In a new Frontiers publication, scientists from the International Maize and Wheat Improvement Center (CIMMYT) outline how to achieve an ecologically based approach to sustainable management of soil fertility, particularly for smallholders.
What is ecological nutrient management (ENM)?
Across the globe, smallholder farming communities only have limited resources to improve their financial and food security, and soil degradation is common. Ecological nutrient management (ENM), an agroecological approach to managing the biogeochemical cycles that regulate soil ecosystem services and soil fertility, can prevent degradation and preserve soil health.
Five principles guide ENM strategies:
- Building soil organic matter and other nutrient reserves.
- Minimizing the size of nitrogen (N) and phosphorus (P) pools that are most vulnerable to loss.
- Maximize agroecosystem capacity to use soluble, inorganic N and P.
- Use functional biodiversity to maximize presence of growing plants, biologically fix nitrogen and access sparingly soluble phosphorus.
- Construct agroecosystem and field scale mass balances to track net nutrient flows over multiple growing seasons.
Using functionally designed polycultures, diversified rotations, reduced fallow periods, increased reliance on legumes, integrated crop-livestock production, and use of a variety of soil amendments exemplify how ENM works in practice. A key principle is to underpin agroecosystem resilience through the promotion of soil organic matter accrual and restoration of soil function.
Strategic increases of spatial and temporal plant species diversity are used, that meet farmer requirements. This often involves perennial or semi-perennial bushes and vines that provide food, fuel and fodder while restoring soil fertility. ENM long-term management systems can increase yields, yield stability, profitability, and food security, thus addressing a range of smallholder needs.
Cover photo: A maize-bean intercrop that exemplifies the ENM approach, taken at CIMMYT’s Chiapas Hub, a long-term field experiment. (Photo: Sieg Snapp/CIMMYT)