Irrigation methods for efficient water application: 40 years of South African research excellence

Abstract

The purpose of an irrigation system is to apply the desired amount of water, at the correct application rate and uniformly to the whole field, at the right time, with the least amount of non-beneficial water consumption (losses), and as economically as possible. We know that irrigated agriculture plays a major role in the livelihoods of nations all over the world and South Africa is no exception. With the agricultural water-use sector being the largest of all water-use sectors in South Africa, there have been increased expectations that the sector should increase efficiency and reduce consumption in order to increase the amount of water available for other uses.Studies and research over 40 years, on the techniques of flood-, mobile-and micro-irrigation have contributed to the knowledge base of applying irrigation methods correctly. In a recent study on irrigation efficiency, the approach is that irrigation efficiency should be assessed by applying a water balance to a specific situation rather than by calculating various performance indicators. The fraction of the water abstracted from the source that is utilised by the plant is called the beneficial water-use component, and optimised irrigation water supply is therefore aimed at maximising this component. It implies that water must be delivered from the source to the field both efficiently and effectively. Optimising water use at farm level requires careful consideration of the implications of decisions made during both development (planning and design), and management (operation and maintenance), taking into account technical, economic and environmental issues. An exciting, newly-developed South African Framework for Improved Efficiency of Irrigation Water Use covers 4 levels of water-management infrastructure: the water source, bulk conveyance system, the irrigation scheme and the irrigation farm. The water-balance approach can be applied at any level, within defined boundaries, or across all levels to assess performance within the entire water management area.

Innovation Through Research and Development for Irrigation Water Management

“…Over 20 years, different projects were completed, including research for design procedures of flood irrigation which were documented in four volumes (Kruger, ). In the period from 1987 to 1999, contributions were made by researchers in various organisations, through WRC‐supported projects, on computerised design procedures for irrigation systems; performance management to increase the efficiency of water application through centre pivot nozzles and sprinkler emitters (Reinders, ). Micro and drip irrigation are considered to be amongst the most efficient irrigation methods and potential exists for further expansion of the area under irrigation, subject to well‐established technical and economic requirements (Backeberg and Reinders, ).…”

Informing Equitable Water and Food Policies through Accurate Spatial Information on Irrigated Areas in Smallholder Farming Systems

“…The impacts of climate change, such as increasing temperatures, frequency, and intensity of drought, and flooding, coupled with population growth, urbanisation, land the proportion of cultivated areas that are irrigated was similar for small-and large-scale irrigation in one province, Limpopo [23,24].…”

Canola (Brassica napus L.) water use indicators as affected by sustained deficit irrigation and plant density in central Free State, South Africa

“…On the other hand, water user associations require https://doi.org/10.17159/wsa/2023.v49.i2.3965 this kind of information for balancing the supply and demand of water by all the farming enterprises at scheme level (Steduto et al, 2007;Barnard et al, 2015). Agricultural engineers may also benefit from this knowledge when designing irrigation systems (Reinders, 2011).…”