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Wang Q.,CAS Shenyang Institute of Applied Ecology | Wang S.,CAS Shenyang Institute of Applied Ecology | Wang S.,Huitong National Research Station of Forest Ecosystem
Applied Soil Ecology

Labile soil organic matter (SOM) can sensitively respond to changes in land use and management practices, and has been suggested as an early and sensitive indicator of SOM. However, knowledge of effects of forest vegetation type on labile SOM is still scarce, particularly in subtropical regions. Soil microbial biomass C and N, water-soluble soil organic C and N, and light SOM fraction in four subtropical forests were studied in subtropical China. Forest vegetation type significantly affected labile SOM. Secondary broadleaved forest (SBF) had the highest soil microbial biomass, basal respiration and water-soluble SOM, and the pure Cunninghamia lanceolata plantation (PC) the lowest. Soil microbial biomass C and N and respiration were on average 100%, 104% and 75%, respectively higher in the SBF than in the PC. The influence of vegetation on water-soluble SOM was generally larger in the 0-10cm soil layer than in the 10-20cm. Cold- and hot-water-soluble organic C and N were on average 33-70% higher in the SBF than in the PC. Cold- and hot-soluble soil organic C concentrations in the coniferous-broadleaved mixed plantations were on average 38.1 and 25.0% higher than in the pure coniferous plantation, and cold- and hot-soluble soil total N were 51.4 and 14.1% higher, respectively. Therefore, introducing native broadleaved trees into pure coniferous plantations increased water-soluble SOM. The light SOM fraction (free and occluded) in the 0-10cm soil layer, which ranged from 11.7 to 29.2gkg-1 dry weight of soil, was strongly affected by vegetation. The light fraction soil organic C, expressed as percent of total soil organic C, ranged from 18.3% in the mixed plantations of C. lanceolata and Kalopanax septemlobus to 26.3% in the SBF. In addition, there were strong correlations among soil organic C and labile fractions, suggesting that they were in close association and partly represented similar C pools in soils. Our results indicated that hot-water-soluble method could be a suitable measure for labile SOM in subtropical forest soils. © 2010 Elsevier B.V. Source

Wang Q.,CAS Shenyang Institute of Applied Ecology | Wang Q.,Huitong National Research Station of Forest Ecosystem | Zhong M.,CAS Shenyang Institute of Applied Ecology | Zhong M.,University of Chinese Academy of Sciences | And 2 more authors.
Biology and Fertility of Soils

Litter decomposition is a major fundamental ecological process that regulates nutrient cycling, thereby affecting net ecosystem carbon (C) storage as well as primary productivity in forest ecosystems. Litter decomposes in its home environment faster than in any other environment. However, evidence for this phenomenon, which is called the home-field advantage (HFA), has not been universal. We provide the first HFA quantification of litter decomposition and nutrient release through meta-analysis of published data in global forest ecosystems. Litter mass loss was 4. 2 % faster on average, whereas nitrogen (N) release was 1. 7 % lower at the home environment than in another environment. However, no HFA of phosphorus (P) release was observed. Broadleaf litter (4.4 %) had a higher litter mass loss HFA than coniferous litter (1.0 %). The positive HFA of N release was found in the coniferous litter. Mass loss HFA was significantly and negatively correlated with the initial lignin:N litter ratio. The litter decomposition and N release HFAs were obtained when mesh size ranged from 0.15 mm to 2.0 mm. The HFA of litter decomposition increased with decomposition duration during the early decomposition stage. The HFA of N release was well correlated with mass loss, and the greatest HFA was at mass loss less than 20 %. Our results suggest that the litter decomposition and N release HFAs are widespread in forest ecosystems. Furthermore, soil mesofauna is significantly involved in the HFA of litter decomposition. © 2012 Springer-Verlag Berlin Heidelberg. Source

Wang Q.,CAS Shenyang Institute of Applied Ecology | Wang S.,CAS Shenyang Institute of Applied Ecology | Yu X.,Huitong National Research Station of Forest Ecosystem
Land Degradation and Development

