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Soil nutrient studies

Last updated on August 31, 2026

Soil nutrient studies have been conducted for agronomic and environmental purposes, in several regions of British Columbia. The studies provide snapshots in time of soil fertility status of phosphorus and potassium. The studies also provide information to interpret post-harvest soil nitrate and soil test phosphorus as indicators of risk for loss of nitrate or phosphorus from agricultural soils.

What's new

A Decade of Post-Harvest Nitrate Monitoring in the Hullcar Valley

This report reviews a decade (2016-2025) of post-harvest soil nitrate monitoring in 40 – 50 agricultural fields within the Hullcar Valley.

Highlights:

  • Annual crops generally had greater residual nitrate compared to the perennial forage crops in the 0-90 cm profile
  • Mean post-harvest soil nitrate throughout the 2016-2025 monitoring period ranged from 35-57 kg NO3-N ha-1 which is acceptable for a properly fertilized crop. The mean post-harvest soil nitrate is below the provincial 100 kg NO3-N ha-1 threshold for required Nutrient Management Plans (NMPs)
  • Over the study period, only 4.6% of the 40-50 fields had post-harvest nitrate levels exceeding 100 kg NO3-N ha-1 in the top 30 cm. Notably, no field exceeded 100 kg NO3-N ha-1 for more than one year. Furthermore, approximately two-thirds of all soil nitrate was consistently found in the top 30 cm
  • Mean soil nitrate at the 60-90 cm depth has remained lower than initially measured in 2016 when monitoring began and has remained consistently below 5 ppm
  • A benchmark study from fall 2016 to spring 2020 showed some downward redistribution of soil nitrate, mainly from the 0-30 cm to 30-60 cm soil layers during the non-growing season. Overall, changes in total profile nitrate were not statistically significant, indicating that the dominant pattern of nitrate movement was often redistribution within the profile rather than a measurable net loss from the entire 0-90 cm soil profile

2024 Soil Nitrate Study:  Hullcar Valley

Highlights

  • Monitoring the year-to-year trends of post-harvest soil nitrate is useful for improving the efficiency of nitrogen use
  • Post-harvest soil sampling after the 2024 growing season was completed on 50 fields lying above Aquifer 103 in the Hullcar Valley of the North Okanagan to a 90-cm depth
  • The area-weighted average soil nitrate value for the entire sampling area for 2024 was similar to 2023 (76 and 78 kg NO3-N ha-1, respectively), as was the median soil nitrate value (62 and 62 kg NO3-N ha-1 respectively)
  • Among the fields sampled, 62% of the nitrate in the sampled 90 cm of soil was found in the 0-30 cm layer on average, while 21% and 16% was found in the 30-60 and 60-90 cm layers, respectively.

Read the final report:

Past reports:

Raw data:

Soil Nutrient Study 2020

The Soil Nutrient Study 2020 (PDF, 1 MB) was conducted in selected areas of the Okanagan-Similkameen Valley, Vancouver Island and the Thompson River Regional District (TNRD)

Previous Studies

2012 Fraser Valley Soil Nutrient Survey (PDF, 1.2 MB)

2012 Fraser Valley Soil Nutrient Survey - results by crop group:

Contact information

AgriService BC

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E-mail: AgriServiceBC@gov.bc.ca