All samples must be dried and then homogenized by grinding the plant tissue to a prescribed particle size. This process is usually for leaf and petiole samples. Please consult with the lab before sending whole plant samples. The method interpretation is calibrated for the fourth leaf from the top of the cotton plant. A composite of at least 10 petioles are required for a complete sample.
Analysis is by selective-ion electrode.
As mentioned above, the method interpretation is calibrated for the fourth leaf from the top. Analysis is by emission ICP spectrophotometer.