Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 1: Summary and Recommendations

 
 
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 Introduction | Conclusions | Recommendations | Other project volumes

Introduction

Environmental sustainability is essential for the survival, growth and prosperity of the agricultural industry in Alberta. It is defined as maintaining a balance among economic viability and environmental assets (soil, water, air, and biodiversity) such that ecosystem integrity is upheld for future generations. In order for the agricultural industry to best plan for the future, an understanding of the current state of environment and the impacts of agriculture on the environment are required.

Alberta Agriculture and Rural Development has led several long-term projects to assess soil and surface water quality and the impact of agriculture on these natural resources. The Assessment of Environmental Sustainability in Alberta’s Agricultural Watersheds (AESAAW) project was initiated in 2007 to consolidate project information from three provincial initiatives:
  • Alberta Environmentally Sustainable Agriculture (AESA) Water Quality Monitoring Project
  • AESA Soil Quality Monitoring Project
  • Alberta Soil Phosphorus Limits Project
These initiatives monitored and assessed soil and water quality within representative agricultural areas of Alberta. The AESAAW project summarizes the results from these projects to:
    i) Provide a provincial synopsis on the current impacts of agriculture on environmental sustainability in Alberta with a focus on soil and water quality
    ii) Provide recommendations that address the future sustainability of agricultural watersheds in Alberta
    iii) Identify information gaps in current research and future directions
The AESA Soil and Water Quality Monitoring Projects were developed to address recommendations from the Canada-Alberta Environmentally Sustainable Agriculture (CAESA) Agreement. Under the CAESA Agreement, scientific and producer-led studies were undertaken to broadly assess the impact of agriculture on the environment. It included the first comprehensive assessment of the industry’s impact on water quality in Alberta.

CAESA recognized that management of key nutrients, such as phosphorus, within the agricultural industry was required in order to improve sustainability of Alberta’s agricultural watersheds. Recognizing that little scientific information was available, the Alberta Soil Phosphorus Limits Project was initiated in 1999. The project determined soil phosphorus limits for agricultural lands that would protect surface water quality in Alberta from degrading.

Conclusions
    1. A comprehensive soil and surface water quality database is now available for Alberta’s agricultural areas.
    • Data were collected through the Alberta Environmentally Sustainable Agriculture (AESA) soil (1998 to 2006) and water quality (1997 to 2006) projects for representative agricultural regions of Alberta.
    • Soil quality data from 42 sites were representative of cropland managed under progressive practices in Alberta.
    • Water quality data from 23 small watersheds represented the varying degrees of agricultural intensity (low, moderate, and high) and agricultural management (dryland and irrigated).

    2. Provincial scale soil and surface water quality have remained relatively constant during the last decade.
    • Most key measures of soil quality were unchanged during the monitoring period, with the exception of agronomic soil test phosphorus (STP) levels and bulk density. Although the STP levels slightly increased, levels remained below the agronomic threshold of 120 kilograms/hectare in the top 15 cm of soil.
    • Soil bulk density tended to decrease with time as practices improved to include more reduced tillage and use of forages in rotation.
    • Overall, nitrogen and phosphorus concentrations in surface water did not change in agricultural watersheds during the monitoring period.

    3. A field-scale relationship exists between phosphorus concentrations in the soil and surface water; however, a relationship between nitrogen in the soil and surface water was not apparent.
    • Non-manured benchmark AESA soils averaged less than 70 kilograms/hectare of STP. Soils with long histories of heavy manure application could have STP values in excess of 1000kilograms/hectare.
    • The risk of phosphorus loss to runoff water increased with increasing STP concentrations.
    • Soils that were amended with manure and had STP concentrations above the agronomic threshold lost more phosphorus to surface waters.

    4. Surface water quality guidelines for nutrients were generally exceeded in Alberta’s agricultural watersheds.
    • Water quality guidelines were exceeded more frequently as agricultural intensity increased.
    • In the high agricultural intensity watersheds, water quality guidelines for total phosphorus (TP) and total nitrogen (TN) were most often exceeded. Total phosphorus met the protection of aquatic life guideline <12% of the time and TN met the guideline <16%.
    • Low agricultural intensity watersheds met TP and TN guidelines <59 and <85% of the time, respectively.

    5. Surface water quality will deteriorate if agricultural intensity increases using current management practices.
    • The AESA data support previous studies that show as agricultural intensity increases, water quality decreases.
    • Nutrient and pesticide concentrations and detection frequencies increase with agricultural intensity; however, bacteria data do not follow the same trend with agricultural intensity.
    • The presence of fecal bacteria in agricultural streams appears to be more closely related to ecoregion characteristics, which reflect differences in livestock management and wildlife communities.

    6. Low level concentrations of a variety of pesticides were commonly found in agricultural watersheds.
    • Thirty-seven of 68 pesticides analyzed in the water quality monitoring program were detected at least once from 1999 through 2006.
    • Most of the pesticides detected were herbicides. The eight most common herbicides detected were 2,4-D, MCPA, dicamba, clopyralid, triclopyr, MCPP, picloram, and imazamethabenz-methyl.
    • The types of herbicides detected in each watershed tended to be associated with agricultural intensity and management.

