1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Bureau of Soils and Water Management (Bureau of Soils and Water Management) - Philippines

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

International Centre for Research in Agroforestry (ICRAF) - Kenya

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Quand les données ont-elles été compilées (sur le terrain)?

26/06/1999

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

1.4 Déclaration sur la durabilité de la Technologie décrite

Est-ce que la Technologie décrite ici pose problème par rapport à la dégradation des terres, de telle sorte qu'elle ne peut pas être déclarée comme étant une technologie de gestion durable des terres?

Non

1.5 Référence au(x) questionnaire(s) sur les Approches de GDT

2.1 Courte description de la Technologie

Définition de la Technologie:

Within individual cropland plots, strips of land are marked out on the contour and left unploughed in order to form permanent, cross-slope barriers of naturally established grasses and herbs.

2.2 Description détaillée de la Technologie

Description:

Natural vegetative strips (NVS) are narrow live barriers comprising naturally occurring grasses and herbs. Contour lines are laid out with an A-frame or through the ‘cow's back method’ (a cow is used to walk across the slope: it tends to follow the contour and this is confirmed when its back is seen to be level). The contours are then pegged to serve as an initial guide to ploughing. The 0.3-0.5 m wide strips are left unploughed to allow vegetation to establish. Runoff flowing down the slope during intense rain is slowed, and infiltrates when it reaches the vegetative strips. Eroded soil collects on and above the strips and natural terraces form over time. This levelling is assisted by ploughing along the contour between the NVS - through ‘tillage erosion’ - which also moves soil downslope.
The vegetation on the established NVS needs to be cut back to a height of 5-10 cm: once before planting a crop, and once or twice during the cropping period. The cut material can be incorporated during land preparation, applied to the cropping area as mulch, or used as fodder. This depends on whether the farmer has livestock or not, on personal preference, and on the time of cutting. If the grass is applied as mulch or incorporated, the technology can be considered to be an agronomic, as well as a vegetative, measure.
NVS constitutes a low-cost technique because no planting material is required and only minimal labour is necessary for establishment and maintenance. Some farmers had already practiced the technology for several years before the intervention of the ICRAF (The World Agroforestry Centre) in 1993. ICRAF came to realise that farmers here preferred NVS to the recommended ‘contour barrier hedgerows’ of multipurpose trees- which land users viewed as being too labour intensive. When farmers became organised into ‘Landcare’ groups, NVS began to gain wide acceptance.
Land users appreciate the technique because it effectively controls soil erosion and prevents loss (through surface runoff) of fertilizers applied to the crop. As an option, some farmers plant fruit and timber trees, bananas or pineapples on or above the NVS. This may be during establishment of the contour lines, or later. The trees and other cash perennials provide an additional source of income, at the cost of some shading of the adjacent annual crops.

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.6 Date de mise en œuvre de la Technologie

Indiquez l'année de mise en œuvre:

1993

Si l'année précise est inconnue, indiquez la date approximative: :

• il y a moins de 10 ans (récemment)

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• par le biais de projets/ d'interventions extérieures

Commentaires (type de projet, etc.) :

It evolved in the area with some adaptations.

3.1 Principal(aux) objectif(s) de la Technologie

• réduire, prévenir, restaurer les terres dégradées

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Major land use problems (compiler’s opinion): Loss of topsoil through sheet erosion and rills, leading to rapid soil fertility decline. In turn soil fertility decline results in the need for increasing levels of fertilizer inputs to maintain crop yield. However, these fertilizers are often washed away by surface runoff - a vicious circle.
Major land use problems (land users’ perception): Soil productivity decline; need more inputs to maintain crop yield.

3.3 Informations complémentaires sur l'utilisation des terres

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

Nombre de période de croissance par an: :

• 2

Précisez:

Longest growing period: 240 days (Mar - Dec)

3.4 Groupe de GDT auquel appartient la Technologie

• mesures en travers de la pente

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

Si la Technologie est uniformément répartie sur une zone, indiquez la superficie couverte approximative:

• 100-1 000 km2

Commentaires:

Total area covered by the SLM Technology is 110 m2. The technology has been practiced by a few farmers for the past several years. With the entry of the International Centre for Research in Agroforestry (ICRAF) in 1993; farmers became organized and the technology gained wide adherence.

3.6 Mesures de GDT constituant la Technologie

Commentaires:

Type of agronomic measures: mixed cropping / intercropping, mulching, legume inter-planting, manure / compost / residues, contour tillage
Type of vegetative measures: aligned: -contour

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (caused massive erosion and loss of productivity), Lack of enforcement of legislat./authority (no clear cut policy and support from LGU). Secondary causes of degradation: overgrazing (over population of livestock, low land ratio), education, access to knowledge and support services (farmers are not fully aware of simple SWC approach), Agricultural causes (unsustainable practice in farming)

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• réduire la dégradation des terres

Commentaires:

Secondary goals: prevention of land degradation, rehabilitation / reclamation of denuded land

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

A - Spacing of natural vegetative strips depends on the slope.
B - The insert shows the evolution of terraces over time through tillage and soil erosion, leading to accumulation of sediment behind the strips (steps 1-3).

