FIGURE 2.

Chlorophyll fluorescence parameters at the flowering (A–F) and pod set (G–L) in peanut with four rates of biochar in the 2018 and 2019 growing seasons. F_v/F_m, maximal efficiency of PSII photochemistry after dark adaptation; Φ_PSII, actual efficiency of PSII photochemistry after light adaptation; Φ_NPQ, quantum yield for energy dissipated via Δ pH and xanthophyll-regulated processes; Φ_NO, quantum yield of non-regulated energy loss in PSII; qP, photochemical quenching; and NPQ, non-photochemical quenching. B0, B10, B20, and B40 represent biochar application rates at 0, 10, 20, and 40 t ha⁻¹, respectively. For each parameter in each year, mean data with different letters denote significant difference among treatments at P < 0.05.