Lecture 15: Water and Agriculture

by Warangkana Na Phatthalung, Prince of Songkla Univesity

Agriculture is the main water user everywhere, due to irrigation. Therefore, irrigation is crucial for food supply. That was the introduction of Dr. Sylvian Perret’s talk entitled “What is sustainability in agricultural use of water?”. There are three related research questions, as the following aspects should be considered: first, how much water is used? Unfortunately, there are no measuring devices. However, there are several key factors that can be related to water used in agricultural economics (is water costly or is water profitable enough?) and environmental impacts (is there resource depletion or resource pollution?) of agricultural water use. Dr. Perret provided the example of AquaCrop, a new version of CROPWAT 8.0, an irrigation model from Food and Agricultural Organization of the United Nations (FAO) that can also be used to evaluate water used for irrigation. The calculation procedures are based on crop-soil-climate water balance and evapotranspiration. Another existing scientific method is the water footprint based model available for analyzing the environmental impacts of agrifood products. The second research question is how much money do we get from water use? Many production factors that can be related are supply costs, water fees (if any), water values for other crops and in other sectors. So, we should know the value ($) per cubic meter used. The third question is what are the environmental interactions between water and agriculture? The Life Cycle Analysis (LCA) is a comprehensive approach to evaluate the environmental impacts of the production, the use, and disposal of a product. Nevertheless, the sustainable trade-off in agriculture-water relations for choosing between benefits, production, employment, water resource protection, and ecosystem protection require probably a bit of each. There are several key points that can provide for sustainability in agricultural use of water. Knowledge on the value of water is important, in particular for the agricultural sector to use water efficiently.