Zimbabwe, the African nation in southern Africa that was once considered as the continent’s bread basket, is now increasingly relying on food imports. The country reels from increasingly recurrent droughts, the most recent being the El Nino-induced 2023-24 drought that resulted in almost 80 per cent crop failure.
Increasingly frequent and longer droughts, shorter rainy seasons and hotter temperatures are making crop failure a existential crisis for the agrarian majority, which comprises 70 per cent of the 16 million population in Zimbabwe.
Experts have warned that by 2100, arid and semi-arid regions across Africa could increase by 5-8 per cent.
As for Zimbabwe, temperatures have risen by 1°C since 1980, while annual rainfall has decreased 20-30 per cent.
For the farming community in the Mazvihwa region, situated in the arid Zvishavane district in south-central Zimbabwe, both wet and dry years hardly make a difference as their geography receives a maximum of 400 mm of annual rainfall.
This is due to the rainfall’s distribution pattern and high temperatures that render it inadequate to make rain-fed agriculture sustainable.
Traditionally, farming in this area was always concentrated in wetlands, but as the population grew, some villagers had to gamble with dryland farming, focusing on drought-resistant crops like sorghum and millet, as the idea of cultivating crops like maize (corn) seemed far-fetched.
In the 1960s, the British colonial government confined Zephaniah Phiri to an arid eight-acre piece of land in the Mazvihwa area and blacklisted for formal employment for his political activism.
Phiri was left with two options — to adapt or perish. He opted for the former.
He started experimenting with many farming techniques centering around water conservation. He began capturing runaway water from hill slopes, directing it into deep trenches he had dug in his crop fields at the bottom of the hill.
For this, he was arrested thrice by the colonial administration on the charges of ‘farming in a waterway’.
However, intrigued by Phiri’s continued defiance and his bountiful harvests even in the face of a severe drought in 1972-73, the British administrators visited his farm. They were impressed by his water harvesting methods and eventually dropped the charges against him.
Buoyed by this official approval, Phiri started digging deep pits to store large quantities of water for future use.
By 1983, Phiri’s two water storing pits had a combined capacity of 1.5 million litres, allowing him to farm his land throughout the year.
Inspired by Phiri’s success, starting in the 1980s, fellow smallholder farmers in Mazvihwa began incorporating his techniques and focused on rainwater harvesting, which yielded unprecedented results.
By the time Phiri passed away in 2015, more than 10,000 people, both Zimbabweans and foreigners, had visited his farm to learn his water management techniques.
Muonde Trust, a non-profit organisation dedicated to popularising indigenous innovation in Mazvihwa, has since built on Phiri’s work to promote these water harvesting techniques throughout the country.
Rainwater harvesting has become the mainstay of successful smallholder farming in the Mazvihwa area, Daniel Ndlovu, research officer of Muonde Trust said.
“In the past, it was not possible to grow crops that require a lot of water like maize, but with these techniques, some farmers actually have enough water to last until the start of the next rainy season,” Ndlovu added.
He recalled that the last rainy season was so poor that the area received only 200 mm of rain, resulting in very little water left to be collected. Zimbabwe’s rainy season starts in November and lasts until March. It is during the seven dry months that the harvested rainwater is vital for the farmers.
The water management infrastructure is owned at family level as individual farmers dig trenches and ponds in their fields and the water is put to both agricultural and domestic uses.
For over a decade, George Nyamadzawo, a professor of Soil and Environmental Science at the Bindura University of Science Education (BUSE) in Zimbabwe has worked with smallholder farmer communities in the Marange area, another arid area on the eastern part of the country.
From his research, Nyamadzawo established that over 50 per cent of rainwater is lost by surface runoff and evaporation, with only 15-30 per cent retained by the soil, which is insufficient for crop production.
The area receives average annual rainfall of 200 mm and maize yields are as low as 0.4 tonnes per hectare, more than three times lower than the national average.
Nyamadzawo said that in their studies a number of systems were implemented in order to capture runoff water from the rock catchments.
These included the diversion of runoff water into the field through contour channels, installation of cross-ties along contour channels, the fortification of contour channels with infiltration pits and the use of in-field water harvesting techniques such as ridging and sub-surface waternets.
He noted that as a result of these measures, soil and water loss from runoff reduced by more than 50 per cent and 75 per cent, respectively.
“After integrating tight contours and infiltration pits, we managed to increase crop yields to at least three tonnes per hectare,” Nyamadzawo noted.
Some of the farmers have achieved maize yields of 4-6 tonnes / hectare, while vegetable production also increased 10 times.
In the aftermath of the poor rains in 2023-24, the government of Zimbabwe has prioritised bolstering of the irrigation networks to decisively move away from overreliance on rain-fed agriculture.
The Ministry of Land, Agriculture, Water, Fisheries and Rural Development has also pledged to establish 900 pilot and learning sites to demonstrate the principles of integrated rainwater harvesting and soil health improvements and to replicate this success across the country.