Real-life examples of irrigation practices revolutionizing agriculture in dry areas
Flood irrigation in Ethiopia, a success story to be emulated or an environmental disaster to be avoided by the rest of Africa?
For many years, Ethiopia’s Awash River flood basin has been the center of much of the agricultural production in the Horn of Africa. Producing field cereal crops as varied as Teff, Sorghum, Rice, and the more recent staples of maize together with wheat and exotic horticultural crops such as beetroot, sweet potatoes, cucurbits such as melons, citrus fruit, leafy greens such as cabbages, spinach, etc.
As discussed in the relevant article, Spate Irrigation is the main system most small-scale Ethiopian farmers use. Runoff water from flash floods is channeled and harvested in storage dams, both below the soil and above the ground surface, from where it is further channeled to fields.
Based on research data, Ethiopia is witnessing a significant increase in wheat production. It is the third largest producer in Africa after South Africa and Egypt. More specifically, 30% of the small-scale farmers’ income derives from wheat production. A critical factor in achieving this has been the use of Spate Irrigation over the past couple of decades.
While this practice has greatly benefited local agricultural production, examining the case more closely is important.
While the water used is typically already runoff water, the subject of runoff loss does not have as great an economic bearing as it would say the water was being taken from a running river in the middle of the dry season, so in essence, Spate Irrigation utilizes water that could potentially pose a risk to flooding and damage to the environment. Issues to do with the allocation of the amount of water amongst the farmers, crops to be grown, alternatives to simply flooding the land when more efficient methods such as drip irrigation could be used, and the long-term environmental effect of flooding are other key areas of consideration to be looked at.
What can Africa learn from Israel’s success in Irrigating arid lands?
The state of Israel is a shining example to Africa of what can be achieved when water use efficiency is maximized. In 1959, an Israeli company called Netafim developed and patented the world’s first surface drip irrigation system comprising plastic pipes with small emitters from which water passes out in drops, thus making Israel the birthplace of this water-use efficient technology known as drip irrigation. As of 2020, Israel has only 20% of its land mass as arable land, of which half has to be irrigated; annually, it exports $1.3 billion of Agricultural produce and $1.2 billion of Agricultural inputs and technology. Israel is a world leader in water use efficiency technologies; it recycles up to 86% of the water, has five desalination plants, and produces more than 600 million cubic metres of water/per year.
Israel, like many other African nations, has water regulatory and monitoring government agencies to ensure that water use falls within set levels as per the scale of crop production capacity of the water body from where it is drawn and to see that there is limited waste. These state agencies are key to having a water-use-efficient agricultural sector. Levies paid by farmers in direct proportion to the amount of water used help finance such institutions’ operations. The difference in how these agencies function in African nations is mainly due to the capacity and expertise to carry out such operations in the early stages of development.
Irrigation scheduling is also key in attaining water use efficiency. Scheduling requires training on record keeping, physically identifying soil moisture levels through methods such as determining the field capacity/ soil moisture using the “feel method”, use of soil augers, and, where possible, the use of electronic soil moisture measuring probes.
Crop type will determine the water efficiency levels that are to be considered. As indicated in figure 1, there is a direct relationship between biomass (organic matter content) and WUE. The larger the crop grows, the more water will be absorbed. In the case of cereal crop production, the use of water is much higher per square meter than in horticultural crops, which have lower plant populations. Therefore, drip irrigation was selected as suitable for growing horticultural crops instead of cereals since the latter crop has a much higher plant population and, hence, a higher water requirement. However, with more focus on research and development, we may do away with the high volumes of water applied in producing cereals such as wheat and maize. Getting this correct will mean adjusting plant populations accordingly, developing new types of drip line emitters, and applying this method only on crops grown on the right soil with physical properties found suitable. Drip irrigation has, for many years, been used on “green” maize, which is grown to be eaten fresh, often though only on small hectares.
If successful, it has the potential to revolutionize cereal crop production, reduce water wastage, and cut the carbon footprint from center pivot irrigation, amongst many other benefits. Drip irrigation works as a very efficient form of irrigation and can work on cereal crops grown in large areas if we get the R&D right.
How to Enhance Water Use Efficiency
To attain good water use efficiency in irrigated crop production today requires practical in-the-field applications such as computer/ sensor managed drip/ micro jet irrigation, R&D into drip line emitters, cheaper recyclable plastic drip lines, sensor-driven warning systems for leaks, blockages, thermal remote sensing (using both satellite generated (Geographic Information Systems (GIS) and drone captured aerial photography) for crop water stress detection, fertilizer application, harvesting, biological pest control, crop and variety selection with preference being to grow the earlier maturing crops and varieties which tend to require less water right up to plant maturity.
Another novel technology becoming more popular by the day is reusable dew-collecting plastic trays and nets, which can also greatly reduce the additional water requirement by up to 50 percent for some crops. With the abundance of waste plastic that could be recycled to make dew/ fog capturing devices, the range of options for increasing water use efficient agricultural systems is wide.
Fig 11. Fog/ Dew Collection. Source: Wikicommons
Africa will ultimately have to find its own fit to its own unique challenges as far as becoming more water-use efficient is concerned. The copy-and-paste way of doing things in Africa rarely works. Therefore, the right approach is to slowly put on trial some of the methods that have yielded success in nations such as Israel, the Andean states of Peru, Chile and even in European countries such as Portugal, all of which have had to overcome challenges with water use efficiency in the agricultural sector. Drip irrigation, which has been in widespread use in Africa for over 25 years, remains a true success story of Israeli innovation and shows the potential that lies in other simple-to-use technologies and practices being able to yield similar success over time once introduced into Africa.
Alenaheyu T. (2010) Spate Irrigation in Ethiopia, Potential, Development, Status and Challenges, http://www.iwmi.cgiar.org/Publications/Other/PDF/proceeding-flood-based_farming_for_food_security_and_adaptation_to_climate_change_in_Ethiopia-potential_and_challenges-chapter-1.pdf
Andulaem T. G and Mulatu K. (2020) Review of Irrigation Practices in Ethiopia, Lessons from Israel, https://www.eng.uc.edu/~beaucag/DripIrrigation/Papers/review-of-irrigation-practice-in-ethiopia-lessons-from-israel.pdf
Hatfield L. Jerry (2019) Water Use Efficiency: Advances and Challenges in a Changing Climate, https://www.frontiersin.org/articles/10.3389/fpls.2019.00103
Zwedie, H. S. (2022) Wheat Policy Yield and Production in Ethiopia, https://www.tandfonline.com/doi/full/10.1080/23322039.2022.2079586