Maize yields from rotation and intercropping systems with different legumes under conservation agriculture in contrasting agro-ecologies

Maize (Zea mays L.) is a key food security crop in Eastern and Southern Africa (ESA). Maize yield gaps are large in the smallholder farming systems of ESA but can be closed by a combination of improved crop varieties and sustainable cropping systems. On-farm trials were conducted in five countries of ESA over a seven-year period to assess the effects of different cropping systems on maize productivity. Cropping systems tested were conventional practice (Conv_sole) compared with variants of conservation agriculture (CA) such as sole maize (CA_sole), intercropping (CA_intercropping) and rotation (CA_rotation). Maize yield varied with cropping system and agroecological conditions. In highlands, CA_intercropping (3709 kg ha(-1)) outperformed Conv_sole (3456 kg ha(-1)), CA_sole (3596 kg ha(-1)) and CA_rotation (3545 kg ha(-1)) with similar legumes in the cropping system. The CA_rotation (3050 kg ha(-1)) out-yielded the other treatments (2645-2864 kg ha(-1)) in lowlands where similar legumes were grown in the cropping system. Without rotation practices, CA_sole (3596 kg ha(-1)) outperformed the conventional and CA_intercropping treatments (2954-3036 kg ha(-1)) in highlands with similar legumes in the cropping system. In lowlands, CA_intercropping (2802 kg ha(-1)) out yielded the other treatments (2485-2658 kg ha(-1)). The highest maize yield was from CA systems with groundnut (3609 kg ha(-1)) and common bean (3307-3576 kg ha(-1)) under rotation and intercropping practices, respectively. Maize-pigeon pea intercropping (35 %) and maize-groundnut rotation (31-43 %) under CA had the highest maize yield advantages over the conventional practices. The most stable maize yields were from the maize-common bean systems under CA. There is scope for promoting CA cropping systems integrated with grain and forage legumes to address maize productivity challenges on smallholder farms of ESA.

Automated summary

Maize is a key food security crop in Eastern and Southern Africa, and improving crop varieties and sustainable cropping systems can help close yield gaps in smallholder farming systems. On-farm trials in ESA revealed that maize yield varied with cropping systems and agroecological conditions, with conservation agriculture practices like intercropping and rotation showing potential to enhance productivity.