adminSifelani Tsiko
Agriculture and weather experts have renewed calls for Zimbabwe’s agro-ecological zones, commonly referred to as natural regions, to be reclassified to optimise land use and productive efficiency in the wake of the devastating impact of climate change. University of Zimbabwe agricultural meteorologist Professor Emmanuel Mashonjowa told Zimpapers Syndication recently that existing natural regions which were drafted over 55 years ago have shifted owing to global warming, changes in land use patterns and land reform.
Zimbabwe’s five natural regions, says Prof Mashonjowa, are now outdated.
In the past few years, agricultural and weather experts have held a series of meetings to push for the re-defining of these ecological regions based on temperature, rainfall patterns and terrain to find what is suitable in each region in terms of cropping, farm technologies and farmer adaptation.
The Meteorological Services Department spearheaded the crafting of the revised agro-ecological zones, but up to now, nothing has materialised.
Government, too, has largely remained silent on the matter.
Agricultural, weather and climate change specialists briefly co-operated in the initial efforts, but all this has not translated into a meaningful re-zoning.
“Zimbabwe needs to re-classify its agro-ecological regions as a matter of urgency to help optimise land use and productive efficiency,” Prof Mashonjowa says.
“The existing ones were done in the 1960s and since then, changes have occurred in terms climate, rainfall patterns and land reform. I feel strongly that as academics, we have been a huge let-down in terms of pushing for the reclassification of the zones.”
Other experts say many farmers still stick to seed varieties that are no-longer suitable in the wake of challenges posed by climate change in their regions.
“The remapping will help in coming up with suitable seed varieties for the new regions to ensure maximum productivity,” says a crop expert with a Government agricultural institute.
High rainfall Region I in eastern Zimbabwe is reported to have expanded by 106 percent, while Region II has shrunk drastically by nearly half, according to a study by Mr Raymond Mugundani and other academics with the Midlands State University’s water and land resources department in 2012.
Researchers observed that Region III shrunk 14 percent while drought–prone Regions IV and V increased by between 5,6 and 22,6 percent respectively.
Natural Region I, for example, is said to have moved westwards, and now covers an area of 14,439km2 (3,7 percent of the whole country), compared to 7 024 km2 (1,8 percent) in the previous classification.
Region V, according to Prof Mashonjowa, now covers about 126 829 km2 (32,5 percent of Zimbabwe), while in the previous classification by Vincent and Thomas, the area constituted 26,7 percent of the country.
“The natural zones were put in place to maximise production and efficiency. With climate change, we need to conduct extensive studies to reclassify the zones. These natural regions have evolved in terms of rainfall, land use and potential for agricultural production.
“Rainfall regimes in some zones have declined while in others, they may have increased.
“Land reform has also brought sharp changes and we need to check whether these zones are still optimal for the use patterns set in the ‘60s.
“The University of Zimbabwe physics department has conducted studies which have shown changes in the country’s agro-ecological zones, but needed to collaborate with other researchers and stakeholders to examine the trends comprehensively.”
The present agro-ecological classification of Zimbabwe was done by Vincent and Thomas (1960) using only rainfall as the main factor.
A review was done in 1978 by a researcher only identified as Ivy.
These researchers demarcated Zimbabwe into five natural regions based on the effectiveness of the rainfall.
Classification is in the order of decreasing agricultural potential, and researchers say over 75 percent of the communal farms are located in marginal rainfall regions IV and V, which receive rainfall below 600mm per annum.
The soil there is typically loose and infertile and erratic rainfall patterns make rain-fed cropping a risky undertaking. Under these conditions, farmers are limited to drought-tolerant crops, with ranching being the alternative.
Climate change has reshaped the whole game, and researchers say success in crop production is likely to depend on land management techniques that conserve and increase the total soil water available to crops.
There is no doubt that an assessment of shifting patterns of natural regions in Zimbabwe is helpful to guide the nation’s future agricultural development and guaranteeing its food security. — Zimpapers Syndication
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