Recent Advances in Agroforestry: Accelerating Transition from Conventional to Climate-Resilient Farming

Transcription

1 Recent Advances in Agroforestry: Accelerating Transition from Conventional to Climate-Resilient Farming P. K. R. Nair University of Florida, Gainesville, FL, USA Keynote Presentation Fourth European Agroforestry Conference Nijmegen, The Netherlands May 2018

2 The Coming of Age of Agroforestry During the past four decades AF has been transformed from a vague concept to a robust land-use discipline Its role has been clearly demonstrated in! Sustaining crop yields! Diversifying farm production! Realizing ecosystem services! Ensuring environmental integrity Initiated in resource-poor developing countries, today it is a vehicle for transitioning from traditional practices to sciencebased technologies to address land-management problems world-wide.

3 Agroforestry: A Major Component of Most Development Paradigms Agroecology Agroecosystem mgt Carbon farming Climate resilient farming Climate smart agriculture Conservation agriculture Integrated natural resource management (NRM) Landcare Multifunctional agriculture Organic agriculture Ecoagriculture/ Permaculture Ecofarming REDD/ REDD+/ REDD++ Evergreen agriculture Satoyama (Japanese) Forest farming Social forestry Holistic land management Sustainable agriculture Agroforestry figures prominently Sustainable the concept of all these and many other intensification similar paradigms

4 AGROFORESTRY: the purposeful growing of trees and crops and/or animals in interacting combinations for a variety of objectives (Nair, 1993) Bridging the Economy Ecology Divide Estimated to be practiced on over 1 billion ha of land by 1.5 billion farmers in the tropics (ICRAF, 2009). Globally the area under AF (currently practiced or potentially available) is ~ 1.6 billion ha (Nair, 2012). In Europe, ~20 million ha, silvopasture (17.7 Mha) being the most dominant (AGFORWARD 2017).

5 AGROFORESTRY The Family Farm Family Farm: A farm owned and operated by a family. The basic unit of agricultural economy of much of human history and continues to be so in developing nations. Two terms: Small farm and Family farm. The focus of the former is on farm size; it is on ownership and control of the farm in the latter. Both terms are used synonymously An estimated 2.6 billion people produce more than 70% of the world's food on more than 500 million of the so-called small (family) farms (CIRAD, FAO).

6 Global Distribution of Agri Land Agri. land (M ha) # Farms (Mill) # Small farms (Mill) Agri. land in small holder (M ha) % agri. land by smallholders Av size of small farms (ha) Africa 1, Asia Pac (India) Europe LAC N Am GLOBAL 5, , Compiled from FAOSTAT ( Data on number and size of farms obtained from national authorities.

7 Credit: Reganold & Wachter (2016). Organic agriculture in the twenty-first century. In: Cook et al. (2016) Source: Nature Plants.

8 AGROFORESTRY: Enhancing Ecosystem Resilience Ecosystem Resilience: The ecosystem s stability and capacity of tolerating disturbance and restoring itself. AF can be a buffer against some disturbances caused by: Stochastic events Fires, flooding, windstorms, insect population explosion, Human activities Agriculture, deforestation, introduction of exotic plants/ animals, that lead to pollution, natural-resource mismanagement, biodiversity decline, anthropogenic climate

9 Climate Resilient Farming: What is it? Is like Sustainability:! A much abused or differently interpreted word! Is understood more by intuition; evades a clear definition. The capacity for a socio-ecological system to:! Absorb stresses and maintain function in the face of external stresses imposed upon it by climate change &! Adapt, reorganize, and evolve into more desirable configurations that improve the sustainability of the system, leaving it better prepared for future climate change impacts (Folke, 2006; Nelson and Brown, 2007). In the context of AF as a strategy for CRF, the most prominent issues are Carbon (C) Seq especially Soil C Seq (SCS) and other ecosystem services.

10 C Sequestration in Land-Use Systems Aboveground (Vegetation) Belowground (Soils) AFS are believed to have a higher potential to sequester C because of their perceived ability for greater capture and utilization of growth resources (light, nutrients, and water) than in single-species crop- or pasture systems. Estimates of C stored in AFS (Mg C ha -1 ): Aboveground: 0.29 to yr -1 Belowground : 30 to 300, up to 1-m depth.

