Soil Productivity Vital for Economical Crop Production

By Farooq Baloch

Increasing food prices have been a concern not only in America but also in the rest of the world. However, the research at the University of Nebraska-Lincoln helps farmers to reduce the cost of food with minimum impact on the environment.

According to UNL Professor of Agronomy, Richard Ferguson, increasing the efficiency of nitrogen fertilizer helps maintain soil and water quality.

Improved soil and water quality, he said, will increase crop productivity, reduce the costs of food and prevent soils from environmental degradation.

"Soils in Nebraska are naturally quite productive compared with much of the rest of the world," Ferguson said. "Nebraska today has the largest area of irrigated production in the United States."

He said these resources in Nebraska provide great capacity for crop and livestock production. "It's a resource that we want to be able to maintain or build."

Ferguson, who specializes in soil science in the Department of Agronomy and Horticulture, said if farmers can produce more with the same inputs, it will help protect their incomes.

He further said while increasing efficiency, farmers have to minimize environmental impacts, and at the same time maintain the soils for production in the future.

Ferguson's research deals with a broad scope of soil science. His specific research interests include soil fertility and crop nutrition - within that, his primary areas of research and extension relate to understanding the variability of the soil as a resource and management techniques, a process called site-specific crop management, or precision agriculture. In precision agriculture or precision farming, Ferguson said the inputs such as fertilizers, seeds or water can be managed differently in different areas of the crop field to best utilize the soil resources.

He said it is important to sustain and even improve the quality of soil, which has been degraded by agricultural use over the years.

"Soil quality or productivity is foundational to our existence as humans," Ferguson said. "Our economies, our livelihoods and our existence are based primarily on plants as a food source and in many cases, plants may be fed to animals, which also become a food source for humans."

The professor said a lot of basic human life relates back to soil quality and its ability to serve as a resource to produce food. "Our primary interest is in maintaining that as a resource for human health," he said.

Dr. Richard Ferguson

Environmental and Economic Benefits
Ferguson said improving the efficiency of nitrogen fertilizer helps protect the soil from environmental degradation caused by leaching or gaseous loss of nitrogen.

Improving the efficiency of nitrogen fertilizer also can help protect groundwater from nitrate contamination.Infants and nursing mothers are particularly susceptible to potential health hazards caused by high levels of nitrogen in groundwater. He said young infants don't have the enzyme that helps protect against nitrate issues, which affect a body's ability to carry oxygen.

Ferguson said the use of nitrogen fertilizer to some degree is a global warming contributor because of the nitrous oxide emissions; thus, minimizing nitrogen use by improving its efficiency can reduce nitrous oxide emissions.

"We are working on ways to improve efficiency of nitrogen fertilizer use, particularly through spatial tools," he said.

He said his research team is using optical sensors, also called crop canopy sensors, to detect the nitrogen status of a crop and adjusting the fertilizer rate based on sensor output.

Ferguson said food in the U.S. is relatively inexpensive, but its prices are going to increase because of global demand. "So our goals are to try and be as efficient as we can, not just for consumers in Nebraska but also for those in the world."

Ferguson said nitrogen fertilizer is one of the largest expenses that farmers
have in producing a crop. Improved efficiency can reduce farmers' expenses as well as the cost of production, which will ultimately reduce the cost of food.

"Our main goals are continued improvements in productivity and efficiency," he said, "and fertilizer inputs to maintain or improve profitability for the farmer."

Doing so, Ferguson said, will benefit the economy of the state significantly. "We have seen that farmers have done an excellent job, over the last 20 years plus, of steadily improving how efficiently they use fertilizers," Ferguson said.

He said the yields farmers produce every year are higher with the same or less fertilizer input.

"The amount of fertilizer farmers apply to raise a bushel of corn, for example, is about half now what would have been 20 years ago," Ferguson said, "and that's through collective efforts of many scientists. That's an area that we've really been able to show significant progress in."

Soils in Nebraska: a Comparative Advantage
"In Nebraska, at least we have soils that are fairly young meaning that they have not been heavily weathered through climate," he said, adding that in the southern and eastern U.S., soils are more heavily weathered and their natural nutrients have been more depleted.

"Soils in Nebraska need very little additional inputs for optimal crop production," Ferguson said, "but as you go farther elsewhere in the U.S., soils may need more inputs to maintain high productivity."

According to Ferguson, agriculture research is not well-funded compared to some other types of research.

"Funding is always an issue. There are always things that we'd like to do more gracefully or more broadly that we don't have resources to do," he said. Ferguson said nitrates in groundwater is an issue. He said Nebraska farmers are doing better than they used to, but they still have areas of the state with high-nitrate groundwater.

In those areas, communities have to either treat the water or drill new wells and that can be quite expensive. "My research is trying to mitigate them out of fertilizer that moves to ground water. We can protect against those costs."

Soil carbon, which has been reduced by tillage, is a central issue in Nebraska and is also becoming more of a global issue since it has ramifications for climate change and productivity of soils.

Ferguson said many of the soils have about half of that soil carbon now than what originally was present in native prairie.

"So one aspect of our research is how to maintain or build soil carbon through reduced tillage or no tillage through inputs of fertilizers," he said, "so nitrogen is key in that process to allow us to build soil carbon."

Global Similarities
He said there are soils and climates worldwide that are similar to what one would find in Nebraska and therefore, the research conducted in Nebraska is very translatable to those climates and those soils in other parts of the world.

Ferguson said the goal of the research is to maintain soil productivity, which comes back to playing their part of doubling the food production by 2050.