The key role of Agroforestry and Soil Health in the Ecological Intensification of Agriculture
Edmundo Barrios
Eco-Intensive Agriculture Conference – KNAW Amsterdam, The Netherlands - 21 April 2015 Outline
1) Degrading our natural capital
2) Agroforestry: ecological facilitation in action
3) Linking trees, soil biota and ecosystem services
4) Fostering knowledge sharing
5) Challenges and opportunities Outline 1) Degrading our natural capital Millennium Ecosystem Assessment 2001-2005
Steffen et al. 2004 IGBP Planetary Boundaries
Rockstrom et al. 2009 Ecology & Society Planetary Boundaries
Steffen et al. 2015 Science BIODIVERSITY IN PERSPECTIVE
Planned and managed AGBD aboveground biodiversity Above-ground: planned, managed biodiversity ? ? BGBD Unplanned and unmanaged Below-ground:belowground unplanned, unmanagedbiodiversity biodiversity ?
Diversitas 2005 DEFORESTATION AND BIODIVERSITY LOSS BRAZILIAN AMAZON (1988-2008)
3.5
3.0
2.5
2.0
1.5
1.0 Million year per deforested Million ha 0.5
0
Nepstad, 2008 WWF-UNFCC BGBD likely higher than Aboveground
7000* 51.4*
*updated using Bardgett & van der Putten 2014 Nature Barrios 2007 Ecological Economics Are we looking at the tip of the iceberg?
Aboveground biodiversity
Belowground biodiversity SOIL BIOLOGICAL FUNCTION AND THE PROVISION OF ECOSYSTEM SERVICES
Adapted from Kibblewhite et al 2008 in Barrios et al, 2012 SOIL HEALTH
A measure of the state of natural capital that reflects the capacity of soil to respond to agricultural management by maintaining both the agricultural production and the provision of other ecosystem services
Kibblewhite, Ritz & Swift 2008 Phil.Trans.R.Soc. Outline
1) The Global context and Agriculture 2) Agroforestry: ecological facilitation in action AGROFORESTRY
TREES + CROPS and/or ANIMALS (Spatial or Temporal arrangement) SIGNIFICANT ECOLOGIC & ECONOMIC INTERACTIONS
Silvopastoral system colombia INTENSIFICATION & FUNCTIONAL DIVERSITY LOSS
Primary Forest Rubber Plantation Cassava Garden
Increased habitat modification Biodiversity loss Functional diversity loss
Tree Tree cover cover loss loss
34 1 species species Jones et al. 2003 J. Applied Ecology Habitat provision by trees
TREE-AGBD
Pollinators TREE-BGBD Bio-control agents
WaNuLCAS HABITAT PROVISION BY TREES
• Microclimate buffering
SOLAR SOIL CROP TRANSPIRATION SOIL WATER IRRADIATION TEMPERATURE SOIL EVAPORATION AVAILABILITY Some effects of trees are mediated through impact on soil biota – trees increase abundance Mean density of different soil biota and calculated response ratios
Barrios et al. 2012 – Soil Ecology & Ecosystem Services. D.H.Wall et al (Eds) Some effects of trees are mediated through impact on soil biota – trees increase activity Greater soil biological activity (earthworms) near trees but effect greater for some tree species than others
Pruned trees
Free growing trees
Earthworm cast weight
Sample with no earthworm casts
Eartworm casts
Pauli et al. 2010 Pedobiologia TREES AS HOTSPOTS OF BIOLOGICAL ACTIVITY IN AGRICULTURAL LANDSCAPES
“Refugia” Sustaining ecological functions
Barrios et al. 2012 – Soil Ecology & Ecosystem Services. D.H.Wall et al (Eds) TREES AS HOTSPOTS OF BIOLOGICAL ACTIVITY IN AGRICULTURAL LANDSCAPES
“Refugia” Sustaining ecological functions
Barrios et al. 2012 – Soil Ecology & Ecosystem Services. D.H.Wall et al (Eds) TREES AS HOTSPOTS OF BIOLOGICAL ACTIVITY IN AGRICULTURAL LANDSCAPES
Barrios et al. 2012 – Soil Ecology & Ecosystem Services. D.H.Wall et al (Eds) TERMITES, DRYLANDS & CLIMATE CHANGE
Trees and termite activity can increase the resilience of dryland ecosystems to climatic change
Bonachela et al. 2015 Science Are we looking at the tip of the iceberg?
