Seasonal Variations and Driving Factors of Soil Respiration and Its Temperature Sensitivity to Fertilizer Addition in Phyllostachys edulis Plantations of Southern China

Soil respiration (SR) is a vital indicator of soil quality. With global warming and soil fertility degradation, understanding the evolution of fertilization and SR along with their response to climate change is crucial. This study used specially formulated fertilizers (N : P : K 17 : 8 : 5) in Phyllostachys edulis plantations in Yongan city, Southern China, to explore changes in SR and its temperature sensitivity (Q10) under five different fertilization (0, 15, 30, 50, and 75 kg ha–1) covering all seasons. Within a certain range of fertilizer application, both SR and Q10 increased. However, when fertilizer application exceeded a threshold, both SR and Q10 decreased instead. At the seasonal scale, both SR and Q10 exhibited a seasonal pattern, with higher values during summer and lower values during winter. Furthermore, SR in spring consistently higher than that in fall. The primary driving factors of SR varied among the seasons, with soil temperature being the dominant factor in spring, while C/N was predominant during summer, fall, and winter. However, soil pH was the primary driving factor of Q10 in all seasons. These findings provide valuable insights for optimizing sustainable forest management practices to improve soil health.