Researchers at the International Maize and Wheat Improvement Center (CIMMYT) spent eight years working with smallholder farmers in Zimbabwe to answer a practical question. Can no-till farming, drought-tolerant maize, and the right legume rotation produce more food in dry areas? After running trials on real farms in Masvingo and Rushinga from 2018 to 2025, the answer is yes. The catch is that the first three years often look worse before yields start to improve.
What was tested
The trial compared two ways of farming the same crops.
- Conservation agriculture (CA) means no ploughing, leaving crop residues on the soil, and rotating crops each season. Read more about conservation agriculture.
- Conventional practice (CP) is the usual ploughing and planting that many smallholders still do.
The crops in the rotation were maize, sorghum, pearl millet, cowpea, and groundnut. Rainfall during the trial swung from a low of 614 mm to a high of 1,647 mm in a single season. The 2023/2024 El Niño year wiped out grain reserves on many farms and forced families to sell livestock to survive.
Maize yields under conservation agriculture
In the first three years of CA, maize yields were lower than or about the same as those under conventional ploughing. Then they pulled ahead. By year 7, fields under CA produced 10% to 15% more maize than fields under conventional tillage. Two hybrids stood out across all sites. PAN53 and PGS63 handled dry conditions better than the other varieties in the trial. Picking the right hybrid for your area matters as much as the farming method, as covered in this guide on choosing the best maize variety.
The lesson for farmers is simple. Do not give up on no-till in the first season or two. The system needs time for soil structure, soil moisture, and organic matter to build up.
Cowpea beat groundnut as the rotation crop
When farmers rotated maize with cowpea instead of groundnut, the whole system produced more food and animal feed. Total energy from the rotation reached 26 to 27 GJ per hectare under CA with cowpea, compared to 19 to 21 GJ per hectare under conventional tillage with groundnut. That is roughly a third more food and feed from the same piece of land.
Cowpea has a deep taproot, tolerates drought, and matures quickly. It also fixes nitrogen back into the soil, which feeds the next maize crop and cuts the fertilizer bill. The general benefits are well documented in this overview of crop rotation with legumes.
How many plants to put in the ground
The trial also tested plant density and found clear sweet spots. Maize performed best at around 55,000 plants per hectare, and cowpea at around 90,000 plants per hectare. Going denser than these levels did not add yield in dry conditions because the plants started to compete with each other for water.
Sorghum and millet still have a role
Sorghum, pearl millet, and finger millet showed big differences between varieties on the same field. Some performed much better than others. For farmers in the driest parts of the country, the message is to test several local varieties and stick with the ones that hold up. The same logic is playing out in Kenya, where smallholders are turning to sorghum as an alternative to maize in drylands.
What this means for your farm
Across all four trial sites, conservation agriculture combined with drought-tolerant crops raised total energy yield by 3% to 10% and made yields more stable from one season to the next. The stability matters as much as the yield bump, because it means fewer years of empty granaries.
The package only works when all four pieces are in place at the same time.
- No-till and crop residue cover on the soil
- A drought-tolerant maize hybrid suited to your area
- A legume rotation, with cowpea as the strong choice in dry zones
- Plant densities that match your rainfall
In Zimbabwe, only about 10% to 15% of smallholders currently follow all three CA principles. The early-year yield dip is a real barrier for families who cannot afford to wait three seasons. Subsidies, better weather information, and regular visits from extension officers will decide how many farmers can afford to make the switch and stay with it long enough to see the gains. For more on the broader strategy, see this article on climate-resilient crops.
References
- Thierfelder, C., Mhlanga, B., & Ngoma, H. (2026). Bundling conservation agriculture with drought-tolerant crops improves system productivity and stability in Zimbabwean smallholder systems. Field Crops Research, 343, 110487.
