1.2 Detalhes do contato das pessoas capacitadas e instituições envolvidas na avaliação e documentação da tecnologia

Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)

Programme d’Appui à l’agriculture Productive (GIZ / PROMAP)

Nome da(s) instituição(ões) que facilitou(ram) a documentação/ avaliação da Tecnologia (se relevante)

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH (GIZ) - Alemanha

Nome da(s) instituição(ões) que facilitou(ram) a documentação/ avaliação da Tecnologia (se relevante)

Misereor - Alemanha

1.3 Condições em relação ao uso da informação documentada através de WOCAT

Quando os dados foram compilados (no campo)?

01/07/2012

O/a compilador/a e a(s) pessoa(s) capacitada(s) aceitam as condições relativas ao uso de dados documentados através da WOCAT:

Sim

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Hand-dug trenches contribute to the restoration of tree cover and prevention of water erosion on slopes.

2.2 Descrição detalhada da tecnologia

Descrição:

This technique is designed to restore communal land on slopes and highland pediments. It involves manually excavating trenches 3 to 3.5 m long and 0.6 m deep, spaced 4 m apart in staggered rows. This results in around 625 trenches per hectare. The excavated earth is piled downhill of the trenches, which are aligned perpendicular to the slope. In the middle of each trench, a 0.40 m high step is left on which the tree seedling is planted. The tree receives the water it needs from the trench where it collects.

Purpose of the Technology: The main purpose of this technique is to restore tree cover on degraded, unfertile land and prevent water erosion on slopes by reducing the flow of water that threatens land downstream. The trenches reduce gully erosion and pedimentation of areas with a fragile soil structure. Like all afforestation measures, in the medium term, this technique is effective in protecting the land against water and wind erosion. The shade provided by the trees also lowers the temperature of the soil and the infiltration of water in the hand-dug trenches contributes to groundwater recharge.
Areas restored using hand-dug trenches can subsequently be exploited to a limited extent in accordance with strict controls.

Establishment / maintenance activities and inputs: The technique is very labour intensive. Work must begin immediately after harvesting when the soil is still moist and workable. A protection and monitoring system is required to ensure that grazing animals do not damage the young trees. The mortality of trees after planting is relatively high (survival rate is about 60%), and dead trees must be replaced systematically during the first three years. Good community organisation is required.

Natural / human environment: Hand-dug trenches are particularly useful when rainfall is low, as they retain water and make it available to the trees growing in them. In years when rainfall is abundant or there are violent downpours, the young trees are protected, as they are planted on a raised step within the trench, although there is a risk of flooding in the event of very heavy rain.

2.3 Fotos da tecnologia

2.5 País/região/locais onde a tecnologia foi aplicada e que estão cobertos nesta avaliação

2.6 Data da implementação

Caso o ano exato seja desconhecido, indique a data aproximada:

• 10-50 anos atrás

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:

• através de projetos/intervenções externas

Comentários (tipos de projeto, etc.):

Developed, implemented and disseminated as part of projects and programmes undertaken from the 1980s onwards to combat desertification and improve natural resource management. Implemented by German Development Cooperation (BMZ, GIZ, KfW) in Niger by projects e.g. PDRT (Projet de développement rural de Tahoua - Tahoua Rural Development Project)

3.1 Principal/principais finalidade(s) da tecnologia

• Reduz, previne, recupera a degradação do solo

3.2 Tipo(s) atualizado(s) de uso da terra onde a tecnologia foi aplicada

Comentários:

Major land use problems (compiler’s opinion): water erosion (gully, sheet), wind erosion, degraded and infertile land

Nomadism: Yes

Semi-nomadism / pastoralism: Yes

Cut-and-carry/ zero grazing: Yes

Improved pasture: Yes

Mixed: (eg agro-pastoralism, silvo-pastoralism): Yes

Other grazingland: agropastoralism

Selective felling of (semi-) natural forests: Yes

Forest products and services: timber, fuelwood, fruits and nuts, grazing / browsing, other forest products / uses (honey, medical, etc.)

Type of cropping system and major crops comments: armers are mainly agropastoralists with some communities specialised on pure pastoralism

Constraints of common grazing land

Constraints of forested government-owned land or commons

3.3 Mais informações sobre o uso da terra

Abastecimento de água para a terra na qual a tecnologia é aplicada:

• Precipitação natural

Comentários:

Water supply: Also mixed rainfed - irrigated and post-flooding

Número de estações de cultivo por ano:

• 1

Especifique:

Longest growing period in days: 120; Longest growing period from month to month: August to October

Densidade animal (se relevante):

1-10 LU /km2

3.4 Grupo de GST ao qual pertence a tecnologia

• Solo/cobertura vegetal melhorada
• Gestão de irrigação (inclusive abastecimento de água, drenagem)

3.5 Difusão da tecnologia

Especifique a difusão da tecnologia:

• Uniformemente difundida numa área

3.6 Medidas de GST contendo a tecnologia

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Comentários:

