We have several year's experience with a dormant season procedure for sampling shoots. There are still many details to work out, but it appears to show promise for some nutrients. The procedure is to collect a sample of 30 to 40 moderately vigorous shoots (10" to 20" long) from the lower part of the canopy in the middle of winter (January). We have also experimented with shoot sampling in September and obtained similar results. The samples are dried and sent to a lab for standard nutrient analysis.
Based on deficient trees in the sand tank trial, we have developed deficiency thresholds for several nutrients. These should be considered very preliminary as we don't know how they might be affected by variety, tree age, environmental conditions etc. However, they are presented here so a grower or consultant interested in the procedure has a place to start. We have had the most experience with zinc and feel this procedure might be a valuable tool to supplement the standard mid summer leaf sampling protocol.
FREP Summary 2004
FREP Summary 2005
FREP Summary 2006
FREP Final Report - 2007
Developing a Better Nutrient Sampling System -2005 Plant & Soil Conf
Dormant Shoot Sampling