A recent study published in the Journal of Soil and Water Conservation ("Upper Susquehanna watershed and New York State improvements in nitrogen and phosphorus mass balances of dairy farms.") suggests that, collectively, dairy farms in New York and in the New York portion of the Upper Susquehanna Watershed (USW) have significantly reduced N and P use over the past ten years without sacrificing productivity.
In the study, whole-farm nutrient mass balances (NMBs) completed by 189 New York dairy farms, including 91 located in the USW were analyzed. The trend study shows that, in 2004, the USW farms averaged an N balance of 77 lbs/acre and a P balance of 9 lbs/acre. In 2013, that average was 46 lbs N/acre and 5 lbs P/acre. Balances for the entire state were slightly higher but showed similar trends. If all dairy farms in the state and the USW followed similar trends, this suggests reductions in total N and P imports of 26 - 30% for N and about 20% for P, comparing 2004 versus 2013. Expressed in lbs of nutrients, this amounts to 9.5 million lbs of N and 0.9 million lbs of P when comparing 2013 versus 2004 for the Upper Susquehanna Watershed, and 66 million lbs of N and 6.6 million lbs of P for the state.
A pound not imported is a pound less that could be lost to the environment so the reductions shown in the article reflect a reduced risk of N and P losses to the environment, as well as greatly improved nutrient efficiency.
To read more, see: What’s Cropping Up?: “Greatly Improved Nutrient Efficiency Demonstrates New York Dairy Farmers’ Environmental Stewardship.”