Sloping Agricultural Land Technology (SALT)

Summary

In Asia, one big problem is the rapid depletion of its forest cover. With less than one third of the world's land area, Asia carries over half of the world's population. As population grows, shifting cultivators move into newly opened areas and begin to practice 'slash and burn' agriculture. Mass deforestation for economic reasons is carried out in a reckless way. Compared with the rest of the world, Asia has very little land that is suitable for cultivation, about 20% of the land now under cultivation in many Asian countries has been considered 'degraded' by Food and Agriculture Organization (FAO) of United Nations with some other countries approaching 50%.

The Philippines, predominately an upland country, is one example of deforestation and land degradation. It has almost 30 million ha and in the 1950's, about 16 million ha was classified as natural forest. Today, less than 1 million ha of the natural forest remains. In the same period, the population has almost doubled and the marginal or fragile lands have increased from 2 million ha to 12 million.

In the southern part of the Philippines the Mindanao Baptist Rural Life Centre (MBRLC) a NGO has developed in 1978 a soil conservation and food production farming scheme called SALT, based on the use of tree and shrub legumes. SALT is a simple, timely, low cost and applicable method of upland farming. This technique appeared to be successful. Soil erosion was minimized, soil fertility restored, crop yields were sustained and improved income for the farmers.

Other than the Philippines, other Asian countries including Sri Lanka and Indonesia have developed upland farming systems very similar to that of SALT. By using SALT, small scale upland farmers in the Philippines and throughout Asia can conserve soil, reduce their purchase of commercial fertilizers, increase their yields and income and become generally self- sufficient. In this way, those living in the marginal, hilly areas can break out of the common cycle of expensive monoculture, dependence on imported fertilizers and insecticides, and indebtedness to large landowners or banks.


The Text

In Asia, one big problem is the rapid depletion of its forest cover. With less than one third of the world's land area, Asia carries over half of the world's population. As population grows, shifting cultivators move into newly opened areas and begin to practice 'slash and burn' agriculture. Mass deforestation for economic reasons is carried out in a reckless way. Compared with the rest of the world, Asia has very little land that is suitable for cultivation, about 20% of the land now under cultivation in many Asian countries has been considered 'degraded' by Food and Agriculture Organization (FAO) of United Nations with some other countries approaching 50%.

The Philippines, predominately an upland country, is one example of deforestation and land degradation. It has almost 30 million ha and in the 1950's, about 16 million ha was classified as natural forest. Today, less than 1 million ha of the natural forest remains. In the same period, the population has almost doubled and the marginal or fragile lands have increased from 2 million ha to 12 million.

A huge problem when forest trees are extensively cut without replanting, combined with improper farming of fragile, sloping lands is soil erosion. The erosion of topsoil - which man plants his food crops - is extremely serious in Asia. Soil formation is a very slow process. Topsoil is rich and fertile because of its organic matter content and is capable of supporting the growth of food crops. Topsoil stores plant nutrients, air and moisture. The nutrients in topsoil are crucial - they are the food of plants. Therefore it is very important to protect hilly land from soil erosion.

In the southern part of the Philippines the Mindanao Baptist Rural Life Centre (MBRLC) a NGO has developed in 1978 a soil conservation and food production farming scheme called SALT, based on the use of tree and shrub legumes. SALT is a simple, timely, low cost and applicable method of upland farming. This technique appeared to be successful. Soil erosion was minimized, soil fertility restored, crop yields were sustained and improved income for the farmers.

SALT is a form of alley farming in which field and perennial crops are grown in bands 4-5 m wide between contoured rows of nitrogen-fixing leguminous trees and shrubs (NFTS). The latter are thickly planted in double rows to form hedgerows which prevents soil erosion and maintains fertility of the soil. When the hedge reaches 1.5-2m in height, it is cut back to 40 cm and the cuttings are placed in the alleys between the hedgerows to serve as mulch and organic fertilizer or green manure. On a SALT farm, a farmer can grow varieties of crops familiar to him. If farmers leave the land fallow for one or two cropping cycles, the NFTS will continue to grow and overshadow the crop area. By the time the land is reverted to cultivation, the soil has been enriched by the large amount of NFTS leaves and there is no erosion to contend with. In addition, the trees may be harvested later for firewood and charcoal. Because of SALT's initial success, three more SALT variants have been developed.

One of the good qualities of SALT is that it is culturally acceptable as the farming techniques are in harmony with Asian beliefs and traditional practices. In the Philippines, SALT also fits into the framework of the government's rain-fed resources development strategy for the uplands and almost every major non-government organization that is working in upland agriculture is implementing the same type of program as SALT.

In an experiment performed to verify the effectiveness of SALT system in controlling soil erosion, it was found that there was almost 58 times less erosion in the SALT system than in the non-SALT treatment. The annual rate of soil loss from the SALT system was 3.4t/ha which is well within the tolerable limits for soil loss of 10-12t/ha/year.

Furthermore, a ten year economic study conducted at the MBRLC farm showed that 1 ha SALT area can increase an upland farmer's income substantially. After adopting SALT, farmers' income increased from P4,595 to P15,981 ha/ year.

Other than the Philippines, other Asian countries including Sri Lanka and Indonesia have developed upland farming systems very similar to that of SALT. By using SALT, small scale upland farmers in the Philippines and throughout Asia can conserve soil, reduce their purchase of commercial fertilizers, increase their yields and income and become generally self- sufficient. In this way, those living in the marginal, hilly areas can break out of the common cycle of expensive monoculture, dependence on imported fertilizers and insecticides, and indebtedness to large landowners or banks.

Despite the many benefits of this shrub and tree legume-based alley farming system, there are still many upland farmers in the Philippines who are not adopting the SALT scheme. SALT should also not be considered the perfect farming system.

Thus, as Watson and Laquihon, who have substantial involvement in SALT, stressed:

'There is not and never will be one system for all farmers.... To   establish a one-hectare SALT farm requires much hard work and discipline. It took many years to deplete the soil of nutrients and lose the topsoil, no system can bring depleted, eroded soils back into production in a few short years. The price of soil loss is poverty, but we have seen land restored to a reasonable level of productivity by using SALT.'

Reference:

ECHO Technical Note#72; SALT for Slopeland Crop-Based Agriculture by Harold R. Watson, MBRLC; Sloping Agriculture Land Technology (SALT) in the Philippines by W.A. Laquihon and M.V. Pagbilao.