Geoscience Reference
In-Depth Information
shift from the traditional destructive farming practices (e.g., “kaingin” system or
swidden cultivation) of upland farmers and forest migrants to more sustainable
farming systems in the uplands. “Kaingin system is observed to be one of the
major factors influencing soil erosion in the uplands and siltation of lowland areas
in most of the project sites”. If this SALT technology will be widely adopted by
the majority of upland farmers - particularly the beneficiary - communities and
people's organization partners, this can drastically reduce siltation in downstream
areas and coastal waters. In a short period of time, the technology can improve soil
and water quality and the rejuvenation of forests (re-greening effects).
A 10-year study (Watson and Loguihon 1980-1990) showed that a hectare
of land farmed according to SALT can increase an upland farmer's income
dramatically. Even in the first 2 years of the study, SALT yielded gross incomes
which were much higher than the $49.00/crop/ha of farms using traditional practices
(burning, plowing, constant weeding, and chemical fertilizers). When the permanent
crops (coffee, cacao, banana, etc.) started producing the annual gross income from
SALT further increased to $571.49/ha in 1984 and $622.38/ha in 1985 (Box
15.1
).
Box 15.1: Use of SALT in Practice - Step by Step
First contour lines are established by using an A-Frame, a simple device for
laying out contour lines across the slope. It is made of a carpenter level and
three wooden or bamboo poles nailed or tied together in the shape of a capital
letter A with a base of about 90 cm wide. The carpenter's level is mounted at
the cross bar. The contour lines are spaced 4-5 m apart.
1. One-meter strips along the contour lines are plowed and harrowed to
prepare for planting. Stakes which were driven while using the A-Frame
serves as guide during plowing.
2. Along each prepared contour line, two furrows are laid. With a distance of
12 cm between hills, two to three seeds are planted per hill which serves as
hedgerows. Hedgerow species are
Flemingia macrophylla
(
syn
.
congestal
),
Desmodium rensonii
,
Calliandra calothyrsus
,
Gliricidia sepium
,
Leucaena
diversifolia
,and
L
.
leucocephala
.
3. The space between rows of nitrogen-fixing trees on which the crops to be
planted is called a strip or alley. Cultivation is done on alternate strips (i.e.,
2, 4, 6 and so on) to prevent erosion as unplowed strips hold the soil in
place.
4. Permanent crops such as coffee, cacao, banana, and others of the same
height may be planted when the nitrogen fixing species are sown. Perma-
nent crops are planted every third strip. Tall crops are planted at the bottom
of the farm while the short ones are planted at the top.
(continued)
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