Water

387 Plant Science Hall
Department of Agronomy and Horticulture
University of Nebraska-Lincoln
P. O. Box 830915
Lincoln, NE 68583-0915

(402) 472-5554 (402) 472-8650
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Professor of Agronomy and Horticulture, University of Nebraska
cassman_web_copy.jpg PhD

The need to meet food demand while protecting environmental quality and natural resources for future generations is a scientific challenge that has been grossly underestimated, and this theme provides a unifying framework for my research. Agricultural systems must ultimately contribute to solving the most pressing environmental problems facing humankind because agriculture is practiced on 33% of the earth's surface. Hence, the ultimate goal of my research and educational programs is to ensure that increases in food production do not compromise the quality of soil and water resources or threaten the ecological integrity of natural ecosystems. Current projects focus on understanding process controls on carbon sequestration in agricultural soils, energy efficiency of major rainfed and irrigated cropping systems in the north-central USA, the potential for ecological intensification of maize-based cropping systems, and use of crop simulation models to improve crop and soil management decisions. As a member of interdisciplinary research teams, our goal is to seek fundamental knowledge about the dynamic, interactive effects of climate and crop/soil management practices on short- and long-term performance of agroecosystems-with a focus on carbon sequestration, greenhouse gas emissions, nitrogen and energy efficiency, and crop productivity.

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Rosamond L. Naylor
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This past autumn the Freeman Spogli Institute for International Studies (FSI) in conjunction with the Woods Institute for the Environment launched a program on Food Security and the Environment (FSE) to address the deficit in academia and, on a larger scale, the global dialogue surrounding the critical issues of food security, poverty, and environmental degradation.

"Hunger is the silent killer and moral outrage of our time; however, there are few university programs in the United States designed to study and solve the problem of global food insecurity," states program director Rosamond L. Naylor. "FSE's dual affiliation with FSI and the new Stanford Institute for the Environment position it well to make significant steps in this area."

Through a focused research portfolio and an interdisciplinary team of scholars led by Naylor and CESP (Center for Environmental Science and Policy) co-director Walter P. Falcon, FSE aims to design new approaches to solve these persistent and under-prioritized problems, expand higher education on food security and the environment at Stanford, and provide direct policy outreach.

Productive food systems and their environmental consequences are at the core of the program. While many of these systems are global in character, but they are influenced significantly by differing food objectives, income level, and instruments among nations. The program thus seeks to understand the food security issues that are of paramount interest to poor countries, the food diversification challenges that are a focus of middle-income nations, and the food safety and subsidy concerns prominent in richer nations.

Chronic hunger in a time of prosperity

Although the world's supply of basic foods has doubled over the past century, roughly 850 million people (12 percent of the world's population) suffer from chronic hunger. Food insecurity deaths during the past 20 years outnumber war deaths by a factor of at least 5 to 1. Food insecurity is particularly widespread in agricultural regions where resource scarcity and environmental degradation constrain productivity and income growth.

FSE is currently assessing the impacts of climate variability on food security in Asian rice economies. This ongoing project combines the expertise of atmospheric scientists, agricultural economists, and policy analysts to understand and mitigate the adverse effects of El Niño-related climate variability on rice production and food security under current and future global warming conditions. As a consequence of Falcon and Naylor's long-standing roles as policy advisors in Indonesia, models developed through this project have already been embedded into analytical units within Indonesia's Ministry of Agriculture, the Planning Ministry, and the Ministry of Finance.

"With such forecasts in hand, the relevant government agencies are much better equipped to mitigate the negative consequences of El Niño events on incomes and food security in the Indonesian countryside," explain Falcon and Naylor.

Food diversification and intensification

With rapid income growth, urbanization, and population growth in developing economies, priorities shift from food security to the diversification of agricultural production and consumption. "Meat production is projected to double by 2020" states Harold A. Mooney, CESP senior fellow and an author of the Millennium Ecosystem Assessment. "In China alone, meat consumption has more than doubled in the past generation." As a result, land once used to provide grains for humans now provides feed for hogs and poultry.

These trends will have major consequences on the global environment-affecting the quality of the atmosphere, water, and soil due to nutrient overloads; impacting marine fisheries both locally and globally through fish meal use; and threatening human health, as, for example, through excessive use of antibiotics.

An FSE project is looking at these trends as it relates to intensive livestock production and assessing the environmental impacts to gain a better understanding of the true costs of this resource-intensive system. A product of this work recently appeared as a Policy Forum piece in the December 9, 2005, issue of Science titled "Losing the Links Between Livestock and Land".

Numerous factors have contributed to the global growth of livestock systems, lead author Naylor notes, including declining feed-grain prices, relatively inexpensive transportation costs, and trade liberalization. "But many of the true costs remain largely unaccounted for," she says. Those costs include destruction of forests and grasslands to provide farmland for corn, soybeans, and other feed crops destined not directly for humans but for livestock; utilization of large quantities of freshwater; and nitrogen losses from croplands and animal manure.

