Determining maize water stress through a remote sensing-based surface energy balance approach
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ORIGINAL PAPER
Determining maize water stress through a remote sensing‑based surface energy balance approach Edson Costa‑Filho1 · José L. Chávez1 · Louise Comas2 Received: 15 September 2019 / Accepted: 20 February 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Determining water stress levels of vegetated surfaces is crucial for irrigation scheduling. This paper aims to evaluate a new method for obtaining crop water stress index (CWSI) based on the estimation of sensible heat flux using an aerodynamic temperature gradient approach. Data were collected on a deficit irrigated maize field at a research farm located in Greeley, Colorado, USA, in 2017 and 2018. The irrigation treatment used subsurface drip. Weather data were measured on-site at 3.3 m above ground level. RED and NIR surface reflectance data were obtained on-site through multispectral radiometer measurements. Nadir surface temperature data were measured using infra-red thermometers at 1 m above canopy. CWSI estimated values were used to assess daily soil water stress index (SWSI), calculated from measurements of volumetric soil water content (VWC) and management allowed depletion (MAD) of 40%. Results show that SWSI is best represented through a non-linear rational CWSI function. Modeled CWSI estimates were compared to measured surface heat fluxes, resulting in a mean bias error of − 0.02 and a root mean square error of 0.09, while errors were 0.02 and 0.06 when compared with observed CWSI based on canopy transpiration measured with plant sap flow devices. Results seem to validate the proposed sensible heat flux-based CWSI model. The CWSI approach presented could be used to manage irrigation and conserve water resources for maize in semi-arid regions.
Introduction Irrigation scheduling and agricultural water management practices have shifted toward optimizing crop yield and conserving water and soil resources due to climate change and population growth. Maize is an essential commodity across the United States of America (USA). The susceptibility of yield loss due to the climate change conditions is evident across the USA. These conditions affect most productive Communicated by José L. Chávez. * Edson Costa‑Filho [email protected] José L. Chávez [email protected] Louise Comas [email protected] 1
Civil and Environmental Engineering Department, Colorado State University, Fort Collins, CO 80523, USA
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Fort Collins, CO 80526, USA
2
crops, including maize. According to Chung et al. (2014), maize yield in the USA could suffer a reduction of 29% due to changes in climate that are caused by accentuating extreme conditions (i.e., droughts) by 2050. Within the countryside, the areas that are more susceptible to suffer intense drought seasons due to future reduced rainfall and snowmelt events are the locations within the Midwest of the USA, which include, but not limited to, Kansas, Iowa, Nebraska, and Oklahoma (Tubiello et
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