By Gerry T. Estrera
There are wars and there will always be war.  In Mindanao, there is an on-going war between Muslim rebels, the New People’s Army and the government’s military troops.  But the Mindanao Baptist Rural Life Center (MBRLC) Foundation, Inc., a non-government organization based in Kinuskusan, Bansalan, Davao del Sur, is waging a different kind of war: soil erosion.
But the Filipinos are not paying attention to it. Â Unknowingly, soil erosion is serious threat to any country. Â
“Soil erosion is an enemy to any nation – far worse than any outside enemy coming into a country and conquering it because it is an enemy you cannot see vividly,” said Harold R. Watson, an American agriculturist who received a Ramon Magsaysay Award in 1985 for peace and international understanding.  “It’s a slow creeping enemy that soon possesses the land.”
Watson knows.  He was the former director of MBRLC; he is now retired and back in his hometown in Mississippi.  He came to the Philippines in the 1960s and during that time, he sounded the alarm of deforestation and soil erosion.
But people laughed at him.  They told him, “We’re never going to run out of trees!”  That was before several presidents, other Asian governments, the United Nations – and countless farmers – recognized the value of his insights.
When Ferdinand Magellan “rediscovered” the Philippines in 1521, forests blanketed 95% of the country. When the Ormoc City, Leyte tragedy happened – which left 8,000 people dead – timber cover was only 18%.
In 1971, Watson opened to the public the MBRLC, a research and demonstration farm.  In the beginning, they floundered.  “When I got here, I had no idea what the problems were up in the hills,” said the American who spent almost half of his life in the Philippines. “Farming looked pretty good on the surface.”
Soon, Watson discovered that the problem was the surface: It was washing away.  Loggers – both legal and illegal – were hauling trees out of the once-lush mountains, leaving behind denuded hillsides. Tribal people and migrants were using “slash and burn” methods (kaingin) to clear and farm the uplands, and topsoil was disappearing
faster than what can be replenished.  The result: low production, hunger, and hopelessness.
“Most of these farmers don’t have a vision to see five or 10 years down the line,” Watson said.  “Most live for one more day, and don’t lift their head up.  They’re not thinking about erosion.  It’s ‘What can I get out of the land today, right now?’”
Soil scientists claims 58 percent of the country’s total land area of 30 million hectares is susceptible to erosion.  “For one, the magnitude of soil erosion in cultivated sloping areas has reached an alarming proportion,” deplored Angel C. Alcala, former secretary of the Department of Environment and Natural Resources (DENR) and also a Ramon Magsaysay Awardee.
Soil erosion is not a new phenomenon.  Archaeological sites of civilizations, studies showed, were undermined by soil erosion.  The fertile wheat-growing lands that made North Africa the granary of the Roman Empire are now largely desert.  The lowlands of Guatemala that once nourished a thriving Mayan culture of five million people were drained of their fertility by soil erosion.
That human life should depend for its existence on less than a meter of mixed organic and inorganic debris may come as a surprise to modern man.  Yet it is so.  A compilation of more than a dozen American studies analyzing the effects of erosion on land productivity found that losing an inch of topsoil reduces corn and wheat yields by an average of six percent.
“Without soil, there would be no food apart from what the rivers and the seas can provide,” pointed out Edouard Saouma, former director-general of the UN Food and Agriculture Organization (FAO).  “The soil is the world’s most precious natural resource.  Yet it is not valued as it should be.  Gold, oil, minerals and precious stones command prices which have led us to treat soil as mere dirt.”
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.
“This means that soil is, in effect, a non-renewable resource,” says a FAO publication.  “Once destroyed, it is gone forever.”
Although soil erosion does occur naturally, the process is slow. However, man’s intervention has increased the rate of natural erosion.  According to David Pimentel, an agricultural ecologist at Cornell University, exposed soil is eroded at several thousand times the natural rate.
Under normal conditions, each hectare of land losses somewhere between 0.004 and 0.05 tons of soil to erosion each year – far less than what is replaced by natural soil building processes.
On lands that have been logged or converted to crops and grazing, however, erosion typically takes away 17 tons in a year in the United States or Europe and 30 to 40 tons in Asia, Africa, or South America. On severely degraded land, the hemorrhage can rise to 100 tons in a year.
“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.”
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 explain:
“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 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,” Brown and Wolf contend.  “Failure to respond to the erosion threat will lead not only to the degradation of land, but to the degradation of life itself.”
Fortunately, the MBRLC discovered a sustainable farming system that helps curtail soil erosion.  It is known as Sloping Agricultural Land Technology (SALT).  “The principle of SALT is the same as that used by the Ifugao tribes,” explains Roy C. Alimoane, the current MBRLC director.  “All we are doing is suggesting using nitrogen-fixing trees and shrubs instead of rocks.”
The SALT system still requires careful management of the space between the rows of trees and shrubs.  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.
In the SALT farm, one finds a mix of permanent crops (cacao, coffee, banana and other fruit trees), cereals (upland rice, corn, or sorghum), and vegetables (bush sitao, winged beans, sweet pepper, tomato, eggplant, etc.).  Every third strip of available land is normally devoted to permanent crops.  A combination of various cereals and vegetables are planted on the remaining two strips of land.  Each has its own specific area so that there can be a seasonal rotation.
“Crop rotation helps to preserve the regenerative properties of the soil and avoid the problems of infertility typical of traditional agricultural practices,” Alimoane explains on the importance of regular rotation of crops.
And yes, SALT helps control soil erosion.  Its study showed that a farm tilled in the traditional manner erodes at the rate of 1,163.4 metric tons per hectare per year.  In a SALT farm, there is still erosion but minimal – 20.2 metric tons per hectare per year.
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 like the Philippines within the range of 10 to 12 metric tons per hectare per year.
In comparison, the non-SALT farm has a soil loss rate of 194.3 metric tons per hectare per year.
“Soil is related to the earth much as the rind is related to an orange,” commented 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.”
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