Early-Stage Growth Performance of Apple Trees Under Different Biochar Application Methods in Mineral and Organic Fertilisation Regimes

Biochar has gained attention as a promising soil amendment capable of improving soil structure, nutrient retention and plant resilience to stress. However, its performance in perennial horticultural systems, particularly during the early stages of orchard establishment, remains insufficiently documented. This study, conducted in 2021 in a newly established apple orchard (‘Gala Brookfield Baigent’/P 60) in Wieluń, Central Poland, aimed to evaluate the effectiveness of three methods of using cattle-manure-derived biochar at a dose of 10 t ha−1 (application before ploughing prior to orchard establishment, application to planting holes and surface spreading). Neither tree growth nor fruiting potential were affected by biochar, which made the comparison of its application methods inconclusive. According to the principal component analysis performed, mineral nitrogen showed a tendency to promote the formation of mixed-type buds on short shoots, a propitious growing pattern for intensive orchard management. In contrast, compost fertilisation favoured vegetative growth over generative development, as reflected by the significantly negative coefficient in regression analysis (b = −0.12; 95% CI: −0.25 to –0.00 for the Box-Cox-scaled fruiting-to-growth potential ratio). Nonetheless, the overall growth response of apple trees in the first year after planting to the applied soil-enriching practices was rather modest, with this observation validating the strategy of reducing fertiliser doses during orchard establishment on productive soils maintained in good agricultural condition. Long-term studies under abiotic or nutrient-limiting constraints, as well as the combined use of biochar with microbial inoculants, are recommended to fully elucidate its potential in apple production.