Africa’s rain harvesters: Replicating Zephaniah Phiris’ techniques is ensuring good yields to Zimbabwean farmers in arid areas

Zimbabwe, the African nation in southern Africa that was once considered as the continent’s bread basket, is now increasingly relying on food imports. This is because the country reels from increasingly recurrent droughts, the most recent being the El Nino-induced 2023-2024 drought that resulted in crop failures, ranging up to 80 per cent.  

A concoction of factors that include increasingly frequent and longer droughts, shorter rainy seasons and hotter temperatures is 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 a degree Celsius since 1980, while annual rainfall has decreased 20 to 30 per cent. 

When it rains, it’s harvested

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 which render it inadequate to make sustainable rain-fed agriculture sustainable. 

Traditionally farming in this area was always concentrated in wetlands, but as the population grew, some of the villagers had to gamble with dryland farming, usually focusing on drought resistant crops like sorghum and millet as the idea of cultivating crops like maize (corn) seemed far-fetched.  

Zephaniah Phiri — the pioneering maverick 

In the 1960s, the British colonial government confined Zephaniah Phiri in the country's arid regions, it was his ingenuity which led him to perceive his punishment as a blessing in disguise. 

After being detained for years for his political activism against colonial atrocities, Phiri was released from detention and confined to an arid eight-acre piece of land in his rural home in the Mazvihwa area. Blacklisted for any formal employment, Phiri was left with two options — to adapt or perish. 

He opted for the former.

Stranded on the arid piece of land, Phiri 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 three times by the colonial administration on the charges of ‘farming in a waterway’. 

However, the colonial government was intrigued by Phiri’s continued defiance and his bountiful harvests even in the face of a severe drought in 1972-73, resulting in the British administrators visiting his farm.

Upon realising Phiri’s knack for agriculture, they were impressed by his water harvesting methods and eventually dropped the charges that were pressed against him. 

Buoyed by the confidence from this official approval, in addition to making in-field trenches to capture and retain runoff water, (thus allowing the soil to retain moisture long enough to sustain his crops to maturity) Phiri started digging deep pits to store large quantities of water for use in future. 

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.

Non-profit ensures expansion of rainwater harvesting 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.

“These water harvesting techniques have become so useful for us in arid areas because the rain that we receive is never enough for serious farming. 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.

In 2022 alone, representatives from 34 organisations visited Muonde Trust to get first-hand information and knowledge on the organisation’s water harvesting and other conservation programmes. 

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.

Time-tested techniques

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. His work was focused on the implementation of these water harvesting techniques.

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.

In this area, average rainfall is 200 mm per year and maize yields are as low as 0.4 tonnes per hectare, more than three times lower than the national average (1.39 t/ha). 

Nyamadzawo said that in their studies — that started with 20 farmers in 2014 — 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. 

“When we started, we were just looking at ways of adapting to climate change in semi-arid regions; we were promoting tied contours, infiltration pits and other water harvesting technology as methods that can be used by farmers in dry regions such as these,” Nyamadzawo said. 

“After integrating tight contours and infiltration pits, we managed to increase crop yields to at least three tonnes per hectare,” he added.

Some of the farmers have achieved maize yields of 4-6 tonnes/hectare while vegetable production has also surged 10-fold.

Nyamadzawo has been involved in the training of some 5,000 farmers on water harvesting using tied contours and in-field water harvest for climate change adaptation and mitigation and the establishment of 63 farmer learning centres (FLC) or demonstration sites at which lead farmers were trained. 

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. 

After noticing the success of Nyamadzawo’s projects in Marange, the Ministry of Land, Agriculture, Water, Fisheries and Rural Development has 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. 

Meanwhile, it has been discovered that when some farmers have tried to copy these techniques without help from experts, they have encountered a number of challenges. 

These include lack of availability of necessary equipment and a lack of financial resources, as well as insufficient technical knowledge and information on sustainable, low-cost water harvesting and soil health improvement technologies.