Recommended soil sampling depth for turfgrass
I’ve been recommending a sampling depth of 10 cm (4 inches) for as long as I can remember. This is for soil nutrient analysis samples collected from turfgrass sites. Sometimes I hear recommendations from others for different depths. This is a reminder that I recommend 10 cm.
My multi-page soil sampling instructions document recommends sampling to a 10 cm (4 inch) depth.
Here’s a one paragraph summary of the sampling instructions (from NotebookLM) with a focus on sampling depth:
This document outlines ATC’s comprehensive soil sampling instructions, primarily for turfgrass areas like golf courses, emphasizing precise methodology to ensure accurate analysis for fertilizer recommendations and monitoring changes over time. A critical aspect of these instructions is the sampling depth, which is generally recommended to be 10 cm (4 inches). This depth is measured from the bottom of the grass and top of the soil or thatch, with grass and thatch intentionally left on the sample for standardized removal by machines at the lab. To analyze nutrient gradients by depth, especially for one out of every five greens, a specific protocol requires dividing the sample into two segments: 0–5 cm (0–2 inches) and 5–10 cm (2–4 inches). This layered sampling helps identify gradients in nutrients, pH, and salinity, and assess the impact of liming or acidifying treatments. The instructions stress the importance of maintaining an exact and consistent sampling depth for year-to-year comparisons to ensure reliable tracking of changes over time, and any non-standard depths must be discussed and clearly labeled.
See these posts for more: