Desert greening is transforming dust and sand into farmable soil (2023)
freethink.com
freethink.com
Before you accumulate organics, you change how surface water is captured and absorbed into the ground. It can be as simple as shallow trenches or holes (no deeper than a few feet) to slow down water. That then supports the trees, which starts the ecological succession to reverse desertification.
Sometimes, you don't even need to seed it. Just slowing down water is enough to get the process started.
I'd say though, the biggest factor in turning arable land into desert is our modern, industrial-scale agricultural practices. Mainstream-adjacent methods such as polycropping, agroforestry, integrating livestock grazing, etc. yields more resilient farming systems than the usual practice of annually stripping away topsoil, let alone more divergent practices such as perennial food forests.
A good example is the moringa forest someone grew in their Phoenix, AZ front yard -- a city built in the lower Sonoran desert. Moringas are heat-seeking, drought-tolerant, fast-growing, and that guy's front-yard developed a canopy under which he grew more sun-sensitive plants. (Stuff labeled "full sun" does not mean "full Arizona sun).
The _simplest_ method for reversing desertification is to work with the natural tendencies so it does most of the work for you. That is, you jump start ecological succession away from desertification. You don't start with trees. You start by changing how rainwater is captured. In arid and semi-arid wastelands, although there isn't much rainwater, when it does come, it sheets off the ground. Rainwater harvesting structures as simple as swales (on-contour trenches), or even wide, shallow circles, capture just enough water for ecological succession to kick off. Planting things comes after, and helps accelerate ecological succession.
It's a shame the current climate narrative is so negative, when there's potential life and opportunity to be had, which could stem the flow of people feeling the need to uproot themselves and be refugees on other sides of the planet.