Base cation‐enhancing role of corn straw biochar in an acidic soil

Abstract

Biochar affects base cation retention and leaching when it is used to enhance the base cation status of acidic soil. However, the details of its contribution are not yet clear. In this study, six loadings of corn straw biochar (0%, 2%, 4%, 6%, 8% and 10%, w/w) were applied to an acidic Ferralsol and incubated for 1 year. The results showed that the content of water‐soluble and exchangeable base cations of K, Na, Ca and Mg increased with increasing levels of biochar in amended soil. The percentage of water‐soluble Na, Ca and Mg of amended soil significantly decreased, while the percentage of exchangeable K, Ca and Mg increased significantly after the addition of biochar. For K and Na, biochar affected their leaching concentrations both as a source and by increasing the pH. For Ca, biochar reduced Ca leaching when the biochar loading was ≥4%, and the contribution increased from 30.8% to 100% at 4%–10% loading. For Mg, biochar reduced Mg leaching at biochar loadings 2%–10%, the reduction increasing from 22.0% to 70.5%. The results show that corn straw biochar can increase the content of the soil nutrient base cations K, Ca and Mg by increasing their exchangeable forms and enhance soil retention by decreasing their leaching. Thus, corn straw biochar can be used to effectively improve acidic soil base cation fertility.

Hydrochar Derived from Spent Mushroom Substrate Ameliorates Soil Properties and Nutrient Levels in Saline–Sodic Soil: An Incubation Study

“…The reduced ESP in incubated soils with moderate/light salinization (Table 2, group B and group C) could be attributed to a remarkable increase in Ca 2+ and Mg 2+ . Previous studies have revealed that biochar could be employed for supplying Ca 2+ /Mg 2+ in acidic soil [30]. However, total Ca/Mg content in SMSHC was insufficient to meet the increased concentration of exchangeable Ca 2+ /Mg 2+ , especially in C6 (Table 1 vs. Table 3).…”

“…It may be due to a low-temperature hydrothermal reaction that provides charring products with a more humid, acid-like structure on the surface of SMSHC [32]. In the context of the low available P content, SMSHC improved soil P availability probably by dissolving phosphate crystal phases [30]. A possible explanation for the poor improvement of available P in light saline-sodic soil (Figure 2B) could be due to the negative effect of Ca 2+ on P availability.…”