Abstract
Heavy metal stress in crops is a worldwide problem that requires accurate and timely monitoring. This study aimed to improve the accuracy of monitoring heavy metal stress levels in rice by using multiple Sentinel-2 images. The selected study areas are in Zhuzhou City, Hunan Province, China. Six Sentinel-2 images were acquired in 2017, and heavy metal concentrations in soil were measured. A novel vegetation index called heavy metal stress sensitive index (HMSSI) was proposed. HMSSI is the ratio between two red-edge spectral indices, namely the red-edge chlorophyll index (CIred-edge) and the plant senescence reflectance index (PSRI). To demonstrate the capability of HMSSI, the performances of CIred-edge and PSRI in discriminating heavy metal stress levels were compared with that of HMSSI at different growth stages. Random forest (RF) was used to establish a multitemporal monitoring model to detect heavy metal stress levels in rice based on HMSSI at different growth stages. Results show that HMSSI is more sensitive to heavy metal stress than CIred-edge and PSRI at different growth stages. The performance of a multitemporal monitoring model combining the whole growth stage images was better than any other single growth stage in distinguishing heavy metal stress levels. Therefore, HMSSI can be regarded as an indicator for monitoring heavy metal stress levels with a multitemporal monitoring model.
Highlights
Over the past decades, with the rapid development of China’s industry and urbanization, the problem of soil heavy metal contamination caused by industrial and domestic wastewater discharge, sewage irrigation, and automobile emissions has increased in severity [1]
Results show that heavy metal stress sensitive index (HMSSI) is more sensitive to heavy metal stress than CIred-edge and plant senescence reflectance index (PSRI) at different growth stages
The performance of a multitemporal monitoring model combining the whole growth stage images was better than any other single growth stage in distinguishing heavy metal stress levels
Summary
With the rapid development of China’s industry and urbanization, the problem of soil heavy metal contamination caused by industrial and domestic wastewater discharge, sewage irrigation, and automobile emissions has increased in severity [1]. Excessive heavy metal concentrations hinder crop growth and pose a serious threat to human health by entering the food chain and migrating into drinking water sources [2]. The rapid and accurate detection of heavy metals in crops is vital to diagnose suspected contaminated areas, assess health risks and protect human health [4]. The conventional methods for monitoring heavy metal stress are based on extensive field sampling and laboratory chemical analyses [5]. These processes are time-consuming, expensive, and unable to monitor contamination over large areas [2,3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
