Tilling kills the soil ― and we know it since the 1940’s
In Summer of 1943, as World War II raged on around the planet, a quieter, more discreet phenomenon of equally world-encompassing proportions took place in the small town of Elyria, Ohio. A local investigator, by the name Edward H. Faulkner (1886-1964), published a provocative book with a provocative tittle: “Plowman’s Folly”. Whereas half of the world was occupied in killing the other half, Faulkner had been concerned about keeping everyone fed by preventing us from starving ourselves by killing the source of our food: the soil. And so, in the very first chapter of his book, he plainly stated:
Briefly, this book sets out to show that the moldboard plow which is in use on farms throughout the civilized world is the least satisfactory implement for the preparation of land for the production of crops… The truth is that no one has ever advanced a scientific reason for plowing. (Plowman's Folly, p. 3).
Fast forward sixty-five years and you’ve got the Food and Agriculture Organization of the United Nations listing the following medium and long-term negative consequences of tilling, in 2008:
- Raised risks of losses of water as runoff; of soil as ‘sediment’; of applied inputs – energy, seeds, fertilizers, pesticides;
- Diminished capacities for capture and slow release of both plant nutrients and water;
- Diminished quality of the soil as a rooting environment;
- Diminishing yields, at level costs, year by year; conversely, level yields maintained at rising costs;
- Diminished activity and diversity of soil organisms;
- Lowered resilience of the soil/plant system to adverse conditions;
- Reduced output/input ratios, indicating falling efficiencies of use of inputs;
- Diminished sustainability of farming enterprises.
The idea behind Faulkner’s book is the same idea that animates, nowadays, the movement for Conservation Agriculture: soil is not an abiotic component which has a certain fixed quality (there are no ‘good’ soils or ‘bad’ soils), but a biotic component of the ecosystem whose overall health can be measured, and either improved to make it more productive or decreased up to the point where one may talk of a ‘dead’ soil: a sterile, barren piece of land which has almost no organic matter and no life whatsoever.
This quinoa field in Bolivia is ploughed deeply, which exposes it to wind erosion. When it is not being cultivated, as shown in the picture, it cannot grow any other sort of plant life by itself.
Tilling harms the health of the soil and can ultimately lead to its death, by disturbing every single component of soil health: physically, it grinds the soil to a powder which either compacts tightly or washes away with rain and wind (and then you get the Dust Bowl all over again!), which then in turn disturbs the capability of the soil to absorb and retain water. Biologically, breaking soil open and removing it thoroughly interrupts every single life cycle of every single creature, from earthworms and other beneficial insects to mycorrhizal fungi and beneficial microbiota. Then, as a consequence of these three factors, the chemical composition of the soil is altered and impoverished, producing a reduction of yields to half of their original level in around thirty years, as a case study of maize farms in Kenya showed.
The solution to all of these problems is switching to no-till agriculture, as part of a general switch to Conservation Agriculture as recommended by the FAO, and as important percentages of the world’s farmers are doing today. According to this 2010 paper, only between 1999 and 2009, the number of hectares cultivated under the no-tillage model rose over 150% worldwide, from 45 million hectares to 111 million, and, according to the sources listed here, with an accompanying rise of 77% or 57% in net farm incomes in farms of countries like Paraguay (where 90% of agriculture is non-tillage agriculture) or Brazil (where 50% is non-tillage).
Not tilling the soil is but one part of the three-aspects model of Conservation Agriculture (alongside keeping the soil covered with some main or cover crop and diversifying crop production, to avoid monoculture), but it is probably the most important of them all. And when coupled with the use of organic fertilisers that build up the soil and the soil biology, by inoculating it with varieties of beneficial bacteria and mycorrhizal fungi, it can be the way to not only prevent the destruction of soils but repair a lot of those who have been already damaged. As the FAO states in its own website:
Soils under CA generally improve with time. This means the rate of degradation and erosion is less than the rate of soil build-up. For this reason even highly degraded soils should improve and become productive under CA.