Effect of biochar applications on soil phosphorus availability under different soil moisture levels
Soil moisture level is crucial to soil phosphorus (P) availability. However, there is no quantitative research on the relation between soil P availability and moisture level. In addition, biochar application could also alter soil P availability at different moisture levels. In this study, a 16-day soil incubation experiment was conducted at a laboratory-scale to analyze the effects of soil moisture and P fertilization regimes (P-laden biochar fertilizer and conventional mineral P fertilizer) on soil P availability and fractionation. The results showed that soil P availability was positively correlated with soil moisture level (Pearson coefficients ranged from 0.46 to 0.91). High moisture level would lead to less amount of P in readily available fractions under P-laden biochar application. However, even with less P in readily available fractions, P-laden biochar could maintain soil P availability (117.7 mg P m-2) at a similar level as the conventional P fertilizer (116.1 mg P m-2).