Irrigation is the artificial application of water to the soil usually for assisting in growing crops. Agriculture that relies only on direct rainfall is referred to as rain-fed farming.
Sources of irrigation water can be groundwater extracted from springs or by using wells, surface water withdrawn from rivers or dams, or non-conventional sources like treated wastewater, desalinated water or drainage water.
Irrigation systems typically being used in South Africa today include:
- Flood irrigation
- Draglines, quick-coupling lines
- Micro irrigation
- Drip irrigation
These irrigation systems can be defined under the following types:
- Static (micro and sprinkle) – these systems remain static while water is applied.
- Moveable (quick coupling; dragline; hop-along; big gun; rotating boom) – these remain static during irrigation but are moved, manually or mechanically, between irrigations.
- Moving (centre pivot; linear and travelling irrigator), which move by themselves during irrigation.
- Flood (basin; border; furrow; short furrow) – water flows over the soil surface for spreading and infiltration purposes.
Irrigated agriculture plays an important role in stabilising the production of food and eventual food security. Although it uses 60% of the available water in South Africa, it does not do so at the expense or the detriment of any other sector of the economy. Yet no farmer would disagree that the demand on our scarce water resources makes the efficient use of all water in South Africa a necessity.
Source: adapted from a letter written by Johannes Möller, at the time of being president of Agri SA, to the Minister of the Department of Water Affairs
Commercial Farmer Points of Interest
Computer Software for Farmers
Irrigation scheduling is defined as the correct amount of water being applied to a crop at the correct time. We have only a limited resource of water, which should be utilised in the most efficient way possible. By optimising scheduling principles we can:
- Prevent over and under watering
- Facilitate crop manipulation
- Prevent unnecessary crop stress
- Create ideal air-water balance
- Manage soil water buffer
- Optimise salinity management
- Prevent soil compaction
- Save on energy costs
- Promote root development
- Improve fertiliser uptake
- Maximise harvest potential
Water legislation means that a farmer has to budget for how much water will be used. By using scheduling software the farmer can tell exactly how much water he used so that he can estimate how much he’s going to need for the next year as required. Some software companies have addressed the new regulations by developing software solutions that can successfully keep track of water budgeting information and spray records.
One module uses climate and soil moisture information to generate irrigation recommendations. It will also help predict water requirements. By loading this information, you will be able to make use of a second module which controls the irrigation in the field. This module also can determine when to irrigate in order to prevent frost or to cool down the plants by keeping track of temperature readings. By means of radio or of wired links, the pumps and valves in the field are controlled.
Source: DFM SoftwarePrecision irrigation means that land can be differentially irrigated according to variations in soil type, topography, soil-water capacity, yield potential. Accepting these differences (and irrigating according to them) translates into less wastage of water and fertiliser.
For the newcomer
Over-irrigating wastes water, and fertilisers and soil nutrients are diluted to below the root zone. And them more fertiliser is used! This leads ultimately to algal blooms and eutrophication downstream.
The Network on Irrigation Research and Extension for Smallholder Agriculture (NIRESA) was founded in 1996 to facilitate the exchange of ideas and practices about smallholder irrigation in South Africa. It is a platform for scientists, extension officers and students to exchange ideas, network and strengthen irrigation activities across the country. NIRESA is housed at the Water Research Commission. Contact Dr Sylvester Mpandeli at sylvesterm [at] wrc.org.za.
Find out about the support offered by the Department of Water and Sanitation (DWS) to resource-poor irrigation farmers.
Drip irrigation is the ideal solution for small-holders. It uses specially designed pipes pre-fitted with advanced drippers. The irrigation system drips the exact amount of water and nutrients that crops need right at the root zone. Thus, every drop of water is effectively used to raise quality and increase year-round yields.
Why drip irrigation is so successful:
- Keeps soil aerated
- Reduces weed growth
- Cuts down diseases and fungi
- Uniform, efficient water distribution
- Minimised evaporation and water run-off
- Enables easy control of water consumption
- Most efficient, accurate use of water and nutrients
Local business environment
Downloading the latest Agricultural Outlook by the Bureau for Food and Agricultural Policy (BFAP) and doing a search for “irrigation” will bring the reader to relevant passages across all crops where irrigation features. Find the document at www.bfap.co.za.
Department of Water and Sanitation (DWS) www.dwa.gov.za
- Selecting the “Document Library” menu option on the website will provide a spread of available information, including reports and strategic plans.
