Cranberry Station Phosphorus in Cranberry Nutrient Management Carolyn DeMoranville UMass Cranberry Station
2 Cranberry Station Why is this important?
3 Cranberry Station What have we done? Plot scale work to define P requirement – >0 but <22 kg Field-scale: Enlist growers to reduce well below 22 kg/ha (‘not to exceed’ level) Collect data from their farms – Crop yield – Tissue P – Water quality Use these data to make the case for others to adopt reduced P
4 Cranberry Station Results of surveys conducted in January 2008 (2007 season); January 2009 (2008 season); March 2010 (2009 season). season Management choice N:P P>N36%15% N:P P no more than N34%61% Plan to reduce P use next season36% Reduced P use51%65%
5 Cranberry Station Grower P reduction sites study P rate in kg/ha Site # P applied 2008 P applied 2009 P applied 2010 P applied 2011 P applied
6 Cranberry Station Through 2012 season
7 Cranberry Station Data from
8 Cranberry Station Standard range = 0.1 – 0.2% Tissue P % dry weight Site Avg. kg/ha P
9 Cranberry Station Comparison of TP in flood releases Years of P reduction Site
10 Cranberry Station Harvest flood P concentrations
11 Cranberry Station Winter flood P concentrations Note: scale is 10x less than for harvest flood
12 Cranberry Station Harvest flood 1 acre-foot = 1233 m 3 1 lb = 0.45 kg
13 Cranberry Station Change (kg/ha released) HarvestWinter Year Year Year Year Applied P Pre-2003 = 22 kg/ha Avg. starting 2003 = 11 kg/ha Site 1
14 Cranberry Station Potential impact Site 1 Bog is ~25 ha In 2003, the 2 floods (winter/harvest) contained 117 kg P 8 years later, the floods contained 17 kg P 85% reduction
15 Cranberry Station Next steps Continue and expand monitoring study, recruit growers to use 5 kg/ha P Large grant to begin to install and evaluate methods to remove or minimize P from discharge water – filters, other BMPs
16 Cranberry Station Questions?
Cranberry Bog Total Phosphorus CES/SMAST Field Expt. TP Fertilization (kg/ha/yr) TP incoming (kg/ha/yr) TP leaving (kg/ha/yr) TP export (net) (kg/ha/yr) Bog ID Mean EH PV BEN WS M-K ASH Mean A Flow-through Bog was found to have a higher annual TP loss of 9.9 kg/ha/yr (Howes & Teal 1995)
18 Cranberry Station Yield (Mg/ha) comparison of 4 or 6 years prior to that in Site P (kg/ha/yr) 4 years prior yield 6 years prior yield average 1 8.3* * **? 22.3** 710.3* * ** *