For green agriculture to flourish in the developing world, informed decisions must be
taken not just by individual farmers but also by politicians, research managers, planners,
donors, and investors. What works best at the level of the farm field must be complemented
by insights into social and biophysical dynamics at the landscape level.
How will today’s decisions about land use affect the complexion and
health of our planet’s diverse ecosystems tomorrow? When a region’s soils are
shallow or heavily eroded, what type of agriculture can meet the needs of the poor without
degrading natural resources? What uses of expansive savanna lands will most reduce the
buildup of greenhouse gases in the atmosphere? What are the effects of livestock
production on forest cover?
These are the kinds of questions that CIAT and its partners are addressing
as they set research goals, support policy making, scale up the benefits of technology,
and gauge the actual or potential impact of interventions.
Participatory land-use planning
Colombia’s Eastern Plains, or Llanos Orientales, cover 26 million hectares—a
vast expanse of savannas, rarely as flat and grassy as outsiders might imagine. Rolling
hills and uneven plains, streams and rivers, ravines and gallery forests, cultivated
fields and pasturelands, villages and towns all mesh together with grasslands in this
complex landscape. It’s the nation’s only available frontier for agricultural
expansion in the coming century.
In the Orinoco region of the Llanos, CIAT has been assisting four administrative levels
of government—region, department, municipality, and village—in land resource
planning, with funding from the Colombian Ministry of Agriculture and Rural Development.
The country’s official land-use planning process is an interlocking exercise. Each
administrative level, starting with municipalities, submits its plans to the next level
up. The CIAT project makes geographic information system (GIS) tools and expertise
available for individual planning exercises, while also streamlining the overall flow of
spatial information between the various planning levels.
The municipality of Puerto López in Meta Department serves as a precisely defined
testing ground for various GIS techniques used in planning. At the rough geographic center
of Colombia, the municipality covers nearly 7,000 square kilometers. Two-thirds is
"dissected" high plains—heavily eroded lands marked by numerous depressions
and hills. The remaining area is divided between flat high plains and lower lands with
poor drainage.
Working with Puerto López planners, CIAT GIS specialists developed a computerized
land-resource planning tool based on a commercial program called MapMaker Popular. Menus
and tutorials were translated into Spanish by CIAT and are now available free of charge to
planning specialists working with the Center.
The rationale behind the development of this easy-to-use tool is that it can help
municipalities plan according to their own stated needs and aspirations, thereby
increasing the chances of the land-use plan being put into practice. Until now, simple but
effective planning tools have not been available. As a result, some municipalities have
been forced to hire outside consulting firms to help them meet their land-planning
obligations to the regional government.
Remote sensing specialist Nathalie Beaulieu, who leads the CIAT team, stresses the
importance of participatory analysis to get the planning exercise off on the right foot.
Stakeholders describe the actual state of land use, compare it with the altered state they
are aiming for, and propose actions to bridge the gap. This process, says Beaulieu,
"can greatly ease the diagnosis phase as well as consensus building among
stakeholders. It also sets the basis for monitoring and evaluation."
Agreeing on goals and action plans requires a lot of good information. In preparation
for the planning exercise, the team mapped current and potential land uses in the
municipality.
Options include conservation and tourism, restoration of natural vegetation, raising
livestock, production of various annual and perennial crops (especially fruit), and tree
plantations. The municipal "wish list" of possible future uses is based on
expressed local needs and preferences, current land uses, market opportunities, and the
climatic fit of crop species.
Using soil data already available, the planners produced municipal maps that divide
land into 10 categories. These are based on several "limiting" criteria: land
slope, flooding frequency, drainage capacity, and soil depth, texture, and fertility. By
analyzing various land uses in light of these factors, the team was able to recommend
which areas of the municipality are suitable for specific activities.
For example, in the flat high plains, where much of the rural population lives, soil
depth and drainage are moderate, but fertility is low. The land was judged suitable for
semi-intensive livestock production on planted pastures, mechanized production of certain
annual crops, and the growing of fruit trees, rubber, oil palm, and forest plantations. In
contrast, mechanized cropping in flat areas of the dissected high plain, where the human
population is in any case low, was not recommended, partly because the soil is too
shallow.
In January 2000 the Puerto López municipal council submitted its land-use plan to the
regional agency charged with reviewing such documents, Corporinoquia. It was received
"with congratulations."
Beaulieu notes that GIS-based estimates of the biophysical suitability of land for
specific purposes are just one input to the planning process. Community needs, local
economic conditions like markets and labor availability, and environmental factors not
covered by the evaluation method also need to be taken into account.
