Soil sample composition over time

Question

I tested my garden soil (NPK for guidance in applying fertilizers) but now I'm questioning my results.

I collected the soil as per the instructions and left it to dry in a bucket. Once dry, I left it for several months in a garage, exposed to open air.

Would this change the amount of phosphorus or nitrogen detected by a soil test? These two components came back as depleted.

If you followed some technical instructions, then that's how it is. Care to share the origin and content of the instructions ? — Rohit Gupta, Feb 27 '23 at 01:48
The instructions did not specify if a sample needed to be processed within a certain window — nuggethead, Feb 27 '23 at 02:46

score 1 · Answer 1 · answered Feb 27 '23 at 16:45

Unlikely, unless you had just applied a volatile form of nitrogen fertilizer (inclusive of tilling in legumes, evidently)

Phosphorous is essentially non-volatile, so drying in a bucket sould not remove any (it's lost by leaching, erosion, and plant uptake)

1 Answers1