Abstract:

Forest management measures have a significant impact on carbon and nitrogen cycling in the forest ecosystems. In order to understand any effect of different fertilization treatments on water-soluble organic carbon, nitrogen (WSOC, WSON) contents, and emission of greenhouse gases, a fertilization experiment was conducted in the typical Phyllostachys edulis stands located in Lin'an, Zhejiang Province. Six treatments were applied in this study: 1) no fertilization; 2) ordinary fertilization amount; 3) 2 times of ordinary fertilization amount; 4) half of ordinary fertilization amount; 5) only nitrogen fertilizer; and 6) P fertilizer and potash. WSOC and WSON contents, and emission rates of greenhouse gases (CO₂ and N₂O) were determined. The results showed that CO₂ and N₂O emission rates significantly increased with increase in the amount of fertilization (P<0.05). In comparison with the control treatment, application of urea significantly increased emissions of CO₂ and N₂O (P<0.05). The emission of CO₂ was not significantly changed after 1 month of calcium superphosphate and potassium chloride application, while it significantly increased (P<0.05) after 6 months. Large amount of fertilizer (treatment 2 and treatment 3) significantly increased WSOC content (P<0.05); and relatively small amount of fertilizer (treatment 4) and fertilization of super-phosphate and potassium chloride (treatment 6) had no significant effect on soil WSOC content. Fertilization treatment (except for treatment 6) significantly increased WSON content (P<0.05). Correlation analysis showed that CO₂ and N₂O emission rates from the soil of P. edulis stands were significantly correlated to WSOC and WSON contents, respectively, indicating that increase in contents of WSOC and WSON caused by fertilization was probably the reason for the increase in emission of greenhouse gases.

Key words: Phyllostachys edulis, fertilization, water-soluble organic carbon (WSOC), water-soluble organic nitrogen (WSON), greenhouse gas