From a gardener's perspective, the great Westward Movement by American pioneers was a logical search for new dirt. Soil used for many years without adequate restorative measures becomes "played out," lacking the nutrition and other qualities needed to support large or small crops. Increasing the bearing capacities of soil requires a variety of strategies. Using easily available services and simple tools, soil can be improved to increase plant production and yield.
Test the existing nutrition content and acid/alkaline balance of your soil. Purchase commercially available soil-test kits or contact your local County Extension office. County Extension testing focuses more closely on local conditions than nationally sold test kits, and test results will include specific recommendations for improving soil. When testing soil, take samples from several parts of your growing area. Large trees, other plantings, and even large rock outcroppings can affect soil quality.
Improve drainage problems that can affect your land's bearing ability. Standing water after rain suggests that you need to dig in amendments like sand or peat moss to aerate soil and prevent root-rot. Soil that always seems dry may need additional organic matter to improve water retention. Visible runoff in your planting area indicates that surface and below-surface nutrients are being washed away. Dig drains, raise beds, or create obstacles to interrupt or redirect runoff away from planting soil. Improving drainage will improve nutrient retention.
Dig in soil enrichments, like compost, fertilizer and manure, depending on your soil-test results. Work in enrichments to a depth of 12 inches, if possible, to encourage plants to develop deep root systems that foster greater growth. (Dealing with drainage issues first ensures that your soil will retain enrichments and improved nutrition for a longer time than before.) Schedule regular additions of enrichments as part of your soil maintenance routine.
Rotate plantings to avoid nutrition imbalance. Annual summer vegetables are notorious "heavy feeders." Change their locations within planting beds from one year to the next, to ensure adequate nutrition and soil recuperation. Tomatoes at the top of the bed move to the bottom next year, with beans planted where the tomatoes were.
Plant cover crops and other plants that add nutrition to soil. Clovers, grains and legumes refix nitrogen and add other nutrition when they are tilled into the ground before summer vegetable planting. Even small gardens can benefit from "wintering over" under a cover-crop: winter wheat, oats, and field peas are among these soil-improving crops.