Hi Sebastian,

SWXD is extractable soil water in mm/day. Water stress is characterized
in DSSAT by empirical forcing functions and using the factors WSED,
WSGD, and WSPD.
As far as I know, the degree of stress is calculated depending on soil
water effects on root growth and the relation between soil water uptake
and actual evapotranspiration.
A plant will inevitably start to wilt if its water potential surpasses
the wilting point which is expressed in MPa (-1.5 MPa is a standard
value, but there are crops which can
have far lower values such as cotton which can tolerate -2.4 MPa). The
wilting point is commonly measured with a pressure bomb using leaf
samples taken from the top
canopy at maximum transpiration intensity. DSSAT does not require this
value as input, neither for calibration nor for simulation.

Studying the source code and relevant literature will provide you with
definite answers for this and other questions.

Good luck!

Cheers,
Matthias

--
Matthias Langensiepen, PhD
Institute of Crop Science and Resource Protection
Faculty of Agriculture
University of Bonn
Germany





Dear list,

Does anybody knows the relationship /difference between the meaning of SWXD (output of water balance in DSSAT 4.5) and Wilting point?

Regards

Sebastian