11 Recent Developments in Carbon Sequestration under AFS Meta-analyses Global Estimates: How realistic and useful are they? Pie in the Sky (can the benefits be actually realized)? A lot of hype, but little science?

12 Meta-Analyses of Soil C Seq under AFS Results of several studies on SCS under AFS are available Enormous variations exist in study procedures and system locations Extrapolation of results is therefore difficult A meta-analysis is one way to address the problem It is a statistical procedure for comparing and synthesizing result from different studies for finding common patterns, discrepancies, or other interesting relationships that may not be detectable from individual studies (Borenstein et al., 2009) When the treatment (or effect size) is consistent among studies, meta-analysis can be used to identify this common effect.

13 Results of a Meta-Analysis Data from 78 peer-reviewed studies, 858 data points SOC stock under various AFS from 25 countries in Asia, Africa, Europe, North America and South America. Soil-depth classes (0 20, 0 40, 0 60, and cm) Agroecological Regions: ASA: Arid and semiarid; LHT: Lowland humid Tropics MED: Mediterranean; TEM: Temperate SOC stocks under AFS were higher in the cm soil depth by: +27% in the ASA region + 26% in LHT, and +5.8% in MED, 5.3% in the TEM AFS aged years had higher SOC stock than < 10-yearold systems across all soil-depth classes and regions.

14 ASA Results of a Meta-Analysis Region LHT MED TEM ASA LHT MED TEM ASA LHT MED TEM Agriculture Forest Pasture Depth (cm) Database: 858 data points from 78 publications in int l peer-reviewed journals SOC stock differences % between AFS vs. Agri/ Forestry/Pasture Soil depth classes: (0 20, 0 40, 0 60, and cm) Agroecol Regions: ASA: Arid & Semiarid, LHT: Lowland humid Tr, Temperate (TEM)) regions Change in SOC (%) Chatterjee, N., Nair, PKR, Nair, VD, Chakraborthy, S (In Press)

15 Sequestering Carbon in Soil An International Conf. May 03 to 05, 2017 Paris, France Over 200 soil carbon experts, farmers, govt officials, NGO and private sector leaders, and advocates from 34 countries met to explore how to advance soil carbon sequestration (SCS) through agriculture and ecosystem restoration. There was consensus that: There must be a comprehensive shift from single species systems to multispecies systems across the agriculture industry Agroforestry systems have significantly higher SC sequestration potential than single species systems.

16 Increasing News/Media Coverage Dec 2, SundayReview Opinion Soil Power! The Dirty Way to a Green Planet By JACQUES LESLIE The last great hope of avoiding catastrophic climate change may lie in a substance so commonplace that we typically ignore it or else walk all over it: the soil beneath our feet. April 18, Can Dirt Save the Earth?

17 Soil C Sequestration: The Larger Challenges How can healthy soils enhance our ability to adapt and be resilient to climate disruption while also helping mitigate greenhouse gas emissions? How do we prioritize a transition from fossil fuels and attain enhanced food security through measurement and verification of C sequestration? How do we advance policies and financing schemes that benefit rural communities and small- and largescale farmers? What practices will improve human and community health and support biodiversity, pollinators, and larger rural landscapes and ecosystems?

18 Other Ecosystem Services: Biodiversity Biodiversity being recognized as one of the best defenses against climate change. The inherently high level of biodiversity of multispecies systems offers several possibilities It is unclear, however, how many species are needed in an ecosystem to sustain the provisioning of ecosystem services Carbon sequestration Biodiversity connection? Tree C stock and species diversity relationship is not always significant IPBES (Intergov. Science-policy Platform on Biodiv. and Ecosystem Services) has recently (March 2018) recognized AF as a biodiversity-promoting activity (

19 Research Directions in Agroforestry Large-scale global/continental estimations based on complex computer models are a common research procedure in climate change research. Applications to AF rather limited. Most of the available models are limited to single species systems; not easily applicable to AFS with complex and uneven plant arrangements. Priorities for field researchers and modelers:! Research-based knowledge on management for each component while grown in combination with other species! Development of varieties suitable for AFS

20 Is Agroforestry being Oversold? Carbon Farming and Agroforestry Regenerative Agriculture Soil Health Soil C Sequestration And, so on Do we have the scientific basis to support all the claims? Have the claims been vetted scientifically? Learn from the tropical experience!