Nitin,

The DSSAT Century model option for simulating soil carbon can be used, but you have to specify stable carbon in order for it to provide realistic results. Papers by Porter et al. and by Basso et al. describe the Century model option and how to initialize the carbon pools, which depend on management history.



DSSAT computes soil organic carbon in all soil layers. In the Century options, it also writes out the total C in the top 20 cm as well as the total C in the entire profile. Stable C is the carbon in organic matter that decomposes very very slowly. I think that you need to read the papers by Porter et al. and by Basso et al. I also recommend that you take one of the DSSAT courses. Setting the initial soil carbon in organic matter and specifying the pools is not very straight forward, and these pools can have a major influence on the dynamics of soil carbon.

Jim



-----Original Message-----

From: DSSAT - Crop Models and Applications [mailto:[log in to unmask]] On Behalf Of Nitin Joshi

Sent: Thursday, October 30, 2014 4:32 PM

To: [log in to unmask]

Subject: Quarry on SOC computation



Hi all...

i want to model soil organic carbon and total nitrogen. I have the measured data for SOC and total N pool at 0-20 cm and i want to simulate it with DSSAT model.

However, l  have following questions regarding the model.



1) Does DSSAT computes soil organic carbon at all the soil layers or only first two layers?



 2) Looking at .OSC file in DSSAT it shows a number of variables like Stable soil organic carbon at user depth (SCDD) i did not understand at what user depth it computes and  where to specify this user depth.



3) there is another variable in the .OSC file such as total soil organic carbon. is it the organic carbon in the entire soil profile or first two layers only?



4) If i use stable soil org carbon at certain depth ? how do i convert it into total soil organic C.



Thanks for help

regards

nitin

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Nitin Joshi

PhD, M-Tech

Water Resources Engineering