Cranberry Agriculture in the Watershed – understanding N impacts

Rachel W Jakuba, PhDScience Director, Buzzards Bay Coalition

Agriculture in the Landscape

• Agriculture can be a significant contributor to N in coastal waters in SE MA, though wastewater is typically the largest source of N

• Cranberry is the dominant form of agriculture in the Buzzards Bay watershed

• While a low relative rate of fertilizer compared with other crops they are closely connected to waterways

Agriculture in the Landscape

• Agriculture can be a significant contributor to N in coastal waters in SE MA, though wastewater is typically the largest source of N

• Cranberry is the dominant form of agriculture in the Buzzards Bay watershed

• While a low relative rate of fertilizer compared with other crops they are closely connected to waterways

TMDLs will require N reductions

• Many coastal waters around Buzzards Bay are listed as impaired for N on 303(d) ‘Dirty Waters’ list

• MA is required to developed TMDLs for these waters that include plans for reducing N

• Massachusetts Estuaries Project develops a target N threshold that a specific estuary can handle and sources of N to that estuary

Distribution of N sources

• N reductions should be distributed across N sources, so it is important to understand the amount of N contributed from cranberry bogs

Agawam River subwatershed Wankinko River subwatershed

Data from Massachusetts Estuaries Project (Howes et al. 2013)

Challenges of managing N from bogs

• Variable process – N loss from cranberries bogs is influenced by management practices

• Limited quantitative information – only two scientific studies in SE MA on N loss from bogs

• Values from the two studies range by over 3-fold for N loading

Reducing Uncertainty

• Study to look at 2 common bog configurations• Partnership between Coalition, UMass Cranberry

Experiment Station, MBL, Town of Carver, Cape Cod Cranberry Growers’ Association

• Funded by DEP and BBNEPLong Tail Pathway Closed Loop

Basic study design

• Look at 3 examples of each bog type (i.e., 6 bogs total)

• Collect data for ~14 months• Measure N & P

concentrations in surface and groundwater before and after it reaches the bog

• Use water flow estimations to calculate the mass of nitrogen leaving the bogs

Basic study design

• Look at 3 examples of each bog type (i.e., 6 bogs total)

• Collect data for ~14 months• Measure N & P

concentrations in surface and groundwater before and after it reaches the bog

• Use water flow estimations to calculate the mass of nitrogen leaving the bogs

Study thus far

• QAPP outlining protocols approved by MA DEP and EPA

• Sampling began in late September with samples collected during the harvest floods

• Analysis of samples is underway• Groundwater appears to be a significant sink

of N

Questions?