Cashew nuts bring a good profit to many West African farmers. In some places, farmers have chosen to grow cashews rather than cotton or cocoa, and cashew has helped many countries expand their exports beyond these two crops.
Cashew trees also help fight desertification and soil erosion. The trees can survive in difficult conditions, including sandy soil.
For more information about the “cashew boom” in Cote d’Ivoire, read this story from Africa Renewal: https://www.un.org/africarenewal/magazine/august-2015/cashing-cashew-nuts-boom 
Harvest time is February through June. Good harvesting and post-harvesting practices help produce a superior product that can fetch a higher price. Some tips:
- Collect nuts when the fruit has fallen to the ground. In hot areas, fruits may need to be collected daily.
- Detach the nut from the fruit using a nylon thread or sharp knife.
- Air dry nuts in the shade for 3-4 days. Avoid drying indoors or on metallic surfaces in the sun.
- Store well-dried nuts in jute sacks and stitch them tight to avoid spillage.
- Sell the nuts the same year they’re harvested to prevent loss in quality.
For more information on good post-harvest practices, read this guide from the UN Food and Agriculture Organization.
Guide to harvesting and post-harvest handling of cashew nuts: http://www.fao.org/3/CA2985EN/ca2985en.pdf