Phosphorus tests and sediment properties
Pearson’s correlations were performed to investigate the relationship between P extraction efficiency and sediment physico-chemical properties (Table. 6). The P extractants were negatively correlated with pH and the correlation was strongest with 0.1 M NaOH. Wang et al. (2012) who found that pH was important soil parameter to all the equations relating P concentration in leachates with Olsen-P, Mehlich III-P, and Bray II- P concentrations. Obviously, the correlation factor was higher for Colwell than other P extractants for EC (r = 0.93, P <0.001). The study by Arfania et al. (2018) revealed that sediment chemical properties such as electrical conductivity, organic matter, pH and calcium carbonate, had effects on the distribution and bioavailability of P pools. Calcium carbonate equivalence (CCE) was negatively correlated with Colwell and NaOH 0.1 M. Olsen, Colwell and 0.1 M NaOH extractant were positively correlated with organic matter content Jalali and Jalali. (2017) reported that pH, and EC made important contributions to most P release from leaching column, while OM and silt content was less contributed on P availability. A positive correlation of Olsen and Mehlich III with the silt fraction indicated the influence of sediment particle size on P bioavailability (Table 6).