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Focus of the study and TOR

Productivity and profitability of maize in Conservation Agriculture systems across agro-ecological regions in Zimbabwe: A synthesis Report for ZIMCAN Prof. P . Mafongoya , Dr. L. Rusinamhodzi, Dr. S. Siziba. Focus of the study and TOR.

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Focus of the study and TOR

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  1. Productivity and profitability of maize in Conservation Agriculture systems across agro-ecological regions in Zimbabwe: A synthesis Report for ZIMCANProf. P . Mafongoya, Dr. L. Rusinamhodzi, Dr. S. Siziba

  2. Focus of the study and TOR Under the guidance of the ZIMCAN, the study will focus on the following areas; • Identify and gather all relevant CA research data in Zimbabwe from the known and respected institutions (CGIAR, University of Zimbabwe, FAO, NGOs) which examine analyze yield and gross margin analysis. This should focus on published research, but also “grey” literature produced by projects e.g. PRP • Technically review the above research in terms of appropriateness and academic rigour with focus on two main areas 1) yield results of CA and 2) socioeconomic results of CA. • Draw up and summarize the main findings from the identified research into a brief but highly articulate document of no more than 10 pages to be peer reviewed by members of ZIMCAN. This will be published in an academic journal.

  3. Methodology • Review of pertinent literature • Meta-analysis of grain yields under CA • Economic analysis: Cost and benefits of CA

  4. Why CA?......... Rusinamhodzi et al (2011)

  5. Does CA meet farmers’ objectives? • mismatch between farmers’ objectives and technology outputs • Farmers are interested in technologies that ensure food security and cash income

  6. Are results universal?

  7. Meta-Analysis of CA data in Zimbabwe Leonard Rusinamhodzi

  8. What is meta-analysis? • a systematic review that employs STATISTICAL METHODS to combine and summarize the results of SEVERAL STUDIES • …….IT IS NOT…… • Analysis of raw data • Multi-locational, multi-seasonal analysis of raw data • Expert opinion • Narrative review articles • Consensus statements (group expert opinion)

  9. Data search criteria The data included in the analysis had to satisfy the following requirements: • Experiments established on or after 2004 • The treatments included a conventional tillage (control) and no-till treatment • Established under rain-fed conditions in Zimbabwe • The experimental design was randomised and treatments replicated at least three times • The test crop was maize • Nutrient management was the same across treatments

  10. Studies used …….about 20

  11. Data required for meta-analysis • Data source i.e. full citation of publication Number Mean Standard deviation Experimental (CA) ne se Control (CP) ncsc

  12. Analysis model - random effects • Assumes that studies were drawn from different populations • Account for two sources of variance. • within-study error in estimating the effect in each study • variation in the true effects across studies. • Study weights are assigned with the goal of minimizing both sources of variance. • We can generalize the findings beyond the studies included in the meta-analysis.

  13. Mean Difference (MD) • Each study used the same scale or variable • meani = meantx – meancontrol • weighti = 1 / variancei = 1 / SDi2 • meansummary = (weighti x meani) / weighti

  14. Summary statistics Literature review – what role for conservation agriculture? Continuous maize Early seasons lead to smaller yield Overall, no yield advantage of CA

  15. Direct seeding

  16. Ripper/ sub-soiler

  17. Planting basins • A comprehensive meta-analysis was done by Nyamangara et al (2013) published in Experimental Agriculture • Used data from the semi-arid areas of southern Zimbabwe from 2004 to 2010 • Basins were superior to CONV in 59% of the experiments and the overall effect was significant (p < 0.001) • A higher rainfall regime (500–830 mm) resulted in a lower WMD for Basins (0.095 t ha) and Ripper (0.105 t ha)

  18. Duration of CA practice

  19. Conclusions • DS has a greater opportunity to increase crop productivity among the CA options available (uniformity × precision) • Biophysical conditions especially amount and distribution of seasonal rainfall are critical • Obvious yield benefits of moisture conservation in the drier regions • The benefits of CA are tied to the management intensity i.e. planting time, weed control, crop rotation, fertilization…… • Results reported by NGOs are important in understanding general CA performance but they misleading due to flawed comparison between what is termed ‘farmer practice’ and CA plot because farmers receive inputs for the CA plots from NGOs.

  20. Middle farm Poor farm Wealthy farm NGO data……….. Economic yield Economic yield Economic yield Homefields Homefields Homefields Outfield Medium-outfield Outfield Garden Garden Manure Outfield Manure Garden Crop residues Crop residues Crop residues

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