Water Productivity in Agriculture: Looking for Water in the Agricultural Productivity and Efficiency Literature

Expectations are that the agricultural sector will have to expand the use of water for irrigation to meet rising food demand, while at the same time the competition for water resources is growing in many regions. Increasing water productivity in agriculture is widely seen as a critical response to help address this challenge. Yet much of the public debate is vague on the meaning of agricultural water productivity - often emphasizing "more crop per drop" as if water were the only input that mattered-, and approaches for assessing and increasing water productivity are seldom addressed systematically. This paper discusses conceptual issues that should be kept in mind when assessing agricultural water productivity, and presents findings from what may be the first survey of the agricultural productivity and efficiency literature with regard to the explicit inclusion of water aspects in productivity and efficiency measurements. The survey comprises studies applying single-factor productivity (SFP) measures, total factor productivity (TFP) indices and frontier models. Studies using deductive methods are also included. A key finding is that the studies tend to either incorporate field- and basin-level aspects but focus only on a single input (water), or they apply multi-factor approaches but do not tackle the basin-level aspects. It seems that no study has yet presented an approach that accounts for multiple inputs and basin-level issues. Deductive methods may provide the flexibility to overcome some of the limitations of the other methods.