Is there any method to estimate indirect (e.g. pedotransfer function) the value for soil's effective field capacity (e FC)? Can we relate empirically the values of e FC with available water content (AWC)?
There have been developed a lot of computer applications. I have used two. One provided by CROPSYST and the other one belongs to USDA and is called ROSETTA.
By the way, the best method i have ever used is porous cup.
thanks a lot Iker, very helpful contribution. I will try them both. Regards
To estimate it, you can use pedotransfer functions (..choosing them according to the place where you have to perform the study and where the functions have been already tested).
In general, the effective field capacity is reached when the role of the gravity vanishes in a saturated soil (not easy to measure at field scale).
If you use porous cups (tensiometer), together with soil sampling to determine soil water content (SWC), you have to set and follow the pressure value at the FC (e.g. -33 kPa).. but, than, is not the real pressure matching the SWC at the FC.. These results are obtained easily and more precisely by means of Richards pressure chambers.
Which type of relation you imagine to find between FC and AWC.. If you want an estimation, you could use soil-plant models as just suggested..
Dear Evangelos,
relating FC and AWC may pose some difficulty as you also have to include a dry limit (wilting point, WP), all affected by multiple parameters. A first idea of how to approach PTFs may be found here: http://www.pollaccowater.org/hydrology/Universal_pedotransfer_function_project_files/PedotransferFunctionFcPWP.pdf (quite detailed description). I suggest you also check some publications by Rawls et al. Good luck :)
I suggest you to use the PTF of Wösten et al. (1999) for european soils (HYPRES database)- based also in Greek soils provided by Aristotle University of Thessaloniki and Agricultural University of Athens -.
http://www.sciencedirect.com/science/article/pii/S0016706198001323
You might find some tools on the web.
Good Luck
bye
Dear Evangelos,
you can measure FC of soil by measurement of soil suction. there is a lot of methods for measurement of soil suction such as tansiometer. but I think the simplest method that is really cheap is Filter paper method.
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