Working in five villages with farmers and the municipal agricultural technical
assistance service, CIAT staff are also helping evaluate potential markets for alternative
crops like citrus, squash, and pineapple. MapMaker Popular is used to draw field
boundaries on maps produced from aerial photographs and satellite images. The maps are
then overlaid with crop and soil data gathered on the ground by farmers and researchers.
This makes it possible to estimate the production costs and benefits of various crops that
interest farmers, in light of the supply requirements of local food merchants.
The CIAT project currently benefits a specific group of Colombian land-use planners.
But it’s generating valuable knowledge about which mixes of data, GIS tools, and
conceptual approaches work best for land-use analysis at various geographic scales, from
the village on up. Other countries and regions thus stand to benefit from the pioneering
GIS work being done in the Colombian Llanos.
Tracking greenhouse gases
Land-use planning in the vast tropical American savannas has important implications for
global warming. That’s one reason it should concern not just the communities and
nations to which these lands belong but the entire world.
Predicting the impact of global warming over the next 100 years remains, at least for
now, the domain of crystal ball gazers and daring climatologists. Yet the causal link
between a hotter planet and emissions of greenhouse gases from human sources is now widely
accepted.
Fossil fuel burning, mainly energy related, is estimated to account for about
two-thirds of emissions of human origin. This is followed by agriculture at 20 percent and
deforestation and biomass burning at 14 percent. While carbon dioxide is the main
greenhouse gas building up, methane and nitrous oxide are important byproducts of
agriculture. Rice paddies and grazing cattle, for example, produce methane, while
fertilizer applications result in nitrous oxide emissions. And, of course, fuel
consumption to run farm machinery contributes significant amounts of carbon dioxide.
CIAT scientist Marco Antonio Rondón recently examined the role of the Colombian
savannas as both a source of greenhouse gases and as a beneficial mechanism—a
"sink"—for capturing and storing them. He focused mainly on methane and
nitrous oxide balances but also looked at "carbon-dioxide-equivalent global warming
potential," a convenient way to measure the combined effect of the three gases using
a single yardstick. It’s the first such study of the greenhouse gas balance in this
important South American ecosystem.
Some findings reinforce conventional wisdom. Others suggest the need to rethink
attitudes toward land uses sometimes considered environmentally detrimental. In
particular, pasture development for cattle production gets a highly positive report card
from the point of view of reducing global warming.
Rondón concludes, not surprisingly, that gallery forests should be a key target of
conservation efforts. These ribbons of trees and other vegetation hug the winding
waterways of the Llanos. They not only provide a home for diverse plants and animals but
also regulate fluxes of methane and nitrous oxide in the region. "Clearly,
regenerating forest on deforested land will provide the best alternative to mitigate
emission of greenhouse gases in the Llanos."
Brush fires are an age-old and natural force of regeneration in the savannas. They
stimulate new plant growth and help maintain biodiversity. Nevertheless, biomass burning,
including fires set by people, is a key source of methane. Rondón recommends actions to
reduce the amount of burning without completely suppressing it. "Conversion of
savanna into croplands or pastures is clearly an advantage," he says, because
carefully managed land is systematically protected from fire and therefore serves as a
buffer. Likewise, promoting the colonization of land adjacent to gallery forests
constitutes a "win-win situation, as it will not only eliminate the burning but also
will increase the methane soil sink strength."
The Colombian savannas support 2.5 million cattle. Their collective "bad
breath," as Rondón calls their expulsions of intestinal gas, amounts to a little
over 100,000 tons of methane per year. It’s the principal source of that gas, more
important than emissions from biomass burning. Why then would pastures and cattle be seen
as a solution?
The answer lies in the net effect of multiple factors. Apart from fire prevention that
comes with careful pasture management, there are added benefits from raising cattle on
nutritionally superior pasture grass and legume mixtures, as is currently happening in
South America. These include the African grass Brachiaria humidicola and the South
American legume Arachis pintoi (a member of the peanut family). CIAT has been researching
and promoting these for several years.
These improved forages drastically cut methane emissions per animal. More important,
compared with native pasture species, they trap far more carbon in the soil surrounding
their deep root systems. They therefore reduce the amount of carbon dioxide that escapes
into the atmosphere. The latter phenomenon was recently confirmed by CIAT and Brazilian
scientists working together.
Rondón notes that the land devoted to pastures is expected to double over the next 20
years in the Llanos. This dramatic increase will likely boost overall methane emissions as
stocking rates (animals per hectare) go up, despite a reduction in emissions per animal.
However, in terms of the overall "budget" of greenhouse gases, the net effect
should be highly positive. This applies to both the 20-year and 100-year projections
covered by the research.
