Fertiliser use on farms

Key Points | Report Card | Technical Information | Data

On this page:

• What is happening in our region
  
• Why fertiliser use on farms is important
  
• What Environment Waikato is doing
  
• What you can do to help
  
• More information
  

What is happening in our region

The Waikato Region contains some of the most productive land in New Zealand and the world.

Over a recent five year period (1997/98 to 2002/03), yearly dairy farm nitrogen fertiliser use increased 84 percent, from 68 kilograms of nitrogren per hectare to 125 kilograms per hectare. Yearly nitrogen fertiliser use on sheep/beef farms increased from six to nine kilograms per hectare.

Over the same five year period, nitrogen leaching increased by 25 percent for both dairy (previously 32 kg N/ha/yr, now 40 kg N/ha/yr) and sheep/beef farms (previously 8 kg N/ha/yr, now 10 kg N/ha/yr).

On average, phosphorus fertility on dairy farms is near the maximum for a high producing farm. Many soil samples (44 to 50 percent) from volcanic and sedimentary soils show excessive phosphorus fertility. About 10 percent of samples from sheep/beef farms have excess phosphorus fertility. Yearly phosphorus runoff is 1.7 and 2.1 kilograms of phosphorus per hectare for sheep/beef and dairy farms, respectively.

• The data were collected for the periods 1997/98 and 2002/2003. Phosphorus (Olsen P) values for volcanic and sedimentary soils were collected for the period 1988 to 2001. View the graphs' data.
  

Why fertiliser use on farms is important

Losses of the nutrients nitrogen (mainly via leaching) and phosphorus (mainly via runoff) to water bodies contribute to algal growth, which leads to a decline in water quality. Nitrogen may also contaminate groundwater, making it unsuitable for drinking.

Nutrient losses generally rise with increasing fertiliser use or excessive soil fertility. While soil nutrient levels should be maintained to ensure sustainable pastoral farming, excessive nutrient inputs should be avoided. Conversely, adding too little nutrient to the soil will result in exhausted, unproductive soils.

Monitoring of nutrient inputs (such as fertiliser addition) and losses allows us to determine the optimum soil nutrient requirements and assess the risks to water quality.

What Environment Waikato is doing

• Environment Waikato tracks changes in fertiliser use and nutrient loss to update this indicator and to assist with policy making and resource consent decisions. Find out more about the rules for fertiliser use in our Regional Plan.
  
• We are working to reduce phosphorus content in runoff, through soil conservation programmes and the Clean Streams project.
  
• We support voluntary guidelines and codes of practice such as the NZ Fertiliser Manufacturer’s Research Association Code of Practice for Nutrient Management.
  
• We provide staff time and expertise to support landcare groups in the region that are involved in riparian management such as planting and fencing.
  
• We provide environmental information including reports on practical land management guidelines.
  
• We encourage the use of nutrient budgeting.
  
• We regularly monitor levels of nitrate and phosphate in groundwater and surface water. These are indicators of the amount of nutrient lost from the land.

What you can do to help

• Get your fertiliser representative or farm advisor to do a farm nutrient budget so as to avoid applying unnecessary fertiliser and thus save money.
  
• Ask your farm advisor about modern farming practices that can be used to reduce nutrient leaching and nutrient runoff. Modern practices include a nutrient budget, a farm nutrient management plan, strategic grazing, nitrification inhibitors, altering the feed composition and alternative fertiliser products.
  
• Waterway margins form an important barrier between land and water. Fence off and protect drains, wetlands and other wet areas. These can act as buffer zones, remove nitrogen from the water before it reaches streams. Fence near streams and rivers to allow a thick grass sward to develop on the stream edge. The sward will help filter out dirty runoff containing nutrients.
  
• Avoid pugging in paddocks adjacent to streams.

More information

• Code of Practice for Nutrient Management
  
• Overseer Nutrient Budget

Find out more about:

• managing farm nutrients
  
• applying effluent to the land
  
• how nitrogen use affects Lake Taupo.

More detail on this indicator, including how and where Environment Waikato collects this information, is available in the Technical Information page.

• Nitrogen Losses from Land
  
• Sources of Nutrients in Rivers
  
• Land Use
  
• River water quality
  
• Lake Taupo's water quality
  
• Nitrate in Groundwater