- Section 26 of the National Water Act (36) of 1998, requires that the abstraction of water for irrigation of crops should be limited, monitored, measured and recorded. Find out more about the Act in the general “Water” chapter or at www.dwa.gov.za.
- Industries with the largest potential contribution to job creation in agriculture are mostly irrigation-based, and so employment could be increased through the expansion of irrigation. The country irrigates some 1,5 million hectares of land and produces about 30% of total output on this land, which is only 10% of our arable land. The National Development Plan (NDP) targets bringing an extra 500 000ha under irrigation. It shows that even expanding the irrigated area by 14 000ha would create some of the million jobs that the NDP looks for in agriculture. The BFAP Baseline Agricultural Outlook 2016-2025 considered this (page 13, 14) and gave it the thumbs up. Two years later, the DWS and the WRC are not that sure and regard the 500 000 ha as “not feasible” (Uys, 2017).
Department of Agriculture, Forestry and Fisheries (DAFF) www.daff.gov.za
- Directorate: Water Use and Irrigation Management Ms Mary-Jean Gabriel Tel: 012 846 8567/9 MaryJeanG [at] daff.gov.za, DWUID [at] daff.gov.za
- Directorate: Infrastructure Support Tel: 012 319 846 8502 ATvC [at] daff.gov.za
DAFF chairs the Water Use and Irrigation Working Group which engages on irrigation initiatives in the provinces. Provincial Departments of Agriculture, the Agriculture Research Council, Water Research Commission, the Department of Water and Sanitation, Department of Rural Development are permanent members of the Water Use and Irrigation Working Group.
The Irrigation Strategy for South Africa has set a target of an increase of more than 50% of irrigated land in South Africa. For future scenarios, the DWS assumes that the amount of water allocated for agriculture remain the same; all land reform projects and revitalisation of smallholder irrigation schemes will use the same amount of water as before. An increase in irrigation will be effected through water use efficiency, and selected new development …
Source: An excerpt from the second chapter, “National Strategic Imperatives”, of the country’s National Water Resource Strategy 2 (NWRS2).
Find the document Irrigation Strategy for South Africa on the internet, or approach DAFF for it.
SA Irrigation Institute (SABI) Tel: 021 850 8220 www.sabi.co.za
SABI has more than 450 members that include inter alia designers, engineers, soil scientists, crop experts, economists and irrigation farmers. Furthermore, there are more than 50 company members, which represent mainly manufacturers and suppliers of irrigation equipment.
SABI’s main roles are:
- irrigation standards and norms;
- being a forum where industry players can raise issues;
- and sharing of knowledge to promote efficient irrigation water use and water conservation
SABI serves the interests of irrigation farmers, irrigation designers and students of irrigation. SABI members are found in the professional, academic, private and government sectors, with increasing membership on the continent of Africa.
Irrigators and farmers who experience problems with their irrigation systems can contact SABI, who will provide a list of SABI Approved Designers, who can be approached for a quotation and technical evaluation. SABI approved Irrigation Designers complete the SABI National Exam and are bound by the SABI ethical code to designing irrigation systems that meet the SABI design norms.
SABI holds a bi-annual SABI National Congress, which attracts local, African and international delegates. For networking and knowledge dissemination, SABI also holds branch meetings and farmers’ days. The Institute offers various AgriSETA-accredited training courses nationwide throughout the year, and publishes the bi-monthly SABI Magazine/Tydskrif, South Africa’s irrigation magazine.
The South African National Committee on Irrigation and Drainage (SANCID) represents South Africa at the International Commission on Irrigation and Drainage (ICID). Details of SANCID representatives may be found on the website, www.sancid.org.za.
Southern African Regional Irrigation Association (SARIA) www.saria.org.za
Other irrigation-related associations and Industry Organisations:
- Landscape Irrigation Association www.sali.co.za
- The Borehole Water Association of SA www.bwa.co.za
- Water Research Commission www.wrc.org.za
- Network on Irrigation and Extension for Small-scale Agriculture (NIRESA) Sylvester Mpandeli, sylvesterm [at] wrc.org.za
- Southern African Plastic Pipe Manufacturers Association (SAPPMA) www.sappma.co.za
Training and Research
SABI, as the recognised representative organisation of the irrigation industry in South Africa, organises and facilitates a series of training courses each year. These are suited to experienced and trainee farm workers, irrigation managers and irrigation designers, and are presented in co-operation with the private sector, universities, research organisations and agricultural colleges all around the country. The SABI courses are accredited by SAQA (South African Qualifications Authority), and are thus recognised as part of the registered NQF (National Qualifications Framework) learning programme.
