Science and Society: Conservation agriculture

2012-10-24T00:04:06Z Science and Society: Conservation agricultureDuane Jeffery - Correspondent Daily Herald
October 24, 2012 12:04 am  • 

The plow is one of the most important inventions in the history of agriculture. Prior to its invention, people depended on digging sticks, either scratched along by hand or pulled by a draft animal. But they were hard work and very inefficient.

The objective, of course, was to break up the ground, most of which had been developing in place for millennia and was heavily crusted or held in place by native vegetation (for example, grasslands), so as to expose the softer and moister soil underneath. This provided a much better seedbed for crops, most of which were sufficiently genetically altered from their ancestral states as to be only poorly competitive with established vegetation.

Then came the plow -- but for centuries, plows were cumbersome wooden things. Then in 1846 a chap named John Deere invented plows with steel moldboards that cut a clean furrow and turned the soil over in nice, soft rows.

But plowing also exposes soil to erosion by wind and water, and the world's fields have been losing soil ever since. In an effort to preserve that precious resource, scientists have been experimenting with "no-till" or "low-till" agriculture. This is for soils that have already been broken up and farmed, so we're not dealing with ancient crusts. And such tillage techniques constitute a fundamental part of modern "conservation agriculture."

Conservation agriculture also encourages farmers to leave the post-harvest crop residue on their fields, rather than burning it off as has been done by cultures around the world for millennia. It attempts to build soil quality, promote better yields, reduce erosion, and lessen reliance on artificial fertilizers, herbicides and insecticides. Clearly, successful programs will be a boon, especially for developing countries.

The Howard G. Buffett Foundation is a private family foundation begun in 1999 that focuses on promoting conservation agriculture in Africa and Central America. They have taken the unusual step of publishing a review of what other groups have learned, "Ten Truths About Conservation Agriculture and Smallholder Farmers" in the Sept. 6 issue of the journal Nature.

First, "smallholder farmers who adopt integrated conservation practices can realize a higher return on investment in terms of labor savings, net income and improved soil quality"-- even in their first year. But this requires combined education programs and site-specific analyses for use of crop residue (some residues are used for feeding livestock). Herbicide use for weed control can be reduced by diverse crop rotations. Building local farmer organizations leads to identification of crop varieties best adapted for specific local conditions, and this characteristically leads to increased crop yields. The focus on soil health and diversity of crops reduces the risk of crop failures. Synthetic fertilizers can be made more efficient with conservation agriculture methods.

But combined efforts and education are clearly critical. Traditional mindsets can be very resistant to change, and it is local people making the initial trials and then promulgating the beneficial results that make the difference. Farmers grouped together make decisions for the long term. They can purchase and share tools and equipment that few, if any, of them could afford singly. And when they become partners in the enterprise, they become part of a team. In Zimbabwe, for instance, Catholic Relief Services signed up 650 farmers to try the new methods.

Five years later, 54,416 farmers were involved. In Mexico's Yaqui Valley nearly all farmers burned the residue from their corn and wheat fields each year. But observation of the results of conservation agriculture changed all that. A decade later, nearly all the farmers use their residue for soil improvement instead.

These practices will not solve all the world's food problems, but they are critical in working toward that end.

Duane Jeffery is an emeritus professor of biology at Brigham Young University.

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