Buffering soil water supply to crops by hydraulic equilibration in conservation agriculture with deep-rooted trees: application of a process-based tree

Farmers deal with risks such as weather, pests, diseases, costs of inputs, market
prices of products, (family) labour availability, policies regulating land use and, in
some contexts, open interpersonal conflict. Perennial components of agricultural
systems, especially trees, provide buffer and filter functions that modify, and
generally reduce, the farmers’ sensitivity to such external variables. Maintaining
a diversity of activities is a time-tested approach to reducing risks (van Noordwijk
et al. 1994). The inclusion of trees that provide annual harvests of fruits or longterm
high-value timber can reduce risk, even if the trade-off in resource capture
is essentially neutral (Santos-Martin and van Noordwijk 2011). Trees shelter
farmers from climate variability and assist in adaptation to longer-term trends (van
Noordwijk et al. 2011a).