The environment is sensitive to the injudicious use of fertilisers. The Resource Management Act, which promotes the sustainable management of natural and physical resources, says (section 17) that every person has a duty to avoid, remedy or mitigate any adverse effect on the environment arising from any activity. To ensure that fertilisers are used safely and effectively within New Zealand farming systems, the Fertiliser Code of Practice has been developed to provide guidelines for sustainable fertiliser use as provided for in the RMA. The New Zealand Dairy Industry has also introduced an on-farm Quality Assurance programme called “Market Focussed” to assist dairy farmers to adopt management practices that help the industry to comply with environmental standards set by the market or regulatory authorities. Both documents seek to ensure that fertilisers are used to optimise pasture production whilst avoiding unnecessary or excessive leaching or overland flow from the soil.