Evaluation of irrigation management practices of barley farmers in the Taung irrigation scheme

Abstract

Since 1996, about 202 small-scale farmer irrigation schemes involving 47 486 ha have been established in South Africa. Of the 37 198 participants, only 37% can be regarded as being commercially orientated. The remaining 63% are food-plot holders who may sometimes sell a proportion of their produce. In addition, there are a large number of smaller schemes « 2 ha) comprising commercial gardens, food-plots and household gardens (Bern bridge, 1996). The South African Breweries (SAB) has been using malt barley for the brewing of beer for more than 100 years. South African Breweries is one the big companies listed on the Johannesburg Stock Exchange (JSE), with a market capitalization in excess of about R40bn ($7bn). In the 1997/98 fiscal year alone, SAB breweries used a total of 280 000 tons of malt barley for the production of beer. Sixty-five percent of this 280 000 tons of barley was supplied by local producers, while the rest (about 35%) had to be imported from other countries such as Canada and the European Union (Tregurtha and Vink, 1999:2). South African Breweries is committed to the development of the barley production industry in South Africa. Hence, this has prompted SAB to give local farmers a guarantee that it will source almost all its barley from them. SAB makes its beer for the world market. The beer industry requires malt barley with a nitrogen content of between 1.5% and 2.0%. Therefore, all agronomic practices that are associated with optimum barley production (such as fertiliser application and pest control) must be taken into account (Anderson, 1998). The demand for water for uses other than those that concern agriculture has increased in the course of time. The amount of available good quality irrigation water, however, has decreased to approximately 50% of available water. Inefficiencies in water use can no longer be ignored because of increasing public awareness of the responsible use of nonrenewable resources (Meyer et aZ., 1990). This necessitates the best possible use of the available water, thus emphasising optimal water use efficiency (WUE). Unfortunately, the approach of many farmers is that inexpensive inputs are not a limiting factor. Previously, this has often resulted in over-irrigation with low economic water use efficiency. Poor water management and poor WUE have been identified as some of the major problems experienced by farmers in most developing countries. Most countries do not monitor the performances of their irrigation systems (Hennessy, 1993). There are many factors that can affect the efficiency of any given system or method, especially the level and design of the system, the design of the sprinkler nozzle, spray devices, capacities and pressure at which water is injected in relation to soil texture, topography and agro-climatic conditions. In addition, farm management can have a major impact on efficiencies, even with regard to the best-designed systems. The production of barley is said to be affected by soil, water, climate and crop management factors. Among these, water use and the application of fertilisers, especially nitrogen, are the most limiting factors in determining irrigation requirements and planning future water management projects. Barley's seasonal water use could vary widely, depending on agro-climatic conditions, soil types, quality and quantity of irrigation supplies and irrigation management practices (Hussain & Al-Jaloud, 1998). Given the above, it is clear that there are several external and internal factors influencing the effectiveness and efficiency of any given irrigation scheme. Therefore, this study was conducted to determine whether the barley farmers in the Taung irrigation scheme are using correct/efficient irrigation management practices.