SALT's objectives on managing land productivity can be accomplished by growing preferred high-value crops. These crops, which can occupy up to 75 percent of the farm area, are grown on the strips between the double hedgerows at a proportion of 2/3 annuals and 1/3 perennials (Laquihon, Suico et al. 1997). Partap et al. (1996) argue that cost-benefit analysis (labor and chemicals versus marketable yield) indicates that for the early years after establishment, the benefits of the hedgerow treatments do not outweigh the costs to the farmer, unless the species planted on the contour is a cash crop. Partap and Watson (1994) also assert that for the first two years, the net income from SALT farming is less than the net income from traditionally farmed lands however in the later years income from SALT farming starts increasing and surpasses the net income from traditional farms. A consistent pattern is that the cost of establishing hedgerows exceeds returns initially (due to labor costs and forgone production), however with time, hedgerows appear to provide yield benefits than the conventional practices (Nelson et al. 1998, Shively 1999). Farmers are more interested in species that have multiple benefits and provide direct impact on both short and long run. Therefore SALT systems that utilize legume shrubs, fruit trees, coffee, cacao or rubber provide useful economic returns. Cash derived from hedgerow trees and/or shrubs may provide an incentive for SALT adoption by farmers, as well as funds to purchase other external inputs and tools (Craswell 1998). SALT enables farmers to stabilize and enrich the soil and to grow food crops economically as very little to no inputs (such as chemical fertilizers) are required. Under low input conditions SALT performs as an optimum production system focusing on long term sustainability. The SALT scheme is tailored for small farms and for raising both annual food crops and permanent crops. Small farmers with few tools, little capital and little knowledge of modern agriculture can use SALT effectively (Partap and Watson 1994). (Malla, 2014, pp.32-33)

The advantages of SALT are that it is simple, applicable, low-cost and timely method of upland farming. It is a technology developed for Asian farmers with few tools, little capital, and little formal education in agriculture. Contour lines are determined by using an A-frame transit that any farmer can learn to make and use. A farmer can grow varieties of crops he is familiar with and old farming patterns can be utilized in the SALT system. (Mindanao Baptist Rural Life Center Editorial Staff, 2012, p.3) SALT is not a miracle farming system or a panacea for all the upland problems. To establish a 1 ha SALT farm requires much hard work and discipline–there is no easy way. It takes 3-10 years to deplete the nutrients of soil and to lose the topsoil; no system can bring depleted, eroded soil back into production in a few short years. Soil loss leads to low yields and poverty, but land can be restored to a reasonable level of productivity by using SALT (Mindanao Baptist Rural Life Center Editorial Staff, 2012, p.7)

SALT is culturally acceptable because the farming techniques are in harmony with Asian beliefs and traditional practices. Major reasons for the dislike of contour hedgerows are: reduction in arable land area, lateral spread of hedgerows over the field and shading vegetable crops, regular maintenance requirements, and not providing immediate financial return (Poudel 1998). Constraints include the tendency for the perennials to compete for growth resources and hence reduce yields of associated annual crops. Moisture competition between hedgerows and associated crops was seen as a problem when alley cropping is used in drier areas, particularly if the hedgerows are spaced closely (Kang 1993). But the major problem is the extra labor needed to prune and maintain the hedgerows. Vegetative techniques like SALT are generally less expensive but labor-demanding compared to engineering practices. (Malla, 2014, pp.35-36) A high labor requirement in establishing and managing hedgerows was one of the major constraints to the adoption of complex SALT systems. Many farmers were resistant to adopting SALT mainly because the technology was labor (and skill) intensive (Nelson 1998, Garrity 1999, Cramb 2000, Cramb et al. 2003). In a study by Shively (1999), farmers reported 54 percent greater labor use per hectare on hedgerow plots than conventional plots. Researchers also found that farmers’ labor investment to prune their leguminous-tree hedgerows was about 31 days per hectare, or 124 days of annual labor for four pruning. This increased the total labor for upland rice an average of 64 percent. Labor for a maize crop increased 90 percent due to pruning operations. Such an increase in production costs was seldom rewarded by a commensurate increase in returns (Garrity 1999) (Malla, 2014, pp.49-50)

The objectives of SALT are: (a) to control soil erosion through the establishment of double hedgerows of leguminous shrubs or trees, (b) help restore soil structure and fertility through crop rotation and by cutting the branches every 30-45 days and incorporating these back into the soil, and (c) to produce food efficiently. Thus, SALT helps considerably in the establishment of a stable ecosystem (Palmer, 1992 cited by Watson, undated). There are four (4) variations of SALT developed by MBRLC. (de Guzman et al., 2015, p.28) As a proven system of upland farming, SALT has certain good qualities over both the traditional techniques of slash-and-burn and conventional terrace farming. • The SALT system protects the soil from erosion. • SALT helps restore soil fertility and structure. • SALT is ecologically sound. • The SALT farm can easily revert back to forestland if left unfarmed. (Mindanao Baptist Rural Life Center Editorial Staff, 2012, p. 7) The effect of SALT practice on annual total runoff and soil loss is made apparent by several studies. Paningbatan (1995) reported a four-year long (1988-1991) field experiment conducted on a 1.2-ha foot slope of Mount Makiling at an experimental farm in Laguna, Philippines. In 1989, soil loss was very large (124 ton/ha) in the farmer’s practice (T1). With the use of buffer hedgerows and contour cultivation (T2), soil loss was reduced to 40 ton/ha. When the hedgerow trimmings and crop residues were used as mulch in addition (T3), soil loss was markedly reduced to 3 ton/ha. Similar results were also observed in the data for 1990 and 1991. (Malla, 2014, pp. 30-31) Besides controlling erosion, the buffer hedgerow in an alley cropping system can serve as an effective living structure for nutrient cycling. The ability of nitrogen fixing trees to grow on poor soils and in areas with long dry seasons makes them good plants for restoring forest cover to watersheds, slopes and other lands that have been denuded of trees. Through natural leaf drop they enrich and fertilize the soil. There is also a reduced need for expensive inputs like chemical fertilizers (Partap and Watson 1994) because of the organic matter that is added to the farm. In addition, they compete vigorously with coarse grasses, a common feature of many degraded areas that have been deforested or depleted by excessive agriculture thus reducing the labor to cut the grass. Maniego (1986 in Paningbatan 1995) reported that 5 tons of dry herbage from Leucaena hedgerow trimmings produced in one year can provide about 145 kg N, 15 kg P and 75 kg K per hectare, which could supply the fertilizer needs of the alley crops. The SALT project on the island of Mindanao reported that hedgerows occupying 20% of the land area produced about 290 kg N and 100 kg K per hectare per year (Watson and Laquihon, 1985). Furthermore, as the age of hedgerows increases, soil-conserving and yield-enhancing properties improve (Shively 1999). (Malla, 2014, pp. 32)