Technical knowledge required for field staff / advisors: moderate. Technical knowledge required for land users: moderate.

Main technical functions: reduction of slope angle, reduction of slope length, control of dispersed runoff. Secondary technical functions: improvement of ground cover, increase of infiltration, increase in soil fertility

Agronomic measures:
Mixed cropping / intercropping - Material/ species: annuals/perennials; Remarks: laid out alternately.
Mulching - Material/ species: crop residues; spread on the surface
Legume inter-planting - purpose: for nitrogen fixation
Manure / compost / residues - Material/ species: animal, crop residues
Contour tillage - Material/ species: Contour strips are laid into 6-10 meters apart depending on slope gradient.

Vegetative measures:
Aligned, along contour
Vegetative material: T : trees / shrubs, F : fruit trees / shrubs, C : perennial crops, G : grass, O : other
Vertical interval between rows / strips / blocks (m): 1
Spacing between rows / strips / blocks (m): 5
Vertical interval within rows / strips / blocks (m): 8
Width within rows / strips / blocks (m): 0.5

Narrow grass barriers
Vegetative material: grass
Number of plants per (ha): dense grass
Width within rows / strips / blocks (m): 0.5-0.7

Trees/ shrubs species: Acacia mangium, Eucalyptus deglupta, Gmelina arbarea
Fruit trees / shrubs species: Mango, Durian, Rambutan, Jackfruit
Perennial crops species: Coffee, rubber, pineappe
Grass species: Bamboo, setara, napier, Panicum spp.
Other species: Legumes

Slope (which determines the spacing indicated above): 30%
If the original slope has changed as a result of the Technology, the slope today is (see figure below): 2%
Gradient along the rows / strips: 20%

4.3 Informations générales sur le calcul des intrants et des coûts

Spécifiez la manière dont les coûts et les intrants ont été calculés:

• par superficie de la Technologie

Indiquez la monnaie utilisée pour le calcul des coûts:

• dollars US

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Layout of contours with the use of an A-frame (or cow’s back method, see Annexe T3)) placing wooden pegs along the contours.	Végétale	dry season/before land preparation
2.	Seeding (T, F, C)	Végétale	dry season
3.	Transplanting	Végétale	onset of rainy season
4.	Land preparation	Végétale	dry season/before planting

4.5 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	labour		1,0	15,0	15,0	100,0
Equipements	animal traction		1,0	40,0	40,0	100,0
Equipements	tools		1,0	25,0	25,0	100,0
Equipements	stakes (pegs)		1,0	4,0	4,0	100,0
Coût total de mise en place de la Technologie					84,0

Commentaires:

Duration of establishment phase: 12 month(s)

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Initial ploughing along the contour: leaving unploughed strips.	Agronomique	onset of rainy season / before each season
2.	Planting	Agronomique	onset of rainy season / each cropping season
3.	Mulching	Agronomique	dry season / only whensufficient crop residues
4.	Fertilization	Agronomique	early vegetative stage / each cropping season
5.	Interim cultivation/weeding	Agronomique	vegetative stage / each cropping season
6.	Ploughing mulch into the soil during normal land cultivation.	Agronomique
7.	Weeding (T, F, C), Slashing grass	Végétale	rainy season /2 times
8.	Spreading the cut materials evenly in the alleys (between strips) as	Végétale	rainy season /2 times (weeded materials)
9.	Pruning	Végétale	before and during cropping /2 times per cropping

4.7 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	labour		1,0	36,0	36,0	100,0
Equipements	animal traction		1,0	40,0	40,0	100,0
Equipements	tools		1,0	2,0	2,0	100,0
Coût total d'entretien de la Technologie					78,0

Commentaires:

Machinery/ tools: plough, harrow

Costs of establishing contours and maintenance by slashing are calculated by total length of NVS. This example is from a typical field with an 18% slope: at an NVS spacing of 5 m, the approximate total linear distance for one hectare is 2,000 m. In this example, the farmer has paid for everything him/herself (see section on acceptance/adoption). Note that the establishment cost is more or less equivalent to the cost of standard land preparation by ploughing. When 'enrichment planting’ of the strips is carried out, extra cost for seedlings (of fruit trees for example) and associated labour for planting are incurred.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

Slope is the dominant factor in cost calculation. The steeper the slope, the more difficult the mobility is and the more closely-spaced the contours are .

