Evaluating crop-specific responses to salinity and drought stress from remote sensing

Abstract

Food security is projected to be threatened by increasing co-occurring stresses (e.g., drought and salinity) under global climate change. To mitigate major impacts on food production, the tolerances and vulnerabilities of crops to these threats need to be characterized. The aim of this research is to assess the tolerances of crops to the combination of drought and salinity stress across plant functions under real-life settings. Using five traits, we evaluated the impacts of drought and salinity tolerance on a multitude of crops across throughout the United States. We assessed the dominant stress as well as the onset of combined and individual effects of drought and salinity from March to October. We indeed observed that stress impacts strongly depended on time. In addition, we observed that crops were more sensitive to combined salinity and drought than to individual stresses, although stress impacts significantly varied between time and species. Of the individual traits, leaf Area Index (LAI) was triggered first by stresses, followed by the fraction of vegetation cover (FVC) and the fraction of absorbed photosynthetically active radiation (FAPAR), and leaf water content (Cw) and leaf chlorophyll content (Cab) were the last to respond to stresses. In comparison to other species, almond demonstrated greater resilience to combined drought and salinity, whereas soybean and maize were more drought tolerant. In combination, our study provides a way of assessing the tolerance of various crops to co-occurrent stresses both independently and in combination. By allowing applications to other co-occurring stresses and vegetation types, our approach creates a quantitative foundation to inform sustainable food production.