Plowing's Dark Secret


While the following study on the merits of plowing may not hold much significance for the majority of us, it does hold clear implications for many farmers in the U.S. and, more significantly, the millions living in Asia and Africa. In a study published online this week in the Proceedings of the National Academy of Sciences, the University of Washington's David Montgomery examined whether no-till farming — as opposed to plowing — prevented soil loss on a large scale.

No-till farming first came to the attention of conservationists when they realized that plows — and particularly the mechanized plows introduced in the 1930s — were accelerating soil loss, exposing dirt to rain and wind and lowering agricultural output. This technique helps protect the soil by leaving crop stubble on the surface and leaves fields unturned. Numerous case studies have revealed that no-till farming greatly reduces erosion.To determine if there really was a link between no-till farming and the prevention of soil loss on a large scale, Montgomery gathered a wealth of erosion data from all over the world and compared no-till erosion losses to those from plow-based farms. He found that plowless farms, on average, lost about 0.082 mm of soil each year — a rate close to the natural geologic rate of 0.03 mm/year — while plow-based farms lost about 1.5 mm of soil to erosion (almost 20 times as much). The latter lost soil 90 times faster than new soil was produced.

Indeed, as we've explained in the past, no-till farming holds many advantages over conventional farming: in addition to reducing erosion, it also helps retain water, reduces the energy needs for crop cultivation and raises the carbon content of soil. Farmers can simply drill their seeds through crop stubble into undisturbed soil.

Encouragingly, reports recently issued by the UN Food and Agriculture Organization (FAO) have described the rapid expansion of this method in Africa, Asia and Europe over the past few years.
Given the early level of success farmers in those regions have already experienced, we are likely to see this practice continue to grow.

Via ::ScienceNOW: The Dirty Truth About Plowing (news website)

See also: ::Shhhh, We've Got a Secret: Soil Solves Global Warming, Part 1, ::Losing Soil
Image courtesy of chasealpha1 via flickr

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