|Book Group Author:||NA|
Halfway through the 20th century, a curious shift took place in the concept and definition of the agronomic term "crop water requirements." Where these crop needs were originally seen as the amount of water required for obtaining a certain yield level, in the second half of the 20th century, the term came to mean the water needed to reach the potential or maximum yield in a certain season and locality. Some of the multiple academic, economic, social, and geopolitical aspects of this conceptual shift are addressed here. The crucial role of the production ecologist Cees de Wit in formulating this paradigmatic shift in the 1950s is discussed. It is seen how the incipient concern for an expected global scarcity of water resources has contributed to a trend back to the conservative view of crop water control of de Wit. The development over the years of engineering and agricultural science concepts concerning irrigation and crop water control is presented as an evolution from practical husbandry to specialized applied science; from an empirical, ecological approach to a mainly physical/mathematical discipline. In the section "The scientific heritage of Occam and Bacon," it is argued that this development regarding irrigation is part of a general trend in agricultural (and other) sciences and technologies over the last 150 years, although tendencies to return to a more holistic approach have, at times, occurred. The current mainstream concepts and methods in the art and science of crop water control, far from being objective and value-free, often act as "a siren song" for decision-makers responsible for daily irrigation practice and regional or global water resource management. The seductive "tune" of maximum yields, concurrently the highest crop water use, drowns out the more modest aim of making an efficient use of the available water resources. The latter's allure might, however, become the more compelling as a greater scarcity of physical water resources becomes more important than scarcity of land and labour.
|Pages:||173 - 187|
|Journal:||Agriculture and Human Values|
crop yield, irrigation, plant water relations, watermanagement, water requirements, water use efficiency, water resourcemanagement, watering, Plant Water Relations (FF062), Soil WaterManagement (Irrigation and Drainage) (JJ800) (Revised June 2002)[formerly Soil Water Management]