For monitoring surface acidity in no-till fields, to what depth should the second sample be taken?

When monitoring surface acidity in no-till fields, taking the second sample at a depth of 2 inches is essential for obtaining an accurate representation of the soil’s pH levels in the top layer. The top 2 inches of soil is critical because it can influence seed germination, plant growth, and microbial activity in the rhizosphere, particularly in no-till systems where soil disturbance is minimized.

In no-till practices, the upper layers of soil are more subject to the effects of surface application of fertilizers, lime, and organic matter, which can significantly alter pH in this zone. Thus, sampling at this depth allows for evaluation of how amendments and other factors are affecting soil acidity where they will have the most immediate impact on crops. Collecting samples deeper than this may lead to results that do not accurately reflect the surface conditions benefiting plant growth and soil health.