Scientists are looking at a new approach to farming in the Chesapeake Bay watershed: moving corn and soybeans away from streams and slopes, and replacing them with hay.
“Other than when wastewater treatment plants came into compliance in the Chesapeake Bay watershed, no other practice has been shown to have as large an effect on nitrogen, phosphorus and sediment reductions as simply reallocating existing crop percentages to less risky landscapes,” says Patrick Drohan, assistant professor of pedology at Penn State’s College of Agricultural Sciences. “Even without additional best management practices, just moving row crops such as corn and soybeans away from streams and off steep slopes can make a huge difference.”
But will it catch on with farmers? That remains to seen.
Drohan was one of the lead researchers in a university study — supported by the USDA’s National Institute of Food and Agriculture — that looked at the drainage area of the Conewago Creek watershed, a major tributary of the Chesapeake Bay that drains thousands of acres of farmland in Lancaster and Dauphin counties, which is considered a “hot spot” for nutrient pollution into the bay.
Fei Jiang, a recent soil science Ph.D. graduate and postdoctoral scholar at Penn State, and a lead researcher on the project, used a computer program called the Soil and Water Assessment Tool to model crop growth and losses of total nitrogen, phosphorus and sediment for an eight-year period from 2010 to 2017.
Based on the model results, she developed an algorithm to reallocate crop rotations within existing farmland to reduce total nitrogen, phosphorus and sediment losses based on soil properties while maintaining a similar production area for each rotation.
In the study, hay was reallocated onto landscapes most vulnerable to erosion and nutrient loss, whereas corn-soybean rotations were reallocated onto less vulnerable areas.
In findings published in the journal Agricultural Systems, those crop reallocation simulations resulted in a 15% reduction in total nitrogen losses, a 14% reduction in total phosphorus losses and a 39% reduction in sediment losses at an average annual scale across the watershed.
Jiang said that she hopes the study will open a dialogue with the farm community.
“Originally, I worried that this research will be seen as too theoretical, that farmers will never change what they grow and where they grow it, and the research wouldn’t have any real meaning,” she said. “But given the sharp reductions in pollution that we have shown are possible with this fresh approach, I think people will be convinced to consider giving it a try. This model is actually doable in real life.”
The concept of concentrating production in certain areas and replacing existing crops with alternatives in other areas is new in the U.S., but it has been the subject of considerable experimentation in the European Union, Drohan said.
In countries such as Ireland and the Netherlands, scientists are exploring the potential of a soil-based, land-use framework to achieve economic and environmental targets in agriculturally dominated watersheds.
“The agricultural norm is for farmers to dictate what, when and where to plant based on market demand and the most economically efficient use of land resources for the individual farm enterprise,” Drohan said. “The EU is exploring a different approach in impaired watersheds; however, this framework has not been tried in the United States.”
But the devil will be in the details.
“Future research is needed to understand how this approach affects farm-level factors, because implementation may require some farmers to change the type of crops they grow and how profits are shared,” Drohan said. “Models for how farmers could cooperate exist from several different fisheries around the world — such models are referred to as co-management strategies. Economic payment or incentive strategies, such as the EU’s Common Agricultural Payment scheme, also could be explored to incentivize cooperation as an alternative to the USDA farm bill.”
This story was adapted from a Penn State University press release.