CIAT soil scientist Richard Thomas says improved pastures may provide an added but
indirect benefit with regard to reducing global warming. "At the moment you
can’t plant trees on the native savannas, because the nutrient level is too low and
there’s a long dry season of 5 to 6 months. Fires are also a threat to forests. But
introduced grass-legume mixtures build up soil structure and fertility." With proper
pasture management, he says, it would eventually be possible to plant trees in some areas,
gradually increasing forest cover. Since tropical forests are still the most robust carbon
sink per unit of land area, this strategy would have a positive effect on the earth’s
atmosphere.
Rondón concludes that "pasture is the only land-use option identified in this
study that can shift the land from a net source into a net sink of atmospheric greenhouse
gases." He adds that predicted rural development of the region, including a tripling
of crop production over two decades, will be beneficial from this point of view.
But he adds a final word of caution: When converted to permanent crops or pasture, the
soils of the Llanos become highly susceptible to degradation, especially through soil
compaction. This potential problem, which begs for improved tillage practices,
"should never be forgotten" in planning for the future.
Forest margins in the balance
The effect of improved pastures on another vital agroecosystem in Latin
America—the region’s tropical forest margins—has been controversial for
many years. The central issue is often framed like this: Does pasture
intensification—using new technology to produce more beef or milk per
hectare—increase or decrease deforestation?
Recent analysis by a multidisciplinary team of CIAT and collaborating national
scientists suggests that the question may be backwards. They argue that the more
appropriate question is how deforestation influences pasture intensification. Their
answers are based on economic, production, and forest-cover data gathered from three Latin
American countries by the Tropileche Consortium. CIAT coordinates this work under the
Systemwide Livestock Program of the Consultative Group on International Agricultural
Research (CGIAR). The program is convened by the International Livestock Research
Institute (ILRI).
One conclusion from Tropileche’s research is that intensive production
technologies like those promoted by CIAT help maintain forest cover only when they are
cheaper than expanding into new forested areas using low-management methods that support
fewer animals per hectare. Those older strategies not only eliminate trees but can also
degrade newly created pastures in a matter of a few years.
Areas with adequate roads and services as well as strong, mature markets for milk and
meat tend to be heavily deforested. And land is expensive. Cattle regions of Costa Rica,
where milk and meat are produced on many small hillside farms, are an example. In this
situation it’s cheaper for farmers to adopt high-quality grass-legume pasture
technology and dry season protein supplements, such as the shrub legume Cratylia argentea,
when they want to boost production. They can raise more animals per hectare, avoiding both
the heavy capital cost of buying new land and the risk of degrading existing pastures. The
evidence also suggests that farmers adopting the new technology set aside their steeply
sloping land for reforestation and protection of water resources.
Conversely, areas with immature markets and weak infrastructure, like the frontier
lands of the Peruvian Amazon, have more forest cover and much lower land prices. There
it’s often cheaper for cattle producers to cut down trees for pasture expansion than
to intensify with new technology. Although the benefits of new technology could be very
large for the Peruvian forest, economics gets in the way.
Livestock production in Colombia’s Caquetá Department, an Amazonian region of
thick tropical forest and forest margins, represents an intermediate pasture-forest
dynamic. Available data show clearly that cattle ranching in the region is undergoing
dramatic technological change. A CIAT survey of 226 farmers, focused on farmer adoption of
the legume Arachis pintoi, indicates that the area sown to improved pastures increased
from 26 to 58 percent of total farm area between 1986 and 1997.
Interestingly, the average proportion of forested area on the surveyed farms also went
up, from 7 to 10 percent during the same period. This record of change is too small to
permit a solid conclusion, as it falls within the study’s statistical margin of
error. But it does suggest that intensification through forage-based technology does not
cause deforestation. Whether the benefit is temporary or permanent remains to be seen.
The authors note that, for good or for ill, "forest margin regions will continue
to have cattle for the foreseeable future, because producers need the incomes and
consumers demand the products." In the developing world, they note, livestock
production has expanded so fast that some observers are calling it the "next food
revolution."
Given this scenario, the authors underline the urgent need to complement more
sustainable animal production technologies with national policy interventions. Creating
national parks and reserves, promoting nontraditional forest products, and using
carbon-sink payments to compensate private landowners who protect trees are among the
possible strategies, current and future.
CIAT’s analysis of the links between improved pastures and forest cover is an
effort to zoom out on the issue of sustainable technologies, to see patterns in the larger
picture of human livelihoods and environmental protection. It injects important new
evidence into research agenda and policy setting for an agroecosystem that hangs in the
balance between heedless destruction today and mindful management for tomorrow.
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