Sustainable Agriculture Extension Manual

The water-harvesting innovations of Phiri Maseko, Zimbabwe

Every drop of rainwater is valuable in dry areas. But it is dry areas where a lot of soil erosion occurs and the water is lost. This happens more on steeper slopes. It is to address this problem that Mr Phiri Maseko, now in his seventies, has devoted his life. He has done this by developing many examples on his own small farm, as well as training many others in his methods.

The Phiri family lives on a 3-hectare plot in Runde communal area, Zvishavane, in Zimbabwe. This area is dry and prone to droughts: it has an average annual rainfall of 570 mm.

Soils

Phiri's plot is located on the slope of a hill and faces north-north-east. At the top of the hill is a bare rock outcrop, immediately below which is the homestead. The thin, grey soils are predominantly sand. Further down the slope through the yard and across the road into the cropping area, the soils become deeper, darker and less stony. Their clay content increases, especially towards the wetland in the north of the property. The wetland experiences seasonal waterlogging and is the source of a stream.

The ruware

One of the most important resources (one that many would see as a disadvantage) is the large granite dome, or ruware, above the plot. In an uncontrolled situation this rock could cause severe erosion by channelling a lot of water onto the land below it where the Phiri family live and farm. Instead, however, the rock provides the main source of water for the trees, crops and household.

Tiers of stonewall terraces catch and direct the flow of water so that it can sink into the soil and replenish the underground store. The terraces trap grass seeds and create swathes of protective vegetation. Silt traps ensure that the terraces do not get choked with sand.

Most of the water is then channelled into a seasonal unsealed reservoir to encourage efficient infiltration of water into the soil rather than storing it on the surface. Some of the water can be siphoned into a storage tank made from bricks and plaster. Phiri knows that if a season is good enough to fill the reservoir three times then it will have sunk enough water underground to last for two years. Harvesting water at the top of the slope recharges the groundwater so that crops, trees and natural vegetation will have moisture available to them in the soil.

Around the homestead Below the ruware is the yard where the family lives. The terrain is quite steep, and it is extensively terraced with strong, stone structures built along the contours. The family grows a wide variety of fruits and vegetables, and keeps chickens, ducks and turkeys. The many trees around the homestead thrive on the water harvested higher up, which moves slowly downslope underground.

Some of the water harvested from the ruware can be stored in a tank made from bricks and plaster.

The road

Between the homestead garden and the cropping area is a dust road. Phiri has seen the need to control the runoff from this surface and take advantage of it by channelling the water and allowing it to seep into the soil above the fields. He has dug large pits into the soil at the side of the road. Around these pits the indigenous vegetation has visibly benefited. Thick shrubs and small trees are growing, and the grass is dense.

The cropping area

The Department of Agricultural and Technical Services pegged out contours in the cropping area (see the section on Marking contour lines). The Phiri family grows a variety of crops in between contour ridges here. Along these ridges Phiri has dug rectangular infiltration pits, 4 m long, 2 m wide and l m deep. The front end of the pit is bevelled to avoid undermining of the banks. The pits are covered with dense, tall grass, which stabilizes the structure. Three wells in the cropping area are fed by the water that is harvested higher up. A network of irrigation pipes and ditches supplies crops with extra water during drought. Some vegetable gardens and a nursery are located close to two of the wells to take advantage of the extra water.

Infiltration pits dug in existing contour pitches. The pits measure 4 m by 2 m, and are 1 m deep.

The wetland

In the north of the farm and at the lowest part is a natural wetland that Phiri has protected and harnessed for crop cultivation and water storage. He has dug two ponds there. The larger is higher up the slope and contains fish. This overflows into the smaller pond downhill. Reeds, sugarcane, bananas, Kikuyu and elephant grass are planted densely on the banks of the ponds to hold the soil. Phiri encourages all farmers he meets to grow reeds. They conserve the soil and are a valuable cash crop, as they are used in basket-weaving. Phiri gives free banana seedlings to the projects that he is involved with.

The main pond has a rope-and-washer pump and a tyre pump. Water from these seasonal ponds are used for irrigation via the ditches and pipes.

Benefits

Phiri's farm produces a crop in dry years when his neighbours do not get a harvest. Phiri is able to produce something all year round: crops in the rainy season, vegetables in the dry season, and bananas all year. The water harvested, conserved and used has a great value for food security and income. Nevertheless, Phiri feels he could make even more use of the water he harvests, for example by digging more ponds. —For more information, contact Phiri Maseko, Zvishavane Water Project, Zimbabwe.

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