Annual rye - Hardy in zone 8b and germinates quickly. This is a moderately fast growing cover crop that will die back once the weather warms up in late May for East Texas. I mow my rye cover crop once it hits 8 inches tall. By mowing and leaving the clippings I provide green manure and reduce weed pressure. In East Texas weeds grow even in the winter. A tall, cold-hardy cover crop is essential. This cool season cover crop will also provide winter forage for animals.
Austrian peas - Hardy in zone 8b and in colder growing zones. Austrian peas are much more cold hardy than annual rye and will survive freezing temperatures down to about 18 below F. That is considerably colder than East Texas will possibly ever see. This cover crop is a nitrogen fixer. This means the plant accumulates nitrogen and as the plant decomposes when its season has ended, the nitrogen is released into the soil. This makes an excellent choice for areas that will remain fallow the following grow season.
Mustard - broadleaf mustard is hardy in zone 8b and attracts beneficial insects to the field or garden. This cover crop can be sown in late September and germinates quickly. Broadleaf mustard is one of the best cover crops for managing soil pests such as nematodes. For soil pest control, incorporate the crop back into the soil before it blooms. As the plant matter decomposes it produces a chemical called glucosinolate which produces thiocyanate, the sulfur compound that naturally biofumigates your garden soil.
Another benefit of broadleaf mustard is its ability to improve soil structure and loosen hard, compacted garden soil. If allowed to bloom it will attract early spring beneficial insects. It’s also edible, however once it blooms the leaves are bitter and not as pleasant tasting when cooked.
Buckwheat - makes an ideal cover crop for weed suppression between rotational growing. Sow buckwheat in the late summer. In East Texas, zone 8b this would be after Labor Day. It does not tolerate extreme heat and will wilt on excessively hot days. Buckwheat is a great additive to other cover crops you might be sowing in September or early October. It germinates quickly and prevents weed growth that might smother the second cover crop. Mixed with annual rye you will have the benefit of attracting beneficial pollinators to your late summer garden and reduce weed pressure that could choke out the annual rye seedlings before they are established. The first hard frost will kill Buckwheat. This is typically around the second week of November in East Texas, at which time your winter cover crop should be well established.
Over time, a cover crop regimen will increase soil organic matter, leading to improvements in soil structure, stability, and increased moisture and nutrient holding capacity for plant growth. Reducing runoff and improving filtration or added benefits of improved soil structure. source
A cover crop will increase soil quality by improving biological, chemical and physical soil properties.
Ready to grow your own cool season annuals? You might enjoy this post all about growing Cool Season Annuals
https://www.nrcs.usda.gov/wps/portal/nrcs/detail/ny/technical/?cid=nrcs144p2_027252#:~:text=A%20cover%20crop%20will%20increase,reducing%20nutrient%20runoff%20and%20leaching. accessed 10/16/22