SALT: a possible answer to environmental problems in the uplands

Crops are planted between hedgerows. (Henrylito Tacio)

By Henrylito D. Tacio

Farming in the Philippines is at a crossroads. The reason: it is facing several environmental problems: climate change, soil erosion, deforestation, flooding, and dry spell. All these lead to minimal production, low income, food insecurity, and malnutrition.

There is one possible answer to these woes: SALT. No, it’s not about the mineral composed primarily of sodium chloride. But rather, it’s the acronym for Sloping Agricultural Land Technology.  

SALT has been promoted by the Mindanao Baptist Rural Life Center (MBRLC) Foundation, Inc., a non-government organization based in barangay Kinuskusan of Bansalan, Davao del Sur.

“SALT is one of the solutions to the problems that beset the country these days,” explains Jethro P. Adang, the current director of the center. “But it seems that most experts are looking for big things that can help curb, if not arrest, the difficulties we have gotten into.”

Just like the prophet David who defeated the giant Goliath with just a slingshot and a stone, the problems which most upland farms are now facing can be solved by going back to the basics, Adang said. “We don’t need modern technologies and high gadgets to defeat the enemy. All we have to do is use what God has provided us through the years.”

About 60% of the country’s total land area of 30 million hectares are uplands. As population continues to swell in the lowlands, many farmers are now moving to uplands, bringing with them the agricultural techniques they practice in the lowlands.

Crops are planted between hedgerows. (Henrylito Tacio)

SALT, which earned the center’s former director, Harold Ray Watson, the coveted Ramon Magsaysay Award–the Nobel Prize of Asia–for peace and international understanding, is an answer that should be given much attention.

“Basically, the SALT method involves planting of field and permanent crops in 4–5-meter bands between double-controlled rows of nitrogen fixing trees and shrubs,” explains Adang.

Examples of field crops are legumes (beans, peas, and pulses), cereals (upland rice, corn, and sorghum), root crops (sweet potato, cassava, carrot, and taro), and vegetables (cabbage, ampalaya, tomato, eggplant, etc.). Permanent crops include cacao, coffee, banana, citrus, and fruit trees. 

This is where food security enters the picture. “Most farmers are locked into one crop,” Adang points out. A farmer may plant his farm with eggplant and when he harvests the crop, there would be a glut in the market.

But with SALT, a farmer can harvest every now and then. “The farmer has something to look forward to,” Adang says. “Because the harvested crops are just enough for the market, there is a tendency that the price of his produce is much higher.”

Natural farming is practiced in a SALT farm. Double hedgerows of leguminous perennials are planted at 4-5 meters intervals on equal-elevation contours. The hedgerows are pruned frequently (every 5-6 weeks) and the prunings are applied to the crops as a source of fertilizer. This means less expenses for the farmer. 

Flemingia macrophylla is one of the recommended hedgerow species. (Henrylito Tacio)

The prunings also serve as mulching materials. Mulching creates a microclimate for the plant to grow and perform better. It also protects the soil from erosion during heavy rainfall because the soil is not directly exposed to rain. More importantly, it reduces the salinity level of the soil.

In a SALT farm, you find a mix of permanent crops, cereals, and vegetables. 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,” explains Adang on the importance of regular rotation of crops.

The principle of SALT is the same as that used by the Ifugao tribes 300 years ago.  “All we are doing is suggesting using nitrogen fixing trees and shrubs instead of rocks,” Adang points out.

Examples of nitrogen fixing trees and shrubs include “ipil-ipil” (Leucaena leucocephala) and “madre de cacao” (Gliricidia sepium). Introduced species like Desmodium rensonii, Flemingia macrophylla, and Indifogera anil are also good hedgerow materials.  “We recommend that a combination of these species be planted all over the SALT farm,” Adang suggests.

Fruit trees are planted along with harvestable crops like corn and pineapple. (Henrylito Tacio)

According to Adang, the reason why SALT came into existence was because of soil erosion. Some years back, the Department of Environment and Natural Resources (DENR) reported that 22 provinces in the country had an “alarming” soil erosion rate.  Batangas and Cebu, for instance, had lost 80-85% of their topsoil to erosion.

“Soil erosion is an enemy to any nation – far worse than any outside enemy coming into a country and conquering it because erosion is an enemy you cannot see vividly,” said Watson when he received the RM Award in 1985.  “It’s a slow creeping enemy that soon possesses the land.”

SALT helps control soil erosion. A seven-year study conducted at the MBRLC showed that a farm tilled in the traditional manner erodes at the rate of 1,163.4 metric tons per hectare per year. In comparison, a SALT farm erodes at the rate of only 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 10-12 metric tons per hectare per year.  The non-SALT farm has an annual soil loss rate of 194.3 metric tons per hectare.

As SALT is an example of agroforestry (a collective name for all land-use systems and practices where woody perennials and crops are planted together), it offers other valuable ecological advantages.

“SALT greatly reduces the risk of drought, landslides, floods, the silting over of low-lying areas, and wind erosion – all of which are linked to the radical transformation of the natural environment and the destruction of the mountain forests,” Adang says.

But Adang admits that it’s not an easy task to follow the SALT system diligently. “We have had our failures, too,” he admits. “I can take you to a lot of farms that started out with SALT, and about halfway through the farmers just gave up. Part of it could be our fault; maybe we didn’t motivate them adequately.”

Maybe MBRLC’s approach is still not completely right. After all, there is no perfect technology or solution for a developing country like the Philippines. “The whole thing is terribly complex,” Watson, now retired and is back in Mississippi, told this author when he was still in the country. “When you start to fill up a big hole, it takes a lot of shovelfuls.  In an economy like this, in a poor country like this, it takes a lot of grains of sand.” 

Photos by Henrilito Tacio

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