Farmers use manure and mineral fertiliser to boost soil fertility and increase crop yields. Nitrogen and phosphorous are particularly important. Excess nutrients end up in rivers and lakes, and eventually in the sea. They can result in eutrophication and excessive algal growth in river systems, fjords and coastal waters.
Agriculture and eutrophication
One source of inputs of nutrients from agriculture is the manure and mineral fertiliser applied to arable land and pasture. Nitrogen is relatively easily leached directly from the soil, whereas most phosphorus is bound to soil particles, but can be washed out into river systems and the sea by soil erosion. Other sources of nutrients are leaks and discharges from silos, slurry storage systems and milking parlours.
Runoff of nitrogen and phosphorus from farmland causes the most widespread pollution, and can result in persistent eutrophication problems – excessive algal and other plant growth and oxygen depletion in river systems and coastal waters. Discharges from silos and slurry stores can give rise to similar problems, but generally on a more local scale.
Greatest impacts along the Skagerrak coast
Agricultural runoff causes most pollution along the Skagerrak coast. There is a risk that the waters along much of this stretch of coastline will fail to meet the 2021 deadline for achieving good ecological and chemical status, which is the aim set out in the Water Management Regulations. Municipal waste water is another important source of inputs of nutrients to coastal waters in the Skagerrak.
Overall inputs remaining stable
Intensification of agriculture tends to result in higher releases of nutrients. Crop yields are often increased by applying more fertiliser per unit area, and more livestock are kept on the same area of land, making it necessary to apply more manure per unit area. In both cases, nutrient runoff will increase.
To avoid this, Norway requires arable farmers to plan fertiliser application to avoid a surplus of nutrients, and there are rules limiting the number of livestock that may be kept per unit area of land.
Legislation and grant systems
During the 1980s and 1990s, a system of legislation and grants or low-cost loans was developed to encourage farming practices that would reduce runoff from agricultural land and point discharges from silos and manure storage systems. The system has been amended and adapted over the years.
The legislation includes various regulations under the Pollution Control Act and the Land Act. There are rules on the levelling of steep and hilly farmland to prevent runoff, and regulations on manure and silage effluent that are intended both to reduce point discharges from storage facilities and runoff after application of organic fertilisers.
The regulations relating to production grants set out a number of environmental standards farmers must meet to be entitled to grants, including drawing up an environmental plan and a fertiliser application plan. A farmer who does not comply with the requirements may lose part of the production grant.
There is a system of grants for environmental measures in agriculture to encourage farmers to take steps to reduce erosion and runoff. They can for example apply for grants to establish grassed waterways, construct waste water treatment facilities, re-open culverted streams or establish vegetation zones along rivers and streams.
In addition, each county has drawn up a regional environmental programme for the agricultural sector, describing the main environmental problems in the county and the types of grants available to farmers. Projects and practices that may be eligible for grants include:
- discontinuing autumn tillage, so that there is stubble rather than bare soil during the winter
- planning fertilisation rates to avoid a nutrient surplus
- maintaining or planting vegetation zones between farmland and water bodies
- not fertilising too close to rivers and lakes.
Norway’s international obligations
Norway has undertaken a number of international obligations to limit or reduce nutrient inputs, for example under the EU Water Framework Directive and the North Sea Declarations. The local and central government authorities are coordinating efforts to comply with these obligations.