Do Farming Practices Affect Water Quality?

Wetlands offer a natural way of filtering and purifying nutrient-rich water.

By Darrell Corkal, Prairie Farm Rehabilitation Administration, Saskatoon

• agriculture is the greatest nonpoint source pollution problem in the United States
• 50 to 70% of the assessed surface waters in the U.S. have been contaminated by agriculture through cropland soil erosion, over-grazing, and pesticide and fertilizer application
• fertilizer and manure can create water quality problems such as excessive nitrate and phosphorus levels, and in the case of manure, pathogenic microorganisms can contaminate water supplies
• water borne infections are estimated to affect 940,000 people and cause about 900 deaths each year in the U.S Are these only concerns in the United States? Not likely. A study on surface water quality taking place under the Green Plan in Saskatchewan has been focusing research primarily on small surface water supplies. While the majority of sites studied would not necessarily pose problems for nitrate contamination with drinking water, phosphorus levels are high enough in most to cause eutrophication (excessive algae growth and insufficient oxygen in water).
  These facts may lead producers to question whether their water is safe for human or animal consumption. But they must also ask themselves what they might be doing to degrade their water quality, and what they can do to improve it.
  So what can a producer do? Is farming technology doomed to degrade water quality in an effort to keep production competitive? Certainly not. A range of practical alternatives referred to as "Best Management Practices" are available to producers. They include:
• constructing vegetated buffer zones for all riparian areas adjacent to cropland or grazing land; do not farm adjacent to any water source whether it be a river, lake or dugout
• ensuring sensitive groundwater aquifers are protected and ensuring that all wells are operated and maintained so no farming practice can degrade the groundwater
• practising no-till farming
• ensuring nutrient management is accurate; over-application of fertilizers is costly and will certainly degrade surface and groundwater quality
• where manure is used as a fertilizer, following safe application practices, ensuring sensitive land does not receive applications (e.g. where shallow groundwater supplies will be contaminated) and ensuring the timing of the application does not coincide with a surface runoff event such as spring snowmelt
• preserving or even constructing wetlands; they are a natural way of filtering and purifying nutrient-rich water
• applying chemicals at correct dosages and only when necessary, and managing chemicals to ensure no spills or wastage occurs
• considering contour farming or strip farming
• reducing erosion with appropriate crop rotations, shelterbelts, grassed runways, diversions, sediment basins, etc.
• managing pasture land by not over-grazing
• practising livestock exclusion from water and bringing water to the livestock
• managing all farm waste (human, animal, and hazardous chemicals including pesticides, fuels, and cleaning agents)

Any Best Management Practices that producers are able to incorporate into farming operations will result in improved water supplies. However, water quality problems will not simply vanish. There is no magic pill or quick fix for an ecosystem, and natural eutrophication is inevitable throughout the semi-arid and arid Prairies. However, with improved agricultural practices, the land and water resource will be able to sustain and even develop Prairie agriculture and industry. Improved water quality will also offer improved quality of life.