Please see the papers published on this aspect. If you know the initial C loaded through litter and analyse the remaining C content left in the pouch after decay at different time intervals, the data on natural logarithm of C content could be plotted against the time (t) to get the decay constant as slope of the line.
Please send me some papers for calculation on k values using non-linear regression. Is it possible to do the non-linear regression in Ms-Excel. Please suggest...