Perceived wisdom amongst gardeners is that you dig the soil over every winter/spring in preparation for spring crops. Likewise, farmers plough fields and do secondary cultivations such as rotavating or harrowing. It's almost taken as read - that's how it's always been done, so why question it?
There are many good reasons for digging or cultivating. But there are equally as many bad ones, largely relating to soil health. See, the problem is, we just don't understand enough that soil is an incredible ecosystem - complex, rich, diverse and supports life when treated well. The standard to which many farmers treat their soil is truly abysmal, seeing it as nothing more than a medium in which to grow plants and pour on agro-chemicals.rivers), is quite incredible - and yet most people disregard its vital importance. A single teaspoonfull of healthy soil contains billions of organisms!!
I decided to start an experiment last year to see just how good no-dig growing is. I've been inspired by the wonderful Charles Dowding, who is a real pioneer of the no-dig approach, having an excellent 1.5 acre growing site and has written an excellent book, Organic Gardening. To think that just a 6 inch deep layer of soil, across the world, supports almost the entire human population (bar products from seas and rivers) is incredible.
In the picture is a field of lettuce, taken last June. The three beds on the right have lettuce grown through white plastic, to minimise water loss and weed invasion. On the left are two beds that have just a layer of mature compost (about an inch or two's depth when laid), and then not cultivated.
There was no difference in the growth rates between the two and it was noticeable that whilst (of course) more weeds came up on the left, they got fewer through the season, because the soil wasn't being turned over. It also looks a lot better and doesn't involve any plastic.
For this reason I will be expanding the area I use zero tillage, looking carefully at the effects it has on soil quality, water holding capacity and weed burden over time. I'll come back to this subject in the summer.