Photo: Farm in Kenya, Alex Ruane

By Marc Corbeels, Ken Boote and Carolyn Mutter

Smallholders systems are often characterized by low soil fertility due to limited use of fertilizer inputs and ongoing soil degradation. This affects how crop respond to climate change. But many crop models were created for high fertility cropping systems. How well do they work in other systems?

The predictive capacity of crop models under climate change in low soil fertility / low input cropping systems characteristic of the tropics and subtropics needs to be improved in consideration of the following factors:

  1. Degraded soil systems with minimal fertilizer inputs may be more sensitive to other crop growth limiting factors than weather and CO2 changes.
  2. Climate change is likely to strongly affect soil fertility and the ability of crops to acquire and utilize soil water and nutrients in the tropics and subtropics.
  3. Low-input farmers may have limited means to cope with climate change, compared to well-capitalized, high-input farms.

CIRAD, in collaboration with CGIAR centers and CCAFS, is proposing a new AgMIP Activity on crop growth model intercomparison and improvement for interactions of climate change and low soil fertility/low input cropping systems in the tropics and subtropics.