Why is Plant Sap Analysis So Important For Vineyards?
Plant Sap Analysis is a tool that has the power to predict disease and insect susceptibility based on the vine's nutritional integrity.
Here's how plant sap analysis works: Two types of leaves are collected from the vine according to their position. The oldest, most viable mature leaves, and the most recently matured leaves (MRML) are removed and kept in separately marked sample bags (New/Old). A laboratory will draw sap out of the leaves and measure the nutrient content of the sap contained in the leaf.
The lab will generate a report that shows nutrient concentrations in the OLD leaves and the NEW leaves. First, we can identify deficiencies in older leaves, and then severe nutrient deficiencies will show in new leaves. Plant sap analysis finds the location of the last nutrient reserves.
Why is this so powerful? A plant tells us EXACTLY what its nutritional requirements are! Knowing what the plant needs enables us to customize and tailor specific nutrient solutions to optimize the genetic potential of your vines. When we are able to provide exact nutrition needed for optimal performance, we encourage disease and insect resistance!
It is important to monitor the nutritional profile throughout the plant's lifecycle (in the growing season). Conducting plant sap analysis every 2 weeks allows us to see how nutrients trend through the season. Sampling every 2 weeks gives us plenty of time to respond to a possible nutrient deficiency that results in pests, pathogens and yield loss.
Nutrient deficiency can be spotted with tissue analysis 3-4 weeks before we observe visual symptoms of nutrient deficiencies. It is possible to manage nutrition to prevent pests from showing up.
Plant sap analysis correlates perfectly with what is observable in the vineyard. The nutritional profiles of the leaves correlate with disease and insect susceptibility.
For example, when vineyards are battling with insects it is common to see high nitrate levels present in the sap. Insect pests with simple digestive systems like aphids, leaf hoppers, and worms consume the nitrate form of nitrogen. A plant sap analysis from a vineyard experiencing pest pressure will show high levels of nitrate, low levels of total nitrogen, and deficiencies of sulfur, manganese, or molybdenum.
Plant sap analysis provides valuable insight into key nutrient interactions. The values found in sap analysis can indicate that nitrate conversion is not happening properly. Nitrate is converted to the amino form in the leaves when molybdenum, manganese, and sulfur are at adequate levels.
Here is what I'm most excited about: There is a solution to battle insects without the use of pesticides. When photosynthesis and plant metabolism are functioning properly, nitrate levels in the leaf sap can drop to zero. This means there is no more food source for insect pests with simple digestive systems. They either starve, or go somewhere else.
This method of analysis enables us to view concentrations and movement of nutrients throughout the plant at different stages of development. Nutrient deficiencies found in plant sap analysis can be adjusted quickly and effectively in less than 72 hours after application.
Aliki Crop Advisors is here to help your vineyard produce the absolute best wine possible. In another blog, I'll go deeper into the role of secondary metabolites and what they mean to your grapes.
I would love to help your farm transition to regenerative agriculture, and end your reliance on chemical intervention, so that you can produce a higher value crop that provides better nutritional value to those who consume it.