Another P problem

Another P problem
NIWA researchers have found a disturbing national trend of increasing phosphorus (P) levels in rivers draining farmland.
The finding mirrors earlier work on increasing nitrogen levels, and is based on data from NIWA’s National River Water Quality Network for the years 1989 to 2003. We found a strong association between the size of the increases in dissolved phosphorus and the amount of pastoral land use in the river catchment. Increasing levels of both nitrogen and phosphorus may lead to more nuisance algal blooms in rural waterways.

28 February 2007

Another P problem

NIWA researchers have found a disturbing national trend of increasing phosphorus (P) levels in rivers draining farmland.

The finding mirrors earlier work on increasing nitrogen levels, and is based on data from NIWA’s National River Water Quality Network for the years 1989 to 2003. We found a strong association between the size of the increases in dissolved phosphorus and the amount of pastoral land use in the river catchment. Increasing levels of both nitrogen and phosphorus may lead to more nuisance algal blooms in rural waterways. These results suggest that improvements in nutrient budgeting and riparian management are required to reduce losses of nutrients from pastures into waterways.

This research was funded by the Foundation for Research, Science & Technology.

Last year, NIWA prepared a major report on river water quality for the Ministry for the Environment: http://mfe.govt.nz/publications/ser/state-trends-river-water-feb05/index.html

More about nutrient budgeting: www.ew.govt.nz/enviroinfo/land/management/nutrients/index.htm

No.12 2005