A non‐destructive and real‐time method of monitoring leaf nitrogen status in wheat

Abstract

Non-destructive assessment of leaf nitrogen status is helpful for precision nitrogen management in crop production. This study was conducted to quantify the relationships of leaf nitrogen concentration on a leaf dry weight basis (LNC) and leaf nitrogen accumulation on a soil area basis (LNA) to canopy hyperspectral reflectance in wheat. Both LNC and LNA increased with increasing nitrogen rates, along with marked changes in canopy hyperspectral reflectance. The sensitive spectral bands for LNC and LNA occurred mostly within visible light and the near-infrared regions. The hyperspectral parameters REPle, λo and mND705 were linearly related to LNC, and MSS-SARVI, FD742, PSSRb and SDr/SDb were linearly related to LNA. Testing of the REPle and mND705 gave the R 2 values of 0.752 and 0.695 between the measured and estim ated LNC, relative errors (RE) of 14.4 and 16.5%, whereas for FD742 and SDr/SDb, the R 2 values were 0.872 and 0.828, with RE of 14.1 and 15.2% respectively.

A spectral parameter for the estimation of soil total nitrogen and nitrate nitrogen of winter wheat growth period

“…The traditional method for determining the nitrogen concentration in plants and soil mainly relies on indoor chemical analysis, which is time-consuming, labour-intensive, and for the most part, incapable of meeting the requirements discussed above (Debaene, Niedźwiecki, Pecio, & Żurek, 2014;Liang et al, 2018). In recent years, hyperspectral remote sensing technology has become a new technical means to quickly assess and monitor crop nutrient levels and soil nutrient content (Nguyen & Lee, 2006;Yao, Feng, Zhu, Tian, & Cao, 2007;Jung, Vohland, & Thiele-Bruhn, 2015;Thorp, Wang, Bronson, Badaruddin, & Mon, 2017;Sithole, Ncama, & Magwaza, 2018;Sorenson, Quideaua, & Rivardb, 2018;zhang, Li, Zheng, Qin, & SukLee, 2019).…”