Application of Biochar Changed the Status of Nutrients and Biological Activity in a Calcareous Soil

Low nutrient availability and biological activity are the main challenges in calcareous soils with low organic matter (OM) content. The purpose of the present study was to evaluate the responses of soil nutrient status and biological traits to addition of corn residue biochar produced at different pyrolysis temperature in a calcareous soil. Biochars were made at 200 (BC200), 350 (BC350), and 500 °C (BC500), added to a calcareous soil at 1 and 2% ( w / w ) and were incubated for 90 days. The application of biochars increased soil organic carbon (SOC), electrical conductivity (EC), cation exchange capacity (CEC), total N [1.21- to 1.41-fold], available P [1.71- to 2.65-fold], K [1.53- to 2.60-fold], Mn [1.14- to 1.21-fold], microbial respiration [1.21- to 2.23-fold], substrate-induced respiration [1.22- to 2.63-fold], microbial biomass carbon [1.20- to 2.24-fold], the activity of catalase [1.80- to 2.93-fold], and dehydrogenase [1.47- to 2.30-fold], which varied with the pyrolysis temperature and application rate. Generally, all the measured biological attributes were higher in BC200 than the other treatments. The BC200 biochar increased soil inorganic nitrogen [1.14- to 1.21-fold] and available Fe [1.12- to 1.17-fold], Zn [1.32- to 1.42-fold], and Cu [1.06- to 1.10-fold]. In contrast, the BC500 at 2% rate decreased available Fe, Zn, and Cu. The findings revealed that the application of corn biochar obtained at 200 °C to calcareous soil was more efficient for improving the nutrient availability and microbial activity.