Collecting soil and foliar samples in Christmas tree fields now can help you adjust your nutrient management program for the next growing season.
Christmas tree growers can use foliar sampling as a tool for “fine-tuning” their nutrient management program. It compliments soil testing by reflecting what the tree has actually picked up from available soil nutrient pools. A foliar test can also indicate a problem before visual symptoms appear or any growth reduction is evident. Michigan State University Extension recommends using foliar analysis along with a soil test in the fall to optimize the following season nutrient management program in Christmas tree farms.
When to take your foliage samples
Studies indicate that there is considerable variation in plant nutrient concentrations depending on the time of year. Ideally, you want to collect samples when the nutrient concentrations in the foliage are relatively stable. For Christmas trees grown in Michigan, we recommend that samples be collected in late fall (mid-October through December).
How to collect samples
In addition to seasonal variation in tissue nutrient concentrations, variations also exist with respect to age as well as location of the tissue being sampled. We recommend you collect 2 to 3 ounces of needles from the current growing season growth, taken from the upper third of the crown of the tree, staying away from the leader.
If you are seeing a problem in your field such as off-color or poor growth, make sure to collect separate “good” and “bad” samples to potentially help diagnose a nutrient deficiency problem. Keep the samples cold and dry and mail them to the testing laboratory, such as A & L Laboratories, as soon as possible after they have been collected. Assign a sample name or number so you can keep track of the fields and take detailed notes if you are seeing problems.
Source:msue.anr.msu.edu