Socio-ecological and farmer targeting for CA interventions

Jens A. Andersson, CIMMYT southern Africa, Hararej.andersson@cgiar.org

Marc Corbeels, CIRAD, Montpellier, France marc.corbeels@cirad.fr

CA meta-analysis -introduction• Growing number of studies have been carried out

comparing the practices of conservation agriculture (CA) to conventional tillage (CT) in Sub-Saharan Africa

• Conducted under a range of conditions (climate, soil, crop management, cropping systems)

• The effects of CA on crop yield compared to CT are diverse

CA-meta-analysis: aim• Better understanding of crop responses to CA• Identifying the agro-ecological and management

conditions that favor positive crop responses to CA • Contributing to better targeting the investments with

CA development and research

CA meta-analysis: methods• Search of scientific literature on the effects of the CA (no-tillage, crop residue mulching and

rotations) on crop yields in SSA • 42 (peer-reviewed) papers were selected for the final dataset with 61 independent studies• Meta-analysis: random effects model to calculate effect sizes • Weighted mean difference in grain yield between the CA and CT treatment • Weight given to each study was calculated as the inverse of the variance

CA meta-analysis: overall results

• Large variability in grain yield responses (from positive to negative) to CA compared to CT

• NTM had the largest positive mean (378 kg ha-1) followed by NTR with a positive mean of 142 kg ha-1, and then NT with a negative mean (- 24 kg ha-1)

CA meta-analysis: short-term• Positive responses: under conditions where water stress occurs (e.g. dry

spells), since mulching increases soil water availability (e.g. Mkoga et al. 2010; Mupangwa et al. 2012; Thierfelder and Wall 2009).

• Negative responses: i) under high rainfall, as mulching may exacerbate waterlogging (Thierfelder and Wall 2012); ii) increased weed competition and problems with seeding (Mashingaidze et al. 2012).

CA meta-analysis: long-term

• Yield benefits are expected to accumulate over time, because CA is known to gradually improve biological, chemical and physical properties of the soil

• Results from a meta-analysis of existing crop yield data from long-term experiments in sub-Saharan Africa do not confirm this hypothesis, and show large variation in the data

Data from: Vogel (1993), Lal (1997), Nehanda (2000), Moyo (2003) and Thierfelder et al. (2013)

CA meta-analysis: legume-effect

• meta-analysis of results from long-term experiments in sub-humid and semi-arid regions of the world

Rusinamhodzi L, Corbeels M, van Wijk M, Rufino MC, Nyamangara J, Giller KE. Long-term effects of conservation agriculture practices on maize yields under rain-fed conditions: lessons for southern Africa. Agron Sustain Dev 2011;31:657-673.

CA meta-analysis: other factors…..

• Aim: the development of a CA suitability or ‘adoption potential’ tool

• explore the key elements of a quick identification tool for targeting CA interventions in Africa.

CA targeting

CA targeting: using adoption studies?

• ex-post insight into suitability

• but, methodological weaknesses limit their value for targeting

bias - data collection in project context (incentivised adoption)

unclear / reductionist definitions (‘minimum tillage on part of land in year x’)

limited to farm-level ‘determinants of adoption’

Andersson, J. A., D'Souza, S. (2014) From adoption claims to understanding farmers and contexts: A literature review of Conservation Agriculture (CA) adoption among smallholder farmers in southern Africa. Agriculture, Ecosystems and Environment,187, 116–132. doi:10.1016/j.agee.2013.08.008

QATOCA ?• Qualitative expert-based self-assessment tool/guide for CA adoption

• to assess the ‘relative likelihood of CA adoption’ or ‘adoption potential’ of site-specific CA practices within the context of a project’

• a list of questions with answer statements and scores

• i) characteristics of CA as an object of adoption; ii) the capacity of the promoting organization(s); iii) attributes of the dissemination strategy; iv) institutional frame conditions at village and regional level, v) market conditions at the village & regional levels; vi) community attitude towards CA

• for diagnosing the supporting and hindering factors of CA adoption in a given (project) area.

Ndah HT, Schuler J, Uthes S, Zander P, Triomphe B, Mkomwa S, Corbeels M. Adoption potential for conservation agriculture in Africa: a newly developed assessment approach (QAToCA) applied in Kenya and Tanzania. Land Degrad Dev 2012; http://dx.doi.org/10.1002/ldr.2191

Ndah HT, Schuler J, Uthes S, Zander P, Traore K, Gama M, Nyagumbo I, Triomphe B, Sieber S, Corbeels M. Adoption Potential of Conservation Agriculture Practices in Sub-Saharan Africa: Results from 5 Case Studies. Environ Manage 2013; http://dx.doi.org/10.1007/s00267-013-0215-5

QATOCA - limitations

• strong focus on promotional organizations (assumption: knowledge limiting factor rather than the farming context)

• all assessment criteria treated equally - difficult to sort priorities

• respondent selection bias - public knowledge construction, project interests

• higher level analysis - understanding farmer adoption decision making? farmer diversity?

Ojiem, J. O., de Ridder, N., VanLauwe, B., & Giller, K. E. (2006). Socio-ecological niche: a conceptual framework for integrationof legumes in smallholder farming systems. International Journal of Agricultural Sustainability 4(1), 79–93.

Elements of targeting tool

• Multi-level/scale analytical tool

• socio-ecological niche

• dimensions of technology adoption

Sumberg, J. (2005). Constraints to the adoption of agricultural innovations: Is it time for a re-think? Outlook on Agriculture 34, 7–10.

Dimensions of technology adoption

Sumberg, J. (2005). Constraints to the adoption of agricultural innovations: Is it time for a re-think? Outlook on Agriculture 34, 7–10.

• Functional markets (input/output)

• Access to financial capital

• Presence of extension services

• Relative land abundance

• Communal tenure arrangements

• Institutional and policy settings

• Agro-ecological potential

Key contextual factors?

• Performance of CA

• Returns on investment and costs

• Availability and competing uses for crop residues

• Capital for herbicides and implements

• Labor availability vs demand

• …

Farm factors?

• Functional farm typology:

• Capital income, resource endowment (cash availability; source of income; land:labour ratio)

• Labour availability, incl. hiring in/out of labour

• Access to market

• Production strategies: (e.g. market vs self-consumption; animal vs crop production)

• (Management skills, education, social hierarchy and tradition)

Mapping farm(er) diversity for CA?

‘prerequisite conditions’ for CA adoption

‘farmer-technology matches’

Contextual factors agro-ecological, socio-cultural,

institutional, economic

Farm factors & types production orientations, resource endowments,

local ecological conditions

‘CA suitability’

CA practices / technologies (packages)

Farmer diversity

Thank you