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Xu T.-T.,Shandong Agricultural University | Xu T.-T.,Shandong Provincial Key Laboratory of Soil Erosion and Ecological Restoration | Dong Z.,Shandong Agricultural University | Dong Z.,Shandong Provincial Key Laboratory of Soil Erosion and Ecological Restoration | And 7 more authors.
Research of Environmental Sciences | Year: 2014

In order to study the effects of Salix psammophila sand barrier on soil particle size distribution (PSD) and soil organic carbon (SOC), multi-fractal features of soil PSD and SOC of a mobile sand dune, a fixed sand dune of a two-year sand barrier and a semi-fixed sand dune of a seven-year sand barrier were analyzed in Maowusu Sandy Land with the multi-fractal method. The results showed that the silt, clay and very fine sand contents of setting sand barrier dunes increased, while those of the fine sand and medium coarse sand decreased. The heterogeneity and width of soil PSD could be reflected by the multi-fractal parameters such as D1/D0(i. e. , information dimension/capacity dimension) and ∂-f(∂) (i. e. , multi-fractal spectrum). The ratios of D1/D0 of the fixed dune and semi-fixed dune were higher than that of the mobile dune, and the decreasing order of D0 was: sand dune with seven-year sand barrier (1.01) > mobile sand dune (1.00) > sand dune with two-year sand barrier (0.93). The order of D1 was mobile sand dune (0.91) > sand dune with two-year sand barrier (0.88) > sand dune with seven-year sand barrier (0.65). The multi-fractal parameters were obviously related with the soil clay content. The soil plasma content increased when the soil heterogeneity was large. There was an obvious decreasing trend in SOC content of the three different types of dunes. There was a strong correlation between the SOC content and D1/D0 of PSD. Therefore, the multi-fractal soil parameters can be used as an indicator to reflect the concentration of soil nutrients. There was an obvious increasing trend of SOC content for the three different types of dunes with the setting years, and the SOC content of the seven-year sand barrier was significantly different from the other two sand dunes. Additionally, there was a significant correlation between the SOC content and the multi-fractal parameters of PSD. Therefore, the multi-fractal parameters can be used to interpret the change of soil nutrient status. Source


Fu J.-P.,Taishan Forest Ecosystem Research Station | Fu J.-P.,Shandong Agricultural University | Li C.-R.,Taishan Forest Ecosystem Research Station | Li C.-R.,Shandong Agricultural University | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2012

The invasion of Phytolacca americana has produced serious damage to the coastal shelter forests in China. In order to search for the effective measures for controlling the growth of P. americana, several plots in the Robinia pseudoacacia forest invaded by P. Americana to the relatively same extent were installed, and the measures of physical control(mowing and root cutting) and chemical control(spraying herbicides) were adopted to control the invasion of P. Americana, taking the site with good growth of Amorpha fruticosa in the forest and without any control measures as the comparison. The results showed that mowing could rapidly decrease the growth of P. americana in the same year, but the growth recovered in the next year. 1/3 root cutting only reduced the aboveground growth of P. americana in the same year, and the growth was recovered in the third year; while 2/3 root cutting and whole cutting could effectively cleanup the P. americana plants all the time. Spraying quizalofop-p-ethyl and paraquat only killed the aboveground part of P. americana in the same year, but this part of P. americana recovered to the normal level in the next year; while spraying 45 g·L-1 of glyphosate could completely kill the whole P. americana plants till the third year. The growth of P. americana at the site with good growth of A. fruticosa and without any control measures maintained at a low level all the time, suggesting that planting A. fruticosa in R. pseudoacacia forest would be an effective approach to prevent and control the P. americana invasion. Source


Wang Y.-P.,Shandong Agricultural University | Wang Y.-P.,Taishan Forest Ecosystem Research Station | Xu T.,Beijing Forestry University | Zhu W.-R.,Shandong Agricultural University | And 6 more authors.
Chinese Journal of Applied Ecology | Year: 2015