The effects of forest conversion on soil fertility are still not well understood in subtropical zones. This issue was addressed by comparing chemical properties of soil in a secondary forest and a Chinese fir (Cunninghamia lanceolata Hooker) plantation at the Huitong Experimental Station of Forest Ecology. Total N, available P, NO 3 --N, cation exchange capacity (CEC) and exchangeable Al 3+ and H + of soil were significantly lower in the pure Chinese fir plantation (PCP) than in the secondary forest while soil organic carbon (SOC), total K and exchangeable Na + had a tendency to decrease in the PCP. In contrast, soil pH and percentage base saturation (PBS) significantly increased due to forest conversion, and available K, NH 4 + and exchangeable Ca 2+, Mg 2+ and K + tended to increase in the PCP. Some underlying processes responsible for the differences in soil fertility between the secondary forest and the Chinese fir plantation were low litterfall and root input to soil and site preparation in coniferous plantations. There was no significant difference in the effect of slope position on chemical properties of soil in the PCP and the secondary forest. Results indicated that the conversion of secondary forests to coniferous plantations leads to a decline in soil fertility. © 2010 John Wiley & Sons, Ltd. Source

Chen L.-C.,CAS Shenyang Institute of Applied Ecology | Chen L.-C.,Huitong National Research Station of Forest Ecosystem | Wang S.-L.,CAS Shenyang Institute of Applied Ecology | Wang S.-L.,Huitong National Research Station of Forest Ecosystem

Allelopathy of Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.] has been considered an important cause of productivity decline in successive rotations in Chinese fir plantations. Growth of Chinese fir germinants was measured to understand the allelopathic potential of its leaves and roots, as well as its rhizosphere soil, from different plantation ages. Results show that aqueous extracts from Chinese fir leaves and roots and rhizosphere soil significantly inhibited the growth of germinants. Leaf aqueous extracts showed the strongest inhibitory effects indicating that allelochemicals were produced by the leaf and released into the soil through the roots. Leaf and the root aqueous extracts, as well as the rhizosphere soil, from older Chinese fir plantations exhibited stronger allelopathic potential. Tissue aqueous extract from a 27-year-old Chinese fir showed stronger inhibitory effects on the growth of germinants compared with that from a 3-year-old one. More cyclic dipeptides were found in the leaf aqueous extract; and even more were found in the tissue aqueous extract and in the rhizosphere soil from older plantations. This suggests that more cyclic dipeptides are produced by leaves and released into the soil through the root exudation as Chinese fir plantations increase in age. © Institute of Chartered Foresters, 2012. All rights reserved.. Source

Zhang W.,CAS Shenyang Institute of Applied Ecology | Zhang W.,Huitong National Research Station of Forest Ecosystem | Wang S.,CAS Shenyang Institute of Applied Ecology | Wang S.,Huitong National Research Station of Forest Ecosystem
Soil Biology and Biochemistry

Soil organic carbon (SOC) dynamics and nutrient availability determine the soil quality and fertility in a Chinese fir plantation forest in subtropical China. Uniformly 13C-labeled Chinese fir (Cunninghamia lanceolata) and alder (Alnus cremastogyne) leaf litter with or without 100mg NH 4 + or NO 3 - were added to the soil. The purpose was to investigate the influence of N availability on the decomposition of the litter and native SOC. The production of CO 2, the natural abundance of 13C-CO 2, and the inorganic N dynamics were monitored. The results showed that Chinese fir (with a high C:N ratio) and alder (with a low C:N ratio) leaf litter caused significant positive priming effects (PEs) of 24% and 42%, respectively, at the end of the experiment (235d). The PE dynamics showed that positive PE can last for at least 87d. However, the possible occurrence of a significant negative PE with a sufficient incubation period is difficult to confirm. The application of both NH 4 + and NO 3 - was found to have a stimulating effect on the decomposition of Chinese fir and alder leaf litter in the early stage (0-15d) of incubation, but an adverse effect in the late stage. Compared with NO 3 -, NH 4 + caused a greater decrease in the PE induced by both Chinese fir and alder leaf litter. The effects of NH 4 + and NO 3 - on the PE dynamics had different patterns for different incubation stages. This result may indicate that the stability or recalcitrance of SOC, especially in such plantation forest soils, strongly depends on available leaf litter and application of N to the soil. © 2011 Elsevier Ltd. Source

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