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Quantification of wheat water-use efficiency at the shire-level in Australia

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Doherty, A., Sadras, V. O., Rodriguez, D. and Potgieter, A. (2010) Quantification of wheat water-use efficiency at the shire-level in Australia. Crop and Pasture Science, 61 (1). pp. 1-11. ISSN 18360947 (ISSN)

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Article Link(s): https://doi.org/10.1071/CP09157

Abstract

In eastern Australia, latitudinal gradients in vapour pressure deficit (VPD), mean temperature (T), photosynthetically active radiation (PAR), and fraction of diffuse radiation (FDR) around the critical stage for yield formation affect wheat yield and crop water-use efficiency (WUE≤yield per unit evapotranspiration). In this paper we combine our current understanding of these climate factors aggregated in a normalised phototermal coefficient, NPq≤(PAR FDR)/(T VPD), with a shire-level dynamic model of crop yield and water use to quantify WUE of wheat in 245 shires across Australia. Three measures of WUE were compared: WUE, the ratio of measured yield and modelled evapotranspiration; WUEVPD, i.e. WUE corrected by VPD; and WUE NPq, i.e. WUE corrected by NPq. Our aim is to test the hypothesis that WUENPq suits regional comparisons better than WUE or WUE VPD. Actual median yield at the shire level (19752000) varied from 0.5 to 2.8t/ha and the coefficient of variation ranged from 18 to 92%. Modelled median evapotranspiration varied from 106 to 620mm and it accounted for 42% of the variation in yield among regions. The relationship was non-linear, and yield stabilised at ∼2t/ha for evapotranspiration above 343mm. There were no associations between WUE and rainfall. The associations were weak (R 2≤0.09) but in the expected direction for WUEVPD, i.e. inverse with seasonal rainfall and direct with off-season rainfall, and strongest for WUENPq (R2≤0.40).We suggest that the effects of VPD, PAR, FDR, and T, can be integrated to improve the regional quantification of WUE defined in terms of grain yield and seasonal water use. © CSIRO 2010.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Diffuse radiation Evapotranspiration Photothermal quotient Regional production modelling Vapour pressure deficit Yield crop production crop yield hypothesis testing latitudinal gradient photosynthetically active radiation quantitative analysis rainfall vapor pressure water use efficiency wheat Australia Triticum aestivum
Subjects:Agriculture > Agriculture (General) > Agriculture and the environment
Agriculture > Agriculture (General) > Agricultural meteorology. Crops and climate
Agriculture > Agriculture (General) > Methods and systems of culture. Cropping systems
Agriculture > Agriculture (General) > Improvement, reclamation, fertilisation, irrigation etc., of lands (Melioration)
Plant culture > Field crops > Wheat
Deposited On:17 Jan 2023 04:15
Last Modified:17 Jan 2023 04:15

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