The Philippines is currently facing a very serious soil erosion problem. According to the Department of Environment and Natural Resources (DENR), 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.
Almost two decades ago, 22 provinces in the country were reported to have serious soil erosion problems. Among those that had been losing their topsoil at “alarming” rate, were Cebu, Batangas, Marinduque, Ilocos Sur, and La Union.
This worries soil scientists as 58% of the country’s total land area of 30 million hectares are 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.
In agricultural lands, soil scientists estimate that it takes 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 erosion is any nation’s enemy – far worse than any outside enemy coming into a country and conquering it because it is an enemy you cannot see vividly,” commented Harold R. Watson, former director of the Davao-based Mindanao Baptist Rural Life Center (MBRLC). “It’s a slow creeping enemy that soon possesses the land. We must consider ourselves in a state of emergency; our topsoil is all going…”
Studies have shown that as much as 20 percent of eroded materials end up in rivers, reservoirs, and irrigation canals. Siltation likewise can cause serious damage to coral reefs and coastal fisheries.
“Soil erosion also causes a host of other serious problems that threaten a country’s productivity and depletion of its wildlife and other natural resources,” pointed out Watson, who received a Ramon Magsaysay Award for international understanding in 1985.
Authors Lester R. Brown and Edward C. Wolf contend that soil erosion threatens food production. In their book, “Soil Erosion: Quiet Crisis in the World Economy,” they contend:
“The loss of topsoil affects the ability to grow food in two ways. 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 percent 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.
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 of these 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 also 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.
Meanwhile, Watson 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!”
He 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.”
