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Measuring and Modeling the Water Balance in Low-Rainfall Cropping Systems

OAR@ICRISAT

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Relation http://oar.icrisat.org/11075/
http://dx.doi.org/10.13031/trans.12581
10.13031/trans.12581
 
Title Measuring and Modeling the Water Balance in Low-Rainfall Cropping Systems
 
Creator Whitbread, A M
Hoffmann, M P
Davoren, C W
Mowat, D
Baldock, J A
 
Subject Climate Risk
Crop Modelling
Soil
Cropping and Farming Systems
Soil Science
Water Resources
 
Description In low-rainfall cropping systems, understanding the water balance, and in particular the storage of soil water
in the rooting zone for use by crops, is considered critical for devising risk management strategies for grain-based farming.
Crop-soil modeling remains a cost-effective option for understanding the interactions between rainfall, soil, and crop
growth, from which management options can be derived. The objective of this study was to assess the error in the prediction
of soil water content at key decision points in the season against continuous, multi-layer soil water measurements made
with frequency domain reflectometry (FDR) probes in long-term experiments in the Mallee region of South Australia and
New South Wales. Field estimates of the crop lower limit or drained upper limit were found to be more reliable than laboratory-
based estimates, despite the fact that plant-available water capacity (PAWC) did not substantially differ between the
methods. Using the Agricultural Production Systems sIMulator (APSIM) to simulate plant-available water over three-year
rotations, predicted soil water was within 7 mm (PAWC 64 to 99 mm) of the measured data across all sowing events and
rotations. Simulated (n = 46) wheat grain production resulted in a root mean square error (RMSE) of 492 kg ha-1, which is
only marginally smaller than that of other field studies that derived soil water limits with less detailed methods. This study
shows that using field-derived data of soil water limits and soil-specific settings for parameterization of other properties
that determine soil evaporation and water redistribution enables APSIM to be widely applied for managing climate risk in
low-rainfall environments.
 
Publisher American Society of Agricultural and Biological Engineers
 
Date 2017
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://oar.icrisat.org/11075/1/Measuring%20and%20Modeling%20the%20Water%20Balance%20in%20Low-Rainfall%20Cropping%20Systems.pdf
Whitbread, A M and Hoffmann, M P and Davoren, C W and Mowat, D and Baldock, J A (2017) Measuring and Modeling the Water Balance in Low-Rainfall Cropping Systems. Transactions of the ASABE, 60 (6). pp. 2097-2110. ISSN 2151-0040