Biochar Impacts on Acidic Soil from <i>Camellia Oleifera</i> Plantation: A Short-Term Soil Incubation Study

Nowadays, biochar is increasingly used widely as an important soil amendment to enhance soil nutrients availability. Therefore, we investigated the effect of <i>C.</i><i>oleifera</i> shell biochar (CSB) on <i>C.</i><i>oleifera</i> plantation soils to provide evidence that <i>C. oleifera</i> shell as a raw material in biochar has great potential to be a soil amendment. For this, a short-term incubation experiment was conducted in controlled conditions to evaluate the effects of CSB application on two soil chemical properties, microbial biomass, and enzymatic activity. We compared two acidic soils, mixed with CSB of three pyrolysis temperatures (300, 500, and 700 °C), and two application rates (3% and 5% (<i>w</i>/<i>w</i>)), incubated for 180 days. The results showed that the soil pH, total P (TP), and available P (AP) significantly increased under 5CSB700 in two soils, and indicated CSB application rate and pyrolysis temperature had a significant impact on soil pH, TP, and AP (<i>p</i> < 0.05). CSB application also significantly increased the total inorganic P in two soils and presented a significantly positive correlation with soil pH, TP, and AP under redundancy analysis. The results suggested that CSB application has a variable effect on soil enzymatic activity, microbial biomass C (MBC), and microbial biomass P (MBP) on average, while it increased the soil microbial biomass N (MBN) in both soils. We concluded that CSB could be a soil amendment to increase soil nutrients of <i>C.</i><i>oleifera</i> plantation soils. Before the application of biochar to <i>C.</i><i>oleifera</i> plantation forest soils, long-term studies are required to assess the effects of biochar under field conditions and its promoting effect on the growth of <i>C. oleifera</i>.