Tropentag, September 10 - 12, 2025, Bonn "Reconciling land system changes with planetary health"

Arrangement, timing, and synergy: Rethinking maize-soybean intercropping for productivity gains in Southern Africa

¹Swedish University of Agricultural Sciences (SLU), Crop Production Ecology, Sweden
²International Maize and Wheat Improvement Center (CIMMYT), Sustainable Agrifood Systems Program, Zimbabwe
³International Institute of Tropical Agriculture, Agronomy, Malawi
⁴International Maize and Wheat Improvement Center (CIMMYT), Malawi

Abstract

Intercropping improves resource-use efficiency and crop synergy. In Southern Africa, adding soybean to maize systems can increase total yield and protein output per area. This study assessed maize–soybean intercropping under varied spatial (sole, within-row, 1-1, 2-2, 4-4 strips) and temporal (Early, Medium, Late) arrangements at Chitedze (Malawi), Villa Ulongue (Mozambique), and Msekera (Zambia) using split-plot design in the 2022-2023 and 2023-2024 cropping seasons, replicated four times. Key parameters included soil moisture, chlorophyll (SPAD), grain yield, harvest index (HI), and total land equivalent ratio (TLER).
Soil moisture during flowering (maize) and podding (soybean) was highest in early/medium plantings. At Chitedze, moisture reached 5.7% compared to 4.2% in late. At Msekera, 2:2 and 4:4 strips retained 44% and 32%, respectively above 25.5% in sole cropping.
Chlorophyll content followed moisture and yield dynamics. Chitedze: SM Early (69.8), 2:2 Early (65.3), WR Early (62.7); lowest: 4:4 Late (42.4). Villa Ulongue: highest SM Early (58.9), second WR Early (56.3), lowest SS Late (42.1). Msekera: highest WR Early (60.2), second SM Early (58.7), lowest 4:4 Late (30.6).
TLER favoured early strip systems: 4:4 Early (4.71), 2:2 Early (4.31) at Chitedze; Villa Ulongue 4:4 Early (2.37); Msekera 2:2 Early (1.56).
Soybean yields peaked: Chitedze 2:2 Early (2,392.7 kg/ha); Msekera 4:4 Early (2,288.1); Villa Ulongue 4:4 Early (2,245.6).
Maize yields: Chitedze SM Early (3,564.2), Villa Ulongue SM Early (3,285.7), Msekera SM Early (3,177.3).
Overall, early and medium planting with 2-2 and 4-4 strips improved yields and TLER compared with sole cropping, offering productive, protein-rich systems for smallholders.

Keywords: Chlorophyll content, grain yield, harvest index, intercropping, land equivalent ratio, maize, planting windows, soil moisture, soybean

Contact Address: Pacsu Simwaka, Swedish University of Agricultural Sciences (SLU), Crop Production Ecology, Uppsala, Sweden, e-mail: pacsu.simwakaslu.se