I'm very excited to have found your thread, I've spent hours pouring over it today. Unfortunately I don't think I have very much permaculture wisdom to impart that hasn't already been passed on, but permaculture application in Chad is something that has been on my mind and heart for years and is even what had originally inspired me to dig into permaculture in my home in the midwest USA starting ~5 years ago.
I've spent a decent amount of time in Chad over the last several years, and have dear friends in Chad, multiple families, who have been living in the country for nearly a decade. The challenges are so real. My heart hurt with every familiar challenge you described, that is such a struggle to relay to other well-intention poster who hasn't experienced it. The nomadic tribes and roaming livestock, the views on ownership, the termites, the dryness! I laugh at our aversion to bare soil, if only! All of my time spent in Chad (Mostly in Salamat) was in the April/May, so I only got to see the dryest hottest portions time of the year and never got to see the rainy season.
We understand permaculture as a system, and it's the challenges you face that show just how far that system extends beyond just the boundaries of your plot that lead to successful harvest. Societal, cultural, infrastructure, spiritual. I'm reminded how much we in developed nations and western cultures take for granted in the systems we enjoy that support our efforts.
I'm so excited to hear about and keep up with and support you in your efforts.
It was my visits to Chad and seeing the struggles there specifically that have inspired me to try to create digital technologies / web based tools to help enable better sharing of information and technique related to regenerative/sustainable agriculture for regional/climate specific challenges. This forum is great, but there is a wealth of articles/blogs/scientific literature that is probably applicable as well, and nothing to structure it for your needs. I want to structure it and make it available to the millions coming online via smartphones every year. I see so much opportunity for better connection of existing resources and information to those in challenging climates to be connected with others who are experimenting and have solved problems they're facing.
I'm burdened for Chad and other developing nations and their agricultural practices. The practices that are going to receive funding, training, resources, be it via NGO support, local government, World Bank / WHO funding, or commercially, are going to all be based on industrial practices where there is commercial interest or mainstream commercial agricultural support. Indigenous and sustainable practices will be lost. What I saw in Chad was a history of misuse, mis-application, and destructive practices that we've even already learned from in the 'western' world but those mistakes we've made and learned from have not been caught up on. I never got a picture, but if you could find some of the large scale 'agricultural fields' in Chad during the dry season and post it here, the vastness of the dry cracked nothingness extending for miles, it is astonishing.
One of the families I spent time with spent a lot of time learning, experimenting, and trying to grow and be fruitful and I tried to assist with ideas/inspiration as I could, though I certainly didn't have as good of advice as the masses on this forum. That family was successful with raising rabbits, banana circles, and several trees in their limited/typical sized lot in Am Timan. Malabar Spinach was a favorite I don't think I've seen mentioned yet. Chickens were great to combat the scorpions and other pests. Their brick-stone wall surrounding their plot was instrumental in their ability to create a good microclimate for living, growing. It protected from the roaming livestock and wind. With eventual shade from trees, and walls to keep the cool air in moisture in, it made a tremendous difference. It was culturally acceptable for them, it was standard in their location. Everyone had one. It would seem like that should be a high priority for you, though I know you have a sizable lot.
One of the tools I've created helps you find your climate analogue. It takes the city you input, considers its Köppen-Geiger climate classification as well as your elevation and latitude, and looks for other cities in the world with similarities. Learning these cities can help you expand your research base. There are probably not a lot resources written for Boudamasa, but there are a good number of other cities around the world that have similar characteristics that might help you learn other ideas/techniques/inspiration.
Here are the analogues for Boudamasa:
There are cities (some quite large, >1million in population) in Nigeria, Venezuela, Columbia, Burkina Faso, Sudan, Peru, Ethiopia, Brazil, Curaçao, Cameroon, Angola, CAR, and Samolia with similar characteristics. This tool doesn't verify an exact match, eg their wet/dry seasons may be different than yours, but they might enable more research possibilities.
I hope you can take a respite at Zakouma at some point. You should consider it important for your native wildlife and plant life, and permaculture related studies and observations.
Finally, if you've never heard of CLTS (Community Lead Total Sanitation), I'd recommend you check it out. My friends in Chad were involved with this program for a brief time, in seeking to help eliminate open deification in some of the communities they served. I believe, though I have never validated or developed this idea, that some of the principles in this approach could be powerful and/or helpful in considering ways to introduce helpful change and support in the community for some of the things you may be looking to implement.
A good book that briefly covers the CLTS approach, and a book I recommend for ANYONE that seeks to influence, is "The Power of Moments" by Chip and Dan Heath. Fascinating book, and good brief coverage of CLTS, and speaks to why I think this methodology may have merit to your situation.
I wish you the best and hope to hear more from you as the years go on. If you have a blog or ministry email list I'd love to be added. I can connect you with some tremendous people in NDJ, hopefully you are already well-connected and supported 'locally'.