I would like to develop a calibration curve for N fertilizer management of wheat through NDVI measurement using a GreenSeeker optical sensor under conservation agriculture conditions and also to identify the potential yield and N response of the wheat. To do this, an experiment was conducted using two wheat cultivars and eight N rates: 0, 50, 100, 150, 200, 250, 300 and 350 Kg N/ha.
Do you have any idea how many NDVI readings are needed and at what particular growth stages of wheat for the relationship between NDVI and grain yield?
And do you know by any chance what equations I should consider checking their goodness of fit?
I suggest that you design and test a sampling protocol to statistically answer your question to the level of precision that you may need. I also suggest that you also use a conventional lab measure for comparison.
You probably want to peruse the information at the Oklahoma State University website https://www.nue.okstate.edu/ and maybe also this background information : https://extension.okstate.edu/fact-sheets/the-history-of-the-greenseeker-sensor.html to learn a bit more about the development of the calibration in the original devices.
Is a linear N application rate increase (50 kg/ha steps) going to provide you the most useful information for your experiment? At what point does the green-ness of the crop stop increasing vs the yield? Would you be better off having more concentrations at the low end of the range, and fewer at the top? Assuming the maximum N dose 350kg/ha) will provide maximum green-ness, why waste effort measuring marginal decreases when you can improve knowledge at the inflection points of the curve?
Thank you Professor Milham @Milham for your prompt reply and your valuable suggestion.
Thank you Professor Matthew Wheal for the links and your suggestion.
- Badges
- Science topic
- Similar topics
- Engineering
- Computer Engineering
- Computer