CTWN function / Fertilizer input issue

[chporter]

When fertilizer event data is input in the survey data, the CTWN function does not correctly modify the fertilizer N inputs. CTWN N-sensitivity works only with FEN_TOT (total seasonal N). (See IGB wheat data, for example.)

Medium level importance. This can wait until after the Vic Falls workshop to handle, but RRTs need it soon.

[MengZhang]

I think for this case, we need to add another CTWN function to work with the data set which would like to use the existing fertilizer events rather than create new events via DOME.