Secondary types of degradation addressed: Et: loss of topsoil, Hg: change in groundwater / aquifer level

Main causes of degradation: soil management (Unadapted land use methods, reduced or abandoned fallow periods), crop management (annual, perennial, tree/shrub) (Neglect of fallow periods and crop rotation), droughts (due to heat waves), population pressure (rapidly growing population increasing pressure on land), land tenure (insecure access to land and collectively managed communal land), poverty / wealth (very poor population)

Secondary causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (deforestation through overgrazing and fire wood collection), over-exploitation of vegetation for domestic use (firewood collection), overgrazing (cattle, sheep and goats), change in temperature (Climate change: heat waves), change of seasonal rainfall (more variable onset of rains), Heavy / extreme rainfall (intensity/amounts) (more variable and intensive rains), wind storms / dust storms (frequent storms), floods (due to intensive rain storms), labour availability (some migration of men to nearby cities), education, access to knowledge and support services (high level of illiteracy)

3.8 Redução, prevenção ou recuperação da degradação do solo

Especifique o objetivo da tecnologia em relação a degradação da terra:

• Recuperar/reabilitar solo severamente degradado

Comentários:

Secondary goals: prevention of land degradation, mitigation / reduction of land degradation

4.1 Desenho técnico da tecnologia

4.2 Especificações técnicas/ explicações do desenho técnico

Trenches are manually excavated 3 to 3.5 m long and 0.6 m deep, spaced 4 m apart in staggered rows. This results in around 625 trenches per hectare. The excavated earth is piled downhill of the trenches, which are aligned perpendicular to the slope. In the middle of each trench, a 0.40 m high step is left on which the tree seedling is planted. The tree benefits from the water collected in the trench.

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: retain / trap, control of dispersed runoff: impede / retard, control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, control of concentrated runoff: drain / divert, improvement of ground cover, stabilisation of soil (eg by tree roots against land slides), increase of infiltration, increase / maintain water stored in soil, water harvesting / increase water supply

Secondary technical functions: increase in organic matter, increase in nutrient availability (supply, recycling,…), increase of groundwater level / recharge of groundwater, sediment retention / trapping, sediment harvesting, reduction in wind speed, increase of biomass (quantity), promotion of vegetation species and varieties (quality, eg palatable fodder)

Vegetative measure: planted in trench
Vegetative material: T : trees / shrubs, G : grass

Vegetative measure: Vegetative material: T : trees / shrubs, G : grass

Retention/infiltration ditch/pit, sediment/sand trap
Spacing between structures (m): 4
Depth of ditches/pits/dams (m): 0.6
Length of ditches/pits/dams (m): 3.5

Vegetation is used for stabilisation of structures.

4.3 Informação geral em relação ao cálculo de entradas e custos

Especifique a moeda utilizada para os cálculos de custo:

• Dólares norte-americanos

4.4 Atividades de implantação

	Atividade	Tipo de medida	Periodicidade
1.	marking out the contour line	Estrutural
2.	laying out the trenches in staggered rows	Estrutural
3.	digging two rectangular microcatchments separated horizontally by a flat surface	Estrutural
4.	making a hole in the central area	Vegetativo
5.	planting the seedlings	Vegetativo
6.	sowing grass on the ridges	Vegetativo

4.5 Custos e entradas necessárias para a implantação

	Especifique a entrada	Unidade	Quantidade	Custos por unidade	Custos totais por entrada	% dos custos arcados pelos usuários da terra
Mão-de-obra	All the Labour	unit	1,0	220,76	220,76
Material vegetal	Seedlings	unit	1,0	41,55	41,55
Outros	Transport of seedlings	unit	1,0	1,93	1,93
Custos totais para a implantação da tecnologia					264,24

4.6 Atividades recorrentes/manutenção

	Atividade	Tipo de medida	Periodicidade/frequência
1.	A protection and monitoring system is required to ensure that grazing animals do not damage the young trees	Vegetativo
2.	dead trees must be replaced systematically during the first three years	Vegetativo

4.8 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

Other costs
• equipment, such as jumper bars, shovels and axes
• 625 tree seedlings
• 15 kg of grass seed
• cost of transporting 2 cartloads of seedlings
• 120 seedlings to replace dead trees.

5.1 Clima

5.2 Topografia

Comentários e outras especificações sobre a topografia:

Altitudinal zone: 200 m a.s.l.

Landforms: Also footslopes and valley floors

5.3 Solos

Caso disponível anexe a descrição completa do solo ou especifique as informações disponíveis, p. ex. tipo de solo, PH/acidez do solo, nitrogênio, capacidade de troca catiônica, salinidade, etc.

