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This review provides an overview of Water Research Commission (WRC)-funded research over the past 36 years. A total of 28 WRC reports have been consulted, 13 of these compiled by the University of the Free State, 4 by the University of Fort Hare, and the remainder mainly by the ARC-Institute for Soil Climate and Water. This work has resulted in extensive capacity building in this field -numerous technical assistants and 58 researchers have been involved, of which 23 are still active in research.The focus on the water flow processes in the soil-plant-atmosphere continuum (SPAC), with particular emphasis on processes in the soil, has greatly enhanced understanding of the system, thereby enabling the formulation of a quantitative model relating the water supply from a layered soil profile to water demand; the formulation of logical quantitative definitions for crop-ecotope specific upper and lower limits of available water; the identification of the harmful rootzone development effects of compacted layers in fine sandy soils caused by cultivation, and amelioration procedures to prevent these effects; and management strategies to combat excessive water losses by deep drainage.The explanation of the way in which SPAC is expressed in the landscape in the form of the ecotope has been beneficial with regard to the extrapolation of studies on particular SPACs to the large number of ecotopes where detailed studies have not been possible. Valuable results are reported regarding rainfall and runoff management strategies. Longer fallow periods and deficit irrigation on certain crop ecotopes improved rainfall use efficiency. On semi-arid ecotopes with high-droughtrisk clay and duplex soils and high runoff losses, in-field rainwater harvesting (IRWH), designed specifically for subsistence farmers, resulted in maize and sunflower yield increases of between 30% and 50% compared to yields obtained with conventional tillage.An indication of the level of understanding of the relevant processes that has been achieved is demonstrated by their quantitative description in mathematical and empirical models: BEWAB for irrigation, SWAMP mainly for dryland cropping, and CYP-SA for IRWH.Five important related research and development needs are identified. The WRC has played, and continues to play, an important role in commissioning and funding research on water utilisation in agriculture and has clearly made an excellent contribution to the progress made in addressing the needs and requirements of subsistence, emergent and dryland farmers in South Africa.

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Hensley et al. (2000) proposed an in‐field rainwater harvesting (IRWH) technique for rural farmers located east of Bloemfontein South Africa, a semi‐arid environment. This technique combines the advantages of water harvesting, no‐till and basin tillage to stop ex‐field runoff on high clay soils. The full agronomic potential of the IRWH technique has not, however, been reached because the main cause of water loss is evaporation. Evaporation dominates the hydrological cycle in semi‐arid environments. This paper reviews the nature and design of the IRWH system, specifically the effect of mulch type on evaporation and yield. The effect of mulch type on yield is described by an infiltration ratio of the basin versus the runoff area over a period of three years. The function of the basin and catchment area is also discussed. The function of the basin area was to stop ex‐field runoff completely, to maximize infiltration and to store the collected water in the soil layers beneath the evaporation sensitive zone. The catchment area was designed to promote in‐field runoff and to act as a storage medium for water. Results from this research provide a new perspective on mulch management within water harvesting systems. Copyright © 2012 John Wiley & Sons, Ltd.