I am a former principal scientist at ICRISAT Sahelian Center in Niamey, Niger. I would like make some comments regarding your V0 draft of the report “Agroecological approaches and other innovations for sustainable agriculture and food systems that enhance food security and nutrition. I apologise for the tardiness of my reaction, due to five funerals in the past month. I hope you can still have a look at my suggestions about two subjects that I feel are missing in your draft: the role of soil variability and the role of wetlands and their interaction with surrounding drylands, especially in semi-arid regions. To keep this message to a manageable size I will discuss the role of wetlands in semi-arid areas in a separate message.
The role of within-field soil and crop growth variability in semi-arid areas
In western, mechanised agriculture, where production circumstances can often be controlled to a large degree, homogeneity is desirable because it promotes homogeneous crop development. For subsistence farmers, however, who can control their production circumstances only to a very limited extent, homogeneity increases the risk of complete crop failure, especially in semi-arid regions. Soil variability can help spread risks for such farmers, risks caused by too little or too much rain as well as risks caused by pests and diseases.
I attach for you a 12-page, well illustrated brochure (pictures plus captions tell the story) on the role of soil and crop growth variability in the Sahel, based on peer-reviewed research. In my opinion many of the findings included in the brochure are also valid for other semi-arid regions, and some perhaps even in higher rainfall areas. The roles of trees (especially Faidherbia albida) and large mound-building termites (Macrotermes) are also discussed. See also the summary included below.
For your further I also attach my list of publications on dryland agriculture in the Sahel. Feel free to ask for more information on any of those publications. I attach the pdf’s of two key publications from that list:
- on the risk reducing potential of soil and crop growth variability (Brouwer et a. 1993)
- and on spatial variability of nutrient leaching (including P, on sandy soils) and ways of reducing leaching losses of animal manure (Brouwer & Powell 1997).
In Brouwer & Bouma (1997, not attached) the roles of other tree species are discussed, among many other things.
I hope you find this of use. Do feel free to contact me for further input.
With my best wishes for your very useful report,
Kind regards, Joost Brouwer