Hedgerows in the Philippines: To Adapt or
In 1987, researchers introduced contour hedgerows to the Claveria
on-farm research site in Misamis Oriental Province in the Philippines.
The purpose was to reduce soil erosion and build up soil nutrients
in an area where more than half of the farmers cultivate land
with a slope of greater than 15%. Hedgerows caught on and have
spread in the Philippines, not because researchers introduced
the perfect technology, but because they worked with farmers who
adapted the hedgerows to their farms. They eventually developed
a product that best suited farmers' needs and, as a result, reduced
soil erosion by up to 90%. Today, contour hedgerows in the area
are dramatically different from those introduced five years ago.
Farmer-to-farmer training has ensured hedgerows a foothold in
the region and perpetuation of the technique.
Farmers Take the A-Frame
Originally six farmers and two technicians from the International
Rice Research Institute (IRRI) were trained to use an A-frame
to establish contour lines, construct contour bunds and ditches
by ploughing and shovelling, and plant hedgerows of Napier grass
(Pennisetum pupureum) and leguminous trees (Gliricidia sepium).
Over a two-year period they trained 175 farmers who in turn trained
their neighbors until 200 farmers in Claveria had been exposed
to some contour hedgerow training.
IRRI scientists monitored the changes in the contour hedgerows
from 1987 to 1993, and asked individual farmers to evaluate the
contour hedgerow technology. They focused on 55 farmers with 60
fields. In interviews conducted in 1992, the farmers were asked:
"How do you now evaluate your contour hedgerow system?"
The question was designed to allow respondents to answer in terms
of what was most important to them - hedgerow functions, problems
and/or species choice.
Too Much Work!
Initially, farmers found that building contour hedgerows was too
labor-intensive. In the first three years of the trial, farmers
found ways to reduce the amount of labor required to build 100
meters of hedgerow from 14 to 8 hours. The original technique
involved using the A-frame to determine contour lines, double
plowing to create a bund, shovel work to reinforce bunds, planting
a double row of trees and a single row of grasses. Farmers adopted
a time-saving technique which entails plotting the contours with
an A-frame, preparing land in the alley for crops, and, at most,
planting a few trees spaced more than 10 meters apart in the hedgerows.
The unplowed weedy strip between the trees became naturally terraced
and started to form flat alleys with the first season's ploughing.
Farmers took the initiative to gradually change the tree and grass
species in the hedgerows according to their needs. The use of
both original species decreased over time. Farmers found that
although Napier grass controlled erosion and provided animal fodder,
it was too competitive with the alley crops. Napier, like other
forage species, attracted neighbors' animals as pests: 18 % of
the farmers listed this as a problem. For the first four years
of hedgerow planting, none of the farmers used G. sepium as a
green manure for their alley crops. By late 1992, 15% of the farmers
mentioned using G. sepium for this purpose. Farmers began to plant
Setaria spp., Panicum maximum and native grasses and allowed native
weeds to take over some contour hedgerows. Some planted perennial
crops that would bring in a profit, like pineapple. By 1991, 18%
of the fields contained weeds only in the hedgerows.
In 1989, 20% of the farmers planted mulberry trees, hoping to
reap additional income from silkworms. The silkworm project failed
and farmers stopped planting mulberry. In 1992, 16% of the farmers
surveyed thought the mulberry trees were useless without the project.
Farmer Evaluate Hedgerows
Hedgerows produce fodder, especially in the dry season. A few
farmers reported that strips of indigenous grasses were easier
to maintain and were more drought tolerant than introduced grasses.
Others found that hedgerow pruning and deep plowing in the alley
reduced crop-hedgerow competition. Such competition posed a threat
to the rice and maize crops for 35% of the farmers. One-third
of the farmers found that even with the contour-hedgerows it was
necessary to fallow land due to soil nutrient depletion. The higher
productivity of fields with less slope, and better opportunities
in off-farm work also contributed to fallowing.
Some 96% of farmers surveyed saw hedgerows as a way to control
soil erosion. On a 1 hectare basis, hedgerows reduced soil loss
from erosion from 200 to about 20 tons per year. The hedgerows
have been less successful at providing soil nutrients as few farmers
use the hedgerows for green manures. Hedgerows may help solve
problems of erosion, but farmers still need to solve the problem
of soil nutrient depletion for the contour hedgerows to be sustainable.
Fujisaka, S., Jayson, E., and Dapusala, A.1993. Trees, Grasses
and Weeds: Species Choices in Farmer-Developed Contour Hedgerows.
Fujisaka, S. 1993. A Case of Farmer Adaptation and Adoption
of Contour Hedgerows for Soil Conservation. Experimental Agriculture,
Volume 29, pp. 97-105.