Aboveground biodiversity SOIL HEALTH Belowground biodiversity Outline
1) The Global context and Agriculture
2) Agroforestry: ecological facilitation in action 3) Linking trees, soil health and ecosystem services TREE FUNCTIONS AND SOIL HEALTH
Biomass production
Organic BE(1 inputs AG-Organic inputs Up to 20 t ha -1 yr -1 DM containing as much as 358 kg N 28 kg P 232 kg K 144 kg Ca 60 kg Mg
Palm 1995 Agrof. Systems. Slide 26
BE(1 Is this above ground alone? Check Palm 1995 Barrios, Edmundo (ICRAF); 11-4-2015 C CYCLING TREES
Photosynthesis Decomposition
SOIL BIOTA TREE FUNCTIONS AND SOIL HEALTH
Biomass production
Organic inputs
.... BNF . ~60% plant N derived from BNF
BNF rates -1 -1 up to 650 kg N 2 ha yr Nygren et al. 2012 Nutr.Cycl.Agroecol. BNF
BIOMASS QUALITY TREE FUNCTIONS AND SOIL HEALTH
Biomass production
Organic inputs
.... BNF Deep nutrient uptake rate . S.sesban 148 kg N ha -1 down to 4 m soil depth
Buresh & Tian 1998 Agrof. Syst. SAFETY NET Deep nutrient uptake BNF
NUTRIENT RECYCLING BIOMASS QUALITY DEEP NUTRIENT CAPTURE
DEEP NUTRIENT UPTAKE OR Database and a Decision Support Tool for OM management
Function
Wet chemistry Aerobic incubation Polyphenol profile Perfusion method NIRS approaches In-vitro digestibility Palm et al. 2001 AGEE Vanlauwe et al. 2005 SSSAJ TREE FUNCTIONS AND SOIL HEALTH
Biomass production
Organic inputs
Soil cover
.... BNF
Deep nutrient uptake Barrios et al. 2015 AGROFORESTRY & SOIL HEALTH
30% GREATER SOIL MACROFAUNA ABUNDANCE THAN SECONDARY FOREST Pauli et al. 2011 AppSEcol
SLASH & MULCH REDUCE GHG EMISSIONS 5 times lower global warming
potential CO2-equivalent emissions than Slash & Burn Davidson et al. 2008 Global Chge Biol. Castro et al. 2009 CPWF SOIL STRUCTURE: EROSION/C STORAGE
Increased stability of soil aggregates to water contact
BGBD Structure
Reduction in C losses Lower soil erosion and greater potential for soil C storage
Fonte, Barrios, Six 2010 Geoderma TREES INCREASE CROP YIELDS Meta-analysis > 90 trials across Sub-Saharan Africa
• Mean yield of maize after tree fallows is > 1 ton ha -1 doubling the farmer practice • Very large standard error around the mean highlights that performance varies with context and circumstances Ï we need to know where particular trees will increase yield by a large enough amount to be attractive to farmers
Embedding Research “IN” Development Research designs with planned comparisons as part of development efforts testing sufficient options across Yield difference = Treatment – control yield inherent context heterogeneity HGMLs = Herbaceous green manure legumes Sileshi et al. 2008 Plant and Soil Coe, Sinclair & Barrios 2014 COSUST Outline
1) Degrading our natural capital
2) Agroforestry: ecological facilitation in action
3) Linking trees, soil health and ecosystem services 4) Fostering knowledge sharing Agroforestry and local knowledge
Pauli et al. 2012 Geoderma Erosion of a cultural resource
Under Threat
Loss of Local Rural Youth Experienced knowledge migrating to Farmers Cities
HOW TO PREVENT THE LOSS OF BIO-CULTURAL MEMORY? SOUTH-SOUTH METHODOLOGICAL DEVELOPMENT
2000
2014 InPaC-S
Barrios et al. 2012
Participatory blending of Local and Scientific Knowledge Participatory Trials Design Workshops
AKT5 Market Nutrition Gender Large N Filters Exp.
Blending of Local & Best-bet Best-fit InPaC-S Technical Knowledge options Trial Design options
Barrios, Coe & Sinclair 2015 Outline
1) Degrading our natural capital
2) Agroforestry: ecological facilitation in action
3) Linking trees, soil health and ecosystem services
4) Fostering knowledge sharing
5) Challenges and opportunities CHALLENGES & OPPORTUNITIES OPENING THE BLACK BOX
MOLECULAR TOOLS SPECTROSCOPIC TECHNIQUES BGBD SPATIAL ANALYSIS & GIS STABLE ISOTOPES SOIL PROCESSES REMOTE SENSING
INPUTS OUTPUTS
Barrios 2007 EcolEcon Spectral (NIRS) signatures
Bulk soil
PC2 Carton termite mounds
Ant deposits
Earthworm casts PC1
Termite sheathings Organo-mineral termite mounds
Hedde et al., 2005 FuncEcol Implication: Increasing capacity to attribute relative contribution of specific soil organisms to soil structure stabilization Ï greater predictive understanding CHALLENGES & OPPORTUNITIES Developing better understanding of tree/soil biodiversity interactions
Recommendations of what types of tree densities, arrangements and species
maintain essential ecosystem functions provided by soil biota in agricultural landscapes. Predicting BGBD by looking at AGBD
REMOTE SENSING “Local” Indicator Plants
‘Hotspots’ of soil Key Selected Selected biological activity Functional Soil Ecosystem Groups Processes Services
Adapted from Barrios,2007 EcolEcon Identifying, quantifying and mapping hot-spots of ecosystem service providers in agricultural soils Temporal and spatial dynamics as a result of environmental factors in situ
Predictive knowledge of Ecosystem Service Provision Mapping Soil Biota and function in agricultural landscapes AfSIS Sentinel Site Network Developing and testing spatially-explicit approaches for soil biota
Tree density and cover Developing Local Soil Health Monitoring Systems to evaluate Ecosystem Service provision performance Allow rural communities, environmental/agricultural institutions and local government
Prepare for negotiations related to Payment for Ecosystem Services INTERDISCIPLINARY FRAMEWORK Linking functional diversity, social actor strategies, ecosystem services, and land use
Diaz et al. 2011 PNAS AGROFORESTRY
THANK YOU FOR YOUR ATTENTION
Close to half of agricultural land has > 10% tree cover = area of 1 billion hectares and more than 500 million people (Zomer et al 2014)