Irrigation in Africa


It is helpful to have an overview of the available crop irrigation methods. According to the Centers for Disease Control and Prevention, the two primary ways farmers water crops is through irrigation and rain-fed farming. Irrigation pulls water from existing sources, such as groundwater, wells, or rivers, and feeds them into tubes and sprays to water crops. Although these crops are less susceptible to water shortages, they are at risk of contamination if the irrigation water sources are contaminated. Crops may be contaminated by agricultural runoff, such as from pesticides or fertilizers contaminating lakes during rainfall. Contaminated water is not only bad for crop growth, but also may be harmful to the people consuming those crops. Food-borne illnesses may spread through fruits or vegetables and make people sick (CDC Water Contamination).

Although irrigation-fed crops have a more reliable water source, this source will run out if overused. Even so, irrigation can help provide water for crops during times of drought (Shiferaw et al. 2014). Rain-fed farming relies on direct rainfall, which is cleaner, but more susceptible to droughts and water shortages. This is especially the case as climate change worsens and rainfall patterns change (CDC Types of Water).


Below is a list of irrigation systems displayed on the CDC website:


-Surface irrigation
-Localized irrigation
-Drip irrigation
-Sprinkler irrigation
-Center pivot irrigation
-Lateral move irrigation
-Sub-irrigation
-Manual irrigation

If you are interested in learning more about these different types of irrigation, visit CDC's page linked here.

Figure 1: Surface irrigation
In 2010, it was estimated that only 6% of farmland in Africa was irrigated, while 37% was irrigated in the continent of Asia (IFPRI 2010). Africa has the lowest irrigated area and capacity for water storage of all of the regions in the world (Shiferaw et al. 2014). Although 6% may seem like a small percentage, efforts to improve irrigation have picked up more recently. Woodhouse et al. argue that in order for more irrigation to be implemented in sub-Saharan Africa, a reliable water source for farmers must be established. For this to happen, irrigation development must be re-appraised and small-scale farmers must largely be considered. Farmers, especially small-scale ones, are taking actions to launch more irrigation initiatives. By considering small-scale farmers and their interests, it makes it easier for them to adapt to implemented irrigation and to ensure the irrigation system benefits them (Woodhouse et al. 2017).




Although irrigation is extremely helpful for watering crops, it is important to note that it can have unintended consequences. The installation of irrigation can alter rainfall patterns around the immediate and neighboring areas. This can greatly impact surrounding communities, especially if they rely on rain-fed farming. Based on a study done on a large-scale irrigation scheme (the Gezira Scheme) in the African Sahel, a climatic transition region, it was found that rainfall increased to the east, but was impeded over the Gezira Scheme area. This study used a regional climate model to mimic scenarios and also tracked aspects such as rainfall, surface air temperatures, and regional streamflow. The impact on surrounding communities must be considered when implementing large-scale irrigation schemes. Although those who receive additional rainfall may benefit from better crop yields and increased water availability, those with less rainfall will suffer, especially those that rely on rain-fed irrigation for agriculture (Alter et al. 2015).

Figure 2: This figure demonstrates the types of biomes in the Gezira Scheme and the areas with irrigation (Alter et al. 2015)




Comments

  1. Richard taylorDecember 12, 2019 at 1:54 PM

    This is incisive summary drawing on some excellent sources.

    ReplyDelete

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