If a “Do Not Disturb” sign were posted on every piece of arable land, maybe then we would get the message that tilling the soil was a bad idea from the very beginning, and only got worse as we developed more efficient digging tools.
Soil scientists are finally getting the message and are loudly extolling the virtues of no till agriculture. However so far only a few in the agriculture community are listening. Until recently most of the soil scientists sided with the agriculturists. They assumed that mixing the soil layers, or horizons, created by Nature as it produces soil increases crop production.
They also said tilling suppresses the “harmful”(apparently unnecessary?) anaerobic bacteria mostly deep in the soil. Research has shown otherwise – that the ethylene anaerobic bacteria produce is essential to plant health, particularly in making anemia-preventing iron available to plants. Ethylene is also critical in the creation of stable humus and keeping root pathogens in check. Incidentally the term anaerobic is misleading as such bacteria need oxygen, but they get it from CO2 instead of O2. This means that soil dense with CO2 needs to be cycled in from time to time and then phased out as more oxygen rushes in. Tilling disrupts this cycling in and out.
No, Nature did not err during its millions of years of soil creation, and purposefully established layers, each with a necessary function for soil and plant health. The surface layer is rich in fungi which holds soil together, helping to resist the potential eroding effects of wind and water, and consequent pollution of our streams. Commonly the boundary between soil layers is not distinct so that water, organic matter, microbes, air and nutrients can pass freely from one layer to the next. This has proven to be a much better system than the mechanical mixing we have assumed was an improvement. The surface topsoil layer suffers the most when mixed with lower layers. Even a single initial tilling compromises the soil’s integrity, requiring five years or so, depending on the climate, soils and so forth, to regain its original layered arrangement.
In starting a garden on ground that has been deeply compacted an initial chiseling might be called for, or, in relatively small gardens, “lifting” the soil to achieve the necessary loosening, followed by cover cropping, as advocated in Permaculture manuals. I have found that even with a degraded or chemically dependent soil chemical fertilization can be abandoned immediately with a nitrogen rich mulch like grass clippings.
Our need is for food that is palatable, which happens to be mostly annuals, but perennials dominate in wild Nature. Annuals are very fast growing which gives them a big appetite, so a particularly deep mulch is needed to supply the necessary nutrients. Wide plant spacing helps in 
applying thick mulch, which must be added in increments to avoid the matting that occurs with a deep nitrogen-rich mulch. At first the plant roots will not venture far from the mulch layer but in time, with cover cropping and earthworm activity they will forage deeper.
A common criticism of no till gardening is that it would require us to go back to “hunting and gathering”, which is obviously not a possibility with the present large population. Some radical changes are required however. No one needs to go hungry but many of us will go hungry if long-distance transportation of food is not ended.. I feel much greater care would be given to the soils in one’s own country than soils in a far off land. Another change that I see would be in growing more vegetables and fruits and fewer grains, which means a more vegetarian diet. This change would result in increased health and even reduce the gap between the rich and the poor.
When humankind becomes serious in saving the planet and atmosphere no till agriculture and planting more trees, will become the norm as they are the most feasible way of sequestering carbon.
Nature welcomes each new species since species diversity provides ecosystem stability (self-correcting, self-organising capacity). So She has been heartbreakingly patient and even forgiving in our clumsy (read destructive) attempts to find a home here. It has been suggested, with great urgency, that the reason finding a constructive or creative niche has been so difficult for us is because of ego-interference, which divides the world into self and not-self. In Reality however everything arises within Nature, with no such division. Could it be true that saving civilization and the planet is primarily a Spiritual matter in the non-religious sense of transcending the ego? It has been reported that when such transcendence is complete there is not even a separate God.
