Top Soil Sample Depth Needs to be Consistent

Quality soil sampling is critical to correct interpretation of results. We stress to clients this point and write often about collecting and interpreting results.  This has become even more critical as agronomists and growers adopt more precision 4R nutrient management. A few years back AgVise lab completed a demonstration project on the effect of sampling depth for several nutrients. The project had 7 sampling points and 4 depth comparisons at each point. Soil Samples were collected with a Wintex 1000. Twelve cores per point were collected perpendicular to the planted rows of soybeans. The field was a well-drained sandy loam – loam texture, conventional tillage. The data indicated that phosphorus, potassium and zinc levels decreased with depth. Phosphorus & zinc move very little in soil so results were not surprising showing decreasing test levels P with depth. Potash may increase/decrease  with depth depending on subsoil texture. These  results are worth showing growers the importance of quality soil sampling program

Ag Vise concluded: “ The Wintex 1000 has proven to be very consistent when collecting topsoil samples in all soil types”