Simulating competition between cereal and lucerne grown in mixture
Date
2008
Authors
Harris, R.
Gaydon, D.
Bellotti, W.
Unkovich, M.
Robertson, M.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Conference paper
Citation
Global Issues, Paddock Action: Proceedings of 14th Agronomy Conference, 21-25 September 2008, Adelaide, South Australia / M. Unkovich (ed.)
Statement of Responsibility
Conference Name
Australian Society of Agronomy Conference (14th: 2008 : Adelaide, Australia)
Abstract
Data collected from a field experiment in NE Victoria was compared with simulated wheat and lucerne grown in mixture (companion crop) and wheat in monoculture, using the Agricultural Production Systems Simulator (APSIM). Detailed field soil measurements along with specific management inputs were used to parameterise the model, while observed cereal and lucerne production data were used to assess model performance. Root mean squared error (RMSE) and time-series plots quantified agreement between simulated and observed data. APSIM satisfactorily estimated cereal production in monoculture and in the presence of lucerne when autumn soil mineral N was reset in the companion crop simulation. RMSE of 28% and 23% of the observed mean was found in the cereal monoculture and 39% and 20% of the observed mean found in the companion crop simulations, for cereal biomass and cereal grain yield respectively. Without resetting autumn soil mineral N in the companion crop simulation, lucerne growth was over-estimated and cereal growth under-estimated in the final crop of the simulation. This may have been caused by the model over-estimating lucerne soil N uptake during the summer/autumn period. Simulated estimates of lucerne production in the companion crop stubble may have been improved with detailed temporal field observations of lucerne N fixation. Satisfactory model performance indicates APSIM can be used to simulate longer term effects of rainfall distribution and management intervention on companion crop performance, thus identifying the circumstances under which the practice might be feasible.
School/Discipline
Dissertation Note
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Description
Copyright 2008 Australian Society of Agronomy