Effect of Temperature on Organic Carbon Mineralization in Two Types of Soil at Tea Plantations

An incubation test on the yellow and alpine meadow soils collected from the tea plantations in the subtropical region was conducted at 10, 20, and 30℃ to examine the response of the soil organic carbon (SOC) mineralization due to the temperature changes. The results showed that, in a 47 d incubation, both soil type and temperature significantly affected the SOC mineralization with significant interactions between the two factors. At a same incubation temperature, the SOC mineralization accumulation and mineralization constant (k) were significantly higher in the alpine meadow than the yellow soil, but not on the mineralization rate. The cumulative SOC mineralization increased with increasing temperature by 20.90%-91.88% on the yellow soil, and 48.52%-113.88% on the alpine meadow soil. The temperature sensitivity, Q₁₀, on SOC of the alpine meadow soil was significantly higher than that of the yellow soil, suggesting a greater effect of climate warming on SOC mineralization for tea plantations at higher altitudes. In addition, Q₁₀ were higher at lower temperatures (<20℃) than higher temperatures (>20℃), indicating that the mineralization was more sensitive to temperature rise at low temperatures. And, when the temperature was lower than 20℃, the sensitivity of the alpine meadow soil was significant higher than that of its counterpart. Whereas, as the temperature raised beyond 25℃, no significant difference was found between them. The dynamics of SOC mineralization appeared to fit a first-order kinetics function, while the SOC mineralization potential (C_o) increased with increasing incubation temperature.