Positive effects of in-situ composting of tea plant pruning residues on soil fertility, tea quality, and microbial diversity

Tea plant ( Camellia sinensis L.) is a major economic crop in Guizhou Province, China, which generated annually over 6 million tons of tea plant pruning residues. Traditional disposal methods, such as burning and natural degradation, contributed to environmental pollution and slow decomposition. In addition, long-term uses of chemical fertilizers lead to soil compaction and reduce fertility in tea plantations. This study evaluated in-situ field composting of tea plant pruning residues to assess the physicochemical changes during composting, and the effects of compost products on tea plant quality and soil properties. The results showed that the high-temperature phase (≥ 50℃) of composting was maintained for 16 d, and the degradation rate of allelopathic substances exceeded 92 % after inoculation with Clostridium thermocellum sp. Meanwhile, total nitrogen (TN), total phosphorus (TP), and total potassium (TK) increased by 8.24 %–71.22 %, and humic acid content reached 212.66 g kg⁻¹ . Additionally, the application of bio-compost (BC) +chemical fertilization (CF) improved tea plant biomass, quality components, soil nutrients, enzyme activities, and microbial diversity compared to CF alone. However, the impacts of BC and BC + CF on microbial community composition were negligible. This study successfully transformed tea plant pruning residues into high-value organic fertilizers, providing a scientific basis for resource recovery and fertilizer utilization. The findings are crucial for promoting ecological circular agriculture in tea gardens. • In situ bio-composting efficiently accelerated the decomposition of tea pruning residues. • Bio-composting decreased allelochemicals (tea polyphenols, and caffeine) while increased nutrients contents. • Bio-compost was beneficial and safe for tea seedling growth and soil health.