Plant Tissue Analysis

By Darren Hefty

There is a lot of enthusiasm about precision agriculture and rightly so.  To take full advantage of every acre of your fields, though, you must first understand your soils – more specifically, your fertility program.  Feeding your crop is arguably the most important step toward top yields and profitability.  The first class to help you master your fertilizer program takes 50 to 60 minutes and requires an investment of about $400.  It’s called pulling your own plant tissue tests on your farm this spring and summer.  Here’s how it works.

PICK A FIELD

First of all, just pick one field to get started with.  Pick two spots in the field: one that yields very well, and one that you’re struggling with.  Either mark the spots with your GPS or stick a tall flag in the ground so you can find the same areas all through the season.  Then, commit to pulling a sample once per week for a 10- to 12-week period during the growing season.

SAMPLING

Take your samples at the same time and day each week.  We go out at 8 a.m. every Monday morning.  This will give you the most consistency and the best measurement over time on what is actually happening in your fields.  The exact leaves or parts of the plant you take for the sample will change as the crop develops.  Take corn, for example.  Early in the season, you will clip the whole plant off at ground level to send in for analysis.  Later on, you’ll take the top leaf on the plant that is fully developed.  Finally, when you have an ear, you take just the leaf opposite and below the main ear.  Each time you’ll need about a pint of loosely packed leaf material.  If the leaves have dirt or other residues on them, you’ll need to dry brush it off or wipe the leaves clean with a damp cloth.  For complete instructions for a large number of different crops, click here.

THEN WHAT?

It’s possible to see test results and go right out to the field to apply the fertility your crop needs.  More importantly, you will now have great information to adjust your soil fertility program this fall, next spring and for years to come.  In our operation, for example, we saw continued deficiencies most weeks with K, B and Zn when we first started tissue sampling.  Due to that, we dramatically changed our fertilizer program for the better.  Plant tissue analysis has helped Brian and me become better farmers, and it definitely has helped us make much better investments in our fertility program.  We’re confident it will help you, too.

ONE LAST NOTE – There are a handful of agronomists out there saying plant tissue analysis isn’t worthwhile.  Obviously, that’s not true.  The key is to test weekly at the same time of day each week for 10 to 12 weeks.  Do that.  You’ll learn so much, it will be invaluable for your operation.