My last article discussed having better soil by not disturbing it. Another reason for not disturbing the soil is that it contains billions and billions of seeds deposited over no telling how many years. Many are just waiting for an opportunity to sprout. Disturbing the soil gives them that opportunity. Tilling a new garden three years ago that contained solid prairie grasses resulted in a massive invasion (upwards of 100 square feet) of Nut Sedge!
If one must till, two rules are recommended. First, till in colder/cooler weather, as it minimizes microbiological organism damage. Second, cover the soil immediately with mulch, or cover crops. I recently saw a new tractor designed to seed legumes in actively growing corn fields. The legumes will replace some of the nitrogen being used by the corn and keep the soil cooler. If legume cover crops are killed (without tilling) before their seeds ripen, they will leave the soil with more nitrogen than they used. Even if allowed to go to full seed ripening, they will leave the soil with as much nitrogen as they used.
A major objective of organic gardening is to build or at least maintain organic material in the soil. More organic (non-synthetic) fertilizers are now coming on the market that are reasonable priced and work very well. Products range from liquid foliar products to numerous solids, coming mostly from chicken litter, bone, bone and meat, feather, fish and blood meals. A few are water soluble, but many are left on the surface to slowly release their contents into the soil. One of the best improvements, however, comes from cover crops. These crops grab and hold nutrients in their roots and leaves. Killing these cover crops later releases their above and below ground nutrients for other crops, all while keeping the soil covered.