Effects of Forest Restoration Types on Soil Quality in Red Soil Eroded Region, southern China

27 Mar Effects of Forest Restoration Types on Soil Quality in Red Soil Eroded Region, southern China

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Abstract

为了探讨主要森林类型对土壤质量的影响 ,对南方红壤侵蚀区 4种主要森林恢复类型下土壤物理、化学、生物学性状进行 了比较研究 ,结果表明: 不同的森林恢复类型导致了土壤物理、化学和生物学性质的显著差异。 4种森林类型的土壤质量均比长 期干扰下对照的土壤质量高。 人工林土壤质量又相对比天然次生林土壤质量低。 其土壤质量综合指数分别为: 天然次生林 ( 0. 95)、油茶林 ( 0. 68)、杉木林 ( 0. 55)、湿地松林 ( 0. 36)、对照 ( 0. 04)。自然恢复在恢复初期是提高土壤质量的有效途径。导致人 工林和对照土壤质量相对较低的主要因素是: 周期性的森林抚育打破土壤物理结构、凋落物质量较低、凋落物量较低、微生物生 物量较低、微生物功能较差和土壤养分流失严重。 在土壤质量指标选择方面 ,土壤微生物生物量结合微生物功能多样性是反映 土壤生物学活性和土壤质量的较好指标 。

English Abstract

Land degradation and restoration is one of the greatest challenges in subtropical hilly regions. In Southern China, the area of hilly red soil region accounts for 2.0×10~6 km~2. During recent decades, as a result of increasing demand for firewood, timber and food——human disturbance has destroyed vegetation in the region. Due to the vegetation destruction, the region was given the name, “red desert”. As a result, restoring vegetation and improving soil quality became urgent affairs of the region. It is very important to explore the effects of forest restoration types on soil quality for the restoration and management of such degraded ecosystems. In this study, four typical forest restoration types in the hilly red soil region were selected at the Ecological Benefit Monitoring Station of the Yangtze River Protection Forest——the hilly red soil region of Southern Hunan Province, which is located in the small valley of Changchong Village, Langlong Country, Hengyang County of Hunan Province. The four types are natural secondary forest, tea-oil camellia plantation, Chinese fir plantation, slash pine plantation, and the control which was frequently disturbed. The paper reports on the responses of the soil’s physical, chemical and biological properties to the four forest restoration types. From the results of this study, a soil quality index that integrated 13 soil quality indicators was calculated. In addition, the relationships between the soil’s physico-chemical and biological indicators were analyzed. Results showed that: different forest restoration types lead to significant differences in the soil’s physico-chemical and biological properties. The soil quality of selected plots was ranked as follows: 1) natural secondary forest 2) tea-oil camellia plantation 3) Chinese fir plantation 4) slash pine plantation 5) control. The indices of soil quality for the natural secondary forest, tea-oil camellia plantation, Chinese fir plantation, slash pine plantation, and control were 0.95, 0.68, 0.55, 0.36 and 0.04, respectively. The control possessed the lowest soil quality. The soil quality under the natural secondary forest was the highest among four forest restoration approaches. Natural restoration was an effective approach to improving soil quality at the early stage of restoring. The factors influencing the soil quality of plantations and the control were inappropriate artificial tending, lower litter fall production and quality, lower microbial structure and function, and nutrients loss. The findings indicate that among the 13 soil quality indicators, microbial biomass carbon, substrate richness index and Shannon’s diversity index significantly correlated with other 9, 10, 9 indicators respectively. For selecting the soil quality indicator, the microbial biomass carbon combined with microbial function diversity was the better indicator for reflecting soil biological activity and soil quality.