Our land (NE TX, variable rainfall, zone 7/ has historically been used for cattle grazing. We have a huge crop of wooly croton (better known locally as "stinkweed"). I'd say by biomass it outgrows the grass, and it has little use aside from seeds that are edible by ground birds (none appear to be in the area going by sightings, game camera pictures, etc).
"When these plants are abundant, they are generally associated with soil disturbance, lack of soil cover or overgrazing."
Our soil is very sandy (on top of a red clay base), and mostly compacted by the cows... so this fits. The local ag extension agent doesn't seem to know what kind of soil conditions it likes, what would outcompete it, or how to deal with it without involving herbicide.
The people we bought the land from only got it 4 years ago (they sold ~1/3 of their property), and say that they were told the soil needed to be limed. Lime increases the PH, which indicates that the soil is probably very acid (soil tests pending). I've researched liming, and it looks like distributing lime involves tilling the entire area that's being limed. That's a lot of work and a lot of soil disturbance.
We distributed a lot of clover seed last fall, and basically none of it took. We also tried planting some radish, okra, turnips, etc., and none of them took. The only edibles we've seen are a wild persimmon tree and some blackberry brambles.
1) What plants can be used to increase the pH of the soil and improve its quality?
2) What useful pioneer plants are likely to do well in the same conditions that stinkweed does?
3) Should we "give up" and just lime the soil?
4) Should we wait on swales until after the soil has been improved some? My concern is that we might put swales in and then have to till through them to distribute lime if we can't find a natural solution.
I wish I knew enough about acidic soil to be able to advise on what plants might make it more neutral. There are several species of native legumes which you might consider as support plants to improve the organic content of the soil, Illinois Bundleflower, Partridge Pea, and Prairie Clover. One source I know of is http://www.seedsource.com/
Personally I would install the swales first, then you can decide if you want to treat portions of the land with lime and other portions not, to see how each behaves. I think you would be able to add the lime to the soil at the time of planting your support species, after swale construction.
Lime doesnt need to be tilled in. Just spread it on top of the soil, you can even topdress it with a plane if you have to. Going from a Ph of 5.5 to 6 will give you more improvement in your soil then anything else, organic or conventional. I'm not sure how much lime that would take, probably a couple of ton per hectare. You'll get clover to grow, and probably find the stinkweed will get outcompeted by newer species as the soil improves.
I would build the swales now, add a meadow seed mix with at least 27 different plant species (n-fixer, biomass, root/nutrient saver, pest control)
Then if after a year or two you can add tons and tons of lime if your food forest is not improving. You also dont have to mix the lime in
If you are able to get ahold of large quantities of organic material, that could help. You could start by mulching heavily in ane area to create an "oasis" where you could then grow mulch and shade to expand the improved area.
Timing can also be a factor in seed failure. You could try encasing you seed in clay balls to protect it until conditions are right, or try scattering smaller batches of seed at different times to get a better idea what works in your area.
I am surprised that the sand is compacted, so much. Also when is your rainy season, how much rain do you get. Alot of vegetables will reach maturity in less than 60 days. So if you soak your seed and then sow at the start of the rainy season then they will grow and then reseed waiting for the next rainy period. You could digg down to the clay and plan in that. experiment and see what happens. try some beans and peas maybe they will grow a faster tap root than clover thus hitting the soil moisture.
Iterations are fine, we don't have to be perfect
Anderson gave himself the promotion. So I gave myself this tiny ad: