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This study aimed to explore the effects of thinning years on the water holding capacity of litter layer and soil layer in Chinese fir forest, thus to provide a scientific basis for evaluating the response of water conservation function of Chinese fir forest to thinning. In Jingning County, southwest Zhejiang Province, the Chinese fir forest with thinning for 1 year, 3 years, 8 years and unthinning was selected as the research object, and the litter and soil samples were collected. Then, the moisture content, water holding capacity, soil bulk density, non-capillary porosity of litter were analyzed and measured, and the relevant indexes were calculated. The results showed that there was no significant difference in the litter stock on hand of Chinese fir forest among different thinning years (P>0.05). The relationship between litter water holding capacity, water holding rate and water immersion time was in accordance with logarithmic function and power function, respectively. The maximum water holding capacity, maximum retention rate and effective retention rate of litter layer in Chinese fir forest with thinning for 8 years were significantly higher than those in the unthinned forest (P<0.05). The maximum water holding capacity and effective retention rate of litter layer in Chinese fir forest with thinning for 3 years and 8 years were significantly higher than those in unthinned forest (P<0.05). After thinning for 8 years, the soil bulk density of 0-10 cm soil layer in Chinese fir forest was significantly decreased (P<0.05), the non-capillary porosity was significantly increased, and the non-capillary water holding capacity was significantly increased by 22.4% (P<0.05). However, there was no significant effect on the related indicators of soil water storage performance in 10-30 cm soil layer (P>0.05). In conclusion, the water conservation function of litter layer and soil layer in Chinese fir forest was enhanced with the extension of thinning years. [ABSTRACT FROM AUTHOR]

In order to explore the application effect of different light quality as the light source of tobacco growth, by taking Nicotiana benthamiana as the experimental material under the condition of artificial climate chamber, three light sources with different light quality, including LED-v1 (R1.2/B1, R3.4/FR1), LED-v2 (R7.4/B1, R2.9/FR1), and LED-v1/v2 (R2.3/B1, R3.1/FR1), were set up to analyze the response of tobacco growth indicators to different light quality. The results showed that the plant height, stem thick, leaf area, blade number and biomass of Nicotiana benthamiana treated with LED-v1/v2 were significantly better than those of other treatments. Low R/FR and low R/B light quality could increase the N content in the leaves of tobacco, help to synthesize the organic matters and improve the stress resistance, and also improve the economic quality of tobacco. Appropriately reducing the R/B and R/FR values of LED-v1/v2 light quality was more conducive to the growth of f tobacco and its quality improvement. There was no significant difference in the chlorophyll fluorescence parameters such as photosynthetic reaction centre II (ΦPSII)> apparent electron transport rate (ETR), PS II maximal photochemical efficiency (Fv/Fm) among different treatments. In summary, the most suitable artificial light source for the growth of tobacco was LED-v1/v2 (R2.3/B1, R3.1/FR1). [ABSTRACT FROM AUTHOR]

By taking the public welfare forest land in Jiangshan City of Zhejiang Province as the research object, based on the measured data of fixed sample plots and sublot of public welfare forest, the water conservation capacity and value of litter layer and soil layer in different forest stands were quantitatively measured and analyzed. The results showed that the effective interception amount of litter in different forest types of public welfare forest in Jiangshan City was coniferous and broad-leaved mixed forest>broad-leaved forest>Chinese fir forest>pine forest>moso bamboo forest. In the same depth of soil layer, the difference of soil physical properties and water holding capacity was not obvious. The soil layer contributed more than 99 % of the water conservation quantity of forest land. The order of water conservation ability was coniferous and broad-leaved mixed forest>broad-leaved forest>moso bamboo forest> Chinese fir forest>coniferous mixed forest>pine forest>shrub forest. The total annual water conservation quantity of public welfare forests in the whole city was 18 7,7869 million tons, with the value quantity of 1.979 billion yuan. The water conservation quantity per unit area was about 2813 t ⋅ hm-2, and the value quantity per unit area was about 29,700 yuan ⋅ hm-2. In Jiangshan City, the water conservation capacity of public welfare forest was stronger in the east, while the water conservation capacity of public welfare forest in the north was relatively weak. [ABSTRACT FROM AUTHOR]

In order to understand the effect of exocarp removal on the seed germination and seedling growth of Ardisia violacea which was a rare and endangered plant, two treatments, peeled and unpeeled, were set up with four replicates to study the seed germination and growth traits of Ardisia violacea. The results showed that the emergence time of the unpeeled seeds of Ardisia violacea was delayed by 19 days, which was significantly later than that of the peeled seeds (P<0. 05) ; The seed emergence rate was 70. 3% - 75. 6 %, and there was no significant difference between the unpeeled and peeled seeds (P> 0. 05) ; The growth of Ardisia violacea seedlings showed an "S-shaped" curve of "slow-fast-slow". By the end of the growth, the plant height, ground diameter, leaf length and leaf width were respectively in the range of 5. 32 to 5. 34 cm, 0. 12 to 0. 13 cm, 4. 40 to 4. 96 cm, 2. 08 to 2. 12 cm, and the number of leaves ranged from 13. 4 to 14. 8, so there was no significant difference between the unpeeled and peeled treatments (P>-0. 05). In conclusion, the existence of pericarp had no significant effect on the germination and seedling growth of Ardisia violacea, and the seedlings could be directly sown. [ABSTRACT FROM AUTHOR]

CO2, N2OH4 and CH4 are important greenhouse gases, and soils in forest ecosystems are their important sources. Carya cathayensis is a unique tree species with seeds used for high-grade dry fruit and oil production. Understory vegetation management plays an important role in soil greenhouse gases emission of Carya cathayensis stands. A one-year in situ experiment was conducted to study the effects of understory removal on soil CO2, N2O and CH4 emissions in C. cathayensis plantation by closed static chamber technique and gas chromatography method. Soil CO2 flux had a similar seasonal trend in the understory removal and preservation treatments, which was high in summer and autumn, and low in winter and spring. N2O emission occurred mainly in summer, while CH4 emission showed no seasonal trend. Understory removal significantly decreased soil CO2 emission, increased N2O emission and CH4 uptake, but had no significant effect on soil water soluble organic carbon and microbial biomass carbon. The global warming potential of soil greenhouse gases emitted in the understory removal treatment was 15.12 t CO2-e • hm-2 • a-1, which was significantly lower than that in understory preservation treatment ( 17.04 t CO2-e • hm-2 • a-1). [ABSTRACT FROM AUTHOR]

The change characteristics of soil organic carbon and microbial function diversity in Chinese hickory Carya cathayensis stands with different intensive-management durations (5, 10, 15 and 20 years) were studied. The results showed that soil total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC) decreased significantly, while the stability of soil C pool increased significantly after the conversion from evergreen and deciduous broadleaf forest to intensively-managed forest (IMF). TOC, MBC and WSOC in the hickory forest soil decreased by 28.4%, 34.1% and 53.3% with 5-year intensive management, and by 38.6%, 48.9% and 64.1% with 20-year intensive management, respectively. The proportions of carboxyl C, phenolic C and aromatic C in the hickory forest soil all increased significantly, and the aromaticity of soil organic C increased by 23.0%. Soil microbial functional diversity decreased greatly after intensive management of Chinese hickory forest. Significant differences in average well color development (AWCD) were found between the 0- and 5-year treatments and the 10-, 15- and 20- year treatments. The microbial diversity indexes (H) and evenness indexes (E) in the 0- and 5-year treatments were much greater than in the 10- and 20-year treatments. Correlation analysis showed that there were significant correlations among soil TOC, WSOC, MBC, AWCD, H and E. [ABSTRACT FROM AUTHOR]

The samples of different age (1-4 years old) Phyllostachys praecox plants and their organs (leaf, branch, and culm) were collected from their main production area in Lin'an County, Zhejiang Province of East China to study the contents and the uptake and accumulation characteristics of silicon and other nutritional elements, as well as the interrelations between Si and other nutrient elements. In the P. praecox plants, the C content in aboveground part was in the order of culm >branch>leaf, whereas the Si, N, P, K, Ca, Mg, Al, Fe and Mn contents were in the order of leaf>branch>culm. Mn was mainly accumulated in leaf, while the other nine nutrient elements were mainly accumulated in the culm of 1-year old plants. The average Si content in the aboveground part of 3-4 year old plants was 13. 66 g.kg-1, suggesting that P. praecox belonged to Si accumulation plant. The leaf N, P, K, and Mg contents decreased, while the C, Al, and Mn contents increased with increasing plant age. The Si uptake by the aboveground part was mainly occurred in the second year (57. 1%), while the N and K uptake was mainly in the first two years (67. 7% - 93. 7%). Thereafter, the N and K flowed out from the aboveground part, with the outflow rates reached 19. 1% -39. 1% of the total accumulated amounts. The Si in P. praecox was significantly correlated with Ca, Al, and Mn, and negatively correlated with N, P, K, and Mg. [ABSTRACT FROM AUTHOR]

To investigate the effects of the conversion from native shrub forest (NF) to Chinese chestnut plantation (CP) on the soil carbon (C) and nitrogen (N) pools, soil samples were collected from the adjacent NF and CP in Anji County of Zhejiang Province, with their water-soluble organic C (WSOC), microbial biomass C (MBC), readily oxidizable C (ROC), water-soluble organic N (WSON), and microbial biomass N (MBN) determined. The spectral characteristics of soil organic C were also determined by using nuclear magnetic resonance (NMR) technique. After the conversion from NF to CP, the soil alkalyzable N, available phosphorus, and available potassium contents increased significantly, while the soil WSOC, MBC, ROC, WSON, and MBN were in adverse. The soil organic C in both NF and CP was dominated by alkyl C and O-alkyl C, but the proportions of O-alkyl C and carbonyl C in soil organic C decreased while the proportions of alkyl C and aromatic C as well as the alkyl C / O-alkyl C ratio and the aromaticity of soil organic C all increased significantly after the conversion from NF to CP, indicating that this conversion increased the stability of soil organic C pool significantly. In conclusion, the conversion from NF to CP and the intensive management of CP decreased the contents of soil labile C and soil N but increased the stability of soil C pool significantly. [ABSTRACT FROM AUTHOR]

A long-term field experiment was conducted at a Chinese hickory ( Carya cathayensis ) plantation from 2011 to 2021, with the purpose of researching the effects of long-term sod cultivation on hickory plantation soil fungal communities and enzyme activities and providing experience for ecological management in other plantations. Sod cultivation included oilseed rape ( Brassica chinensis , BR), Chinese milk vetch ( Astragalus sinicus , AS), and oilseed rape+Chinese milk vetch (BA), and clear tillage (CT) served as a contrast. The soil fertility, fungal community composition and diversity, and soil enzyme activities were determined. The results showed that:① long-term sod cultivation significantly increased soil nutrient contents and availability, and pH increased variably from different sod cultivation treatments ( P <0.05). ②The soil fungal community composition was changed by long-term sod cultivation. The relative abundance of Ascomycota, which utilized the readily decomposed organic matter, was increased, whereas the relative abundance of Basidiomycota, which degraded stubborn organic matter, decreased. Long-term sod cultivation shifted the soil dominant genera, as BR and BA increased the relative abundance of somemycorrhizal fungi that could form mutually beneficial structures with dominant plant genera after sod cultivation,whereas AS increased the relative abundance of saprophytic fungi that could decompose the remains of dead plants and animals. The soil fertility factors including pH, available nitrogen, microbial biomass nitrogen, and water-soluble organic carbon were revealed to have a significant influence on the soil fungal composition ( P <0.05). ③ Moreover, long-term sod cultivation stimulated the activities of soil enzymes involved in the carbon and nitrogen cycle. Apart from BA, sod cultivation treatments decreased the activities of alkaline phosphatase, which was involved in the soil P turnover. The correlation analysis demonstrated that the correlations between activities of enzymes decomposing carbon and nitrogen and soil fertility were significant ( P <0.05 or P <0.01). The activities of phosphatase were positively correlated with soil microbial biomass carbon and nitrogen. Long-term sod cultivation could improve soil nutrient content and availability, optimized soil fungal community structure, and promoted soil nutrient turnover enzyme activities.

Methane (CH 4 ) and nitrous oxide (N 2 O) are two extremely important greenhouse gases in the atmosphere. Nitrogen fertilizer is an important factor affecting CH 4 and N 2 O emissions in rice fields. Rational application of nitrogen fertilizer can not only promote high yields of rice but also reduce greenhouse gas emissions. Existing studies have shown that nitrogen reduction and optimal application can effectively improve the nitrogen use efficiency of rice on the basis of ensuring the yield and reduce the loss of N 2 O caused by nitrification and denitrification of excessive nitrogen in soil. Fertilization times and fertilizer types have significant effects on CH 4 and N 2 O emissions in paddy fields. In this study, a field experiment was conducted for two consecutive years (2019-2020) to study the effects of fertilizer application on CH 4 and N 2 O emissions from rice fields by setting up four treatments consisting of no fertilizer (CK), customary fertilizer application by farmers (CF), twice fertilizer (TT), and 20% replacement of chemical fertilizer by organic fertilizer (OF) using static chamber-gas chromatography. Additionally, the effect of integrating rice yield and integrated global warming potential (GWP) on the greenhouse gas emission intensity (GHGI) per unit of rice yield was analyzed to explore fertilizer application for yield increase and emission reduction in a typical rice growing area in the middle and lower reaches of Yangtze River. The results showed that:① compared with those of CK, the fertilizer treatments reduced CH 4 emissions by 14.6%-25.1% and increased N 2 O emissions by 610%-1836% in both years; ② compared with those of CF, both the TT and OF treatments showed a trend of increasing CH 4 emissions and reducing N 2 O emissions. CH 4 emissions increased by 1.8% ( P >0.05) and 14.0% ( P <0.05), respectively. The annual average of N 2 O emissions decreased by 63.3% ( P <0.05) and 49.2% ( P <0.05) in both the TT and OF treatments, respectively. ③ Compared with that of CK, both fertilizer applications increased rice yield and reduced GHGI; compared with that of CF, the OF and TT treatments increased the average annual rice yield by 17.0% and 10.7%, respectively, and reduced GHGI by 6.8% and 13.7%, respectively. The OF treatment had a better yield increase than that of the TT treatment, and the TT treatment had a slightly better emission reduction than that of the OF treatment. In terms of combined yield and GHG emission reduction, both twice fertilizer (TT) and 20% replacement of chemical fertilizer by organic fertilizer (OF) could reduce the intensity of GHG emission per unit of rice yield and achieve yield increase and emission reduction while ensuring rice yield.

In order to explore the impacts of the land use conversion from a Phyllostachy pubescens (moso bamboo) forest to a Torreya grandis cv. Merrillii plantation, as well as the cultivating years of the T. grandis cv. Merrillii plantation, on the soil microbial community, this research studied the soil microbial structure and diversity of a moso bamboo forest, T. grandis cv. Merrillii plantations (5, 10, and 30 a), and a T. grandis cv. Merrillii - mountain rice interplanting plantation (5 a) using the high-throughput sequencing technique, and the relationship between the microbial community and environmental factors was further explored. The results showed that after the land use change, the Shannon index and Chao1 index of the soil bacterial community increased significantly; the Simpson index increased significantly in the 30 a T. grandis cv. Merrillii plantation, whereas the Shannon index decreased significantly. Both the Simpson index and Chao index of the soil fungal community had no significant difference under different land use types. whereas the Shannon index was significantly decreased in the 30 a T. grandis cv. Merrillii plantation. PCoA analysis of the soil microbial community at the genus level showed that land use type played a vital role in driving the changes in soil bacterial and fungal communities. The compositions of the soil microbial communities between the two 5 a stands were most similar. The dominant phyla of soil bacteria mainly included Acidobacteria, Proteobacteria, Actinobacteria, and Chloroflexi. The results of cluster analysis showed that the soil bacterial community changed significantly at the genus level after the conversion of land use; the abundance of most dominant bacterial communities decreased with increasing cultivation. The fungal community was mainly composed of Ascomycota, Basidiomycota, and Zygomycota, whose changes in community characteristics were similar to those of bacteria. The results of RDA analysis showed that pH, organic matter, available phosphorus, available potassium, and water-soluble organic carbon and nitrogen were significantly correlated with soil microbial community. Therefore, these soil fertility properties might be the driving factors affecting the structure of bacterial communities. This study provided a theoretical basis for solving the problem of soil quality deterioration in T. grandis cv. Merrillii stand land management.

Monthly phytolith-occluded organic carbon (PhytOC) content in living leaves and litterfall of Moso bamboo (Phyllostachys edulis) were measured for a year. The PhytOC sequestration rate in living leaves of different months were compared with that in annual litterfall to determine the optimum sampling time of living leaves for estimating PhytOC sequestration rate of Moso bamboo. The contents of phytoliths and PhytOC in living leaves of Moso bamboos were 23.45-101.07 g·kg -1 and 0.73-1.98 g·kg -1 , respectively, with significant difference among different months. The monthly PhytOC sequestration rates of living leaves of Moso bamboo in different months ranged from 0.75 to 7.68 kg·hm -2 ·a -1 . The maximum and minimum rates of the PhytOC sequestration occurred in December and April respectively, with significant difference between them. There was no difference between the PhytOC sequestration rate in living leaves of Moso bamboos in February or December and that of litterfall in the whole year. Therefore, February or December should be the optimal month of sampling living leaves for estimating the PhytOC sequestration rate of Moso bamboo stands.

A pot experiment was conducted in a greenhouse on one-year-old clonal seedlings of Cunninghamia lanceolata. Five treatments were designed including control, conventional fertilization and three exponential fertilization treatments, with N application rates of 0, 0.5, 0.5, 1.0 and 2.0 g·seedling -1 , with N applied at 20 times at 10-day interval. The height, ground diameter, biomass, chlorophyll fluorescence and N absorption were measured after 210 days of N application. The results showed that fertilization significantly promoted the seedling height, ground diameter and biomass with the optimal values of 59.0 cm, 6.0 mm, 52.99 g·seedling -1 , in exponential fertilization treatment of 1.0 g N·seedling -1 . Chlorophyll fluorescence in exponential fertilization treatments was significantly higher than that in conventional fertilization. The photochemical quenching, PS2 electron transport rate and photochemical efficiency of PS2 in exponential fertilization treatments increased first and then decreased, with the optimal values of 0.89, 35.79 and 0.71 in 1.0 g N·seedling -1 treatment. N contents in different organs of C. lanceolata clonal seedlings were in the order of leaf > root > stem. Compared with the CK, the N contents in root, stem and leaf increased by 39.6%, 16.6% and 41.1% in the conventional fertilization treatment, and by 22.6%-81.4%, 27.3%-152.6% and 73.6%-135.5% in exponential fertilization treatments. N contents in root, stem and leaf in the exponential fertilization treatments of 1.0 and 2.0 g N·seedling -1 were significantly higher than those in the conventional fertilization treatment. P and K contents were not significantly different among the different organs. Considering the characteristics of seedling growth, chlorophyll fluorescence, the contents of N, P and K, the exponential fertilization treatment of 1.0g N· seedling -1 was the best in cultivating C. lanceolata clonal seedlings in this experiment.

Land consolidation has become a main means of achieving the intensive use of land resources, which ensures the dynamic equilibrium and requisition-compensation balance of the total cultivated land in China. However, the intensive disturbance during the land consolidation may affect the soil quality. In order to investigate the effect of land consolidation on soil microbial diversity, we studied the changes of soil microbial community diversity after 1-year and 4-year land conso-lidation by using PLFA method. The results indicated that compared with no consolidation (Z0), for land consolidation after 1a (Z1a), the soil pH value increased by 14.6%, the soil organic carbon content decreased by 65.4%, the phospholipid fatty acids content and relative abundance of all the microflora decreased significantly (P<0.05) by 43.4%-63.7% and 25.2%-53.9%, respectively, and the ratio of fungi/bacteria (F/B) decreased significantly by 35.9% (P<0.05), while the ratio of Gram-positive bacteria/Gram-negative bacteria (G + /G - ) increased significantly by 56.1%. These were significantly related to the increased pH value and the decrease of organic carbon content. The Shannon index and evenness index (E) of soil microbial diversity were significantly decreased, with significant differences observed among Z0 and Z1a, Z4a. After 4-year land consolidation, the indices characterizing soil microbial community diversity were improved compared with those after 1-year land consolidation. In summary, the land consolidation could significantly affect the composition of soil microbial communities, and decrease the stability of the soil ecosystem.

Samples of fresh leaves and leaf litter, as well as soils taken from 0-10 and 10-30 cm layers, were collected in four types of typical forest ecosystems both in subtropical (Phyllostachys pubescens, Pinus massoniana, Cycloba lanopsisglauca, and Cunninghamia lanceolata stands) and in tropical climates (Vatica mangachapoi, Musa basjoo, Heveabrasiliensis, and Acacia mangium stands) for measurement of PhytOC (phytolith-occluded organic carbon) contents. The phytoliths in both leaves and soil samples were extracted by a microwave digestion method and their PhytOC contents were determined by alkali dissolution-spectrophotometry method. It was found that, among the four types of subtropical forests, the PhytOC contents of leaves, litter and 0-10 cm soil layer were the highest in P. massoniana stand (230.24, 229.17 and 20.87 g·kg -1 ), the lowest in P. pubescens stand (30.55, 37.37, and 3.38 g·kg -1 ), and the PhytOC content of the 10-30 cm soil layer was the highest in C. glauca stand (18.54 g·kg -1 ), and the lowest in P. pubescens stand (2.90 g·kg -1 ). For the four tropical forests, A. mangium stand (377.66 g·kg -1 ) and V. mangachapoi stand (46.83 g·kg -1 ), respectively, deposited the highest and lowest contents of PhytOC in the leaves, while the highest and lowest contents of PhytOC in the litter were observed in H. brasiliensis stand (218.23 g·kg -1 ) and M. basjoo stand (27.66 g·kg -1 ), respectively. Also among the tropical forests, the highest PhytOC contents in the 0-10 cm and 10-30 cm soil layers were observed in A. mangium stand (23.84 and 24.90 g·kg -1 ), while the lowest values occurred in M. basjoo stand (3.89 and 3.93 g·kg -1 ). The PhytOC contents in transitioning from leaves to soils (0-10 cm layers) decreased by 97.4% for C. lanceolata, 94.9% for C. glauca, 90.9% for P. massoniana, and 88.9% for P. pubescens in the subtropics, and by 95.9% for H. brasiliensis, 93.7% for A. mangium, 93.3% for M. basjoo, 63.7% for V. mangachapoi in the tropics. There was no significant difference in PhytOC contents between leaves and litter for the following five forest types: P. pubescens, P. massoniana, C. lanceolata, V. mangachapoi and H. brasiliensis. However, significantly higher PhytOC contents in leaves than in litters were measured in C. glauca, M. basjoo, and A. mangium. The findings that significantly lower PhytOC contents occurred in soils than in fresh leaves and leaf litter regardless of type of forest ecosystem suggested that phytolith was not stable during the pathway from plants to soil via the forest litter.

Soil CO2 effluxes in natural broad-leaved forest and the conversed Chinese fir plantation in Linglong Mountains Scenic of Zhejiang Province were evaluated by using static closed chamber and gas chromatography method. The results showed that soil CO2 efflux showed consistent seasonal dynamics in natural broad-leaved forest and Chinese fir plantation, with the maximums observed in summer and autumn, the minimums in winter and spring. Soil CO2 effluxes were 20.0-111.3 and 4.1-118.6 mg C . m-2 . h-1 in natural broad-leaved forest and Chinese fir plantation, respectively. The cumulative soil CO2 emission of natural broad-leaved forest (16.46 t CO2 . hm-2 . a-1) was significantly higher than that of Chinese fir plantation (11.99 t CO2 . hm-2 . a-1). Soil moisture did not affect soil CO2 efflux. There was a significant relationship between soil CO2 efflux and soil temperature at 5 cm depth. There was no significant relationship between soil CO2 efflux of natural broad-leaved forest and water soluble organic carbon content, while water soluble organic carbon content affected significantly soil CO2 efflux in Chinese fir plantation. Converting the natural broad-leaved forest to Chinese fir plantation reduced soil CO2 efflux significantly but improved the sensitivity of soil respiration to environmental factors.

To investigate the effects of different forest stands in subtropical China on the communities of soil ammonia-oxidizing microorganisms, we characterized the abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and the community structure of AOA in soils under stands of broad-leaved (BF) , Chinese fir (CF) , Pinus massoniana (PF) and moso bamboo (MB) forests using real-time quantitative PCR and denaturing gradient gel electrophoresis (DGGE). The results showed that the AOA gene copy numbers (1.62 x 10(6)-1.88 x 10(7) per gram of dry soil) were significantly higher than those of AOB genes (2.41 x 10(5)-4.36 x 10(5) per gram of dry soil). Significantly higher soil AOA abundance was detected in the MB than that in the CF (P < 0.05), and the latter was significantly higher than that in the BF and PF soils (P < 0.05). There were no significant differences in the soil AOB abundance among the four forest stands. As indicated by DGGE pattern, soil AOA species varied among the four forest stands. There was a difference in the soil AOA communities between the CF and MB stands. The AOA demonstrated a competitive advantage over the AOB in the soils under these major subtropical forests. Soil pH, concentrations of soil available potassium and organic carbon as well as the forest type were the main factors that influence the variation of AOA community structure and diversity.