Naylor and her research team are seeking better ways to track all costs of livestock production, especially the hidden ones related to ecosystem degradation and destruction. "What is needed is a re-coupling of crop and livestock systems," Naylor says. "If not physically, then through pricing and other policy mechanisms that reflect social costs of resource use and ecological abuse."

Such policies "should not significantly compromise the improving diets of developing countries, nor should they prohibit trade," Naylor adds. Instead, they should "focus on regulatory and incentive-based tools to encourage livestock and feed producers to internalize pollution costs, minimize nutrient run-off, and pay the true price of water."

Looking ahead

The future of the program on Food Security and the Environment looks bright, busy, and expansive. While a varied portfolio of projects is in line for the upcoming year, a strong emphasis remains in the area of food security. Building on existing research at Stanford, researchers are identifying avenues for enhancing orphan crop production in the world's least developed countries-crops with little international trade and investment, but with high local value in terms of food and nutrition security. The work seeks to identify advanced genetic and genomic strategies, along with natural resource management strategies, to improve orphan crop yields and stability, enhance crop diversity, and increase rural incomes through orphan crop production.

Another priority area of research centers on the development of biofuels. Biofuels are becoming increasingly a part of the policy set for world food and agriculture. As countries such as the United States seek energy self-reliance and look for alternatives to food and feed subsidies under WTO (World Trade Organization) rules, the conversion of corn, sugar, and soybeans to ethanol and other energy sources becomes more attractive. New extraction methods are making the technology more efficient, and crude oil prices at $60 per barrel are fundamentally changing the economics of biomass energy conversion. A large switch by key export food and feed suppliers, such as the United States and Brazil, to biofuels could fundamentally alter export prices, and hence the world food and feed situation. A team of FSE researchers will assess the true costs of these conversions.

The FSE program recently received a grant through the Presidential Fund for Innovation in International Studies to initiate new interdisciplinary research activities. One such project links ongoing research at Stanford on the environmental and resource costs of industrial livestock production and trade to assess the extent and rate of Brazil's rainforest destruction for soybean production. "Tens of millions of hectares of native grassland and rainforest are currently being cleared for soybean production to supply the global industrial livestock sector," says Naylor. A significant share of Brazil's soybeans is being shipped to China, where rapid income growth is fueling tremendous increases in meat consumption."

A team of remote-sensing experts, ecologists, agronomists, and economists will be looking at the ecological effects on the landscape through biogeochemical changes and biodiversity loss, the impacts of land clearing on the regional hydrologic cycle and climate change, the economic patterns of trade, and the role of policies to achieve an appropriate balance between agricultural commodity trade, production practices, and conservation in Brazil's rainforest states.

"I'm extremely pleased to see the rapid growth of FSE and am encouraged by the recent support provided through the Presidential Fund for Innovation in International Studies," states Naylor. "It enables the program to engage faculty members from economics, political science, biology, civil and environmental engineering, earth sciences, and medicine-as well as graduate students throughout the university-in a set of collaborative research activities that could significantly improve human well-being and the quality of the environment."

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Humans have changed ecosystems more rapidly and extensively in the last 50 years than in any comparable period of human history. We have done this to meet the growing demands for food, fresh water, timber, fiber, and fuel. While changes to ecosystems have enhanced the well-being of billions of people, they have also caused a substantial and largely irreversible loss in diversity of life on Earth, and have strained the capacity of ecosystems to continue providing critical services.

Richly illustrated with maps and graphs, Current State and Trends presents an assessment of Earth's ability to provide twenty-four distinct services essential to human well-being. These include food, fiber, and other materials; the regulation of the climate and fresh water systems, underlying support systems such as nutrient cycling, and the fulfillment of cultural, spiritual, and aesthetic values. The volume pays particular attention to the current health of key ecosystems, including inland waters, forests, oceans, croplands, and dryland systems, among others. It will be an indispensable reference for scientists, environmentalists, agency professionals, and students.

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Island Press, Washington, DC in "Ecosystems and Human Well-being: Current State and Trends."
Authors
Rosamond L. Naylor
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Global meat production is becoming increasingly industrialized, spatially concentrated, and geographically detached from the agricultural land base. This Policy Forum reviews the process of livestock industrialization and globalization, and its consequences for water, nitrogen, and species-rich habitats in meat- and feed-producing regions often vastly separated in space. It argues that pricing and other policy mechanisms which reflect social costs of resource use and ecological change are needed to re-couple livestock and land in producer countries, drawing on examples from Europe and the United States. It also argues that consumers can play an important role in setting a sustainable course.

