add nutrient data to dataframe
- we have soil nutrient data from May and September 2022, September 2023, and June-August 2024
- the 2022 and 2023 should be similar (soil sampling + lab analyses at the University of Eastern Finland), whereas 2024 nutrient information is obtained by PlantRootSimulators (PRS probes)
- the aim is to write a script to combine the final data frame ("run_all_main" script output of all measurement campaigns) with the different nutrient data