Estimating leaf nitrogen concentration based on the combination with fluorescence spectrum and first-derivative

Abstract

Leaf nitrogen concentration (LNC) is a major indicator in the estimation of the crop growth status which has been diffusely applied in remote sensing. Thus, it is important to accurately obtain LNC by using passive or active technology. Laser-induced fluorescence can be applied to monitor LNC in crops through analysing the changing of fluorescence spectral information. Thus, the performance of fluorescence spectrum (FS) and first-derivative fluorescence spectrum (FDFS) for paddy rice (Yangliangyou 6 and Manly Indica) LNC estimation was discussed, and then the proposed FS + FDFS was used to monitor LNC by multivariate analysis. The results showed that the difference between FS ( R 2 = 0.781, s.d. = 0.078) and FDFS ( R 2 = 0.779, s.d. = 0.097) for LNC estimation by using the artificial neural network is not obvious. The proposed FS + FDFS can improved the accuracy of LNC estimation to some extent ( R 2 = 0.813, s.d. = 0.051). Then, principal component analysis was used in FS and FDFS, and extracted the main fluorescence characteristics. The results indicated that the proposed FS + FDFS exhibited higher robustness and stability for LNC estimation ( R 2 = 0.851, s.d. = 0.032) than that only using FS ( R 2 = 0.815, s.d. = 0.059) or FDFS ( R 2 = 0.801, s.d. = 0.065).

Recent applications of novel laser techniques for enhancing agricultural production

“…tillering and shooting, respectively. Furthermore, the use of first-derivative fluorescence spectrum was recently proposed to enhance the accuracy of LNC monitoring by obtaining more fluorescence characteristics (Yang et al 2019(Yang et al , 2020. In another work, Thoren and Schmidhalter (2009) reported the implementation of laser-induced chlorophyll fluorescence technique to determine the nitrogen content and biomass of oilseed rape under red laser excitation at 630 nm.…”

Plant–soil feedback and plant invasion: effect of soil conditioning on native and invasive Prosopis species using the plant functional trait approach

“…These indexes might give further understanding on how invaders can facilitate the success of more invaders. Biomass and plant height reflect the efficiency of plants in nutrient acquisition and competitive strength ( Moles et al., 2009 ); SLA is related to plant growth rates ( Knops and Reinhart, 2000 ; Garnier et al., 2001 ); leaf nitrogen reflects the photosynthesis rates as most N in the leaves is located in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo), the main enzyme of carbon fixation ( Yang et al., 2020 ); and leaf carbon content is connected to nutrient acquisition ( Xing et al., 2021 ). We measured SRL, which is the ratio between the length and mass of roots and considered an important trait in expressing the plant efficiency in nutrient and water uptake ( Ostonen et al., 2007 ).…”

Effect of restricted grazing or feeding with total mix ration environments on the properties of milk quantity and quality from dairy cows of different genotypes

“…Liu et al (2019) used hyperspectral 1order differential technology to monitor maize leaf spot disease and achieved good results. He et al (2016) and Yang et al (2020) analysed the correlation between the different order spectral differential indices and nitrogen (N) content of crop and selected the spectral differential indices with strong correlation to build the N content estimation model, which achieved good results. Pereira da Conceição et al (2020) successfully identified two mycotoxicogenic Fusarium species associated with maize based on hyperspectral differentiation technology.…”