We are considering use new techniques to study the soil organic carbon and nitrogen cycle/availabity to plants in a biosolid application land. Does anyone have some kind of survey about new techniques/tools/methods to study soil N or C? Mainly N.
Thank you for your time!
Probably, you may try with the following for the N :
1. Leaf color chart developed by the International Rice Research Institute, which is inexpensive.
2. Chlorophyll meter, it has been used since the 1990 by the researcher to assess N status of plants.
3. Optical sensors, it is an electronic tool that have become important for N management. It includes GreenSeeker, the Crop Circle, and rapid scan CS-45 sensors. They can be used as a single hand-held unit, or mounted on a tool bar as a gang of multi-row sensors.
There are many soil-based tests of N availability. It's a case of finding one (or more!) that makes sense in the context of what you wish to examine. Soil extracts can used to localise different pools of N, e.g. by extracting with water (N in free solution), salt solution (free solution + adsorbed), CHCl3 + salt solution (free solution + adsorbed + microbial). For each type of extract one could measure total pools of inorganic N or organic N, or even measure specific compounds or classes of organic N (e.g. amino acids). There is also the option of measuring the rate at which inorganic forms of N are produced, i.e. various mineralisation assays. There are suggestions that depolymerisation may be the limiting step in supplying plant-available forms of N, and thus it could be useful to measure rates of proteolysis as an indicator of N availability (see attached paper)
https://doi.org/10.1016/j.soilbio.2017.08.015