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Estimating and partitioning maize evapotranspiration as affected by salinity using weighing lysimeters and the SIMDualKc model
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Orientador(es)
Resumo(s)
Water scarcity and saline stress are primary threats for water use and agricultural production in arid and semi-
arid regions, such as the Hetao Irrigation District, China. The current study, using irrigation with saline water,
developed through three seasons (2017–2019) of field experimental surveillance of mulched maize water use in
two cropped weighing lysimeters. Measurements included crop characteristics (height, LAI, dates of development
stages), soil and water salinity, and daily actual crop evapotranspiration (ETc act). Deficit surface irrigation was
scheduled in 2017 and 2018 seasons, while in 2019 drip irrigation was used aimed at satisfying crop water
requirements. Both approaches aimed at improving irrigation management while controlling impacts of salinity.
The collected information was used to parameterize and calibrate the soil water balance model SIMDualKc. The
model uses the FAO56 dual crop coefficient approach and considers the combined effect of water and salinity
stresses due to salinity of both soil and irrigation water. Results show that the SIMDualKc model adequately
simulates the dynamics of the observed ETc act throughout the three growing seasons. The goodness-of-fit in-
dicators show highly appropriate model fitting of observed ETc act with low RMSE of 0.42 mm d-1 for the cali-
bration and 0.53 mm d-1 for validation. The calibrated standard basal crop coefficients (Kcb) of maize for the
initial, mid, and end stages were respectively 0.15, 1.15 and 0.25, which agree with those recently proposed by
Pereira et al. (2021). Due to the impacts of both water and salt stress in 2017 and 2018, ETc act was much below
the potential value ETc, ranging 64–83%, while in 2019 that percentage increased to 92% due to avoiding water
stress by then. The average Kcb mid act range 0.58–1.06, therefore lower than Kcb mid, with the lower values
occuring in the lysimeter that was irrigated with a large deficit. The irrigation scheduling practiced was assessed
using water use and productivity indicators, which have shown the advantage in using drip irrigation with small
time intervals between irrigations. Moreover, the current study and the calibrated model provide for adopting
irrigation management practices that may save water and control salinity.
Descrição
Palavras-chave
basal crop coefficient drip irrigation hetao irrigation district salinity stress impacts surface irrigation water stress impacts
Contexto Educativo
Citação
Liu M., Shi H., Paredes P., Ramos T.B., Dai L., Feng Z., Pereira L.S., 2022. Estimating and partitioning maize evapotranspiration as affected by salinity using weighing lysimeters and the SIMDualKc model. Agric. Water Manage., 261, 107362
Editora
Elsevier