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Journal Articles
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Science
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Rosamond L. Naylor
Henning Steinfeld
Walter P. Falcon
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Rosamond L. Naylor
Walter P. Falcon
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CESP senior fellows Rosamond L. Naylor, Walter P. Falcon, and Harold A. Mooney released the findings of a new study on the impacts of an increasingly global livestock industry in the Policy Forum of the Dec. 9 issue of Science.

The turkey and ham many are eating this holiday season don't just appear magically on the table. Most are the end product of an increasingly global, industrialized system that is resulting in costly environmental degradation. Better understanding of the true costs of this resource-intensive system will be critical to reducing its negative effects on the environment, says an interdisciplinary team of researchers led by Stanford University's Rosamond Lee Naylor, Walter Falcon, and Harold Mooney.

"Losing the Links Between Livestock and Land" appears in the Policy Forum in the Dec. 9 issue of Science. It represents a synthesis of research by professors at Stanford University, the University of Virginia, the University of California at Davis, the universities of Manitoba and British Columbia in Canada, and the United Nations LEAD (Livestock Development and Environment) program within the Food and Agricultural Organization of UN.

"Sixty years ago, the link between the livestock production and consumption was much more clear and direct, with most consumers getting their meat and dairy products from small, family-owned farms," says lead author Naylor, an economist. Co-author Falcon agrees. "When I was growing up in Iowa, almost all farmers kept both chickens and pigs."

Today, meat consumption has sky-rocketed, and large-scale intensive livestock operations provide most of those products, both in the U.S. and around the world.

Particularly striking is the growth in demand for meat among developing countries, Naylor notes. "China's meat consumption is increasing rapidly with income growth and urbanization, and it has more than doubled in the past generation," she says. As a result, land once used to provide grains for humans now provides feed for hogs and poultry.

Numerous factors have contributed to the global growth of livestock systems, Naylor notes, including declining feed-grain prices; relatively inexpensive transportation costs; and trade liberalization. "But many of the true costs remain largely unaccounted for," she says. Those costs include destruction of forests and grasslands to provide farmland for corn, soybeans and other feed crops destined not directly for humans but for livestock; use of large quantities of freshwater; and nitrogen losses from croplands and animal manure.

Nitrogen losses are especially problematic, says James Galloway of the University of Virginia. "Once nitrogen is lost to the atmosphere or to water, it can have a large number of sequential environmental effects. For example, ammonia emitted into the atmosphere can in sequence affect atmospheric visibility, forest productivity, lake acidity and eventually impact the nutrient status of coastal waters."

Naylor cited Brazil as a specific example of the large impact on ecosystems and the environment. "Grasslands and rainforests are being destroyed to make room for soybean cultivation," she said. The areas are supplying feed to the growing livestock industry in Brazil, China, India and other parts of the world, leading to "serious consequences on biodiversity, climate, soil and water quality."

Naylor and her research team are seeking better ways to track all costs of livestock production, especially the hidden ones related to ecosystem degradation and destruction. "What is needed is a re-coupling of crop and livestock systems," Naylor said. "If not physically, then through pricing and other policy mechanisms that reflect social costs of resource use and ecological abuse."

Such policies "should not significantly compromise the improving diets of developing countries, nor should they prohibit trade," Naylor added. Instead, they should "focus on regulatory and incentive-based tools to encourage livestock and feed producers to internalize pollution costs, minimize nutrient run-off, and pay the true price of water."

She cited efforts in the Netherlands to track nitrogen inputs and outputs for hog farms as one approach. In the U.S., the 2002 Farm Bill provided funds for livestock producers to redesign manure pits and treat wastes, but she notes that much greater public and private efforts are needed to reduce the direct and indirect pollution caused by livestock.

In the end, though, it may be up to consumers to demand more environmentally sustainable approaches to livestock production. "In a global economy with no global society, it may well be up to consumers to set a sustainable course," she added.

Seed funding for the research was provided by the Woods Institute for the Environment, which supports interdisciplinary approaches to complex environmental issues. Naylor, Falcon and Mooney are affiliated with the institute and with the Center for Environmental Sciences and Policy in Stanford's Freeman Spogli Institute for International Studies.

In addition to Naylor, Mooney and Falcon of Stanford and Galloway of Virginia, co-authors are Henning Steinfeld of the United Nations Food and Agriculture Organization; Galloway; Vaclav Smil, University of Manitoba; Eric Bradford, University of California at Davis; and Jacqueline Alder, University of British Columbia.

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Land use has generally been considered a local environmental issue, but it is becoming a
force of global importance. Worldwide changes to forests, farmlands, waterways, and
air are being driven by the need to provide food, fiber, water, and shelter to more than
six billion people. Global croplands, pastures, plantations, and urban areas have expanded
in recent decades, accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. Such changes in land use have
enabled humans to appropriate an increasing share of the planet's resources, but they
also potentially undermine the capacity of ecosystems to sustain food production,
maintain freshwater and forest resources, regulate climate and air quality, and ameliorate
infectious diseases. We face the challenge of managing trade-offs between immediate
human needs and maintaining the capacity of the biosphere to provide goods and
services in the long term.

