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Imitating Natural Ecosystems through Successional Agroforestry
for the Regeneration of Degraded Lands
A Case Study of Smallholder Agriculture in Northeastern Brazil
Jennifer Schulz - Jorge Aubad
Overview
1. Land use and degradation worldwide
2. Objective and Strategy
3. Cultivation concept
4. Case studies in Northeastern Brazil
5. Conclusions
Land use and degradation globally
3 Degradation of land ~ 5 - 6 Mio. Hektar / Year (UNEP 2002)4 Increase in cultivated area ~ 3,8- 5 Mio Hektar / Year (FAO 2003)
1 Population (UNO 2004)
2 Area of agriculture (Wood et al. 2001)
% continental surface
World population in billion people
Objective and Strategy
Objective: Regeneration of degraded agricultural land and environmental functions and services on areas of land use
Landscape scale: Environmental functions need to be gradually replaced on the area of agricultural land use
Strategy for land use: Approximation of agricultural uses to natural ecosystems Imitation of the functional principles of local natural
ecosystems
Guiding image: « natural, intact ecosystems »
Imitation of structure and function of ecosystems
Guiding image: « natural, intact ecosystems »
Imitation of structure and function of ecosystems
Perennialism and Diversity
Vegetation strategies: Optimal use of locally limited ressources (solar energy, water, nutrients)
Succession: 1. Maximum accumulation of biomass 2. Coupling / Association of functional different,
mostly complementary species
Short cycles of water, energy and nutrients, reduction of losses
Concept „Successional Agroforestry“
Font: Götsch, 1997
• Imitation of successional trajectories of the local ecosystem• Acceleration of natural processes through systematic
interventions: dense seeding of fast growing plants (first successional
step includes mainly pioneer colonizers e.g. Leguminosae)
systematic trimming production of mulch for fast accumulation of organic material
systematic creation of gaps through cuttings for
the plantation of use-plants of a higher successional level
Concept „Successional Agroforestry“
Selection of a mixture of locally endemic and culture speciesaccording to 2 criteria:
Stratum + Lifetime
Goals: increasing coupling of different functional types
Concept „Successional Agroforestry“
Font: adapted
from Milz, 2004
Case studies on degraded areas in Northeastern Brazil
1/3 of population of brazil
~ 88% smallholder farmers
Degradation of soils: ca. 50%
Desertification ca. 181.000 km2
strong rural- urban migration
Font: EMBRAPA, 2000
Project A: humid coastal zone
Precipitation: 1300-2000 mm/aSoil: sandy loam, low fertilitySize: 1 hectarProject start: 1994
Initial situation
after 10 years
Leguminosa trees trimmed Fresh layer of leeves (ground)
Neighbours´ field Successional system
Development of an organic soil horizon
Regeneration of a degraded unproductive site
Provision food, construction- and firewood
High level of subsistency for 4 persons on 1 hectar
and increased income due to direct marketing of
organic products including:
Banana, mango, jackfruit, papaya, coffee, avocado, cocoa,
orange, lime, cupuaçu, açai, corn, rice, beans, cassava
Results
Project B:semiarid zone
Prec.: ca. 550 mm/a pot. ETP: 2000 mm/aDry period: 7-9 Month, in periodical dry years 18 monthsSize: 1500 collaborating farmers, 1000 m² experimental area Project start: 1999/2000
Fotos: Instituto de Permacultura da Bahia
2. cultivation year end of rainy season
1. cultivation year 2. month of rainy season
Initiation of the successional system in the rainy season
3. cultivation year end of rainy season
3. cultivation year beginning of dry season
Fotos: Instituto de Permacultura da Bahia
Productivity
Province Cafarnaum
Medium production kg/
ha
Production increase through
successional AF
Rizinus monoculture
Regional Ø 800 kg/ha
factor 1
Rizinus successional system
1497,5 ~ factor 1,9
Productivity * per ha success. system
3337.5 ~ factor 4
* At least 5 additional crops in production
• Participation of 1500 farmer families in 5 communities
facilitated by a payment of 18 US$ per month during 4 years
from the 4th year on - complete subsistency possible
• Regeneration of degraded sites and increase of
productivity without irrigation and external inputs
Decrease of risk for harvest loss through diversity of
perennial and anual plants higher resilience
Provision of environmental goods as an existential basis
Reduction of the strong rural-urban migrations
Project results
• farmers adopt SAF rather in drier zones and conditions of stronger degradation
Critical for success are:
• Capacity building in two directions:
Local knowledge in exchange with external expert impulse
- Training of multiplicators
Organisation of local knowledge exchange and the creation
of farmers associations
Development of local market chains for organic products
Comparison & Critical aspects:
Concept „Successional Agroforestry“ is successful
Conclusions:
Regeneration of an existential basis, local ecological
knowledge and farmers empowerment
improvement of the local livelihood
Stabilization and regeneration of environmental regulation functions at local scale
Potential for regeneration of regulation functions on critical areas within the landscape
Thank you for your attention!