The following courses are presented:
- Irrigation Operator Course
- Irrigation Manager Course (Installation and management of irrigation systems)
- Introductory Irrigation Design Course
- Advanced Irrigation Design Course
To find updates go to the “Training” option on www.sabi.co.za.
The Agricultural Colleges present short courses on irrigation for small scale as well as for commercial farmers. These include a basic introduction to irrigation planning, examination of soil, economics and irrigation scheduling. Find contact details in the “Agricultural education and training” chapter.
Providers of South African Qualification Authority (SAQA) courses, accredited with AgriSETA, offer courses related to irrigation. Find contact details in the “Agricultural Education and Training” chapter or at www.agriseta.co.za.
Websites and publications
Visit the websites listed earlier in this chapter.
- SABI Magazine/Tydskrif is published by SABI every second month. It is distributed to irrigation farmers and associated professionals in South Africa. The publication gives the reader first hand information and a range of topical and technical articles on the irrigation industry in South Africa. Visit www.sabi.co.za for more information and to subscribe to the magazine.
- Newsjet is the newsletter of SABI. Find a copy on their website.
- Irrigation Design Manual – usually given as part of the Irrigation Design Course. Contact SABI for a copy.
The Water Research Commission has numerous relevant publications. One of these is Irrigation water measurement – Guidance for water user associations. Water user associations (WUAs) will be assisted greatly by these guidelines addressing the choice, installation and management of water measuring devices for canal, pipeline and river distribution systems. This and many other publications are available from the Water Research Commission. Call 012 761 9300, email orders [at] wrc.org.za after viewing www.wrc.org.za.
One of the reports by the WRC looks at possible water treatment techniques for farmers employing irrigation water from rivers that are increasingly polluted. Download “Scoping study on different on-farm treatment options to reduce the high microbial contaminant loads of irrigation water to reduce the related food safety risk” at www.wrc.org.za.
SUSFARMS, the Sustainable Sugarcane Farm Management System, deals with irrigation. Contact the South African Sugarcane Research Institute (SASRI) for more information. Call 031 508 7500 or visit https://sasri.org.za/.
Available from the Training Resources Development at Cedara are 8 posters on irrigation. For further information, contact 033 355 9304, or visit www.kzndard.gov.za.
Watch the videos on irrigation at http://saorchard.co.za/irrigation/general-irrigation.
Call 012 842 4017 or email iaeinfo [at] arc.agric.za for the following publications, available from the ARC-Agricultural Engineering:
- Irrigation design manual (Planning and design of irrigation systems)
- Besproeiingsontwerphandleiding (beplanning en ontwerp van besproeiing stelsels)
- Besproeiingsbedryfshandleiding (installering, bestuur en instandhouding van besproeiing stelsels)
- Irrigation User’s Manual (installation, management and maintenance of irrigation systems)
- Besproeiingsontwerphandleiding / Irrigation Design Manual on cd (pdf-format)
- Besproeiingsbedryfshandleiding/Irrigation Users’ Manual on cd (pdf-format)
- The efficient use of labour in sprinkler irrigation systems
- The effects of wind on sprinkler irrigation
- Aspects to consider when selecting sprinklers for use in irrigation systems
- Critical elements which influences the efficiency of small-scale farm sprinkler irrigation systems
- Ingenieursaspekte betrokke by ondergrondse drupbesproeiing
- Engineering aspects of sub-surface drip irrigation
- Laedruk vloeibeheerklep
- Treatment of low quality water for drip irrigation systems
- The performance and care of drip irrigation emitters
- Ondersoek na materiale vir kanaalbelyning
- Investigation into materials for lining of canals
- Petrol-aangedrewe besproeiingspomp vir beginnerboere
- Petrol-driven irrigation pump for emerging farmers
- An evaluation of some irrigation methods for small vegetable gardens in remote rural areas
- Handleiding vir die evaluering van besproeiingstelsels
- Manual on the evaluation of irrigation systems Irrigation made easy (training manual)
Uys, G. 2017. “SA’s water stores too low for proposed NDP irrigation schemes”. Farmer’s Weekly, November 3 page 18.
- Find the irrigation tutorials (USA) at www.irrigationtutorials.com
- International Commission on Irrigation and Drainage (ICID) www.icid.org
- Irrigation Association Australia www.irrigation.org.au
- Irrigation Association (USA) www.irrigation.org
- International Water Management Institute www.iwmi.cgiar.org
- Irrigazette www.irrigazette.com
- Irrigation UK www.ukia.org