High temperature-produced biochar can be efficient in nitrate loss prevention and carbon sequestration

Nitrogen Availability in Biochar-Amended Soils with Excessive Compost Application

“…All the other soils presented insignificant changes, possibly due to their low NH 4 + -N concentrations (≤6 mg/kg). This agrees with the findings of Hailegnaw et al [23] and Jones et al [29], who reported insignificant effects during biochar applications of 8% and 50 t/ha, respectively. The high production temperature of biochar may have resulted in the low CEC of the biochar [23,27], which could be attributed to low polarity (low Oxygen/Carbon or O/C ratio) and the conversion of acidic functional groups on the biochar surface to neutral or basic-fused aromatic groups after losing their oxygen-containing functional groups.…”

“…The addition of biochar alone significantly (p < 0.05) reduced the NO 3 − -N content after 25 days of incubation, but the addition rate had no significant effect on the NO 3 − -N content [28]. The results of the pot incubation experiment [23] indicated that the additions of 0.5%, 2%, 4%, and 8% wood-chip-based biochar resulted in nitrate declining by up to 35%, 70%, 76%, and 81%, respectively, relative to the control. The study results of Yao et al [32] identified a 34% reduction in nitrate leaching following the addition of biochar produced from pepperwood at 600 • C. Similarly, in N-rich soil, 2% and 4% of apple branch biochar reduced soil nitrate contents [34].…”

“…Four proportions of wood chip-based biochar (0.5%, 2%, 4%, and 8%) were added to ten different soils, with the results of the pot incubation experiment [23] indicating that the biochar increased the content of the soil ammonium by up to 184% and decreased it by up to 79%; however, in most cases the effect was insignificant and inconsistent in terms of the time and the rate of the biochar application. The authors also indicated that a significant decline in the content of the ammonium of the four soils was noted during the first week of incubation, showing that all samples had considerably high contents of NH 4 + -N (≥15 mg/kg) in comparison to the other soils.…”

“…The high production temperature of biochar may have resulted in the low CEC of the biochar [23,27], which could be attributed to low polarity (low Oxygen/Carbon or O/C ratio) and the conversion of acidic functional groups on the biochar surface to neutral or basic-fused aromatic groups after losing their oxygen-containing functional groups. The CEC of biochar in this study was very low (5.2 cmol (+)/kg/soil) (Table 1), in association with a lower O:C molar ratio and fewer acidic The high production temperature of biochar may have resulted in the low CEC of the biochar [23,27], which could be attributed to low polarity (low Oxygen/Carbon or O/C ratio) and the conversion of acidic functional groups on the biochar surface to neutral or basic-fused aromatic groups after losing their oxygen-containing functional groups. The CEC of biochar in this study was very low (5.2 cmol (+)/kg/soil) (Table 1), in association with a lower O:C molar ratio and fewer acidic functional groups [21].…”

“…The adsorption effects observed with the high-temperature biochar (700 • C) could be one of the reasons for the decline in the soil nitrate content. Several studies reported the adsorption of nitrate using a high-temperature biochar [8,15,23,31,32]. For a biochar to have any NO 3 − adsorption potential, the pyrolysis process must occur at a temperature of at least 600 • C [26].…”