Low Pyrolysis Temperature Biochar Improves Growth and Nutrient Availability of Maize on Typic Calciargid

Abstract

This experiment was conducted to investigate the effects of biochars, produced from maize straw at different temperatures (300, 400, and 500 °C), on growth of maize. Maximum cation exchange capacity (CEC) (106 cmolc kg‒1) of biochar was observed at 400 °C. The pH, electrical conductivity (EC), and carbon content of biochars significantly increased with increasing temperature, and maximum pH (9.8), EC (3.0 dS m‒1), and carbon content (607 g kg‒1) were observed at 500 °C. Concentration of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) significantly increased with increasing temperature, while of nitrogen (N) decreased. Ammonium bicarbonate–diethylene triamine penta acetic acid (AB-DTPA)–extractable nutrients were decreased with increasing pyrolysis temperature. Shoot and root dry matter of maize increased significantly with application of biochar produced at 300 and 400 °C and decreased significantly at 500 °C. Maximum shoot and root dry matter of maize was obtained at biochar produced at 300 °C. Phosphorus and K concentration in shoots and roots increased with biochar, and it was significantly more with fertilizer application. In contrast to P, shoot and root K concentration increased significantly with increasing pyrolysis temperature. The results of this study indicated that application of biochar produced at low pyrolysis temperature may be a practical approach to improve crop growth.