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Seasonal and inter-annual variability of soil moisture stress function in dryland wheat field, Australia

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Title Seasonal and inter-annual variability of soil moisture stress function in dryland wheat field, Australia
 
Creator Akuraju, Venkata Radha
 
Contributor Ryu, Dongryeol
George, Biju Alummoottil
Ryu, Youngryel
Dassanayake, Kithsiri
 
Subject root zone soil moisture
vegetation biomass
net radiation
 
Description It is assumed that the ratio of actual evapotranspiration (AET) to potential evapotranspiration (PET) is mostly controlled by the soil water content available for ET. This control is formulated using the soil moisture stress function (SSF), where the evaporative fraction (EF) or the fraction of the AET to PET (fPET) is assumed to be either a linear or a non-linear function of soil moisture. We examine the effectiveness of the soil moisture stress function to quantify soil moisture control on EF or fPET over a dryland wheat field in Victoria, Australia. Micrometeorological observations from two cropping seasons were used for the analysis. The efficacy of a root-density-weighted soil moisture estimate in predicting EF and fPET was investigated as against the commonly assumed fixed-depth root zone soil moisture. However, results indicate a strong relationship between EF and available soil water fraction (AWF) in the root zone only when solar radiation is higher than 5 MJ/m2 /day. As the rooting depth increases with vegetation growth, SSF exhibits the strongest correlation with AWF for increasing soil profile depth. In the early and harvest- ing crop growth stages, ET is constrained mostly by surface soil moisture (0–5 cm). In the mid-growth stages, ET is strongly influenced by soil moisture in the root zone (0–60 cm). The shape of SSF, however, changes significantly between the two years (2012 and 2013). It is inferred that different temporal rainfall patterns between the years caused wheat’s different response to water stress.
 
Date 2017-01-15
2017-02-23T13:12:13Z
2017-02-23T13:12:13Z
 
Type Journal Article
 
Identifier https://mel.cgiar.org/dspace/limited
https://www.sciencedirect.com/science/article/pii/S0168192316303987
Venkata Radha Akuraju, Dongryeol Ryu, Biju Alummoottil George, Youngryel Ryu, Kithsiri Dassanayake. (15/1/2017). Seasonal and inter-annual variability of soil moisture stress function in dryland wheat field, Australia. Agricultural and Forest Meteorology, 232, pp. 488-499.
https://hdl.handle.net/20.500.11766/5908
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Language en
 
Rights CC-BY-NC-4.0
 
Format PDF
 
Publisher Elsevier Masson
 
Source Agricultural and Forest Meteorology;232,(2016) Pagination 488,499