No Drop in the Bucket

Drought simulators study effects of reduced water on crops

Two drought simulators designed to test the effects of water deficiency on crops are now operational at the University of Missouri's Bradford Research and Extension Center east of Columbia.

Robert Sharp and Felix Fritschi in front of the drought simulator

CAFNR plant researchers Robert Sharp and Felix Fritschi in front of one of the drought simulators. The simulator allows the investigators to test soybean and corn varieties to various stages of water stress. When funding allows, a network of drought simulators will be built around Missouri to test crops important to the state's regional economies.

The simulators are part of a $1,558,125 Missouri Life Sciences Research Board grant to study how reduced water availability affects plants and crop productivity, and how new breeds of drought-tolerant plants can boost yields.

Researchers in MU's College of Agriculture, Food and Natural Resources (CAFNR) will use the simulators to vary the amount of water that test plants receive, mimicking everything from short dry spells to persistent and severe drought conditions.

The simulators look like 50-by-100-foot greenhouses on railroad tracks. They move away from test plants when the weather is sunny and cover the plots when rain approaches. By varying the position of the greenhouse, researchers can precisely allow a specified amount of rainfall to fall on the plants. Test plots of the same plants just outside the drought simulators provide a scientific control.

Spanning Missouri's Agriculture

When funding allows, additional simulators will be built at theDelta Research Center, Portageville, in the southeastern part of the state, and at the Horticulture and Agroforestry Research Center, New Franklin.

The locations represent Missouri's varied environments, crop species and soil types. This placement allows researchers to test any agriculturally important crop, forage and turf species grown in Missouri and surrounding states.

"This project will create a network of drought simulators unlike any other in America, providing Missouri scientists with state-of-the-art field facilities to conduct a broad range of drought-related translational research," said Felix Fritschi, an assistant professor in CAFNR's Division of Plant Sciences, who leads the effort. "Our objective is to take laboratory discoveries in basic plant drought research and develop real-world products and practices to improve food security and increase profitability for farmers."

Droughts have a devastating effect on farms. Droughts, the leading cause of crop failure, increase consumer costs, kill livestock, reduce crop yields, and trigger wildfires and dust storms. Drought conditions this growing season are as close as Kansas with severe drought plaguing almost all of Oklahoma and Texas.

Part of a Larger Study of Drought

The simulators are critical in drought research as plant responses to drought are complex and currently difficult to study, said Robert (Bob) Sharp, a co-investigator and professor of plant sciences, and new director of MU's Interdisciplinary Plant Group.

Soybeans in a drought simulation

Robert Sharp's laboratory studies how roots of commercially important plants react to water deprivation. The corn roots on the left received adequate moisture as they grew. The water-stressed plant on the right, while appearing normal above ground, has a mere fraction of a healthy root system. Plants with poor root systems convey reduced nutrients to the plant, resulting in reduced harvests or poor quality food. Sharp's research looks to find plants that can still produce in areas of reduced rainfall.

"The ability to manage the timing, duration and intensity of water-deficit stress under field conditions is essential to examine plant responses to drought," he said. "Thus, the drought simulators will bridge the gap between controlled environment facilities, such as growth chambers and greenhouses, and real conditions encountered in the field."

Other co-investigators in the project are MU plant sciences professors Robert Kallenbach, who studies forages that livestock eat, and Grover Shannon, a soybean expert. The project includes 13 collaborators representing diverse disciplines such as water quality, soil biology, soil physics, plant-insect and plant-disease interactions, and plant breeding and genetics.

The drought simulators will allow researchers to:

  • develop new germplasm with increased drought tolerance
  • discover genetic and physiological mechanisms that underlie drought adaptation in plants
  • evaluate drought-related cultural practices that increase crop productivity
  • study the influence of water deficit stress on soil-plant-insect and soil-plant-pathogen interactions

"MU is becoming a significant center of excellence in drought research," Sharp said. "Several scientists here are expanding on long-standing strengths in drought research on the MU campus."

These researchers, a collaborative team of university and USDA scientists, offer expertise from disciplines in plant physiology, plant breeding, molecular biology, biotechnology, entomology, agronomy, plant pathology, turfgrass science, forestry and soil science. They work with other scientists in Missouri as well as Australia, England, India, Mexico, the Philippines and several countries in Africa.

Of particular note, Sharp said, several members have expertise in the critically important but under-studied area of root biology — including Fritschi and endowed professors of soybean biotechnologyGary Stacey and Henry Nguyen. Nguyen also serves as director of the National Center for Soybean Biotechnology housed at CAFNR. Sharp has been studying the physiology of root growth under drought since he joined MU in 1986. He is collaborating with Monsanto to expand his research on root growth regulation in water-deficient maize.

Another area of emphasis in the project is tissue dehydration tolerance, which is the focus of Mel Oliver, research leader of the USDA Agricultural Research Service's Plant Genetics Research Unit on the MU campus. Oliver is studying the genetic characteristics of desiccation-tolerant plants that could be used to improve dehydration tolerance in important commercial crops.

The drought simulators, Sharp said, will provide a vital facility for these and other MU researchers to translate their basic discoveries of drought to the delivery of more drought-tolerant crops to the doorsteps of American farmers.

Development of more drought-tolerant plants may lead to a sizeable economic impact in the region, Fritschi said.

"The value of Missouri crop and forage production amounted to more than $3.4 billion in 2006," he said. "Increased plant productivity under drought conditions promises to have a significant positive effect on crop and forage yields, which will be magnified by any increased productivity on the $2.9 billion Missouri livestock industry."

Soybeans in the drought simulator

The hot summer weather in Missouri created an unexpected opportunity to study how drought conditions impact soybean growth. Soybeans are Missouri's single most important agricultural product.

The impact of drought not only affects crop production but also strikes associated industries, such as the $40 billion American beef cattle industry, which relies on grain crop production or forage to feed livestock.

Drought, a Global Scourge

Historical data shows that some part of the United States experiences a severe drought every year, Fritschi said. In 72 out of 100 years, from 1896 to 1995, more than 10 percent of the country was affected by severe or extreme drought.

In the Missouri River Basin, one part or another experienced drought in 90 out of the 100 years studied, according to the National Drought Mitigation Center. Costs such as lost farm income are estimated to reach between $200 million and $1.24 billion annually for the Great Plains alone and $6-8 billion for the U.S., reported a 1995 Federal Emergency Management Administration study.

The impact of droughts on a global scale is extensive, Fritschi said. Recurring droughts in the Horn of Africa have created ecological catastrophes, prompting massive food shortages and exacerbating political strife. The Darfur conflict, for example, is fueled by decades of drought, desertification and overpopulation. Yield limitations caused by water-deficit stress are likely to intensify, as most global circulation models call for climate scenarios that will worsen drought in many regions, Fritschi said.

"Furthermore, the growing world population increasingly competes for fresh water resources and will require greater productivity per unit of water and land," Fritschi said. "Increased irrigation using nonrenewable water sources and progressing desertification further underline the urgent need for crop varieties that produce greater yields in water-limited environments."

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