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Impact of subsoil constraints on wheat yield and gross margin on fine-textured soils of the southern Victorian Mallee

Rodriguez, D. and Nuttall, J. and Sadras, V.O. and van Rees, H. and Armstrong, R. (2006) Impact of subsoil constraints on wheat yield and gross margin on fine-textured soils of the southern Victorian Mallee. Australian Journal of Agricultural Research, 57 (3). pp. 355-365.

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Article Link(s): http://dx.doi.org/10.1071/AR04133

Publisher URL: http://www.publish.csiro.au

Abstract

The APSIM-Wheat module was used to investigate our present capacity to simulate wheat yields in a semi-arid region of eastern Australia (the Victorian Mallee), where hostile subsoils associated with salinity, sodicity, and boron toxicity are known to limit grain yield. In this study we tested whether the effects of subsoil constraints on wheat growth and production could be modelled with APSIM-Wheat by assuming that either: (a) root exploration within a particular soil layer was reduced by the presence of toxic concentrations of salts, or (b) soil water uptake from a particular soil layer was reduced by high concentration of salts through osmotic effects. After evaluating the improved predictive capacity of the model we applied it to study the interactions between subsoil constraints and seasonal conditions, and to estimate the economic effect that subsoil constraints have on wheat farming in the Victorian Mallee under different climatic scenarios. Although the soils had high levels of salinity, sodicity, and boron, the observed variability in root abundance at different soil layers was mainly related to soil salinity. We concluded that: (i) whether the effect of subsoil limitations on growth and yield of wheat in the Victorian Mallee is driven by toxic, osmotic, or both effects acting simultaneously still requires further research, (ii) at present, the performance of APSIM-Wheat in the region can be improved either by assuming increased values of lower limit for soil water extraction, or by modifying the pattern of root exploration in the soil pro. le, both as a function of soil salinity. The effect of subsoil constraints on wheat yield and gross margin can be expected to be higher during drier than wetter seasons. In this region the interaction between climate and soil properties makes rainfall information alone, of little use for risk management and farm planning when not integrated with cropping systems models.

Item Type:Article
Business groups:Agri-Science, Crop and Food Science
Additional Information:Reproduced with permission from © CSIRO Publishing. Access to published version may be available via Publisher’s website.
Keywords:Root growth; salinity; sodicity; boron toxicity; El Niño; La Niña; ENSO.
Subjects:Agriculture > Agriculture (General) > Soils. Soil science > Soil and crops. Soil-plant relationships. Soil productivity
Plant culture > Field crops > Wheat
Science > Statistics > Simulation modelling
Deposited On:02 Feb 2009 01:37
Last Modified:26 Oct 2011 00:25

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