There are wars and there are wars. In the Philippines, they happen everywhere. In Mindanao, for instance, there is a battle between the Moro Islamic Liberation Front, the New People’s Army and the government’s military troops. But there is a kind of war that has been here since time immemorial and yet no one notices the conflict. It is called soil erosion.
“Soil erosion is an enemy to any nation – far worse than any outside enemy coming into a country a conquering it because it is an enemy you cannot see vividly,” decried Harold Ray Watson, former director of the Davao-based Mindanao Baptist Rural Life Center (MBRLC) Foundation, Inc. “It’s a slow creeping enemy that soon possesses the land.”
The war against soil erosion is for real. As a matter of fact, the Washington, D.C.-based Worldwatch Institute described it as “the next biggest long-term threat to world economic progress and stability after climate change.”
Soil, particularly topsoil, is the single most important resource on a farmland, which is built up over time. It takes about 200 to 1,000 years to form 2.5 centimeters of rich topsoil. But on the average, farmlands are losing 2.5 centimeters of topsoil every 16 years, or 17 times faster than it can be replaced.
“Soil is related to the earth much as the rind is related to an orange,” explains an American geologist. “It is the link between the rock core of the earth and the living things on its surface. It is the foothold for the plants we grow. Therein lies the main reason for our interest in soil.”
As such, the soil erosion threatens food production as it makes farmlands infertile. Studies have shown that loss of a few centimeters of topsoil can reduce the productivity of good soils by 40% and poor soils by 60%.
“No other soil phenomenon is more destructive worldwide than 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.”
Authors Lester R. Brown and Edward C. Wolf explain the phenomenon on how soil erosion affects food production in their thought-provoking book, Soil Erosion: Quiet Crisis in the World Economy.
“The loss of topsoil affects the ability to grow food in two ways,” they write. “It reduces the inherent productivity of land, both through the loss of nutrients and degradation of the physical structure. It also increases the costs of food production.”
The two authors continue: “When farmers lose topsoil, they may increase land productivity by substituting energy in the form of fertilizer. Farmers losing topsoil may experience either a loss in land productivity or a rise in costs (of inputs). But if productivity drops too low or costs rise too high, farmers are forced to abandon their land.”
A study done by the Royal Commission on Environmental Pollution concluded that approximately 30% of the world’s arable crop land has been abandoned because of severe soil erosion in the last 40 years.
The Rome-based Food and Agriculture Organization (FAO) of the United Nations estimates that 25 billion tons of soils are washed into rivers every year. Other land, especially in drier areas, is blowing way.
The world is reportedly losing the equivalent of five to seven million hectares – the equivalent of Belgium and the Netherlands combined – of farmland each year. “The alternative,” if the problem is not solved, “is famine,” an FAO report noted. Soil that is not cared for is no soil at all.
The Philippines is not spared from the problem. In fact, the Department of Environment and Natural Resources (DENR) reported some years back that about a billion cubic meters, or around 200,000 hectares of one-meter deep topsoil, are lost annually due to erosion.
Although citing no statistics on destruction, the Environmental Management Bureau (EMB) lists the occurrence of floods, which always cause enormous destruction in almost all parts of the country, and devastating droughts as proofs of the problem. The non-availability of natural groundwater resources has also been cited as one visible aftermath of soil erosion and forest denudation.
Respected scientists place 58% of the country’s total land area of 30 million hectares as susceptible to erosion. “For one, the magnitude of soil erosion in cultivated sloping areas has reached an alarming proportion,” deplored former environment head Angel C. Alcala.
There’s more to soil erosion than just food production. “More tragically, however, (soil erosion) can result in the loss of the entire soil,” Brady wrote in his book. “Furthermore, the soil that is removed find its way into streams, rivers, and lakes and becomes a pollution problem there.”
This is where sedimentation and siltation occur. In Luzon, for instance, the four major basins – Bicol, Magat, Pampanga, and Agno – are in critical condition due to acute soil erosion and sedimentation. The Ambuklao Dam reservoir had its life halved from 60 to 32 years as a result of siltation.
Soil erosion also causes a host of other serious problems like depletion of the remaining biological diversity. “About 93% of land animal species and 92% of all plant life are connected to topsoil,” wrote Dr. Michael A. Bengwayan, a fellow of Echoing Green Foundation in New York. “Simply said, without the topsoil, their chances of survival are slim. As more topsoil are lost, their extinction becomes more possible.”
Bengwayan said that if an ecosystem has been very degraded due to soil erosion, it takes a very long time for its biodiversity to recover, if it even recovers in that area at all. “The loss of topsoil often results in the death of many native plants,” he deplored. “As a consequence, it threatens the survival of animal diversity that depends on these native plants for existence.”
There are some instances that the eroded soil is so disturbed, which becomes the landscape to be completely infertile. As a result, not much plant life will even grow in the area anymore. “This barren landscape ultimately leads to a major decrease in ecosystem biodiversity for many organisms that can no longer live there,” he pointed out.
Agricultural scientists claim that the control of erosion lies in the control of the flow of the water as slow as possible. This can be done in two ways. The first is by vegetative means which uses plants and the other involves diversion, waterways, contours, terraces, gully control and tillage practices. Other supplementary structure may be ponds, culverts, dikes, ditches, spillways, and weirs.
Several methods are also important in the conversation practices such as applying organic matter, fertilization, crop rotation and cover cropping. All these schemes help minimize soil erosion and help in improving the soil.
“The application of how to make these technologies work is in fact the real concern,” said Alcala, who received a Ramon Magsaysay Award for public service, adding that there is still a lot to explore regarding effective soil conservation practices.
“This is in view of the pursuit to evolve more appropriate measures as seen in traditional technologies like what was done by our ancestors with the Banaue rice terraces,” he reminded.
Watson, also a recipient of the Ramon Magsaysay Award for peace and international understanding, believed there’s no pattern of soil conservation in the Philippines. “You should see those muddy rivers from the air after heavy rains – those are tons of topsoil moving down those rivers. Multiply that day by day, year after year and how much had been moved out – tons!”
The retired agricultural missionary offered these words of wisdom: “Land is not being remade. Soil is made by God and put here for man to use, not for one generation but forever. It takes thousands of years to build one inch of topsoil but only one good strong rain to remove one inch from unprotected soil on the slopes of mountains.”
