Combined biochar and nitrogen application stimulates enzyme activity and root plasticity

Long‐term biochar application promotes rice productivity by regulating root dynamic development and reducing nitrogen leaching

“…This finding is inconsistent with previous meta‐analysis studies that showed biochar application improved (He et al., 2020; Xiang et al., 2017) or had no influence on root biomass (Biederman & Harpole, 2013). Thus, biochar application might not be the most important proxy describing the belowground processes and responses (Song et al., 2020). The root/shoot ratio was lower in the treatment with both N fertilizer and biochar application compared with the N fertilizer only treatment during the whole growth period, except the grain filling stage (Figure 1j).…”

In‐situ biochar production associated with paddies: Direct involvement of farmers in greenhouse gases reduction policies besides increasing nutrients availability and rice production

“…Significant increase of grains N, P, and K concentrations in plants grown on biochar treated soils (both LB and IB) comparing to the control (Table 4) is due to increasing nutrients availability following biochar addition (Table 3). The porous structure of IB (Figure 2) and the presence of cavities of various sizes provided a suitable medium not only for the activity of nitrifying bacteria (Song et al, 2020) but also prevented nitrogen loss (Lehmann et al, 2015). Therefore, fixation of nitrogen at the surface of biochar pores (Nelissen et al, 2012) and the improved nitrification process (W. Huang et al, 2013; Song et al, 2020) are the main reasons for N availability and consequently increasing the concentration of nitrogen in grains (Table 3).…”

“…The porous structure of IB (Figure 2) and the presence of cavities of various sizes provided a suitable medium not only for the activity of nitrifying bacteria (Song et al, 2020) but also prevented nitrogen loss (Lehmann et al, 2015). Therefore, fixation of nitrogen at the surface of biochar pores (Nelissen et al, 2012) and the improved nitrification process (W. Huang et al, 2013; Song et al, 2020) are the main reasons for N availability and consequently increasing the concentration of nitrogen in grains (Table 3). The alkaline nature of biochar due to loss of acidic surface functional groups, mainly aliphatic carboxylic acids (Rutherford et al, 2005), and increasing soil pH (i.e., the liming effect) increased the availability of P and K (Table 3).…”

“…With this in mind, it is not surprising that the percentage of biochar yield in the slow pyrolysis process (IB) is higher than that of the fast pyrolysis (LB) (Table 2). A 2.5‐times higher biochar yield in IB comparing to LB (Table 2) means more functional groups and more negative charged sites and consequently a higher CEC which subsequently improves grain yield via providing a better cations and nutrients availability (Lehmann et al, 2015; Song et al, 2020). Despite a higher CEC in IB (31.1 cmol (+) kg −1 ) compared to LB (24 cmol (+) kg −1 ) (Table 2), no significant difference in response to the grain yield was observed between these treatments (Figure 3a).…”

“…Microscopic images showed that rice husk biochar has pores larger than 10 micrometers (Figure 2). This size of pores plays an important role in the availability of water in the root area and the expansion of root movement in the soil (Asadi et al, 2021; Song et al, 2020). This provides a better condition for plant growth along increase in the root coexisting microorganisms which increases nutrients cycling and nutrients use efficiency (Lehmann et al, 2015; Song et al, 2020).…”