Evapotranspiration for irrigated agriculture using orbital satellites

Abstract

Acknowledging the importance of evapotranspiration as a mediating factor for efficient irrigation management and water balance, the objective of study is to compare the Simple Algorithm for Evapotranspiration Retrieving (SAFER) to the standard method proposed by FAO-56 for real evapotranspiration, as well as prove its value as an implement in irrigation management for the Brazilian Savanna. Data used refers to 2015's harvest of seven center pivots, located in the municipality of São Desidério in western Bahia. For the SAFER algorithm, the images used were acquired by the Landsat-8 satellite during the entire maize crop cycle. The SAFER algorithm estimation demonstrates the spatial and temporal distribution of the evapotranspiration. A maximum evapotranspiration of 5.38 mm d-1 was observed during the crop's reproductive stage. In relation to the standard method, SAFER showed a mean absolute error of 0.40 mm. Thus, concluding that the algorithm can be used to estimate the actual evapotranspiration crop as an alternative to the standard method proposed by FAO-56 for water resources management.

Evapotranspiration mapping of commercial corn fields in Brazil using SAFER algorithm

“…When data were analyzed separately in each phenological phase, valuable information could be extracted ( Figures 10B and 10C). First, we observed very low ET SAFER (close to zero) during the first 30 DAS, similar to the findings of Althoff et al (2019), while ET MFAO remained between 2 and 3 mm d -1 . The main reason for the lower ET values could be the large area of exposed soil background during this period, since after this time, when the corn enters the development phase, ET values increase quickly until 70-80 DAS.…”

“…SAFER algorithm applications involving large heterogeneous areas have shown very good performance (Coaguila et al, 2017;Dehziari and Sanaienejad, 2019;Teixeira et al, 2019Teixeira et al, , 2017Teixeira et al, , 2013. However, when applied to irrigated annual crops, which are more homogenous, SAFER provides unsatisfactory ET estimates during the early stages of crop growth (Althoff et al, 2019;Lima et al, 2019) thus requiring calibration and validation of SAFER algorithm.…”

A Review on Evapotranspiration Estimation in Agricultural Water Management: Past, Present, and Future

“…Evapotranspiration (ET) contributes to the highest water loss in cultivated semi-arid regions [25,26]. Furthermore, the identification of ET's effect on the water budget is essential for water resource management as well as forest growth and species diversity, sustainable crop production, food security, and social stability [8,17,19,[27][28][29]. Therefore, applying more efficient ET-reduction strategies are important to achieve efficient and sustainable water use [30,31].…”

Análise da evapotranspiração e balanço de energia por meio da razão de Bowen e sensoriamento remoto nas culturas da batata e soja

“…A evapotranspiração média da cultura (ETc) foi de 3,44 mm. FRENCH et al, 2015;SALES et al, 2016SALES et al, , 2017ALTHOFF et al, 2019;SOUZA et al, 2020). Esses baixos valores têm como explicação, a influência da reflectância do solo no início do ciclo da cultura.…”

“…Outro fator que pode explicar a presença dos baixos valores da evapotranspiração no início do ciclo da cultura, é o fato do Kc da cultura variar com a alta evaporação de água, devido ao solo descoberto e à utilização do sistema de irrigação. Além disso, resolução espacial das imagens do satélite também desempenha um papel crucial, já que o valor do pixel pode influenciado pela superfície descoberta do solo (WARREN et al, 2014;ALTHOFF et al, 2019). pBIAS -20,44% -10,61%…”