When we do any trial work we take a number of measurements in order to assess the trial. In the main these are visual assessments made by the assessor there is always a set of guidelines however human nature means interpretations can and will be slightly different. This is why it's so important to use professional and independent assessors for this work.
Plant health, Turf colour, Disease %'s are all assessed by eye which is a tried and tested means of assessment that has been used for many years.
In these trial assessments we also use an NDVI meter so we have a completely independent measurement created by something other than the assessor.
NDVI stands for Normalised Difference Vegetation Index and it's a simple instrument that emits light and measures what light returns. By doing this it can measure the health of the plant.
In trials we see figures between 0.59 and 0.85. The closer the figure is to 1 the healthier it is. Rarely will you ever see the figure get above 0.85 though.
Does this tool have any place in the field?
It's certainly not essential - however it does give you an opportunity to measure turf health without it being an opinion. The figure is fairly irrelevant - just like a moisture meter, what might be optimum on one golf course is different for another manager on a different course. I didn't have one when I was a course manager but knowing what I know now how I would I have used one?
Regularly - Like all measurements the more often you do something the better you understand it.
In the same place - taking a reading in the same spot on a daily basis would start giving you some pretty good indications of the plants health.
Agriculture is using this technology on a much larger scale already. Satellites are taking NDVI readings on regular basis and large farmers are using these measurements to help them optimise their yield.
This is where the real value is - regular mapping of land to assess the changes in plants health in different conditions.
We have done a little work on golf courses to see what value there is for turf managers. The resolution is still a little way off from being useful but it is getting there. The standard resolution around 3 years ago was 3 meters per pixel (top image) but that has already moved to 0.7 meters per pixel (bottom image) and this improvement in resolution will continue.
With time this may become a feasible way to look at plant health and use it as a tool to implement ITM strategies but in the meantime the handheld units are a useful tool if you use them regularly.
NDVI meters are available on Turf Rewards which is great way to get hold of some of these agronomic tools and Dr Andy Owen of ICL does a great job explaining how to use one here.......
