Ba. Keating et H. Meinke, ASSESSING EXCEPTIONAL DROUGHT WITH A CROPPING SYSTEMS SIMULATOR - A CASE-STUDY FOR GRAIN PRODUCTION IN NORTHEAST AUSTRALIA, Agricultural systems, 57(3), 1998, pp. 315-332
The potential for cropping systems simulation to assist in the identif
ication and quantification of 'exceptional circumstances' of drought i
mpact on agriculture was assessed. The work focused on the grain produ
ction region of northeast Australia as a case study and used the crop-
soil management simulator, APSIM (Agricultural Production Systems Simu
lator). Wheat and sorghum production was simulated for a range of crop
ping systems and locations and the results averaged as a notional per
unit area 'farm production'. Moving averages over time bases from 1 to
4 years were used to examine variability and drought occurrence. Drou
ghts over different time periods were identified in absolute terms (e.
g. simulated production relative to a median or some lower percentile)
or in probabilistic terms (e.g. the estimated recurrence interval or
odds of experiencing a worse drought). The identification of droughts
using agricultural systems simulation was contrasted with rainfall est
imates of drought for the period of intel est and some differences in
ranking were observed. As the simulated agricultural drought reflects
the impact of factors such as rainfall timing, intensity, and amount a
nd effects of soil water storage on cropping system performance, it is
considered a superior measure of drought severity on farm performance
. Sensitivity analyses revealed little to no effects of the choice of
crop model or cropping system configuration (e,g, planting criteria) o
n the identification of exceptional drought circumstances. (C) 1998 El
sevier Science Ltd All rights reserved.