Identifying biochar production variables to maximise exchangeable cations and increase nutrient availability in soils

CaAl-Layered Double Hydroxides-Modified Biochar Composites Mitigate the Toxic Effects of Cu and Pb in Soil on Pea Seedlings

“…After 80 d of soil incubation, 60 g of soil from each control group was vacuum freeze-dried, milled, and sieved through a 60-mesh sieve to prepare for the determination of the available content of heavy metals, the distribution of heavy metals, pH, SOCC, SOC, APC, and AKC in the soil. The results are summarized in Table 1 The soil pH was determined by a pH meter after shaking the soil for 30 min at 25 °C in the ratio of 2.5 mL of water to 1 g of soil [ 21 ]; the SOCC was measured by centrifuging 3.5 g of soil sample + 50.0 mL of 16.6 mmol/L of hexamine cobalt trichloride (Co(NH 3 ) 6 Cl 3 ) solution for 60 min at 25 ± 2 °C, and measuring the absorbance at 475 nm after shaking [ 22 ]; the soil AKC was generally determined by the ammonium acetate (NH 4 OAc) extraction method [ 23 ]; the soil APC was determined according to the ammonium fluoride hydrochloric acid leaching method [ 24 ]; the soil SOC was determined by the potassium dichromate oxidation spectrophotometric method [ 25 ]; and the available content of Cu and Pb in the soil was determined by flame atomic absorption spectrometry (AA-6880 Shimadzu, Kyoto, Japan) after extraction using the diethylenetriaminepentaacetic acid (DTPA) extraction method [ 26 ].…”