Is 2.5-acre grid sampling an adequate approach?
The adjacent photo illustrates a common problem with creating a prescription map for applying variable rate lime using 2.5-acre grid sampling. In this case, 330- by 330-ft (2.5-acre) grid cells are superimposed on a bare-soil infrared image. The field has terraces which appear as dark lines so it is evident that there is a significant slope in this field. The white areas are eroded Nora soil, with alkaline (high pH) subsoil near the surface. The darker areas are less eroded, and more acid in the upper horizon. If a few cores are taken near the center of a grid cell (red dot), the sample pH is likely to be greater than 7 since it is within the white area. As a result, the entire grid cell will receive no lime. If several cores are taken randomly throughout the grid cell, such as at the yellow dots, and then combined, the result will be nearer the average pH for the grid cell. However, the variability in this grid cell is likely to be as high as it is across the field, so little is acco
Related Questions
- Does McGuff Pharmaceuticals provide adequate support and a defined approach to program management and communication with clients?
- Is the GORE® Survey an accepted approach to sampling volatile and semivolatile compounds in air, soil, and water?
- Is guidance available concerning sampling (number and location) to ensure adequate site coverage?
