关键词: 毛竹林, 施肥, 土壤有机碳, 垂直分布, 季节动态, 闽西

Abstract: [Objective] To reveal mechanisms of soil fertility enhacement in moso bamboo (Phyllostachys edulis) stands and to provide data for the estimation and simulation of carbon (C) balance in forest ecosystems, we investigated the effects of fertilization on spatial and temporal pattern of soil organic carbon (SOC) in the west of Fujian province.[Method] 18 sample plots, in a size of 20 m×20 m, were set in typical pure moso bamboo forest with good growth, using randomized block design in Tianbaoyan National Nature Reserve in Yong'an. Six treatments were applied, including 5-year applications of specialized fertilizer for bamboo (Ⅰ), formula fertilizer fused with nitrogen (N)-phosphorus (P)-potassium (K) (Ⅱ),organic fertilizer (Ⅲ), 1-year applications of specialized fertilizer for bamboo (Ⅳ), organic fertilizer (Ⅴ),and non-fertilization (Ⅵ). SOC contents under different fertilization treatments, soil depths and seasons were analyzed to reveal the vertical distribution and seasonal dynamics of SOC and its relationship with soil quality in moso bamboo forest.[Result] Fertilization had no significant effects on the average SOC content in 0-100 cm soil layer. However, fertilization treatments (Ⅰ-Ⅴ) significantly decreased the SOC content in 0-10 cm soil layer by 9.05%, 27.33%, 28.84%, 18.92%, 25.37% and in 10-20 cm layer by 1.25%, 23.68%, 23.47%, 20.48%, 18.61%, respectively, whereas SOC contents in 80-100 cm layer increased by 2.72%-37.14%, suggesting that fertilization exhibited positive effects on SOC content with soil depth. In addition, SOC content and its standard error decreased with soil depth, indicating that soil C in deep layer was more stable than that in top layer. No significant seasonal changes of SOC content in bamboo forests was observed, but the SOC concentrations in autumn and winter is slightly higher than that in spring and summer. Moreover, SOC content was significantly positively correlated with soil total N, total P, hydrolysis N, available P and available K,but significantly negatively correlated with soil bulk density and pH.[Conclusion] Short-term fertilization had no significant effects on the average SOC content in the 0-100 cm soil layers and the vertical distribution pattern of SOC, but led to a significant decline of SOC in the top soil layers and a slightly increase of SOC in deep soil layer. Moreover, fertilization had no significant effects on the seasonal dynamics of SOC content, indicating that sample data was not a main determinant. Furthermore, SOC content was significantly correlated with soil total N, total P, hydrolysis N and other soil quality factors, demonstrating that minimized soil disturbance, timely and appropriate nutrient supplements, appropriate collection of bamboo shoots and cuttings of bamboo would help to maintain a high level of SOC content and long-term productivity.

Key words: Phyllostachys edulis forests, fertilization, soil organic carbon, vertical distribution, seasonal dynamics, western Fujian Province