Mexican farmers see conservation agriculture in the highland tropics

Faced with rapidly degrading soils and dwindling water supplies, Mexican farmers and researchers have sought with renewed vigor in recent years to apply conservation agriculture principles—reduced tillage, retention of crop residues, and relevant rotations. CIMMYT has long supported Mexico’s efforts in conservation agriculture, both in basic research and in its applications.

As part of a traveling seminar organized by the “Asociación para la Agricultura Sostenible en base a Siembra Directa” (the Association for Sustainable Agriculture based on Direct Seeding, ASOSID), headquartered in Mexico’s El Bajío region, 32 farmer members and 7 researcher/extensionists visited CIMMYT’s Toluca and El Batán research stations during 6- 7 September 2007 to learn how conservation agriculture can be pursued in rainfed, highland environments.

At Toluca the group saw first-hand the work of superintendent Fernando Delgado, who is applying zero-tillage with residue retention on the station and assisting maize farmers of the Toluca Valley in adopting the practices. Early the following morning the group visited the long-term conservation agriculture trial begun at El Batán in 1991, for a presentation and discussion with Nele Verhulst, PhD student from the KULeuven, Belgium, and Chilean student Andrea Chocobar Guerra, working at CIMMYT on her MSc thesis.

The Association was launched in 2002, with support from CIMMYT and several Mexican organizations working in conservation agriculture at the time. According to ASOSID Technical Coordinator, Óscar Contreras Mejía (photo inset above), early efforts to disseminate conservation agriculture in El Bajío went fast, trying to reach as many farmers as possible.

“Things are going a bit slower now—we’re consolidating the technical side,” he says. Now roughly 80% of the area of participating farmers is under zero-tillage.”

Contreras cites as two major technical challenges the introduction of crop rotations in El Bajío, a central Mexico breadbasket where irrigated monoculture has dominated, and managing the large amounts of crop residues that are produced.

“Those could easily be sold for forage, but because we have problems of diminishing soil organic matter, we want to keep residues on the field,” Contreras explains.

Reflecting emerging circumstances in many intensive, irrigated cropping regions of the developing world, Mexico’s El Bajío is facing mounting problems relating, among other things, to improper use of agrochemicals and water. A recent report in the Mexican daily “El Sol de México” said the water table in the state of Guanajuato, in El Bajío, is falling at a rate of 1-3 meters per year. Conservation agriculture provides one avenue for addressing these problems.