Foreword
- Page ID
- 44313
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Agriculture is the largest consumer of global freshwater resources, currently estimated to account for 75 percent of all water diverted for human use. The global population is anticipated to peak at approximately 10 billion in 2050, and our food systems will need to evolve to respond to the increasing population, improving diets, climate change and other political and social changes. The demand for water for food, fiber and fuel is projected to increase by another 50 percent in that time frame. Today, one third of the world’s food is produced on 21 percent of its cultivated land as a result of effective irrigation systems. This clearly highlights the import role irrigation will continue to play in intensifying agricultural production and feeding the world.
Irrigation has a long history. Around the world, water has been diverted for irrigation for thousands of years. In the United States reminants of irrigation infrastructure dating back over 3200 years can be found in the Southwest. For the last 250 years, the total area under irrigation in the U.S. has continuously increased. Despite this expansion and increasing crop productivity, the amount of water used for agriculture has remained relatively stable since the 1980s, showing an improvement in how agricultural water is managed.
With all the gains achieved through irrigation, there remain downsides to consider— and there are many if close attention is not paid to the system, its management, and the sustainability of vital soil and water resources. Over-extraction—or taking more water than can be replaced through precipitation—of both groundwater and surface water is a widespread issue around the world. This is especially true in the absence of robust water accounting to determine the resources available and ensuring overall consumptive use does not exceed system limits. Mismanagement of the water, fertilizer and other agricultural chemicals can lead to degradation of water quality and contamination of ground and surface water resources. That said, well managed irrigation presents the opportunity to minimize the level of contamination.
Farmers’ access to irrigation is a crucial component of a highly productive agricultural system—one that reduces risk and increases resilience. For it to be effective, the system must integrate into the broader farm system, provide the farmer with a solid return on their investment and sustain the vital natural resources upon which the enterprise depends.
Drawing on decades of collective experience in research, teaching, outreach and practice, the authors present the knowledge and technical insights into the development and management of the common irrigation systems adopted across the U.S. and many other parts of the world. The understanding of these systems—combined with the relevant knowledge in other contexts—are critical to addressing water and food security for the future.
Peter G. McCornick, Executive Director
Daugherty Water for Food Global Institute (DWFI)
at the University of Nebraska