Farming and Fertilizers

In many lake watersheds, agriculture is a significant contributor to the economy, but also a source of nutrient pollution. One reason is that large expanses of bare or freshly tilled soil are prone to erosion. These soils are usually fertilized to enhance the growth of plants. Fertilizer ingredients typically include nitrogen, phosphorus and potassium in varying concentrations. If not carefully stored and applied, these fertilizers can also end up fertilizing our lakes. There are actions you can take to protect lake water quality and increase crop productivity.

  • Plant winter cover crops, if needed, to reduce erosion. The roots stabilize soil during run-off and take up nutrients.
  • Although Montana state Streamside Management Zones (SMZs) are less restrictive, we suggest a 100 ft. buffer best protects lake resources.
  • Maintain or create riparian buffer strips of dense native vegetation at least 100 feet in width along all streams, rivers and lakes.
  • Leave a filter strip of rough grass between the riparian area and crops.
  • Strip crop and contour plow where appropriate to reduce the potential for erosion; these practices break up large expanses of tilled soil and slow the flow of run-off.
  • Minimize use of chemical pesticides and herbicides. Use the least toxic options available to prevent polluting water.
  • Apply proper amounts of fertilizer only during the growing season when it can be used by plants. More is not better!
  • Store and apply commercial fertilizers carefully, according to recommendations.
  • Use Best Management Practices (BMPs). Consult your county extension agent, Conservation District or Natural Resource Conservation Service (NRCS) representative for more information.

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