Synergistic use of spectral features of leaf nitrogen and physiological indices improves the estimation accuracy of nitrogen concentration in rapeseed. - Tian, Tian; Wang, Jingang; Wang, Haijiang; Cui, Jing; Shi, Xiaoyan; Song, Jianghui; Li, Tiansheng; Li, Weidi; Zhong, Mingtao (International Journal of Remote Sensing, 2022)