SUCCESS STORY: Farmers learn how to cut erosion on sloping land

Posted: 13 September 2005

Author: Henrylito Tacio

Upland farmers, often regarded as the "poorest of the poor," can substantially reduce soil erosion in their farms by using a system now widely practiced by counterparts in Southern Mindanao in the Philippines.

Called Sloping Agricultural Land Technology or SALT, it has been developed by the Mindanao Baptist Rural Life Center (MBRLC), a non-profit group based in Kinuskusan, Bansalan, Davao del Sur - about 86 kilometres from Davao City.

The system is a simple, low-cost method of tilling the ecologically-fragile uplands, which make up about 60 per cent of the country's land area of 30 million hectares. SALT is particularly suited for small or marginal farmers with few tools, little capital, and little knowledge in agriculture.

Upland farming in Davaousing SALT techniques.© Henrylito Tacio
Upland farming in Davaousing SALT techniques.© Henrylito Tacio
Upland farming in Davao using SALT techniques.© Henrylito Tacio
Steve Musen, an American agriculturist from Kentucky who directs MBRLC, describes SALT as a package technology of soil conservation and food production that integrates several soil conservation measures in just one setting. It incorporates minimum tillage, stubble mulching, contouring, strip cropping, multiple cropping, crop rotation, green manuring, and reforestation.

Soil loss

A study conducted by MBRLC showed that a farm tilled by a traditional upland farmer has a soil erosion rate of 1,162.4 metric tons per hectareover a period of six years. In comparison, a farm using the SALT method has an erosion rate of only 20.2 metric tons per hectare during the same period.

The annual rate of soil loss in the SALT farm is 3.4 metric tons per hectares, well within the tolerable limits. Most soil scientists placeacceptable soil loss limits for tropical countries like the Philippines within the range of 10-12 metric tons per hectare per year. On the other hand, a farm tilled by a traditional upland farmer has an annual rate of soil loss of 194.3 metric tons per hectare.

Contoured bands of nitrogen-fixing shrubs, with crop litter in between to serve as organic fertiliser, Davao, The Phillipines. © John Rowley
Contoured bands of nitrogen-fixing shrubs, with crop litter in between to serve as organic fertiliser, Davao, The Phillipines. © John Rowley
Contoured bands of nitrogen-fixing shrubs, with crop litter in between to serve as organic fertiliser, Davao, The Phillipines.© John Rowley
The Environmental Management Bureau (EMB) of the Department of Environment and Natural Resources (DENR) once reported that at least 22 of the country's provinces were already badly eroded, many of which are major producers of agricultural products. About 200,000 hectares or more of topsoil at one metre are being lost nationwide yearly due to erosion, thereport added.

"The number one threat to the progress of developing countries in the worldtoday is soil erosion," Jeff Palmer, the former project director points out.

This was the primary reason why MBRLC developed SALT. In this system, field and permanent crops are grown in bands 4-6 metres wide betweencontoured rows of leguminous trees and shrubs. These leguminous trees and shrubs are thickly planted in double rows to form hedgerows.

Hedge species

Examples of hedgerow species are Flemingia macrophylla, Desmodium rensonii, Gliricidia sepium (locally known as "madre de cacao" or "kakawate"), and Leucaena leucocephala ("ipil-ipil").

When a hedge is 1.5 to 2 meters tall, it is cut back to a height of 40 centimetres and the cuttings are placed in the strips between thehedgerows, also called alleys, to serve as organic fertilizer or green manure. The hedgerow species are good sources of nitrogen.

Rows of permanent crops such as coffee, cacao, citrus, and banana are dispersed throughout the farm plot. The strips not occupied by permanentcrops are planted alternately to cereals (such as corn, upland rice or sorghum) or other crops (including sweet potato, melon and pineapple) and legumes (mung bean, soybean, sitao or peanuts).

This cyclical cropping provides the farmer with several harvests throughout the year, thus giving him a decent farm income. In addition, a farmer can grow varieties of crops familiar to him. SALT can be adapted to incorporate new or traditional farming techniques.

If farmers leave the land for a season or more - to work in other areas perhaps - the leguminous trees and shrubs will continue to grow and maylater be harvested for firewood and/or charcoal. Most importantly, the leguminous trees and shrubs keep the soil intact since it is not exposed to heavy rainfalls and strong winds.

Long experience

MBRLC has been practicing the SALT system since 1978. It grew out of the problems that farmers shared to MBRLC staff in formal meetings as well as during farm visits. For encouraging international use of the system, former director Harold R. Watson was conferred the Ramon Magsaysay Award for international understanding in 1985.

"With SALT management, we believe that man can become a trustworthy steward of our upland resources if he is in proper standing with God, nature and his fellow men," stressed Watson, who retired in 1996.

With the rapid deterioration of the Philippine uplands, adoption of the SALT system throughout the country is highly recommended with somemodifications, if necessary, to suite local conditions.

The MBRLC has developed other SALT systems: Simple Agro-Livestock Technology (SALT 2), in which goats are introduced into the original SALT system; Sustainable Agroforest Land Technology (SALT 3), a small-scale reforestation system; and Small Agrofruit Livelihood Technology (SALT 4), where various fruits are combined with agricultural crops.

For further details about MBRLC and its projects, send an email or visit the mbrlc website

Henrylito D. Tacio is Planet 21 contributing editor in South East Asia.