Soil Nutrient Studies

Soil nutrient studies have been conducted for agronomic and environmental purposes, in three regions of British Columbia: Hullcar Valley (2016, 2017, and 2018), the Lower Fraser Valley (2012 and 2005), and the Okanagan-Similkameen Valley (2007).

2018 Post-Harvest 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
In the fall of 2018, 39 agricultural fields over or near the Hullcar Aquifer 103 were sampled for a Post-Harvest (Soil) Nitrate Test (PHNT) to compare with 2017 results
Overall, 80% of the total sampled land area (31 fields) had PHNT ratings of ‘Low’ or ‘Medium’
The area-weighted average PHNT value was 25% greater (15 kg N/ha) in 2018 than in 2017, and the median PHNT value of the overall study area was 36% (18 kg N/ha) greater in 2018 than in 2017.
Among the fields sampled, 64% of the nitrate in the top 90 cm of soil was in the 0-30 cm layer on average, at the time of sampling in the fall.
From October 2018 to April 2019, nitrate leached below the 90-cm depth at four of six sites located in the study area for PHNT sampling.
Because post-harvest soil nitrate can leach below the root zone before crop growth resumes the following season in the study area, it is prudent to minimize the amount of post-harvest soil nitrate.

Read the Final Report: