"Nitrogen is an essential nutrient for plant growth. It occurs naturally, but in agricultural systems more nitrogen is commonly added to soils as fertiliser or from livestock waste. Not all the additional nitrogen can be taken up by plants. Some nitrogen will drain (leach) as nitrate from the soil and can enter waterways, potentially causing ecological harm. The amount of nitrate leaching from the soil varies around the country, as a result of different land uses, climates, and soils.
This dataset relates to the ""Geographic pattern of agricultural nitrate leaching"" measure on the Environmental Indicators, Te taiao Aotearoa website. "