Hedgerows in the Philippines: To Adapt or Adopt?

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.

Species Selection

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. Unpublished paper.

Fujisaka, S. 1993. A Case of Farmer Adaptation and Adoption of Contour Hedgerows for Soil Conservation. Experimental Agriculture, Volume 29, pp. 97-105.