In the past, “ipil-ipil” (scientific name: Leucaena leucocephala) gained popularity in rural communities due to its application as a deworming agent for children. The seeds of this plant contain an alkaloid known as mimosine and have been traditionally utilized as a natural remedy to eliminate intestinal parasites such as roundworms and whipworms.
Most Filipinos believe “ipil-ipil” is endemic to the Philippines; it is not. The shrubby tree was brought to the country by Spanish explorers in the late 16th century through the Manila-Acapulco galleon trade. It was initially introduced as a source of fodder for livestock and firewood.
After its introduction, “ipil-ipil” adapted to the local environment and became prevalent throughout the country. Centuries later, during the 1970s and 1980s, rapidly growing “giant” strains (arboreal varieties of the same species, such as the K8, K28, and K67 cultivars) were imported from Central America and promoted as a “miracle tree” for purposes of reforestation, soil enhancement, and animal feed.
Giant “ipil-ipil” was also the central feature of Sloping Agricultural Land Technology (SALT), which Rev. Harold R. Watson introduced to Filipino farmers in late 1970s. SALT is a sustainable upland farming which uses “ipil-ipil” as a way to control soil erosion. The cuttings are also utilized as “green manure” for crops and as fodder for goats.
But that’s going ahead of the story.
In the late 1960s, Rev. Harold Ray Watson, an American missionary hailing from Mississippi, arrived in the Philippines. As a trained agriculturist, he was appointed as an agriculture instructor at Southern Baptist College in Mlang, North Cotabato.
However, Watson aspired to achieve more than mere teaching. His master’s degree focused on agricultural institutions that provide training but lacked practical demonstration areas. He envisioned creating a center where farmers who had received theoretical training could gain practical experience.
“It’s physical training based on the theories they learned in the classroom,” Watson remarked.
His dream became a reality when he assumed the role of director at the Mindanao Baptist Rural Life Center (MBRLC), a registered non-profit and non-governmental organization whose primary aim is to enhance the holistic well-being of individuals, addressing both physical and spiritual needs.
Alongside Filipino staff and some American volunteers, MBRLC commenced its initiatives with local farmers. Many farmers who came to the center expressed concerns about a decline in their crop yields, despite using certified seeds and commercial fertilizers.
Watson, along with a few of his Filipino colleagues, visited some of these farms to investigate the underlying issues. Following a comprehensive assessment, he discovered that the principal challenge was the erosion of topsoil, which is essential for successful farming.
“Without the topsoil, regardless of how intensively a farmer applies fertilizer, optimal yields cannot be achieved. The soil’s ability to produce diminishes because it has lost its health,” the American missionary clarified.
Watson and his Filipino colleagues sought a potential resolution to the issue. They noted that the rice terraces of Banaue have endured over time. The challenge of erosion was addressed by converting steep, sloped land into a series of flat, stair-step levels. This architectural approach significantly reduces water runoff, enabling rainwater to permeate the soil instead of carrying away precious topsoil and nutrients down the mountainside.
The dikes, or earthen barriers, that separate the terraces are generally reinforced with tightly packed clay, mud, and occasionally stones. These compacted formations strengthen the landscape, securely holding the edges together against the substantial forces of water and gravity.
Watson focused on the use of stones. He proposed the idea of utilizing “living belts” instead of stones to prevent erosion. This led him to the concept of planting giant ipil-ipil along the terraces, incorporating not just one hedge but two hedges.
“If there is only one hedge, there remains a possibility that water could seep through and lead to erosion. However, with two hedges, the erosion occurring at the first hedge can be mitigated by the second hedge,” he explained.
If farming is to keep going, soil erosion must be curtailed. Soil, particularly topsoil, is the single most important resource on farmland, which is built over time.
Several studies showed 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 erosion is an enemy to any nation – far worse than any outside enemy coming into a country conquering it because it is an enemy you cannot see vividly,” decried Watson, who received the 1985 Ramon Magsaysay Award for international understanding. “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 erosion threatens food production as it makes farmlands infertile. Studies have shown that loss of a few centimeters of topsoil – the primary resource in growing crops – can reduce the productivity of good soils by 40% and poor soils by 60%.
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.—(Next: Controlling soil erosion through SALT)
