AMARILLO û Growing competition for diminishing fresh water supplies worldwide, coupled with an expanding population, will drive demand for improved dryland agriculture technology, said a Texas Agricultural Experiment Station researcher.
To capture what is being done in the realm of dryland agriculture and where research is needed, Dr. Bill Payne of Amarillo, Experiment Station plant physiologist, joined forces with more than 50 other contributors to write the second edition of Dryland Agriculture. The publication is one of several monographs published by the American Society of Agronomy (http://www.agronomy.org).
The book, which includes 22 chapters filling more than 900 pages, took six years write and edit. In addition to helping write, Payne edited the book with Dr. Paul Unger, retired soil scientist with the U.S. Department of Agriculture-Agricultural Research Service at Bushland, and Dr. Gary Peterson, head of the soil and crop sciences department at Colorado State University
"Agriculture has changed tremendously, as have its priorities, in the past 20 years," Payne said. "For example, the word sustainability was almost unknown when the first edition came out in 1983. Additionally, today's economy is much more global, which has had profound effects upon agricultural production. There definitely was a need for the book to be updated."
An example of changing agriculture as reflected in the new book is the evolution of no-till systems, which is among the greatest advancements in dryland agriculture, he said.
While the exact definition and practice of no-till may vary from country to country depending on machinery, the basic idea is to not disturb the soil and to protect it by leaving crop residue in the field.
"This not only conserves soil, but it conserves water," Payne said.
However, no-till raises new issues of disease and pest management, changes in soil temperature and planting times, and most especially, it can complicate weed control, he said.
The first edition of Dryland Agriculture also only addressed U.S. conditions. A major improvement in the second edition, Payne said, is that it covers dryland agriculture throughout the world.
Greater understanding of the important differences and commonalities of different dryland farming systems is important because of the growing importance of dryland agriculture and the fact that global food supply is increasingly interconnected, he said.
The new international emphasis is critical to the book's importance, Payne said.
"There is growing competition for diminishing supplies of freshwater among countries and different sectors of society," he said. "This is occurring not just in the High Plains, but throughout the world. China and especially India are dependent on food production from finite aquifers."
Many aquifers and other sources of freshwater are being depleted at an unsustainable rate, Payne said. Yet the world has become complacent about food availability. In the 1950s and 1960s, people were aware of the presence and consequences of mass starvation due to low agricultural productivity. But more recently, agricultural research in the U.S. and especially developing countries has received less and less financial support.
"Imagine the economic and political consequences if one-third of the world's population were exposed to an unreliable and diminishing food supply," Payne said.
"What a lot of people don't seem to realize is that a disproportionate amount of our world food supply relies on irrigated agriculture, which in turn depends on shrinking availability of fresh water," he said.
As an example, India faced massive starvation in the 1950s and is now food sufficient, in large part due to irrigated agriculture, Payne said. But India is poised to pass China as the most populous country in the world, while rapidly depleting its aquifers, rivers and streams.
"If we don't improve the efficiency of dryland agriculture, we will potentially face food insecurity for basically one-third of the world's population," he said. "That could cause political instability and other problems."
The book is primarily aimed at academia and is expected to be used as a reference book. It addresses principles of dryland agriculture in general and applications in individual regions. It also identifies research priorities needed to address the individual challenges in specific regions, Payne said.
Topics covered by the book include soil conservation, crop choices and rotation, soil fertility, pest management, mixed crop-livestock systems and research issues such as weather variability, erosion, crop diversity, tillage, and nutrient and soil organic matter.
Many similarities exist from region to region, such as water conservation and soil degradation, but important differences that are often related to social and political settings exists, Payne said.
The balance between profitability and risk avoidance is a factor, he said. Profitability is important in countries with developed markets and economic safety nets, while risk avoidance is a priority to subsistence farmers in developing countries who must avoid starvation.
"Here, people talk about risk in economic terms, whereas in other countries, it is a matter of survival," Payne said.
In the High Plains and other developed regions of the world, dryland agricultural production continues to increase due to the joint efforts of different research fields, including soil science, plant breeding and physiology, and many others, he said.
"Right now, the world is hopeful for more technological breakthroughs, such as those promised by biotechnology," Payne said.