No-Dig means less weeds, less work and better productivity.
"In fact, the soil is more abundant with life and more complex than any other ecosystem above the ground. There are about 50 billion microbes in 1 tablespoon of soil. By comparison, the human population numbers just over 7 billion currently. These organisms include Bacteria, Actinomycetes, Fungi, Yeast, Protozoa, Algae and Nematodes. Furthermore there are arthropods and insects in there as well, including earthworms. That’s a lot of life in the soil!
The soil bacteria form a beneficial relationship with plant roots, and soil fungi form a beneficial relationship with tree roots, helping them access nutrients. The soil organisms carry out the important functions of nutrient cycling, improvement of soil structure to aid water and air movement through the soil and also the control of diseases and enhancement of plant growth. Most of the soil fungi occupy the top 15cm of the soil, while the rest of the organisms live at all different levels."
Digging or tilling disrupts this ecosystem and reduces plant health and productivity as well as encouraging germination of unwanted weeds.
"Digging and turning over the soil exposes a very delicate ecosystem to the air which dries it out, and to the ultraviolet rays of the sun, which sterilize the soil – killing the soil organisms. The soil loses a lot of its nutrients, such as carbon and nitrogen. It also loses a lot of its organic matter, and as a consequence, does not retain water as well. The delicate soil structure is destroyed, compaction of soil occurs, leading to hardpan formation, and reduced water infiltration in the soil, and more surface runoff, which increases soil erosion."