Relay cropping is a form of intercropping where two or more crops are grown simultaneously during part of their life cycles. Intercropping often involves maize and legumes, which increases nitrogen fixing in soils and increased biomass production. The second (or succeeding) crop is planted after the reproductive stage (flowering) of the existing crop but before harvesting. Some of the advantages of relay cropping include better erosion control due to crop cover, reduced spreading of pests and diseases, and crop diversification, plus general soil health. As an added benefit, it mitigates the emission of greenhouse gases through reducing nitrate leaching and increasing carbon sequestration. There is also potential socio-economic benefits for farmers as in many cases relay cropping increases crop productivity.
However, this form of intercropping is not easily implemented in large-scale agricultural systems due to complications in weed control and challenges associated with operating mechanised equipment on fields with relay cropping.
To effectively implement relay cropping, the following steps should be carried out:
- Step 1: Test/experiment with locally available crops to determine if they are complementary and can grow concurrently - cereal crops and legumes are complementary and can generally grow concurrently.
- Step 2: Prepare land through clearing, weeding and a no-tillage approach (Technical Brief 12).
- Step 3: Plant cereal crop first according to normal planting season schedule –during rainy season. Space this cereal crop 70 cm by 50 cm apart.
- Step 4: Prior to cereal harvest, plant the legume crop between cereal crop rows with spacing based on legume planting efficiencies (researched prior to planting for optimum growth).
- Step 5: After cereal has been harvested, bend the dried stalks down to provide more ground cover.
- Step 6: When legumes are ready for harvest, collect the productive pod/seed/bean/nut and leave the stalk uprooted in the field to maximise ground cover.
- Frederick Baijukya, Lydia Wairegi, Ken Giller, Shamie Zingore, Regis Chikowo and Paul Mapfumo. 2016. Maize-legume cropping guide. Africa Soil Health Consortium. Nairobi.
- Food Agriculture Organisation (FAO). 1983. Fertilizer use under multiple cropping systems. Rome.
- The Food and Agriculture Organisation (FAO), 2001. Improving Nutrition through Hone Gardening, Rome.
- The Food and Agriculture Organisation (2015), Traditional Systems makes more Productive Use of Land. Rome.
Benefits
- Increased and diversified crop yield.
- Improved soil quality preventing leaching, and introducing nutrients.
- Increased land cover reducing erosion and improving carbon capturing.
- Food security/farm income increase.
Drawbacks
- Weeding makes this approach labour intensive, and planting and harvesting can become less efficient. This requires consideration, especially if women’s workload increases as a result.
- Carried out precisely to ensure crops are compatible, planting is undertaken at correct times and harvesting is low impact to avoid crop damage.
- Possible competition between plants for nutrients, water, space, etc.
