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.

中文翻译：

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评估植被和水分指数对监测三种地中海作物干旱的敏感性

了解干旱对农作物生产地点（如土耳其西部的塞费里希萨尔-卡瓦克德雷地区）营养健康的影响，对水和作物管理至关重要。这项研究使用Landsat衍生的光谱植被指数，特别是归一化差异植被指数（NDVI），增强植被指数（EVI）和地表水指数（LSWI）来评估和比较它们对三种主要农作物（柑橘，葡萄）的性能和敏感性。和橄榄）在干燥（2008），潮湿（2010）和正常（2015）的气候条件下。结果表明，尽管灌溉了两种（柑橘和葡萄），但三种作物都受到了干旱的影响。但是，葡萄和橄榄比柑橘受干旱影响更大。由于缺乏降水，而且在该地区这几个月的灌溉不普遍，9月和10月的干旱状况更加恶化。因此，本研究旨在使用和比较Landsat衍生的光谱植被指数的干旱敏感性。所有研究指标密切相关（.48≤[R ² ≤0.98）柑桔，葡萄，和橄榄。当葡萄的NDVI值大于0.65时，柑橘的EVI和LSWI大于NDVI；当葡萄和橄榄的NDVI值大于0.6时，LSWI的值大于NDVI。结果表明，在不同气候条件下，从一种作物到另一种作物的干旱检测需要不同的植被指数。我们的发现表明，2008年（干旱年）的灌溉应用不足以缓解整个冬季和生长季节遭受的严重干旱压力。