Interactive Effects of Soil and Foliar-Applied Nanobiochar on Growth, Metabolites, and Nutrient Composition in Daucus carota

Soil amendment with nanobiochar (a novel nanomaterial) may benefit crop production by modulating water-holding capacity, increasing biotic interactions, and providing an additional source of macro- and micronutrients. We reported nano-biochar-induced changes in carrot agronomic, ionomic, and nutriomic profiles. Root-zone application of nanobiochar at four levels [0 (control), 0.1 (S 1 ), 0.3 (S 3 ), and 0.5% (S 5 )] was performed at sowing and foliar spray of nanobiochar suspension [0 (control), 1 (F 1 ), 3 (F 3 ), and 5% (F 5 )] after 30 days of germination. The combined application of soil and foliar nanobiochar induced more growth and improved pigments in the shoot and storage root of the carrot. Results indicated maximum improvements (+ 3–4 folds) in shoot agronomic traits at S 3 F 3 . This trend was also evident in the case of chlorophyll content (both a and b ), some primary and specialized metabolites (sugars, free amino acids, phenolics, flavonoids), and P, N, and K content in leaves which were maximum at S 3 F 3 . The chlorophyll a , b, and carotenoids in shoot showed 2-, 2-, 4-fold, and anthocyanin, β-carotene, and lycopene in roots showed 2-, 2-, and 3-fold increase at S 3 F 3 , and it showed a fold increase in than control. While carrot root weight (4-fold increase than at control) was maximum at S 3 F 1 . The root nutriomic profile revealed the highest N, P, and K content and root pigments (lycopene, beta-carotene, and anthocyanins) at S 3 F 1 , while the least values were associated with control plants. These results showed that nanobiochar could be used as sustainable fertilizer due to its beneficial effects and high nutritional content.