Effects of Biochar on the Availability of Trace Elements in Different Types of Soil

To investigate the effects of biochar on the availability of trace elements (Fe, Mn, Cu, and Zn) in soils with different properties, biochar derived from wheat straw (WSBC) and peanut shells (PSBC) was added to red and yellow-brown soils for pot experiments. The results showed that WSBC and PSBC significantly increased the red and yellow-brown soils' organic matter (SOM) and available potassium (AK), C, and C/N, especially with WSBC in red soil. The total and available amounts of trace elements in red and yellow-brown soil decreased after biochar was applied, where the effect of WSBC on the available of Fe, Mn, and Zn was greater than that of PSBC and the effect on the available contents of Fe, Mn, and Zn was less than that of PSBC. WSBC and PSBC decreased the contents of Fe, Mn, and Zn in the grains in both soils, while they increased the content of Cu in the grains. According to the results of a canonical correlation analysis, there was a competitive relationship between Mn and Cu in the grains. Fe and Zn in the grains were negatively correlated with AP in red soil and positively correlated with AP in yellow-brown soil. This study evaluates the effect of biochar on soil nutrient cycles, ultimately maximizing the application of biochar in the field of agriculture.