Basic Soil and Water Resources and Irrigation Engineering/Agricultural Water Management and Related Terminology
Author: Suat Irmak, Professor and Soil and Water Resources and Irrigation Engineer, University of NebraskaLincoln Koffi Djaman, Research Scientist and Soil and Water Resources and Irrigation Engineer Africa Rice Center (AfricaRice), B.P. 96 Saint LouiAs stated by one of the pioneer irrigation scientists Orson Winso Israelsen (1887-1968), irrigation is an age-old art that has been influencing the well-being of civilizations for thousands of years. Irrigated agriculture has been a vital part of human civilization and has been significantly contributing to food security and aiding in reducing poverty since its beginning. Today, irrigation continues to play a crucial role in meeting the food and fiber demands of a rapidly growing modern civilization as irrigated agriculture currently contributes to about 40 percent of the world's total food/fiber production on only about 20 percent of the total cultivated land. Currently, a little over 800 million acres of land is irrigated globally with surface irrigation methods being the dominant irrigation methods practiced. A fast-growing world population, coupled with changing climate variables and increasing extreme events (both drought and floods), will likely impose substantial demand on future food and fiber production worldwide, which will, in turn, limit the availability of freshwater in producing agricultural commodities. Increasing extreme events can also increase the uncertainty in food productivity due to the uncertainty of the impact of climate change on water resources and crop response to these changes. Estimates by the Food and Agriculture Organization of the United Nations (FAO; 2010), indicate that the worlds population may reach over 9 billion by year 2050, based on the current rate of population growth. Increasing limitations in freshwater resources, coupled with population growth, have increased the competition for water between various sectors and will likely continue to increase the pressure on all disciplines to use water resources more efficiently. However, this pressure will most likely be imposed on irrigated agriculture more than other sectors because over 70 percent of the total freshwater resources withdrawn worldwide are for irrigated agriculture. Therefore, novel ideas and quality research, as well as effective and carefully designed agricultural water management programs, need to be implemented in production fields. This will enhance crop water productivity (crop water use efficiency) to deal with these important issues and be able to keep pace with increasing food and fiber demand.