Bringing Conservation Agriculture Home to Mexico
As part of efforts to promote resource-conserving farm practices worldwide, CIMMYT is now looking closer to home, adopting reduced tillage practices on its research stations in Mexico and helping to promote conservation agriculture among the country's researchers and farmers.
"I didn't draw any blueprints," says Homero Guevara Mata, head of machine maintenance at the center's El Batán station, who approaches his work with a sculptor's self-assurance, going directly from a concept to the metal. He and his team designed and built five of these direct seeding implements in just seven months. "We've tested them here on the station, and they really work!" |
Where Has All the Topsoil Gone?
Soil fertility and productivity are declining on many farms in
the developing world. Soil erosion is widespread, and farming practices
often extract organic matter without ever replacing it. This means that
precipitation runs off, without being absorbed and used by crops. More
and more land is falling into deserts. After many years of irrigation
in some crop areas, the minerals left behind make soils saline and impossible
to farm. Conventional tillage, where land is heavily plowed, causes some
of these problems or makes them worse. There are several ways to fight
these conditions and help keep soils healthy and productive. The two most
important involve reducing soil disturbance to a minimum and keeping a
cover of crop residues on the surface. Crop rotations and green manure
cover crops can also help. Together, these types of practices are known
as “conservation agriculture”— basically because they
work to conserve the soil, water, and other resources on which farmers
depend. The many benefits of conservation agriculture include: better
infiltration and retention of moisture, reduced soil erosion; savings
in labor, water, and machinery use; higher yields; increased soil organic
matter; reduced carbon emissions from tractor use or irrigation pumping;
and less burning of crop residues.
How CIMMYT and Partners Address the
Issues
CIMMYT has worked with partners worldwide, including farmers, to test
and promote conservation agriculture and other resource conserving practices.
Two key partners are the Soil
Fertility Consortium for Southern Africa and the
Rice-Wheat Consortium for the Indo-Gangetic Plains (RWC). Challenges
include overcoming the “culture of the plow,” identifying
and supporting local “champions” of innovation, and increasing
participatory research in farmers fields. Farmers also need training,
among other things to learn of the value of leaving residues on the soil
surface when these have high economic value as fodder. Finally, promoting
these practices also requires lobbying science managers and policymakers
in national programs, and providing support for agricultural machinery
suppliers.
Two examples of the impacts of the above work include adoption of conservation agriculture on 300,000 hectares in Bolivia, and the use of "eco-tillage"—the direct seeding, without plowing, of wheat into rice paddies following rice harvest—on 1.2 million hectares in South Asia. Net benefits in India and Pakistan through higher yields and lower land preparation costs amounted to more than USD 100 million in winter 2003 alone. The success of eco-tillage has opened the way for other resource-conserving innovations, such as permanent beds for rice, wheat, and diverse other crops. The RWC recently received the 2004 King Baudouin Award from the Consultative Group on International Agricultural Research for these and other achievements.
Bringing it Back Home
Interest in conservation agriculture is increasing in Mexico, CIMMYT's
host country, and the center has been contributing in various ways. A
long-term field experiment was begun in 1991 on the center's research
station at El Batán involving 32 different crop management practices.
These include continuous maize and wheat cropping or rotations of both
crops, and varied tillage (conventional, eco-tillage, and cropping on
permanent, raised beds) and crop residue management practices (full, partial,
or no retention). The experiment is entirely rainfed. Results to date
suggest considerable benefits from eliminating plowing, but only if residues
from preceding crop cycles are kept on the soil (See the poster "Tillage,
crop rotation, and crop residue management effects on maize and wheat
production for rainfed conditions in the Altiplano of Central Mexico").
Among other things, the findings provide strong justification for promoting
conservation agriculture practices among farmers in this region and others
like it.
A window on CIMMYT's long-term conservation agriculture trial: Residues in the plot on the left have been removed continuously for years, leaving soil highly compacted and exposed to erosion. Despite generous rains this season and the damp soil, infiltration is so poor that the plants show the leaf rolling typical of drought stress. Residue retention in the plot on the right results in just the opposite and a healthy plant stand. |
Along those lines, Fernando Delgado, superintendent of CIMMYT's research station in Toluca, Mexico, has been working to spread conservation tillage for maize among farmers—including some who possess only 0.25 hectares of land—in the Toluca Valley, and farmer groups in other areas are beginning to show interest (see accompanying article, "Making the Plow Passé").
Getting "In Gear" for Conservation
Agriculture
Delgado and staff of other CIMMYT research stations in Mexico have also
been working with CIMMYT wheat agronomist and farm machinery specialist,
Ken Sayre, to develop and test two prototype implements for sowing seed
directly into crop residues and unplowed soils. "I built the first
prototype three years ago," says Sayre, who is known throughout Asia
for promoting resource-conserving farm practices. "These tractor-drawn
machines have been used in training courses, and commercial versions that
can sow several different crops in diverse conditions will soon be available
to farmers." Five copies of the latest version were designed and
built on Sayre's specifications by CIMMYT metal workers at El Batán
during April-October 2004. According to Sayre, the new implements cost
USD 10,000 each—one-fourth the price of a less versatile, imported
planter.
They will be used among other things for sowing experiments with improved maize and wheat varieties. "The aim is to eventually sow all our trials—roughly 150 hectares—without plowing," says Rodrigo Rascón, superintendent of the CIMMYT station in Ciudad Obregón, in the Yaqui Valley of northern Mexico's desertic Sonora State. The interest is partly because CIMMYT and partners are developing new varieties for conservation agriculture systems, and partly to save resources. "In conventional tillage you need four or five tractor passes to plow up the land, break up the clods, form the furrows and ridges, and then sow," says Rascón. "This way, in one step and with a single implement, you do it all, and you keep your soils in better condition and safe from wind and water erosion."
The practice is sure to arouse interest among Yaqui Valley researchers and farmer groups, who have significantly contributed to and benefited from CIMMYT's research over the years. A multi-crop, multi-use implement developed at the Ciudad Obregón station is the first tool that will either create or reform raised beds, apply fertilizer in various ways, and sow both large- and small-seed crops directly into unplowed land and residues. "Different versions have already been tested and demonstrated to farmers in different parts of Mexico," says Sayre. "Most of the components are locally available. These implements may represent the breakthrough needed in Mexico to spur use of sustainable and profitable conservation agriculture practices in irrigated systems."
November, 2004