Land use and water quality

The issue of land use and land-use intensity has long been linked to water quality globally. Changing land use in New Zealand, especially in pastoral systems, over the last 50 years have caused nitrate-nitrogen (N) concentrations to increase within streams, rivers, lakes and groundwaters (Julian et al. 2017). However, good management practices have also either offset or decreased the concentrations of some other contaminants like phosphorus (P) and sediment (Snelder 2018; McDowell et al. 2019). Nevertheless, the current state of water quality is perceived to be poor by the New Zealand public (Hughey et al. 2019). As a result, policy to improve water quality is becoming more stringent. In this special issue are several papers that address a range of topics related to land use and water quality. I have arranged these topics into two broad categories: (1) Processes that characterise the loss and transport of water quality contaminants from land to water and within aquatic systems, and (2) Assessment of what has and could be done within primary production systems to reduce losses from land to water