Peanut shell biochar improves soil properties and peanut kernel quality on a red Ferrosol

Purpose Biochar has excellent potential to improve crop yield and quality, but its effects vary depending on soil type and agronomic inputs (e.g., irrigation and fertiliser). In this study, we investigate the effects of biochar on peanut productivity and crop quality under different irrigation and fertilisation regime in red Ferrosols. Materials and methods We applied peanut shell biochar (9.2 t ha−1) on a red Ferrosol under field conditions to examine the effects of biochar, irrigation, fertiliser and their interactions on soil properties and yield and kernel quality of the peanut variety ‘Middleton’. Results and discussion Biochar application improved kernel quality by increasing the fraction of the highest commercial grade kernels (grade ‘Jumbo’) but did not affect photosynthesis and yield of peanut. Biochar application also increased soil total C (TC), total nitrogen (TN) and C/N ratio, and changed soil C and N stable isotope composition. Soil K and Zn content was higher in biochar treatments, which partially explains the observed kernel grade improvement. Fertilisation did not improve peanut performance, and irrigation generally had a negative effect on crop yield and physiology, but these data were compromised by high rainfall during cropping. There were few interactions among biochar, irrigation and fertiliser treatments. Conclusions Peanut shell biochar improves soil organic C, nutrient availability and peanut kernel quality under different irrigation and fertiliser rate regimes in field conditions.