In Nigeria, many farmers face the challenge of degraded soil, soils that have lost their fertility and structure due to continuous cropping, erosion, and overuse of chemical fertilisers. Cover crops are one proven and sustainable way to restore soil vitality. Cover cropping protects the soil from erosion, rebuilds its organic matter, enhances nutrient cycling, and improves overall soil fertility. 

This blog post explores how cover crops can rejuvenate Nigerian soils, advocating sustainable agriculture.

What Are Cover Crops and Why Do They Matter?

Cover crops are plants sown primarily to cover the soil rather than for harvest. They act as green manures by enriching the soil with organic matter and nutrients. Many cover crops, especially leguminous ones like cowpeas and mucuna, can fix atmospheric nitrogen into the soil through symbiosis with soil bacteria. This natural nitrogen fixation reduces the need for synthetic fertilisers, which are costly and can harm soil health in the long term.

Beyond nutrient enrichment, cover crops offer other benefits vital to Nigerian farmers:

• Erosion control: Their roots keep the soil intact during heavy rains, reducing the loss of topsoil.
• Weed suppression: Dense cover crops shade the soil, making it harder for weeds to establish.
• Soil structure improvement: Organic matter from cover crop residues improves soil aeration and moisture retention.
• Pest and disease management: Certain cover crops reduce populations of harmful soil nematodes and pests.

Cover Crops for Nigerian Farmers

Several cover crops are well-suited to Nigeria’s diverse agro-ecological zones. These include:

• Cowpea (Vigna unguiculata): A versatile legume that fixes nitrogen and provides fodder.
• Mucuna (Mucuna pruriens): Known as velvet bean, it grows vigorously, suppresses weeds, and improves soil organic matter.
• Soybean (Glycine max): Enhances soil nitrogen and serves as a food and a cash crop.
• Pigeon pea (Cajanus cajan): Drought-tolerant with deep roots that improve soil structure.
• Groundnut (Arachis hypogaea): Fixes nitrogen and improves soil texture.

Dr. Rose Gidado, country coordinator of the Open Forum on Agricultural Biotechnology (OFAB) Nigeria chapter, emphasises innovative agricultural practices to increase yields. Though she focuses on biotechnology, she supports integrated approaches, including cover cropping, to improve soil fertility and empower Nigerian farmers toward food security.

How to Integrate Cover Crops into Your Farming System

To maximise the benefits of cover crops and bring your soil back to life, consider the following practical tips:

1. Choose the right cover crops: Depending on your soil needs, select legumes for nitrogen fixation or grasses for erosion control.
2. Plant at appropriate times: Cover crops are usually sown after harvesting main crops or during off-seasons to protect and enrich fallow soil.
3. Manage cover crop growth: Incorporate or mow cover crops before seed set to prevent them from becoming weeds or competing with main crops.
4. Use crop rotation: Alternate cover crops with cereals or tubers to break pest cycles and balance nutrient use.
5. Combine with organic amendments: Adding compost or manure alongside cover crops enhances soil microbial activity and fertility gains.

Cover crops are a powerful, natural solution to Nigeria’s soil fertility challenges. By planting cover crops suited to local conditions, Nigerian farmers can restore degraded soils, reduce reliance on expensive chemical fertilisers, increase yields, and improve resilience to climate change.