Abstract
The crop coefficient (Kc) is a crucial factor in irrigation decision making. The ability to estimate it directly from satellite imagery can immensely assist growers around the globe in their crop monitoring. Direct estimations of Kc from diverse spectral indices, enable the use of various multi-spectral sensors and increase the ability to map relatively small plots (<1.0 ha). The goal of this study was to examine the accuracy of Kc estimations using different spectral indices with different satellite sensors. To achieve this goal, a database was created. Datasets included 126 satellite images and corresponding Kc from five flux tower sites over four irrigated crops (citrus, corn, alfalfa, and soybean). Kc was estimated remotely from five sensors, by applying previously published indices equations. The results show that the normalized difference vegetation index (NDVI) achieved the highest accuracy (RMSE<0.1 and nRMSE of 10%) among the indices, characterized by only minor accuracy differences between the sensors. The lowest accuracy among all crops was observed in citrus.
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Claims 3
Claim · model-written summary
NDVI had the highest crop coefficient estimation accuracy among indices, with RMSE below 0.1 and nRMSE of 10%.
- Taxon
- citrus, corn, alfalfa, and soybean
Citrus
Glycine max
Medicago sativa
Zea mays subsp. mayse1 - Outcome
- accuracye0
- Direction
- higheste0
- Value
- RMSE<0.1 and nRMSE of 10%e0
- Comparator
- the indicese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results show that the normalized difference vegetation index (NDVI) achieved the highest accuracy (RMSE<0.1 and nRMSE of 10%) among the indices”
e1“four irrigated crops (citrus, corn, alfalfa, and soybean)”
Claim · model-written summary
NDVI accuracy differed only slightly between satellite sensors.
- Taxon
- citrus, corn, alfalfa, and soybeanCitrusGlycine maxMedicago sativaZea mays subsp. mayse2
- Outcome
- accuracy differencese0
- Qualifier
- only minore0
- Comparator
- the sensorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“characterized by only minor accuracy differences between the sensors.”
e1“normalized difference vegetation index (NDVI)”
e2“four irrigated crops (citrus, corn, alfalfa, and soybean)”
Claim · model-written summary
Crop coefficient estimation accuracy was lowest in citrus among the crops.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lowest accuracy among all crops was observed in citrus.”