docCasey Kennedy, USDA-ARS, Pasture Systems and Watershed
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Casey Kennedy, USDA-ARS, Pasture Systems and Watershed
Casey Kennedy, USDA‐ARS, Pasture Systems and Watershed Management Research Unit, East Wareham, MA, [email protected] Nick Alverson, Peter Jaranyama, Hilary Sandler, Carolyn DeMoranville, Frank Caruso, University of Massachusetts Cranberry Station, East Wareham, MA Established Beds (Renovated) Water Source Traditional Beds Water is recycled through the farm New acreage is limited Renovation Squaring off beds New Plantings (Renovated) Recently Renovated 2012, orthophorograph, Google Earth New plantings Pop‐up sprinklers Tile drainage 4‐in‐diameter “French” tiles “Socks” occasionally used 20‐ft horizontal spacing 12‐in depth (from surface to top of drain) Southeastern MA 14,000 acres of cranberry 1/3 of U.S. production Buzzard’s Bay, site of multiple estuarine TMDLs for N Cranberry N loss = 21 lbs acre‐1 year‐1 (Howes and Teal 1995) Two adjacent, identical cranberry beds (4.5 acre) Renovated (2010) 7 length‐wise tile drains (blue) Perimeter ditches (red), no Bed A Bed B center ditch Applied ammonium sulfate fertilizer Low soil pH, 4‐5 1.8‐in rain/snow event (late March 18, 2012) Sampled response over 3 days (March 18‐21) Data collection Flow rate Water sampling Samples analyzed for NH4+ and NO3‐ by colorimetry Bed A Bed B Order‐of‐ magnitude intra‐ bed variation Higher values in bed A Values exhibit rough center‐high pattern samples = ~8 (per tile drain) DIN almost all NH4+ Low (~10%) intra‐tile variation NH4+ Low (~5%) average variation in NH4+ between beds Bed A vs. Bed B 1.7x more drainage in bed A 1.4x more NH4+ mass in bed A Very low NO3‐ in beds A and B Flow drives variation, not concentration Bogs are rich in Fe and other metals Soluble Fe transports into drain Reacts with oxygen to form Fe deposits inside drain Sand and silt clog drain Sand is applied every few years to bog Jet cleaning to remove sand Replace drain 2012, Renovated Bed A Bed B 2005, Pre‐renovation Bed A Bed B Significant variations in tile flows, both within and between beds NH4+ dominant species of N, consistent with fertilizer use and acidic soils Variable N export controlled by flow, invariant N concentrations Controlling factors at two scales: Tile (clogging) Bed (uniformity of peat) Northeast SARE grant Technical support from Cassie Rogers and Kristin Brandt