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Science
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Holly Gibbs
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Biological productivity in most of the world's oceans is controlled by the supply of nutrients to surface waters. The relative balance between supply and removal of nutrients-including nitrogen, iron and phosphorus-determines which nutrient limits phytoplankton growth. Although nitrogen limits productivity in much of the ocean, large portions of the tropics and subtropics are defined by extreme nitrogen depletion. In these regions, microbial denitrification removes biologically available forms of nitrogen from the water column, producing substantial deficits relative to other nutrients. Here we demonstrate that nitrogen-deficient areas of the tropical and subtropical oceans are acutely vulnerable to nitrogen pollution. Despite naturally high nutrient concentrations and productivity, nitrogen-rich agricultural runoff fuels large (54-577 km2) phytoplankton blooms in the Gulf of California. Runoff exerts a strong and consistent influence on biological processes, in 80% of cases stimulating blooms within days of fertilization and irrigation of agricultural fields. We project that by the year 2050, 27-59% of all nitrogen fertilizer will be applied in developing regions located upstream of nitrogen-deficient marine ecosystems. Our findings highlight the present and future vulnerability of these ecosystems to agricultural runoff.

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Nature
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Pamela Matson
Pamela Matson

The global trade in grain and meat between nations is extensive and is projected to grow considerably in the short term. The concept and quantification of "virtual water" involved in these trade exchanges has led to new insights of the larger consequences of global transfers in commodities. FSE will host a small international team of scholars, including economists, ecologists, and livestock specialists to scope out this issue and to expand this concept to include energy and nutrients. By documenting trends, developing scenarios for the future, the group is proposing ways to achieve desired outcomes in a way that is sustainable for the life systems needed to fuel industrial livestock systems.

Richard and Rhoda Goldman Conference Room

Conferences
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Improved understanding of the factors that limit crop yields in farmers' fields will play an important role in increasing regional food production while minimizing environmental impacts. However, causes of spatial variability in crop yields are poorly known in many regions because of limited data availability and analysis methods. In this study, we assessed sources of between-field wheat (Triticum aestivum L.) yield variability for two growing seasons in the Yaqui Valley, Mexico. Field surveys conducted in 2001 and 2003 provided data on management practices for 68 and 80 wheat fields throughout the Valley, respectively, while yields on these fields were estimated using concurrent Landsat satellite imagery. Management-yield relationships were analyzed with t tests, linear regression, and regression trees, all of which revealed significant but year-dependent impacts of management on yields. In 2001, an unusually cool year that favored high yields, N fertilizer was the most important source of between-field variability. In 2003, a warmer year with reduced irrigation water allocations, the timing of the first postplanting irrigation was found to be the most important control. Management explained at least 50% of spatial yield variability in both years. Regression tree models, which were able to capture important nonlinearities and interactions, were more appropriate for analyzing yield controls than traditional linear models. The results of this study indicate that adjustments in management can significantly improve wheat production in the Yaqui Valley but that the relevant controls change from year to year.

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Agronomy Journal
Authors
David Lobell
Gregory P. Asner
Rosamond L. Naylor
Walter P. Falcon
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A new maize (Zea mays L.) simulation model, Hybrid-Maize, was developed by combining the strengths of two modeling approaches: the growth and development functions in maize-specific models represented by CERES-Maize, and the mechanistic formulation of photosynthesis and respiration in generic crop models such as INTERCOM and WOFOST. It features temperature-driven maize phenological development, vertical canopy integration of photosynthesis, organ-specific growth respiration, and temperature-sensitive maintenance respiration. The inclusion of gross assimilation, growth respiration and maintenance respiration makes the Hybrid-Maize model potentially more responsive to changes in environmental conditions than models such as CERES-Maize. Hybrid-Maize also requires fewer genotype-specific parameters without sacrificing prediction accuracy. A linear relationship between growing degree-days (GDD) from emergence to silking and GDD from emergence to physiological maturity was used for prediction of day of silking when the former is not available. The total GDD is readily available for most commercial maize hybrids. Preliminary field evaluations at two locations under high-yielding growth conditions indicated close agreement between simulated and measured values for leaf area, dry matter accumulation, final grain and stover yields, and harvest index (HI). Key areas for further model improvement include LAI prediction at high plant density, and biomass partitioning, carbohydrate translocation, and maintenance respiration in response to above-average temperature, especially during reproductive growth. The model has not been evaluated under conditions of water and/or nutrient stress, and efforts are currently in progress to develop and validate water and nitrogen balance components for the Hybrid-Maize model.

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Journal Articles
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Field Crops Research
Authors
Kenneth Cassman
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