On an unusually warm and sunny day in early November, Agricultural Ecologist Kate Tully, Conservation Biologist Keryn Gedan, Plant Science Graduate Student Dani Weissman, and State Dept. Contractor, Chris Blackwood headed down to the Choptank River watershed in Princess Anne County on Maryland's lower eastern shore to explore a unique phenomenon – a changing dynamic in soil nutrient release due to an increasingly saline water gradient at the interface of riparian forest, agricultural lands, and wetlands. As indicators of climate change become more apparent worldwide, one has made a clear impact on the Chesapeake Bay Watershed—sea level rise. In this region in particular, sea level rise not only causes an apparent loss in low-lying farmland due to inundation of fields but also, as researchers are now finding, causes increased phosphorous release from soils as salt water is pushed farther up along a salinity gradient into tributaries that were once fresh water. The salt water reacts in the small pores of soil to cause release of phosphorous that has been stored over many years due to the long history of farming and fertilizer application in the region. Furthermore, the issue is compounded by the cropping up of chicken CAFOs (concentrated animal feed operation) that choke the waters of the Bay with nutrient pollution, dominantly in the form of excess phosphorous (and nitrogen) as well.
The researchers set out to collect a pilot round of soil and water samples on two privately owned farms that contain these farm-marsh-forest boundaries. These farms are the first in potentially many more in the area, that have partnered with University of Maryland to allow concentrated study of the issue on their land. The effects of salt water intrusion were apparent on these lands—some soy fields had begun to resemble marsh as the water crept in and stands of dead Loblolly pine stood stark and barren on the landscape.
The overall goal of this work is to better understand the issue of phosphorous nutrient pollution in the Chesapeake Bay and to comprehensively define the true detriment that large-scale poultry operations have on the region. The results of this project could potentially play a major role in the development of Maryland’s newly launched Phosphorous Management Tool (PMT) and provide support for Best Management Practices (BMPs) in the area.
- Dani Weissman