There is a saying, feed the soil to feed the plants. As things wind down in the garden, you have a chance to evaluate the health of your soil.
The Maryland Soil Health Card provides information to help you determine the health of your garden soil. Although written for farmers, there is a lot of valuable information the home gardener can use. The health card rates seven soil parameters, including surface residue, infiltration, compaction, organic matter, soil structure, earthworms and soil odor. You can download the score card at: https://extension.umd.edu/sites/extension.umd.edu/files/_images/uploaded/FINAL_MARYLAND_NRCS_Soil_Health_Card_12_16.pdf.
Watch a 13 minute video, How to use the Maryland Soil Health Card at https://www.youtube.com/watch?v=GE2QWaPQ7Sk) which explains how to rate your soil. A shovel, some water, a pin flag (or the cut off section of the longest side of a wire clothes hanger), tape measure and stopwatch are all that you need. Many of these parameters need to be assessed in the fall or spring when there is sufficient moisture in the soil.
If you are not already doing it, try the following to improve your soil health. Always keep soil covered with plants or mulch, to increase water infiltration and reduce erosion and runoff. You can use the pulled-up tops of your regular crops as a mulch for the winter if they don’t have a disease or insect pest. You can also lay grass clippings, leaves, etc. as a mulch to intercept the force of falling raindrops. Planting a grain-type of cover crop will protect the soil from erosion.
Mustard cover crops, in the Brassica family, have long tap roots which will break up compacted soils and pull up micronutrients and bring them into the growing zone for regular crops. Their deep roots increase water infiltration which reduces runoff.
Incorporating compost will add organic matter which in turn will benefit soil structure and texture. This will improve the habitat for soil micro and macroinvertebrates, like earthworms. An easy measure of one of the soil health parameters is the earthworm test. Dig up a shovelful of soil and count how many worms you find. For this, you can include any grubs that are present. A count of 9-11 is excellent, 6-8 is good, 3-5 is fair and 0-2 poor (your soil is calling for help).
If you have grown a legume, such as peas or beans, cut the plant at the soil line after harvest and leave the roots in the ground. Assuming Rhizobia bacteria are present in your soil and have created nitrogen-fixing nodules on the roots, nitrogen will be released into the soil as the roots break down over the winter.
Most cover crops are cold season plants, so can be planted in fall after harvest or early spring before regular planting in the space where regular crops grow. They can also be planted between rows of regular crops during the growing season. Cover crops need to be rotated just as you would rotate your regular crops. Planting brassicas and peas in the same space several years in a row can deplete some soil nutrients. Particular cover crops can help in weed suppression. Other cover crops support pollinators, if allowed to bloom before termination. For more information on cover crops see: https://extension.umd.edu/sites/extension.umd.edu/files/_images/programs/hgic/Publications/GE006_ProtectAndImproveYourSoilWithCoverCrops.pdf.