Hi,
 
The NTRANS module of DSSAT does not consider any effect of soil texture on
SOM and N dynamics. The only effect soil texture has on SOM dynamics of
DSSAT goes via the soil water conditions: a different clay content gives a
different field capacity, wilting point etc.
 
A new SOM module under development for DSSAT, which is based on the CENTURY
soil organic matter model, does consider more direct effects of soil texture
on SOM dynamics, so that with increasing clay content there is [i] a reduced
decomposition rate of microbial SOM component (microbes can be hidden in
small pores); [ii] an increased partitioning of the flow towards the largely
passive SOM component; and [iii] a reduced fraction of CO2 lost at
decomposition.
 
This module will be presented at the Symposium on Crop Modelling next month
at Lleida, Spain.
 
 
Arjan Gijsman
Centro Internacional de Agricultura Tropical (CIAT)
Cali
Colombia
 
> -----Original Message-----
> From: Hiroshi HASEGAWA [SMTP:[log in to unmask]]
> Sent: 24 May, 1999 10:13 PM
> To:   [log in to unmask]
> Subject:      Effect of soil texture on N dynamics
>
> Dear DSSATer,
>
> In the version 3.0, does the NTRANS submodel consider a direct effect of
> soil texture (especially clay content) on N dynamics such as
> mineralization
> or nitrification? I would be grateful if anyone tells me.
>
> Sincerely,
>
>
> Hiroshi Hasegawa
>
> Division of Upland Farming
> Tohoku National Agricultural Experiment Station
>   960-2156
>   Fukushima-shi, Arai, Aza harajuku-minami 50
>   JAPAN
>   Phone; 81-24-593-5151
>   FAX  ; 81-24-593-2155
>   Email; [log in to unmask]
>   http://ss.fk.affrc.go.jp/~hasegawa/