Farmer perceptions on climate change and variability in semi-arid Zimbabwe in relation to climatology evidence

Farmers in semi-arid Zimbabwe prioritise climate variability as their major agricultural productivity-reducing problem. This paper raises the importance of considering local farmers’ perceptions on climate risk, as this greatly influences on-farm investments and decision-making in agricultural management and production in semiarid Zimbabwe. A study was conducted in two districts of semi-arid Zimbabwe using participatory research techniques, to investigate farmers’ perceptions of climate variability and whether these perceptions correspond with historical climatic data. The study showed that farmers perceived climatic and weather patterns to have changed over the past decade or two, as indicated by erratic rainfall patterns, decreased rainfall and temperature increases, leading to crop productivity decline and increased livestock morbidity and mortality. Majority of respondents (75%; n=81) were highly risk-averse, perceiving that most of the seasons in any ten given years could be poor. The climatic data show no evidence that corroborates the farmers’ perceptions, with only temperature showing a clear signal, indicating the influence of other non-climatic factors. The climate data show rainfall variability to be a normal characteristic of the study sites, with deviations from the climatic rainfall means (or the poor seasons) being cyclical and occurring once in every three seasons over the past 40 years. The study highlights strategies that farmers could implement to enhance agricultural productivity in the semi-arid areas to adapt to climate change and variability

Maize productivity and profitability in Conservation Agriculture systems across agro-ecological regions in Zimbabwe: A review of knowledge and practice

Conservation agriculture (CA) is increasingly promoted in southern Africa as a strategy to improve food security and reverse soil degradation in the face of climate change. However, the performance of CA under different environments and its ability to improve ecosystem services is still unclear. The effects of the CA options; direct seeding, rip-line seeding, and seeding into planting basins on maize grain yield, soil health and profitability across agro-ecological regions in Zimbabwe were evaluated through a review of literature in combination with meta-analysis. Overall, CA improved maize yield over conventional agriculture. Compared to conventional agriculture, direct seeding, rip-line seeding, and seeding into planting basins increased yield by 445, 258 and 241 kg ha−1, respectively. However, there was an initial yield decline in the first two years. CA practices reduced soil erosion and bulk density, and increased soil water content in most studies. Under high levels of residue retention (6 Mg ha−1), CA systems exhibited greater macro fauna abundance and diversity than conventional agriculture, particularly termites. Weed pressure tended to increase labour requirement for hand-hoe weeding under CA compared to conventional agriculture. However, the use of herbicides reduced weeding labour demand during the early season. The benefits of CA are tied to the farmers’ management intensity including: time of planting, weeding, fertiliser and herbicide application, and adequate training on equipment use. Economic analysis results showed that on average, a farmer incurs losses for switching from conventional agriculture to CA in the main maize growing regions of Zimbabwe. Based on the six seasons’ data, the losses were least with the ripper in drier areas and worst with the direct seeder in wetter areas. Incorporation of chemical herbicides worsens the economic returns of CA tillage options in all the agro-ecological zones. Overall, the study showed that the rip-line seeding is more attractive in the drier areas than direct seeding. Although not costed in this study, critical is the cumulative reversal of soil degradation associated with consistent CA practice which can sustain agriculture. Results from this review suggest that the benefits of CA depend largely on the type and context of CA being practised. It is thus imperative to profile the technology, the farmer socio-economic circumstances and the bio-physical environment in which the farmer operates for proper geographical and beneficiary targeting to achieve greater impact. More longer-term studies are required to fully elucidate the benefits and context of CA options and practice

Do diatomaceous earths have potential as grain protectants for small-holder farmers in sub-Saharan Africa? The case of Tanzania

Participatory on-farm field trials were set up over three storage seasons, from 2002 to 2005, in different agroecological zones of Tanzania to compare the efficacy of the enhanced diatomaceous earths (DEs) Protect-Its and Dryacides alone or combined with the pyrethroid permethrin. Other treatments included three commercially available synthetic chemical dilute dusts, containing 1.6% pirimiphos-methyl and 0.3% permethrin (Actellic Super and Stocal Super from different manufacturers) and 1% fenitrothion and 0.13% deltamethrin (Shumba Super); traditional protectants; and a locally available DE collected from Kagera in north-west Tanzania. Treatments were applied to maize and sorghum grain and dried beans. Insect pests are the main threat during storage, which in Tanzania includes the devastating larger grain borer, Prostephanus truncatus. All the grain protectants, except the traditional ones, kept damage incidence well below that of the untreated controls, and usually below 10% for periods of 40 weeks of storage. Exceptions occurred when grain was badly infested prior to treatment, in which case Actellic Super dust was more effective than the DEs. Very little difference in damage was observed between the DE treatments until 40 weeks of storage. In addition to the commercially available synthetic grain protectants, Protect-Its 0.25% w/w or Protect-Its 0.1% w/w plus permethrin at 2 mg/kg can be recommended to protect dry un-infested, winnowed maize and sorghum grain that is to be stored on-farm in sacks or woven granary baskets for periods of 4 months or more in Tanzania. Beans can be protected with lower application rates of Protect-Its 0.05% w/w or Dryacides 0.1% w/w. The study also demonstrated that Actellic Super dust obtained from an approved source and applied according to the manufacturer’s recommendations is effective in protecting stored maize, sorghum and beans for periods of at least 40 weeks—contrary to many of the suggestions that this product is no longer effective in Tanzania