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Investigation of Water Dynamics and the Effect of Evapotranspiration on Grain Yield of Rainfed Wheat and Barley under a Mediterranean Environment: A Modelling Approach.

Zhang K, Bosch-Serra AD, Boixadera J, Thompson AJ - PLoS ONE (2015)

Bottom Line: Accurate prediction of water dynamics in such models is essential for models to produce reasonable results.The simulated seasonal evapotranspiration (ET) ranged from 208 to 388 mm, and grain yield was found to correlate with the simulated seasonal ET in a linear manner within the studied ET range.Finally, a two-staged approach using inverse modelling techniques to further improve model performance was discussed.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Technology, Zhejiang University, Ningbo, China.

ABSTRACT
Agro-hydrological models have increasingly become useful and powerful tools in optimizing water and fertilizer application, and in studying the environmental consequences. Accurate prediction of water dynamics in such models is essential for models to produce reasonable results. In this study, detailed simulations were performed for water dynamics of rainfed winter wheat and barley grown under a Mediterranean climate over a 10-year period. The model employed (Yang et al., 2009. J. Hydrol., 370, 177-190) uses easily available agronomic data, and takes into consideration of all key soil and plant processes in controlling water dynamics in the soil-crop system, including the dynamics of root growth. The water requirement for crop growth was calculated according to the FAO56, and the soil hydraulic properties were estimated using peto-transfer functions (PTFs) based on soil physical properties and soil organic matter content. Results show that the simulated values of soil water content at the depths of 15, 45 and 75 cm agreed with the measurements well with the root of the mean squared errors of 0.027 cm(3) cm(-3) and the model agreement index of 0.875. The simulated seasonal evapotranspiration (ET) ranged from 208 to 388 mm, and grain yield was found to correlate with the simulated seasonal ET in a linear manner within the studied ET range. The simulated rates of grain yield increase were 17.3 and 23.7 kg ha(-l) for every mm of water evapotranspired for wheat and barley, respectively. The good agreement of soil water content between measurement and simulation and the simulated relationships between grain yield and seasonal ET supported by the data in the literature indicates that the model performed well in modelling water dynamics for the studied soil-crop system, and therefore has the potential to be applied reliably and widely in precision agriculture. Finally, a two-staged approach using inverse modelling techniques to further improve model performance was discussed.

No MeSH data available.


Cumulative precipitation, potential and simulated ET in the experiments 2006–2007 (a), 2008–2009 (b) and 2009–2010 (c).
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pone.0131360.g006: Cumulative precipitation, potential and simulated ET in the experiments 2006–2007 (a), 2008–2009 (b) and 2009–2010 (c).

Mentions: Fig 6 shows the cumulative daily potential ET and the simulated ET in the growing seasons (the period between sowing and harvest), together with the precipitation for the experiments in 2006–2010. Generally it is the case that seasonal potential ET exceeded the simulated ET by far, suggesting that the crops suffered from water stress rather severely. This is due to the shortage of precipitation to meet the water demand for crops to achieve the maximum growth. Further, it is revealed that the simulated seasonal ET was approximately equal to the total precipitation in the same period. For example, for barley harvested on 26 June 2007, only 52% of seasonal potential ET of 639 mm, i.e 333 mm, was achieved, close to 307 mm provided by precipitation in the same period (Fig 6a).


Investigation of Water Dynamics and the Effect of Evapotranspiration on Grain Yield of Rainfed Wheat and Barley under a Mediterranean Environment: A Modelling Approach.

Zhang K, Bosch-Serra AD, Boixadera J, Thompson AJ - PLoS ONE (2015)

Cumulative precipitation, potential and simulated ET in the experiments 2006–2007 (a), 2008–2009 (b) and 2009–2010 (c).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476743&req=5

pone.0131360.g006: Cumulative precipitation, potential and simulated ET in the experiments 2006–2007 (a), 2008–2009 (b) and 2009–2010 (c).
Mentions: Fig 6 shows the cumulative daily potential ET and the simulated ET in the growing seasons (the period between sowing and harvest), together with the precipitation for the experiments in 2006–2010. Generally it is the case that seasonal potential ET exceeded the simulated ET by far, suggesting that the crops suffered from water stress rather severely. This is due to the shortage of precipitation to meet the water demand for crops to achieve the maximum growth. Further, it is revealed that the simulated seasonal ET was approximately equal to the total precipitation in the same period. For example, for barley harvested on 26 June 2007, only 52% of seasonal potential ET of 639 mm, i.e 333 mm, was achieved, close to 307 mm provided by precipitation in the same period (Fig 6a).

Bottom Line: Accurate prediction of water dynamics in such models is essential for models to produce reasonable results.The simulated seasonal evapotranspiration (ET) ranged from 208 to 388 mm, and grain yield was found to correlate with the simulated seasonal ET in a linear manner within the studied ET range.Finally, a two-staged approach using inverse modelling techniques to further improve model performance was discussed.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Technology, Zhejiang University, Ningbo, China.

ABSTRACT
Agro-hydrological models have increasingly become useful and powerful tools in optimizing water and fertilizer application, and in studying the environmental consequences. Accurate prediction of water dynamics in such models is essential for models to produce reasonable results. In this study, detailed simulations were performed for water dynamics of rainfed winter wheat and barley grown under a Mediterranean climate over a 10-year period. The model employed (Yang et al., 2009. J. Hydrol., 370, 177-190) uses easily available agronomic data, and takes into consideration of all key soil and plant processes in controlling water dynamics in the soil-crop system, including the dynamics of root growth. The water requirement for crop growth was calculated according to the FAO56, and the soil hydraulic properties were estimated using peto-transfer functions (PTFs) based on soil physical properties and soil organic matter content. Results show that the simulated values of soil water content at the depths of 15, 45 and 75 cm agreed with the measurements well with the root of the mean squared errors of 0.027 cm(3) cm(-3) and the model agreement index of 0.875. The simulated seasonal evapotranspiration (ET) ranged from 208 to 388 mm, and grain yield was found to correlate with the simulated seasonal ET in a linear manner within the studied ET range. The simulated rates of grain yield increase were 17.3 and 23.7 kg ha(-l) for every mm of water evapotranspired for wheat and barley, respectively. The good agreement of soil water content between measurement and simulation and the simulated relationships between grain yield and seasonal ET supported by the data in the literature indicates that the model performed well in modelling water dynamics for the studied soil-crop system, and therefore has the potential to be applied reliably and widely in precision agriculture. Finally, a two-staged approach using inverse modelling techniques to further improve model performance was discussed.

No MeSH data available.