There’s really only a few ways to control grass/weeds.
-Smothering (i.e. mulch, plastic or organic, weed barrier)
-Cultivation (popular with farmers before herbicides, the drawback being some damaged roots, erosion, loss of organic matter)
-Animals (not very popular with commercial operations because of potential damage to the trees, and because of new food safety regulations)
Most operations (probably 95%) of the size you mention use herbicides, unless they are growing in a place with little organic matter and essentially no rain (i.e. parts of CA).
I use a combination of organic mulch and herbicide.