    7. There are concerns about possible cumulative impacts of the various herbicides found in the water.
    • Of these eight most commonly detected herbicides, only four have water quality guidelines. The four that do not have guidelines are clopyralid, triclopyr, MCPP, and imazamethabenz-methyl.
    • Only 30 of the 68 pesticides that were analysed have water quality guidelines.
    • Current guidelines do not account for possible synergistic effects of herbicides with the same mode of action or possible chemical interactions.

    8. The Alberta derived soil-runoff phosphorus relationships were able to predict TP and TDP concentrations at a sub-watershed scale.
    • The Haynes Creek M1 sub-basin watershed soilrunoff data suggested that about 80% of TP and 50% of TDP measured in the stream can be directly related to STP values from the top 15 cm soil depth.
    • Detailed data sets are required to assess the relationships for larger watersheds.

    9. Critical source areas, or areas with high nutrient levels and risk of runoff, are likely responsible for the majority of phosphorus losses from agricultural land.
    • A modeling study showed that while the critical source areas with high STP levels represented approximately 35 to 45% of the watershed, these areas accounted for 64 to 70% of the TP export.
    • Other areas within the watershed will also contribute over time and with multiple runoff events.
Recommendations
    1. Alberta’s agriculture industry must focus efforts on reducing nutrient loads from agricultural lands into watersheds through improved on-farm andcritical source area management.
    • Continue to develop science-based, practical, and economical mitigation solutions (Beneficial Management Practices) that producers can implement to reduce nutrient loading to surface waters.
    • Implement appropriate on-farm and critical source area management practices in Alberta’s watersheds through producer-led watershed stewardship groups.
    2. Develop surface water quality targets for nutrients in agricultural watersheds that are achievable, protective, and allow for sustainability in the longterm given best agri-environmental management practices.
    • Current water quality guidelines may restrict agricultural production, particularly livestock development, even with current technology and best management practices.
    • Establish nitrogen and phosphorus water quality targets for agricultural streams based on ambient nutrient concentrations in watersheds with minimal human disturbance; protection of water quality for aquatic ecosystem health; and, livestock development with the best environmentally sustainable management practices.
    3. Assess the impacts of low levels of multiple pesticide residues in surface waters on aquatic ecosystem health.
    • Low levels of pesticides commonly co-occur in Alberta’s surface waters.
    • There are increasing concerns about the cumulative impact of pesticides on the health of aquatic ecosystems.
    • Without water quality guidelines, it is difficult to determine whether pesticides pose a threat to aquatic ecosystems, human drinking water, irrigated crops, or agricultural livestock. -- support the development of surface water quality guidelines by the Canadian Council of Ministers of the Environment (CCME) for the four most frequently detected pesticides in Alberta surface waters (imazamethabenzmethyl, MCPP, clopyralid, and triclopyr).
    • Support implementation and further development of Alberta Environment’s Pesticide Risk Assessment tool to evaluate the potential impacts of multiple pesticides on aquatic ecosystem health.
Other Project Volumes

Volume 2: AESA Soil Quality Monitoring Project

This volume summarizes the long-term soil quality data collected under AESA. The AESA Soil Quality Monitoring Project was implemented to assess the state of soil quality throughout Alberta and the risk of change in soil quality resulting from farm management practices. Forty-two, non-manured soil benchmark
sites were selected to assess trends in soil quality in seven ecoregions. The sites represented a range of agricultural practices.

Volume 3: AESA Water Quality Monitoring Project

This report summarizes the long-term water quality data collected under AESA and CAESA. The AESA Water Quality Monitoring Project was designed to track changes in water quality in agricultural streams in Alberta with time to examine the relationship between agricultural intensity and stream water quality. The study focused on monitoring water quality in 23 small agricultural watersheds with different levels of farming intensity (low, moderate, high, and irrigation) across a representative range of climatic conditions.

Volume 4: Nitrogen Loss in Surface Runoff

The primary focus of the Soil Phosphorus Limits Project was to determine environmental soil phosphorus limits for agricultural lands in Alberta that would protect surface water quality; however, soil and water nitrogen data were also collected. As part of the AESAAW initiative, the nitrogen data from 8 provincial microwatersheds were summarized in 2008 to determine the relationship between soil nitrogen and nitrogen in runoff from agricultural land.

Volume 5: Predicting Phosphorus Losses from Agricultural Areas

Watershed modeling is recognized as a valuable tool for predicting the effect of land management on surface water quality and can be used to make recommendations that may reduce agriculture’s impact on water quality. Modeling is dependent upon field data such as that collected in the AESA and Soil Phosphorus Limits projects. This volume summarizes the AESAAW modeling project. The objectives were to evaluate the performance of the Alberta derived soil-runoff phosphorus relationships at the watershed scale and develop phosphorus export risk categories for selected AESA watersheds. This information can be used to develop watershed scale phosphorus export risk maps, which allows agricultural producers and planners to determine the optimum locations for intensive livestock facilities.

Map showing watersheds and sampling sites
Click on map for larger view

 
 
 
 

Other Documents in the Series

 
  Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 1: Summary and Recommendations - Current Document
Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 2: AESA Soil Quality Monitoring Project
Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 3: AESA Water Quality Monitoring Project
Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 4: Nitrogen Loss in Surface Runoff
Assessment of Environmental Sustainability in Alberta's Agricultural Watersheds - Volume 5: Predicting Phosphorus Losses from Agricultural Areas
 
 
 
 
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This information published to the web on April 29, 2009.
Last Reviewed/Revised on March 31, 2014.