By Sambulisiwe Maseko
Dabane Trust Water Workshops
In arid regions, drip and subsurface drip irrigation have been gradually adopted in recent years. This technology allows a small volume of soil to remain moist by frequent applications of low volumes of water. This limits the rooting zone to the moist soil and reduces water drainage from the rooting zone. In particular, subsurface drip irrigation substantially minimizes soil evaporation compared to surface drip irrigation and improves irrigation WUE by 95% (Chai et al., 2014).
According to Xingfa and Guangyong (2002), water saving in agriculture becomes more and more urgent a task in the world due to shortage of global water resources. Erratic rainfall patterns are increasingly being experienced in Zimbabwe and farmers who mainly rely on rain-fed agriculture like the farmers in Matobo have been met with a number of challenges. There is therefore need to save water even at the irrigated gardens. Carter and Howell (2000) posited that the Drip irrigation system can save as much as 80% of water normally used in other irrigation systems like flood and sprinkler irrigation. Schwankl (1997), noted that with the Drip irrigation system, irrigation takes place on a frequent basis, enabling the water manager to maintain the soil moisture at an optimum level. A well-designed, well maintained drip system can also apply water more evenly than other irrigation methods. Together with irrigation scheduling, these methods can improve plant growth and yield.
For so many years, smallholder farmers in rural areas in semi-arid Zimbabwe have been using the river to their schemes or from reservoirs inside the garden to their cropping beds. This process is labour intensive, time consuming and also results in water wastage. The type of irrigation employed by farmers has an impact on crop growth (Carter and Howell, 2000). According to Waverly Plastics, Zimbabwe, Drip irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above or below the soil-surface. The goal is to place water directly on the root zone and minimize evaporation. Drip irrigation systems distribute water through a network of valves, pipes, tubing and emitters.Depending on how well designed, installed, maintained and operated it is, a drip irrigation system can be more efficient than other types of irrigation systems.
All One irrigation scheme is situated along the Shashani River in Patalika village, Dzembe, Ward 2 in the Matobo District of Zimbabwe. This is a 0.5ha scheme where farmers irrigate their crops using the drip system. This report will document why farmers prefer the Drip irrigation to other systems like Flood irrigation as well as their experiences with the Drip system.
Farmers at All One irrigation scheme highlighted a preference for drip irrigation compared to other irrigation systems e.g. flood irrigation. Observations showed that these farmers were not prepared to use any type of irrigation besides the drip system, which in their own language, they said;
“Kudala sisegehena, angeke sphinde sbuyele khona”
“Previously, we were in hell, we are not going back there”
The three farmers noted that they previously used buckets to ferry water whilst watering their crops. This was either getting water from scoop holes on the river bed or from reservoirs inside the irrigation schemes. The drip, according to them, is easy to use as it makes the job of watering their crops less strenuous.
The Drip irrigation system has allowed the farmers to multi-task in the garden. Farmers are able to carry out other activities in the garden whilst they are irrigating their crops. Previously, in other irrigation schemes that the farmers have been involved in, they would spend 6 to 8 hours each time transporting water from one point to the other. According to the three farmers; No other activities in the garden would be conducted as the process of watering would be both labour intensive and time consuming. This meant that for them to do other activities that needed their attention in the garden, they would either have to put in extra hours or plan for a separate day. With drip irrigation, farmers are able to perform other activities like weeding, land preparation and planting whilst other parts of the garden are being watered.
Moreover, according to Mr. Albert Sibanda, a farmer at All One, “As a result of the Drip system, I leave the garden early and not after dark. This gives me ample time to do other household chores like making sure my cattle are safely in their pens and spending time with my family”. Previously, they would sometimes leave the irrigation scheme after sunset and owing to that they would be tired and needing rest.
Drip irrigation has been said to save water (Carter and Howell, 2000). To either accept or reject the hypothesis, research on gardens using flood and drip irrigation was conducted. Data from All One used. The data is representative of the emitters and discharge of emitters per month on 0.1ha was used. For flood irrigation, water applied per day on 0.1ha and frequency of watering was used. Results show that when using flood irrigation, farmers utilize 480m³ of water per month on 0.1ha whilst when using Drip irrigation, farmers utilize 95.62m³ of water per month on 0.1ha. To note, even in a situation where water applied per m² is reduced and an hour added to the watering time for drip irrigation, drip irrigation still recorded less water on 0.1ha as compared to flood irrigation.
 Assumed there is water distribution uniformity
According to Carter and Howell (2000), challenges, but have had an issue with clogging. According to FAO, one of the problems with drip irrigation is blockage of the emitters. All emitters have very small waterways ranging from 0.2-2.0mm in diameter . Filtration of irrigation water is recommended. Smallholder farmers can have a challenge as they do not have the means and expertise to do this. According to Carter and Howell (2000), clogging disrupts distribution uniformity leading to a decrease in emitter discharge rates. Clogging at All One irrigation scheme . This upsets consistency in water supply amongst the crops.
Farmers at All One irrigation prefer to use the drip irrigation system because it is not demanding in terms of labour and time. They are able to multi-task whilst in the garden and leave the garden early to do other household activities. The system is also seen to save water as compared to flood irrigation. The application of water to the root zone might not mean a direct relationship with water productivity, therefore raising a need for further research. The farmers have been faced with issues of clogging.
Carter A and Howell J (2000). An overview of drip irrigation. Department of Soil Sciences, University of Massachusets.
Chai Q, Gan Y, Turner, C N, Zhang R, Yang C, Niu Y and Siddique M, H K (2014). Water-Saving Innovations in Chinese Agriculture; Volume 126. Advances in Agronomy. Elsevier. https://doi.org/10.1016/B978-0-12-800132-5.00002-X
Schwankl L, (1997). Drip irrigation for Row crops
Waverly Plastics, Zimbabwe.
Xingfa H and Guangyong Li (2002). Present Situation and Development of Sub-Surface Drip irrigation. Transactions of the Chinese Society of Agricultural Engineering.