No way to ask around for what they use in your place?
Beans are staple food, so you should find, and I would be curious to know what is available there...
If there is any chance that tagasaste might help, it has been much used in Australia, and it comes from my place, I grow it too, though it likes higher altitudes 800-1000m). But this is a bush, you can coppice it. Very good forage.
We also have around 600mm of water, but in winter.
If I understand you crrectly, you want a cover crop for the rainy season, not the dry season. This link has some possibilities for your area:
Zim Lion wrote:we are in the communal lands, each family has a homestead and are subsistence farmers.
So, they keep their seeds one year for the next, don't they? Can't they help you?
Then, you can order on internet...
Zim Lion wrote: the idea is for our homestead to be a permaculture model in the community where there is a growing use of pesticides and fertilizers etc.
Sure, when one does not know what's next to it, it seems so easy and so much an improvement! Great project then. Do the people of the area know you well, where are you from?
Zim Lion wrote: I have made a blog on the project which is focusing on the process if building a cob house at the moment. http://dancelikeanelephant.blogspot.com
Wow Zim, that's gonna be one majorly cool house. And it looks like such great fun making it.
I'm sorry I have only seen your post now! I was looking through permies to see if there were any other people posting from zim and came across my old thread. Did you move to the farm in gweru?
We moved into our earthen home 8 months ago and love it, I have found that there are good cover crops here, cow peas are around but have a different name, nyemba beans, lots of pumpkins watermelons, ground nuts that fix nitrogen. Have planted morninga trees and more, have fun trying everything out.