The Dust Bowl crippled the Great Plains states in the 1930s and 40s because of poor soil management in the decades before that.
The mistakes made were partly because of economics – farmers were rewarded for expanding their acreage in order to satisfy the demand for corn and wheat to supply troops in World War I. But the mistakes were also due to the fact that most farmers did not understand the effect of plowing under the native prairie grasses to make room for cash crops. And, after World War II, the popular thing was to make use of the bountiful supply of anhydrous ammonia (high in nitrogen) for supplying the nutrients lost to oxidation and erosion.
Annual ryegrass is akin to those native prairie grasses in at least one respect: they all have very deep roots. And, as you know, it is the roots that protect the soil surface from erosion. Modern agricultural methods include cover cropping, which prevents nutrients from eroding off the property. No more waste of topsoil; less need for adding nutrient inputs to bolster anemic soil.
The other key factor with annual ryegrass’ deep roots is that they seek moisture and nutrients in deeper soil. Roots grow to depths of 6 feet in some places. The benefit is that roots from ryegrass create channels for the corn and soybeans to follow. Once the cover crop is killed in the spring, the roots die and add to the organic matter in the soil, in addition to creating pathways for new rooting crops and infiltration of snow melt and rain.
The annual ryegrass website has tons of good information about growing this cover crop. There are videos, too, and you need only click here. Finally, No-Till Farmer magazine has an article that talks more about the benefits of annual ryegrass.