Research

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Comparing Deep Bed vs conventional legume intercropping (2024)

Augustine Phiri, Dr Keston Njira, and Professor Alan Dixon researched how the use of intercropping in Deep Bed Farming boosts crop yields and improves soil health. The study compared intercropped maize with cowpea, intercropped maize with pigeon pea, intercropped pigeon pea with cowpea, and sole-cropped maize without fertiliser, sole-cropped  maize with nitrogen fertiliser, sole-cropped cowpea, and sole-cropped pigeon pea on both Deep Bed Farming and conventional ridges.

Conducted over the course of two growing seasons, the study highlighted two key findings:

1. Improved soil fertility: Intercropping maize with legumes significantly increased nutrient content such as available nitrate, ammonium, and available phosphorus. The nitrogen-fixing ability of pigeon pea and cowpea enriched the soil, reducing the need for external fertilizers. These effects were significantly higher on Deep Bed Farming compared to ridges over two growing seasons.
2. Enhanced grain yields: Crops grown in legume-based intercropping systems showed higher yields compared to mono-cropped systems. The complementary relationship between legumes and the maize crop improved overall productivity. These effects were significantly higher on Deep Bed Farming compared to ridges over two growing seasons.

 
These findings provide valuable insights into how legume intercropping in Deep Bed Farming systems can significantly improve crop yields and soil health, with important implications for:
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1. Sustainable agriculture: By improving soil fertility naturally, farmers can reduce their dependence on chemical fertilisers, which are often expensive and difficult to access. This makes farming more sustainable and cost-effective.
2. Food security: Higher yields mean more food can be produced on the same amount of land. This is crucial for smallholder farmers who rely on their harvests to feed their families and communities.
3. Economic benefits: Deep Bed Farming systems that incorporate legume-based intercropping not only enhance crop yields and soil health but also translate into tangible economic advantages. Reducing farmers’ reliance on chemical fertilisers lowers their input costs, thus improving their profit margins. Moreover, increased yields mean farmers have excess produce to sell, potentially leading to higher incomes for farmers.
4. Environmental benefits: Deep Bed Farming reduces soil erosion and helps retain soil moisture, which is important in regions prone to drought. The natural nitrogen-fixing process of legumes also reduces the environmental impact of farming.

The study suggests that expanded use of Deep Bed Farming systems incorporating legume intercropping could help address some of the biggest challenges faced by farmers in Malawi. By adopting these practices, farmers can improve their soil health, increase their crop yields, and make their farming practices more sustainable.

Read the full article here.

Reference: Phiri, A., Njira, K. and Dixon, A. (2024) ‘Comparative effects of legume-based intercropping systems involving pigeon pea and cowpea under deep-bed and conventional tillage systems in Malawi’, Agrosystems, Geosciences & Environment, 7(2), e20503

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