In this study, poplar fine roots in two successive rotation plantations were sampled over seasons. Root samples were grouped from first to five orders to examine the seasonal dynamics of carbon and nitrogen contents of poplar fine roots with orders, and compared their differences between two successive rotation plantations, and finally to find the relationships between the fine root growth and the productivity decline of successive rotation poplar plantations. The results showed that non-structure carbohydrates (NSC) content increased significantly with root orders, while nitrogen content decreased. The contents of total carbon and NSC were significantly related to total nitrogen content. Root orders explained 98.2% variance of carbon and nitrogen contents of poplar fine roots, and the difference between rotations only explained 1.7% of variance. Poplar fine roots consisted of more carbon and less nitrogen with root orders, and the seasonal changes in contents of total carbon, total nitrogen and NSC showed significant difference between rotations, while that of the C:N ratio didn't show significant difference. Root order and season showed interaction effect on carbon and nitrogen dynamic. The C:N ratio was about 20:1 in lower order roots, and more than 30:1 in higher order roots. The C:N ratio in summer and autumn was significantly less than those in other seasons, while NSC content was the highest in November. This study indicated that the allocation of carbon and nitrogen in fine roots was closely correlated with fine root orders. Both NSC content and C:N ratio were of greatly important ecological significance in fine root turnover and growth regulation. © 2015, Editorial Board of Chinese Journal of Applied Ecology. All right reserved. Source


Wang Y.-P.,Shandong Agricultural University | Wang Y.-P.,Taishan Forest Ecosystem Research Station | Wang H.-T.,Shandong Agricultural University | Wang H.-T.,Taishan Forest Ecosystem Research Station | And 3 more authors.
Chinese Journal of Applied Ecology | Year: 2013

By using ion exchange resin membrane as a plant root simulator, this paper studied the variations of soil nutrient availability and enzyme activities in a poplar plantation after applying phenolic acid. The exogenous phenolic acid had significant effects on the soil nutrient availability and enzyme activities, and the effects were concentration and time dependent. With increasing phenolic acid concentration, the extraction mass of soil NH4+ N and NO3--N decreased significantly. At high concentration phenolic acid, soil PO43- and Mn2+ availability increased significantly while soil K+ and Fe3+ availability was in adverse, and soil urease and phosphatase activities had a significant decrease while soil catalase and polyphenol oxidase activities increased significantly. With the elongation of incubation time, the availability of soil NH4+ N, PO43-, and Mn2+ increased gradually, while that of soil NO3--N, K+, Fe3+, and Zn2+ decreased significantly. The correlation analysis showed that the availability of soil NO3--N, K+, Fe2+, and Mn2+ had close correlations with the activities of soil urease, polyphenol oxidase, and phosphatase. Source


Wang Q.,Shandong Agricultural University | Zhu W.,Shandong Agricultural University | Liu M.,Shandong Agricultural University | Wang H.,Shandong Agricultural University | And 6 more authors.
Chinese Journal of Applied and Environmental Biology | Year: 2015

By the 454 pyrosequencing technology, this research compared the bacterial communities in poplar plantation rhizosphere and bulk soil for an accurate understanding of bacterial community colonization in the two soil environments. The species annotation showed that rhizosphere soil contained 145 bacterial genera and bulk soil contained 141 bacterial genera, with 8 common genera shared by both at a relative abundance of more than 4%. The 8 genera in common were Acidobacterium GP1, Acidobacterium GP3, Acidobacterium GP6, Gemmatimonas, Bradyrhizobium, Burkholderia, Streptomyces and Acidobacterium GP4. The relative abundance of the same bacterial community was significantly different between rhizosphere and bulk soil environments. Alpha diversity analysis showed that the bacterial community diversity of rhizosphere soil was higher than that of bulk soil, but the difference was not significant. The results of bacterial communities sorting could reflect the variation of soil bacterial communities from rhizosphere to the bulk and the spatial variation among different sampling points, indicating a contribution of about 21.2% variance of bacterial communities by the effect of rhizosphere. Beta diversity analysis showed great difference between rhizosphere and bulk soil samples in bacterial community composition. There were 15 genera specific to rhizosphere soil and 11 to bulk soil. The abundance of 23 genera, mainly cellulose degrading bacteria and nitrogen-fixing bacteria, changed significantly. Selectivity of root to rhizosphere microorganisms is an important mechanism leading to significant differences in the rhizosphere microbial community composition and structure, which may significantly impact the carbon and nitrogen cycles of the root-soil interface. Source

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