|Soil and Water Conservation (SWC) Technologies and Agroforestry Systems (IIRR, 1992, 171 p.)|
Traditional soil and water conservation (SWC) measures were pioneered by the natives and/or ethnic groups found mostly in remote areas of the uplands. These upland areas have long established settlements and have been practicing these technologies for centuries, even before the advent and popularization of modem technologies. These technologies, rooted on sociocultural and religious beliefs, had been developed over many generations and had passed the test of time.
GEN-GEN -- CONTOUR COMPOSTING
Gen-gen refers to a bank or barriers of turf trashes and or earth constructed to control or confine water or prevent passage especially of something undesirable. It is an age-old practice among mountain cultivators in the Cordillera (Ikalahans) as well as the Caraballo and Sierra Madre mountains. This hillside structure is one way of controlling sheet erosion and in sustaining valuable soil nutrients. it combines terracing and composting, thus effectively breaking-up runoff flow and traps eroding soil.
1. The land is first cleared. of scrub vegetation and grasses (construction of gaik or fireline).
2. Trashes are collected and piled at intervals in shallow trench (gen-gen) dug along the contour lines to serve as check for surface runoff and soil erosion.
3. Dirts and weeds taken out during weeding operations and crop refuse after harvests such as vines of sweet potato and ubi tops not required for replanting are piled from time to time on strips.
Gen-Gen - contour composting
4. The land between the gengen(an alleyway) is cultivated and flattened over a period of time and the gen-gen develops into contour paddies.
Usually, sweet potato is planted in a quincunx manner so as to minimize soil erosion and to prevent the fommation of small gullies between the hills of the crop; other crops like pigeon pea are also planted along the trench (gen-gen) itself.
On the average, the swidden/farm is used for four years before it is abandoned. The mean fallow period totals six years, completing a swiddencycle of about 10 years.
In very steep slopes, stakes are driven into the soil to support and hold the piled trash in place.
This is a vegetative soil and water conservation practice of the Batangueffos which aims not only to control soil erosion but also to encourage bench terracing in the field. Essentially, the fammer's choice of the practice in the area is primarily governed by the needs or demand of feeds for cattle.
Land - contour
1. Ipil-ipil (Leucaena leucocephala) seeds are sown, then slightly covered with soil on furrows moving in straight lines across the field without regard for the contour of the land.
2. The seeds are allowed to grow with minimal management except for thinning out in areas too densely planted.
3. It may be a series of one-row strips or a band of ipiPipil in two closely spaced rows.
4. The ipil-ipil trees are cut at a certain height, usually a little shorter than a man's height and the leaves and sprouts are continually pruned for forage. Sometimes, bananas are used instead of ipil-ipil and there are cases also where the combination of the two is being practiced.
There is a practical advantage of aligning the tudling crossway rather than down the slopes because of the farmer's belief that when the forage tree species are to be poured, it is more comfortable and convenient to cut leaves walking across rather than up or down the hillside, espedally if somebody is already carrying the forage.
One limitation is the competition of the tudling species with those of the main crops, making the cultivable area or the effective area smaller.
BALABAG/BABAG OR ITSAKA
In the local dialect, the term means an obstruction (of any kind) usually oriented perpendicular to a known and recuning path so as to stop or control entry, passage, movement or, in this case, water flow.
This practice of the Naaladnons in Naalad, Cebu, primarily aims to arrest the downward movement of soil, especially after heavy rains, thus extending the productivity of the marginal slopes. In addition, the practice also improves and maintains soil fertility (considering the fertilizer trapping of the babag) particularly the organs matter contribution of the decayed wood to the soil. Balabag structures, which literally means "fence", are replaced every four to five years when the wooden stakes and poles decompose and are no longer effective in conserving the soil.
1. Stakes of ipil-ipil are drawn to the ground until about only 0.45 meter high is left above the soil surface.
2. These stakes are established some 0.5 meters apart following the contour of the farm
3. At the base of the pegs, Leucaena poles, leaves, twigs and other debris are horizontally stacked on top of one another across the stakes uphill side to act as barriers to the downward movement of the soil.
4. As dumped branches and leaves decompose, spaces between strips flatten, which makes the entire area appear like- real terraces from a distance.
5. Upon decomposition, the branches and leaves of ipil-ipil are incorporated into the soil to serve as fertilizer.
6. Crops such as tobacco, corn or sweet potato are grown on the farm spaces or alleys between the balabag structures
CANOPY STRUCTURE AND MAINTENANCE
This involves the presence of multilayered arrangement of crops in a single area which minimizes the energy of falling raindrops or conserving water down the slope. Soil and water conservation is achieved by harvesting the crops in blocks. In addition to the yield benefits for several varieties managed separately, the harvesting of small areas leaves little bare soil exposed. If the blocks are allowed to propagate by pakad (or set down adventitious roots), the plants do not need yearly replacement and, hence, maintain a continued canopy for the duration of a cropping cycle. This is also practiced by the upland farmers in the Cordillera region.
DAY-OG OR MULCH COMPOSTING
This is another age-old soil conservation technology by the Cordillera forest dwellers, including the Ikalahans. It involves gathering of grasses and other plant debris to be
spread over the area intended to be planted, primarily to conserve soil moisture and to protect the soil from the impact of raindrops, particularly during heavy rains. Finally, these trashes will undergo decomposition and will serve as organic fertilizer to the crop plants.
It is also practiced in connection with tree planting wherein plant debris are placed at the bottom of the holes and covered with soil before the seedling is planted.
PLANTING OF TALA GADA W (TIGER GRASS)
Some farmers in the Benguet area plant tiger grass as hedgerow species instead of leguminous species. They practice this not only to enhance soil conservation but also to generate additional income when these are made and sold as soft brooms.
Nob: Aside from these six traditional soil and water conservation technologies being described, there are still many other technologies which the upland farmers may have been practicing for quite a long time and may, in fact, have been proven sustainable. The listing and descriptions herein presented are far from complete. Inclusion of the other traditional practices/technologies in this paper was not made possible primarily because of the limitation of available literature and/or documentation on these particular technologies.
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