Іntegrative assessment of biochar impacts on soil chemistry, plant water relations, and photosynthetic pigment content in Fragaria × Ananassa
Abstract
Background. Biochar is widely promoted as a soil amendment that can improve fertility, retain nutrients, and enhance crop performance, yet its effects vary strongly with soil type, application rate, and time since application. Evidence for perennial fruit crops grown on fertile soils without mineral fertilizer remains limited. This study evaluated how biochar affects soil chemical properties, leaf physiology, and fruit production of strawberry under field conditions. Materials and Methods. A two-year field experiment (2024–2025) was conducted with biochar applied at 0, 2, 5, and 10 tonnes per hectare, each treatment replicated in three plots, without synthetic fertilizer. One year after application, composite soil samples were analyzed for acidity, soil organic matter, mineral nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium, plant-available and total trace elements, following national standard methods. Leaf relative water content and photosynthetic pigment concentrations were measured in both years, and individual fruit weight and yield were recorded. Results. Biochar effects on bulk soil chemistry were limited and selective. Phosphorus and potassium, already abundant, and soil acidity remained unchanged. The clearest responses occurred in soluble pools: ammonium nitrogen, water-soluble calcium, and plant-available zinc and mercury declined, while water-soluble magnesium rose sharply, with several effects strongest at the lowest rate. Biochar improved leaf water status in both years and markedly increased chlorophyll b content in the second year, particularly at the highest application rate. In contrast, chlorophyll a and carotenoids levels remained largely unchanged. Compared with the control, fruit weight declined in the 5 t/ha treatment during the second growing season. Conclusions. Biochar produced measurable but modest effects on the soil-plant system that did not translate into yield gains within two years, indicating that benefits on fertile soils emerge slowly and depend on application rate and management.