The science behind cranberry bogs and water pollution
Livestock factory farm operations they are not, but the cranberry bogs in the Buzzards Bay area create quite a bit of nitrogen pollution -- 11 pounds per acre, per year, to be exact.
The measurement, presented at a public workshop hosted by the Buzzards Bay Coalition at Town Hall Tuesday night, is based on two separate studies, each looking at the amount of nitrogen being released into local waterways during harvest time, said Rachel Jakuba, science director of the Buzzards Bay Coalition.
The reason this measurement is so high, Jakuba said, is not due to the nature of the cranberry bogs themselves, but their concentration in the Buzzards Bay area.
“While they have a low relative rate of fertilizer, compared to other agricultural crops, they are closely connected to waterways,” said Jakuba in her portion of the presentation. “It creates a challenge in terms of the water quality of those adjacent waters.”
Though the high release of nitrate, the most damaging form of nitrogen, creates environmental issues on many levels, Jakuba said the biggest concern is of movement of this particular form of nitrogen in surface water, but “the extent of the nitrogen linkage into the groundwater pathway is uncertain.”
In order to reduce this uncertainty, the Buzzards Bay Coalition, UMass Cranberry Station, the Marine Biological Laboratory, and the Cape Cod Cranberry Growers Association formed a partnership to reduce the uncertainty, centering a study around two different bog configurations found in the area.
But despite the partnership’s efforts, the study came away with little in the way of increased clarity regarding nitrogen entering surface water.
“The story is, a lot of variability,” said Chris Neill, director at the Ecosystems Center of the Marine Biological Laboratory. “Bogs are individuals. It’s very difficult to predict exactly whether, for any one bog, any particular form of nitrogen will be higher or lower in the incoming or outgoing water.”
Furthermore, the nitrogen can have many different fates, from simply becoming runoff to being taken into the plants to settling in the bogs themselves. Because of the number of paths nitrogen can take, the partnership only looked at the overall release of nitrogen to the surface water over short time periods.
“We’re going to focus on rain events and floods -- and, again, the bottom line is to get some better numbers to use in the estuary modeling,” said Carolyn DeMoranville, of the UMass Cranberry Station. “The better the numbers, the better the models” -- and the better the models, the better farmers and scientists can tackle the issue.
“The good news is, when we take actions, with management, we can change the situation of our water,” said Jakuba