Hi Jin Wu,


It looks like you are referring to the code of v3.5, since in v4.0 it changed a little. Those meaningless variable names FT and FW were replaced by variables that mean something: TFDENIT and WFDENIT, since there are so many temperature and water factors.

Much of the DNRATE equation seems to come from Godwin and Singh, which I assume is: Godwin, D.C., and U. Singh. 1998. Nitrogen balance and crop response to nitrogen in upland and lowland cropping systems. p. 55-77. In G.Y. Tsuji , G. Hoogenboom, and P.K. Thornton (eds.) Understanding options for agricultural production. System approaches for sustainable agricultural development. Kluwer Academic Publishers, Dordrecht, Netherlands.

Cheers,
Arjan Gijsman



-----Original Message-----
From: DSSAT - Crop Models and Applications [mailto:[log in to unmask]]On Behalf Of Jin Zhong Wu
Sent: Sunday, August 27, 2006 9:42 PM
To: [log in to unmask]
Subject: Re: the definition of NO3(L)

Dear M.E. Asadi:

Thanks for your info.

I have more question:

CERES has an denitrification equation
DNRATE = 6.0*1.0E-05*CW*NO3(L)*FW*FT*DLAYR(L)

Where DNRATE is in kg [N} / ha. As you told me:  NO3(L) is in ug [N]/g [soil])

My question is that:
if the bulk density and unit conversion are included by the 6.0*1.0E-05?   What is the reference paper to derive the 6.0*1.0E-05?

Jin Wu

----- Original Message -----
From: "Dr. mohammad asadi" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, August 25, 2006 3:28 AM
Subject: Re: the definition of NO3(L)


> Dear Jin Wu,
>
>
>  Hello. Be informed that the definition of NO3(L) and NH4 (L) which is soil nitrate (ppm or ug /g soil) and ammonium  respectively in layer L refer to per unit weight of soil (g-1 soil) and  NO3(L) is soil concentration.
>
>
>  Best regards,
>
>  M.E. Asadi
>
>
>
>
>  M. E. Asadi,Ph.D, Research Scientist
>  Tel: 0098-171-3354868 (office)
> Mobile phone: 0098-0911-175-2719
> Fax: 0098-171-3359813
> Mailing Address:
> Mr. Asadi, Mail Box 49175-639, Gorgan, Iran
>
>
>
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