Modern sap analysis can provide a deep dive into what’s happening with plant nutrition.By Frank Giles | Editor, Florida Grower
As growers incorporate biological products that enhance the soil microbiome into their production programs, it can sometimes be difficult to determine the effect the products are having, especially early on. Outside the traditional yield test that compares the treated plot against the check, are there other ways to evaluate product performance?
One tool that might prove useful is modern sap analysis. Many call it a blood test for plants, in part because the samples pulled for sap analysis focus on xylem and phloem in the vascular system of the petiole and leaves.
In simple terms, where traditional tissue samples provide a snapshot of the right now in the plant, sap analysis can peek into the inventory of nutrients and provide a forward look at where nutritional elements will be in the days and weeks ahead. It’s a more comprehensive test. You can get a read on up to 23 different essential nutrients and nutritional indicators with sap analysis.
So, could sap testing help growers evaluate the performance of nutritional-based biologicals? Larry Shafer, an independent consultant with Agro-K, says yes it can. The company is a manufacturer of nutritional and biological products and provides sap analysis for its customers. If a product promises to make more nitrogen available to the plants, that should show up in a sap analysis test, especially if compared to a control check. Safer says they use the tool in their own product development.
“As we are developing nutrition products, we use sap analysis to evaluate their performance before we bring anything new to market,” he says.
Shafer adds that for organic growers, it is a good tool for justifying nutrient applications for third-party certifiers. “Sap analysis is great for that because it can show very specific nutrient deficiencies in the plant,” he says. “The growers can show the results to the certifier to illustrate the need for an application.”
Rob Ford, Midwest Region Sales Manager for Agro-K, has another example how sap analysis could help illustrate a biological product’s performance in making available nutrients tied up in the soil. He notes that Midwest soils are notoriously high in iron with traditional soil testing, but the element often shows up deficient with sap analysis.
When there are ample nutrients in the ground, Ford says the mostly likely culprit of deficiencies in plants is a lack of biological activity in the soil to make them available. These are good examples of the need for using practices to promote such activity and building soil health, he adds.