5.1 Climat

5.2 Topographie

5.3 Sols

Si disponible, joignez une description complète du sol ou précisez les informations disponibles, par ex., type de sol, pH/ acidité du sol, capacité d'échange cationique, azote, salinité, etc.

Soils are developed from fine-grained igeneous rocks. Soil fertility: strongly acid and with high P fixing capacity. Rapid organic matter mineralisation due to high temperature. Soil drainage is generally good except in isolated depressions.

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Population density: 50-100 persons/km2; Annual population growth: > 4%

and own 20% of the land (5).
and own 40% of the land (30).
and own 30% of the land (65).

Off-farm income specification: Carpentry, trade, business, labour for neighbouring farms and other labour intensive agricultural activities (e.g. vegetable production)
Market orientation of production system: Upland rice is grown as subsistence. Maize is sold to feed millers.
Level of mechanization: The terrain limits the extensive use of machineries.

5.7 Superficie moyenne des terres détenues ou louées par les exploitants appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• individu, sans titre de propriété
• individu, avec titre de propriété

Droits d’utilisation des terres:

• loué
• individuel

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Revenus et coûts

Autres impacts socio-économiques

Impacts socioculturels

Impacts écologiques

Cycle de l'eau/ ruissellement

Sols

Biodiversité: végétale, animale

Réduction des risques de catastrophe et des risques climatiques

Autres impacts écologiques

6.2 Impacts hors site que la Technologie a montrés

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

6.5 Adoption de la Technologie

Parmi tous ceux qui ont adopté la Technologie, combien d'entre eux l'ont fait spontanément, à savoir sans recevoir aucune incitation matérielle ou aucun paiement?

• 50-90%

Commentaires:

50% of land user families have adopted the Technology with external material support (2000 families)
50% of land user families have adopted the Technology spontaneously (without external material support) (2000 families)

There is a strong trend towards spontaneous adoption of the Technology. Factor that helped was the formation of Landcare associations which have benefited their members in various ways. There is a strong trend towards spontaneous adoption, especially where Landcare associations are in operation.

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
Easy to establish and maintain
Improve soil fertility
Prevent soil erosion

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Easy to establish and maintain (How to sustain: Transform farmers associations into cooperative which serve as conduits in marketing. Intensify information and education campaign.)
Less competition for space, sunlight, moisture and nutrient. (How to sustain: Ensure continued regular trimming of vegetative strips and use of these as fodder or mulch.)
Low labor and external inputs requirement
Effective in reducing soil erosion (by 90%) (How to sustain: Adopt other supportive technologies like mulching, zero tillage/minimum tillage, etc.)

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

Faiblesses/ inconvénients/ risques du point de vue de l’exploitant des terres	Comment peuvent-ils être surmontés?
High initial establishment cost	Subsidy/assistance from government
Effect of technology is not readily seen	Education about what long term sustainability means
High gestation period for some component of the system	Proper mix of annual and perennial crops

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
Effect on yield and income is not readily felt, since reduced erosion is not easily translated into increased income or yield	Farmers should have supplementary sources of income (eg livestock). Education about what long-term sustainability means.
Reduction of productive area by approx 10%	Optimum fertilization to offset production loss. Nutrients are conserved under NVS and this will result in the reduction of fertilizer requirement after some years.
Creation of a fertility gradient within the alley (soil is lost from the top of the alley and accumulates above the NVS where fertility then concentrates)	Increased application of fertilizer on the upper part of alley.
Overall increase of production value is low	Land users could ask for subsidy/assistance from Government: eg for fertilizers, establishment of nurseries, free seedlings (for higher value fruit trees).

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Managing soil fertility on terraces forming behind vegetative filter strips: An assessment of farmer strategies

Disponible à partir d'où? Coût?

ICRAF, P.O. Box 161, Bogor, INDONESIA

Titre, auteur, année, ISBN:

Crop productivity using forage legumes and grasses as contour hedgerows species in an acid upland soils

Disponible à partir d'où? Coût?

ICRAF, P.O. Box 161, Bogor, INDONESIA

Titre, auteur, année, ISBN:

Garrity DP, Stark M and Mercado Jr A: Natural Vegetative Strips: a bioengineering innovation to help transform smallholderconservation. pp 263–270. 2004.

Titre, auteur, année, ISBN:

in Barker DH, Watson AJ, Sombatpanit S, Northcutt B and Maglinao AR Ground and Water Bioengineering for ErosionControl and Slope Stabilisation.

Disponible à partir d'où? Coût?

Science Publishers inc. Enfield, USA

Titre, auteur, année, ISBN:

Stark M, Itumay J and Nulla S Assessment of Natural VegetativeContour Strips for Soil Conservation on Shallow Calcareous Soil in the Central Philippines.. 2003.

Disponible à partir d'où? Coût?

World Agroforestry Centre (ICRAF), Nairobi, Kenya