Many scheduling approaches have been developed with Water Research Commission funding over the past 4 decades and
deployed with varying levels of success; 2 approaches have won prestigious international awards. Soil-based approaches
which include measurement of matric potential (tensiometry), water content (neutron probes, capacitance sensors) and depth
of wetting (wetting front detectors) have been relatively well accepted by farmers. Atmospheric-based approaches apply,
through biophysical modelling of the soil-crop-atmosphere system, thermodynamic limits to the amount of water that can
evaporate from a cropped surface under particular environmental conditions. Modelling approaches have been quite empirical
or somewhat more mechanistic, generic or crop specific, with pre-programmed (e.g. irrigation calendars) or real-time
output. Novel mechanisms have been developed to deliver recommendations to farmers, including resource-poor irrigators.
Although general adoption of objective irrigation scheduling in South Africa is still low, the high cost of electricity and
nitrogen, and scarcity of water is reviving the interest of consultants and irrigators in the application of these tools to use
water more efficiently. Where adoption has been relatively high, intensive support and farmer-researcher-consultant interactions
have been key contributing factors. We propose 4 avenues in the R&D domain to ensure responsible water utilisation.
Firstly, there is a need to continue to advance existing soil-water measurement technology; and secondly, to further develop
new and emerging technologies, like the use of remote sensing. Thirdly, the user-friendliness should be improved as should
systems that support existing scheduling tools; and finally, we need to appreciate that farmers are intuitively adaptive managers,
and we need to develop simple monitoring tools and conceptual frameworks that enable structured learning.