Biochar ageing improves soil properties, growth and yield of red radish (Raphanus sativus) in a Haplic Cambisol

by Patrick Nyambo, Hammond Motsi, Cornelius Chiduza, Mashapa Elvis Malobane

The use of biochar as a soil ameliorant has recently gained momentum. However, its application has been reported to have some adverse effects soon after the pyrolysis process. This study aimed to determine the effect of different biochar ageing methods and fertiliser applications on selected soil properties, growth, and yield of red radish (Raphanus sativus L.). A 2 x 3 factorial arrangement was used in a complete randomised design (CRD) with three replications. The factors were (1) biochar ageing at three levels, i.e., naturally aged biochar (NB), artificially aged biochar (AB), and fresh biochar (FB), and (2) fertiliser at two levels viz fertilised (F) and non-fertilised (NF). A control treatment (without biochar) was also included. Irrespective of the ageing method used, biochar application significantly increased soil pH, while fertiliser application significantly reduced soil pH throughout the experiment. Similarly, biochar application significantly increased soil hydraulic conductivity compared to the control. However, after ten weeks, significantly higher soil hydraulic conductivity was reported in treatments with AB biochar compared to both NB and FB. The application of fertiliser in biochar-amended soils improves the soil’s hydraulic properties and increases radish growth. The study concludes that AB biochar + fertiliser application improves soil properties and growth of radish.