I understand your desire for ...

I understand your desire for testing. I might suggest that you take current rainfall data, soil types and permeability %. Regardless of ANY testing or censoring equipment or any area  there will only be 2 conclusions. You have too much rainfall causing floods or too little rain causing desertification and destruction of an agricultural industry. Both situations are easily resolved. A) flood control plant more trees especially next to the river banks. Trees respirate up to 300 gallons a day. B) if red clay or desert sand just collect all...ALL of the trash grind it up and make compost, add microbes and water. You have just created soil. Next the soil will hold the moisture Large areas will be come humid. Humidity conducts electricity, it will magnetically attract more moisture which will cause more rainfall. Weather pattern will spiral up reversing the desertification process. New fam land and later forests. Regardless of which desert in the entire world none can change the laws of nature. Nature is a good teacher. Been around for a few billion years.