Scouting for Nutrient Deficiencies in the Vineyard
As we were harvesting Niagara grapes this week, I was noticing some classic potassium (K) deficiency symptoms on the leaves periodically throughout the vineyard. Although there is not much I can do to correct the deficiency at the end of this season, I am going to want to add potassium fertilizer to this block next spring. I would like to add a little more fertilizer where the vines are deficient and a little less where the vines are healthy…but I am never going to remember where that is next season. I would like to use a sensor to tell me the vine potassium status but I do not have that…yet (see the Hi-Res Vineyard Nutrition project). Alternatively, I decided to scout for K deficiency by creating a MyEV Data Collector.
Sometimes the best fertilizer is still the grower’s footprints in the vineyard.
Scouting for late-season potassium deficiency with a spatial data collector.
Inside of the MyEV software, I created a new data collector by tapping on the clipboard in the bottom right of the map screen. In my data collector, I created options to take a photo of the vines I was observing, to take notes, and, most importantly, to rate the severity of potassium deficiency from 0 (no deficiency) to 3 (severe deficiency with crispy black leaves).
In the field, I launched the data collector from the MyEV smartphone application. From there, I could see my location in the vineyard, make observations, and rate the level of deficiency. Once I made a rating, I hit the “Submit” button at the bottom to record my observation. I walked the vineyard at a steady pace and went down every third row, collecting ratings as I walked.
My simple and customized data collector for potassium deficiency.
After hitting “submit” for the last time in the field, I went back to my office and pulled up the “Niagara K Deficiency 2022” data layer saved in MyEV. I checked the data for any errors or strange mistakes I may have made in the field and then interpolated my observations into a spatial map.
My resulting potassium map that I will compare with other data layers I may have and use for variable rate fertilizer applications in the spring.
Could this save you some money?
The price of potassium fertilizer (potash) is up so lets do some quick math to see if you can save some money next spring. Generally, when we see late season K deficiency in a field, we will recommend a recovery dose of 300-400 pounds potash/acre, and this is usually applied uniformly across the block. In this example, we will use a uniform application of 300 pounds potash/acre. For a variable rate comparison, I will suggest a maintenance rate of 100 pounds/acre in the blue zone (where we saw no deficiency), 200 pounds/acre in the green zone, and 400 pounds/acre in the yellow and red zones.
The map key in MyEV gives the area for each zone, and you can download the zone statistics to a .csv file, if needed. With this information, you can calculate how much potash will be needed for the uniform vs variable-rate application. In this example, 0.54 tons potash would be needed for the uniform 300 pound/acre application and 0.42 tons would be needed for the variable-rate application. At $800/ton for potash fertilizer, that would be $432 for the uniform application and $336 for the variable-rate application…a savings of 22%.
In addition to saving over 20% in fertilizer costs, the variable-rate application would be putting more potassium where it is needed and not wasting fertilizer where the vines are already healthy.
Why this may be helpful to you:
No sensor or fancy equipment was needed to generate a useful spatial management map.
It takes advantage of a seasonal and variable observation and the grower’s knowledge.
The Data Collector is a customizable tool.
Data collected in the field are automatically saved in MyEV for processing and visualization.
The resulting map can be directly used for variable rate applications.
I hope you find the MyEV platform useful and we would love to hear how you are using it in your vineyard management. Leave a question or comment here.
