Evaluating the sensitivity of vegetation and water indices to monitor drought for three Mediterranean crops

Abstract

Understanding drought effects on vegetative health for crop producing locations, such as the Seferihisar‐Kavakdere region in western Turkey, is vital for water and crop management. This study used Landsat‐derived spectral vegetation indices, specifically normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and land surface water index (LSWI) to evaluate and compare their performance and sensitivity for three major crops (citrus, grape, and olive) under dry (2008), wet (2010), and normal (2015) climatic conditions. Results showed that all three crops were affected by drought despite two (citrus and grape) being irrigated. However, grape and olive were more affected by drought than citrus. Drought conditions were exacerbated during September and October because of lack of precipitation and because irrigation is not a common practice during these months in this region. Therefore, this study aimed to use and compare drought sensitivities of Landsat‐derived spectral vegetation indices. All studied indices were closely related (.48 ≤ R2 ≤ .98) for citrus, grape, and olive. The EVI and LSWI were greater than NDVI when NDVI values were greater than 0.65 for citrus, and LSWI values were larger than NDVI when NDVI values were greater than 0.6 for grape and olive during the wet year. The results showed that different vegetation indices are needed to detect drought from one crop to another under different climatic conditions. Our findings indicate that the irrigation applications in 2008 (drought year) were not sufficient to alleviate the severe drought stress experienced throughout the winter and growing seasons.

Hyperspectral Imagery Detects Water Deficit and Salinity Effects on Photosynthesis and Antioxidant Enzyme Activity of Three Greek Olive Varieties

“…Additionally, the photosynthesis values of 'Amfisis' measured on the same day appeared to be statistically similar, which leads to an assumption that the 'Amfisis' cultivar demonstrated self-regulation of plant functions; therefore, it presented resistance to moderate salinity and water stresses. The most significant differences among treatments in respect to the last spectral reflection dataset were obtained from the NDVI values, supporting statements of previous studies claiming the NDVI to be a good predictor of water [31,[55][56][57] and salinity stress [28].…”

Exploring innovation adoption behavior for sustainable development of Mediterranean tree crops

“…In order to do this, awareness of the sector's critical issues must be raised: its future will depend on the strength of the ideas that entrepreneurs and technicians will translate into concrete actions. For the future, it will be essential to transfer useful innovation to farms, both process and product (Pereira et al, 2020), by introducing into common practice the results of the great advances made in the field of sensor technology, for precise and timely monitoring of orchard conditions (Campos et al, 2019;Yildirim et al, 2021).…”

Assessing Remote Sensing Vegetation Index Sensitivities for Tall Fescue (Schedonorus arundinaceus) Plant Health with Varying Endophyte and Fertilizer Types: A Case for Improving Poultry Manuresheds

“…NDVI presents a negative correlation with soil brightness and is influenced by the atmosphere, but the Enhanced Vegetation Index (EVI) simultaneously corrects for both [19], potentially resulting in greater sensitivities to grazingland physiological states. Moreover, light is greatly absorbed by water in the shortwave infrared (SWIR) band, which is used by the Land Surface Water Index (LSWI) to detect the amount of liquid water in vegetation and its soil background [20][21][22], again potentially serving as a proxy to grazingland physiological states.…”