Soil fertility is very low - medium

Soil drainage / infiltration is poor - medium

Soil water storage capacity is low - medium

5.4 Disponibilidade e qualidade de água

Comentários e outras especificações sobre a qualidade e a quantidade da água:

Ground water table: > 10m

Availability of surface water: Surface runoff generated by limited but intense rainfalls

5.5 Biodiversidade

5.6 Características dos usuários da terra que utilizam a tecnologia

Indique outras características relevantes dos usuários da terra:

Population density: 10-50 persons/km2

Annual population growth: 3% - 4%

(mostly poor households below poverty line).

Off-farm income specification: men migrate temporarily or permanently to cities for off-farm income, women and men seasonally carry out paid farm work

Market orientation of production system: Most households crop for subsistence , but surplus is sold on the market. Some vegetable growing is just for commercial/ market.

Level of mechanization: Oxes and donkeys used for animal traction.

5.7 Média da área de terra própria ou arrendada por usuários da terra que utilizam a tecnologia

5.8 Propriedade de terra, direitos de uso da terra e de uso da água

Propriedade da terra:

• Estado
• Comunitário/rural

• not titled

Direitos do uso da terra:

• Indivíduo

Comentários:

Traditional land use rights prevail. On fields individual land use rights, communal rights on pasture and forest land (collection of wood and other products (fruits, medicinal plants))

5.9 Acesso a serviços e infraestrutura

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Renda e custos

Impactos socioculturais

Impactos ecológicos

Ciclo hídrico/escoamento

Solo

Biodiversidade: vegetação, animais

Clima e redução de riscos de desastre

6.2 Impactos externos mostrados pela tecnologia

6.3 Exposição e sensibilidade da tecnologia às mudanças climáticas graduais e extremos/desastres relacionados ao clima (conforme o ponto de vista dos usuários da terra)

Mudança climática gradual

Mudança climática gradual

	Estação do ano	Tipo de mudança climática/extremo	Como a tecnologia lida com isso?
Temperatura anual		aumento	bem

Extremos (desastres) relacionados ao clima

Desastres meteorológicos

	Como a tecnologia lida com isso?
Temporal local	não bem
Tempestade de vento local	bem

Desastres climatológicos

	Como a tecnologia lida com isso?
Seca	bem

Desastres hidrológicos

	Como a tecnologia lida com isso?
Inundação geral (rio)	não bem

Outras consequências relacionadas ao clima

Outras consequências relacionadas ao clima

	Como a tecnologia lida com isso?
Período de crescimento reduzido	não conhecido

Comentários:

Damages are generally small but need to be repaired quickly.

6.4 Análise do custo-benefício

Como os benefícios se comparam aos custos de implantação (do ponto de vista dos usuários da terra)?

Como os benefícios se comparam aos custos recorrentes/de manutenção(do ponto de vista dos usuários da terra)?

Comentários:

Establishment of the trenches involves considerable labour and growth of trees takes a couple of years.

6.5 Adoção da tecnologia

Entre todos aqueles que adotaram a tecnologia, quantos adotaram espontaneamente, ou seja, sem receber nenhum incentivo material/pagamentos?

• 0-10%

Comentários:

Comments on acceptance with external material support: The technology has been applied by PDRT on common land using food/cash for work in order to inject money and food into the local communities.

Comments on spontaneous adoption: There was no spontaneous adoption. The technology is designed for common lands and takes considerable labour that only very well organised communities are able to mobilise.

There is no trend towards spontaneous adoption of the Technology

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

Pontos fortes/vantagens/oportunidades na visão do usuário da terra
The young trees are protected of flooding, as they are planted on a raised step within the trench

Pontos fortes/vantagens/oportunidades na visão do/a compilador/a ou de outra pessoa capacitada
Hand-dug trenches retain water and make it available to the trees growing in them. Although the trenches are progressively filled with sediment, which reduces their capacity to retain water, at the same time, the trees develop and become less dependent on stored water.
This technique has proved effective in restoring forest/rangeland sites. The progressive development of grass and tree cover continues on the improved sites, where the tree population is up to 20 years old. After around ten years, the average annual production of wood is 1.3 steres per hectare.
The shade provided by the trees also lowers the temperature of the soil.
In the medium term, this technique is effective in protecting the land against water and wind erosion.
Areas restored using hand-dug trenches can subsequently be exploited to a limited extent in accordance with strict controls.

6.8 Pontos fracos, desvantagens/riscos da tecnologia e formas de superá-los

Pontos fracos/vantagens/riscos na visão do/a compilador/a ou de outra pessoa capacitada	Como eles podem ser superados?
The technique is very labour intensive. Work must begin immediately after harvesting when the soil is still moist and workable.	Good community organisation is required.
A protection and monitoring system is required to ensure that grazing animals do not damage the young trees. The mortality of trees after planting is relatively high (survival rate is about 60%), and dead trees must be replaced systematically during the first three years.

7.3 Links para informação relevante que está disponível online

Título/ descrição:

Good Practices in Soil and Water Conservation. A contribution to adaptation and farmers´ resilience towards climate change in the Sahel. Published by GIZ in 2012.

URL:

http://agriwaterpedia.info/wiki/Main_Page