Land Treatment of Phosphorus, the Third Dimension
Author: Daryl Irvine
Source: Pattle Delamore Partners Ltd
Land treatment systems have traditionally been sized and managed based on hydraulic and nitrogen, loading and treatment capacity, however, phosphorus is becoming a relevant nutrient, more frequently requiring considered management within land treatment systems.
With the now common use of models such as OVERSEER®, providing model estimates of phosphorus migration to surface water from land treatment systems, the risk that phosphorus presents on surface water systems is quantifiable and can no longer hide behind assumptions of continued adsorption onto soils.
This paper provides a summary of the mechanisms of phosphorus behaviour in soils, what the respective soil tests indicate, phosphorus migration pathways, and potential mitigation tools that are available for land treatment systems to minimise phosphorus migration to surface water. In addition this paper also explores potential methods for identifying sustainable phosphorus loading rates for respective land uses, considering factors in addition to plant phosphorus uptake.