Evaluating the Influence of Nitrogen Fertilizers and Biochar on Brassica oleracea L. var. botrytis by the Use of Fourier Transform Infrared (FTIR) Spectroscopy

Abstract

The exponential growth of the human population requires an increasing application of nitrogen (N) fertilizers, causing environmental pollution. Biochar (B) amended soil has been suggested as a sustainable agricultural practice to improve crop yield and mitigate agricultural pollutants’ contamination. Evaluating the effect of fertilization on Brassica crops, in combination with spectral analysis, may specify changes in the chemical composition of the vegetable as a result of N fertilization. This study characterized cauliflower tissues treated with N fertilizer and biochar, employing Fourier Transform Infrared spectroscopy. The experiment was conducted in cauliflower mesocosms treated with two doses of N fertilizer (130 and 260 kg N ha−1) with or without B. Attenuated total reflectance fractions were used to characterize fractions of curds, leaves, stems, and roots in the infrared using a Fourier transform. Principal component analysis was performed to classify the main differences among cauliflower tissues concerning treatments. FTIR spectra of Brassica oleracea L. var. botrytis tissues were related to nitrogen-based agricultural practices. The specific molecules associated with functional groups in cauliflower tissues were phenols, amides, proteins, amines, and glucosinolates. Biochar amended soil resulted in higher peaks that correspond to the stretching of phenols and proteins. The application of sustainable nitrogen fertilizers might influence the absorption bands characteristic of cauliflower’s typical metabolites. The research allows the identification of Brassicaceae’s functional molecules with a potential agronomic application.