Filipino hill farmers are learning how to heal their eroded land

Posted: 6 August 2011

Author: Text and Photos by Henrylito Tacio

Between 1990 and 2005 the Philippines lost a third of its remaining forest cover, leaving the land largely denuded of trees and open to erosion. Here, Henrylito Tacio describes, in words and pictures, the efforts being made to heal the degraded uplands. 

“A few hundred years ago, at least 95 percent of the Philippines was covered by rain forest; only a few patches of open woodland and seasonal forest, mostly on Luzon, broke the expanse of moist, verdant land,” noted Dr. Lawrence R. Heaney, an American curator who holds honorary appointments at the Philippine National Museum.

By the time the Spaniards arrived in the Philippines in the 16th century, scattered coastal areas had been cleared for agriculture and villages. Three hundred years later, rainforest still covered about 70 percent of the country.

Denuded mountains, the Philippines
Denuded mountains, the Philippines. Photo © Henrylito Tacio

But in recent years, the country has lost much more of its forest cover. Between 1990 and 2005, the Philippines lost one-third of its forest cover. “Where have all our forests gone?” environmentalists wondered.

Most of the forests are situated in the uplands, which comprised more than 60 percent of the country’s total land area. “The uplands are fragile areas, and when they are devoid of forests, soil erosion ensues,” explains Roy C. Alimoane, director of the Davao-based Mindanao Baptist Rural Life Center (MBRLC) Foundation, Inc.

Soil, aptly described as “the bridge between the inanimate and the living,” consists of weathered and decomposed bedrock, water, air, organic material formed from plant and animal decay, and thousands of different life forms, mainly microorganisms and insects. All play their part in maintaining the complex ecology of a healthy soil.

In the humid tropics, starting from a sandy base, a soil can be formed in as little as 200 years. But the process normally takes far longer. Under most conditions, soil is formed at a rate of one centimeter every 100 to 400 years, and it takes 3,000 to 12,000 years to build enough soil to form productive land.

“No other soil phenomenon is more destructive worldwide than is soil erosion,” wrote Nyle C. Brady in his book, The Nature and Properties of Soils. “It involves losing water and plant nutrients at rates far higher than those occurring through leaching. More tragically, however, it can result in the loss of the entire soil.”

A recent study by the Royal Commission on Environmental Pollution concluded that approximately 30 percent of the world’s arable crop land has been abandoned because of severe soil erosion in the last 40 years.

“When soils are depleted and crops are poorly nourished, people are often undernourished as well,” Lester R. Brown and Edward C. Wolf contend in their book, Soil Erosion: Quiet Crisis in the World Economy. “Failure to respond to the erosion threat will lead not only to the degradation of land, but to the degradation of life itself.”

SALT system, Philippines
SALT system, Philippines. Photo © Henrylito Tacio

Is there a technology that can help arrest soil erosion and encourages farmers to reforest their farms at the same time? Yes, there is such system and it is called Sloping Agricultural Land Technology (SALT), which the MBRLC has developed.

“The principle of SALT is the same as that used by the Ifugao tribes in Mountain Province,” says Alimoane. “All we are doing is suggesting using different nitrogen fixing trees and shrubs instead of rocks.”

Examples of nitrogen fixing trees and shrubs are kakawate (Gliricidia sepium), ipil-ipil (Leucaena leucocephala) and the introduced species Flemingia macrophylla, Desmodium rensonii, and Indigofera anil. These are thickly planted in double rows to form hedgerows. When a hedge is one-and-half to two metres tall, it is cut back to a height of 40 centimetres and the cuttings are placed in the strips between the hedgerows to serve as organic fertilizer.

The SALT scheme requires careful management of the space between the hedgerows. A combination of permanent, semi-permanent, and annual crops is recommended so as to rebuild the ecosystem and maximize yields while enabling farmers to organize their work time efficiently.

Every third strip of available land is planted to permanent crops. Examples include cacao and coffee, which were recommended by President Benigno S. Aquino III during his second State of the Nation Address. “Both cacao and coffee have steady markets,” says Alimoane. “Cacao has a potential of becoming one of our agricultural exports.”

A combination of various cereals (upland rice, corn, and sorghum) and vegetables (beans, pulses, tomato, eggplant, ampalaya, and sweet pepper) are planted on the remaining two strips of land. Each has its own specific area so that there can be a seasonal rotation. For instance, an area planted to corn previously will be planted with mung bean in the next cropping season.

“Crop rotation helps to preserve the regenerative properties of the soil and avoid the problems of infertility typical of traditional agricultural practices,” explains Alimoane on the importance of regular rotation of crops.

SALT offers many valuable ecological advantages. “This farming system greatly reduces the risk of drought, landslides, floods, and silting over of low-lying land, and wind erosion, all of which are linked to the radical transformation of the natural environment and destruction of the mountain forests,” Alimoane says. “It also replaces ugly eroded and denuded slopes with the luxuriant beauty of abundant vegetation,”

Soil erosion, Philippines
Soil erosion, Philippines. Photo © Henrylito Tacio

But more importantly, SALT also helps control soil erosion. A study conducted at the MBRLC farm showed the rate of soil loss in a SALT farm is 3.4 metric tons per hectare per year, which is within the tolerable range. Most soil scientists place acceptable soil loss limits for tropical countries within the range of 10 to 12 metric tons per hectare per year. The non-SALT farm has an annual soil loss rate of 194.3 metric tons per hectare per year.

“Think globally, act locally” is the cry of environmentalists in terms of global warming mitigation. “SALT is our local initiative in helping the world cut the emission of greenhouses gases,” Alimoane claims.

Trees produce a substantial portion of the earth’s oxygen and remove carbon dioxide, a major greenhouse gas, from the atmosphere. “In some instances, farmers stop farming for a while and leave their farm. In time, the nitrogen fixing trees and shrubs proliferate and create a mini-forest,” the MBRLC director says. “And if they return to till their farms again, the topsoil is still intact as the leaves of the trees ameliorate the bottom areas.”

Alimoane admits that SALT is not a perfect farming system. “There is not and never will be one system for all farmers,” he says. “SALT is not a miracle system or a panacea. To establish a one-hectare SALT farm requires much hard work and discipline.

“It took many years to deplete the soil of nutrients and lose the topsoil; no system can bring depleted, eroded soils back into production in a few short years,” he continues. “The price of soil loss is poverty, but we have seen land restores to a reasonable level of productivity by using SALT.” 

Henrylito Tacio is South East Asia contributing editor to this website.