relative to other maize-pigeonpea systems. Doubled-up legume and farmer practice had pigeonpea litter yield of between 1 and 2 t ha-1 which was at least 0.5 t ha-1 higher than in maize-based systems (p <= 0.05). During the period preceding early maize reproductive stages, Mbili-Mbili increased light interception by 30% and 63% compared to maize-based systems and DUL, respectively. Maize toppings had higher (94%) P content than stover biomass that remained until harvest.ConclusionOverall, maize-legume systems had higher intercropping efficacy than sole maize system, both in interception use efficiency, soil mulch cover, among other soil health benefits. Mbili-Mbili and DUL also had increased phenological benefits on intercropped legumes however, the latter was prone to seasonal weather variability.