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Shenglei Fu - One of the best experts on this subject based on the ideXlab platform.
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effects of experimental nitrogen and or phosphorus additions on Soil nematode communities in a secondary tropical forest
Soil Biology & Biochemistry, 2014Co-Authors: Faming Wang, Zhian Li, Jian Li, Xiaoli Wang, Shenglei FuAbstract:Abstract In tropical forest ecosystems, highly weathered Soils are often considered as relatively nitrogen-rich but phosphorus-poor. Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, little is known about how nitrogen and/or phosphorus additions affect the conditions of Soil food web which is an important component of belowground ecosystems. In the present study, Soil nematode communities were monitored and served as indicators of Soil food web conditions under experimental nitrogen and phosphorus additions in a secondary forest in tropical China. The principal response curves of Soil nematode community structure revealed same tendency of changes under nitrogen and/or phosphorus additions compared with control, in terms of nematode functional guild compositions: apparent successions from communities dominated by He3 and Ba1 to communities dominated by Ba2 and Fu2 occurred after nitrogen and/or phosphorus additions. The diversity of Soil nematode genera was not sensitive to either nitrogen or phosphorus addition. Phosphorus addition significantly suppressed total nematode density, density of omnivore-predators, and four nematode faunal indices (i.e. MI25, EI, SI, and SFI), but increased two faunal indices (i.e. CI and BaI). However, nitrogen addition did not induce remarkable changes of these variables in the present study. Our results suggest that nitrogen and/or phosphorus additions suppress Soil Nematodes in tropical secondary forests, which was inconsistent with our expectation that nitrogen addition was detrimental to and phosphorus addition was conducive to Soil Nematodes in this nitrogen-rich but phosphorus-poor Soil. Furthermore, the effects of phosphorus addition are more powerful than the effects of nitrogen addition. Moreover, phosphorus addition degrades the structure and trophic links of the Soil food web, reduces the carbon utilization of Soil Nematodes, and leads to a more fungal dominated decomposition pathway. The alterations of Soil food web conditions might result in altered ecosystem functioning. Our findings could provide a better understanding of the responses of Soil food web to nitrogen and phosphorus additions in nitrogen-rich but phosphorus-poor Soils.
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Nematodes as indicators of Soil recovery in tailings of a lead zinc mine
Soil Biology & Biochemistry, 2008Co-Authors: Yuanhu Shao, Weixin Zhang, Juecui Shen, Lixia Zhou, H Ferris, Shenglei FuAbstract:Trophic groups and functional guilds of Soil Nematodes were measured under four mine tailing subsystems in the Baoshan lead/zinc mine, Hunan Province, southern China to test the indicator value of Nematodes for heavy metal pollution. No obvious correlation was found between heavy metal concen- tration and the total number of Nematodes. However, the densities of c-p3, c-p4 and c-p5 Nematodes were negatively correlated with Pb and Zn concentrations, suggesting that the abundance of nematode groups of high c-p values is useful indicators of heavy metal contamination. The ''weighted faunal analysis'' provided a better assessment of Soil health condition than Maturity Index (MI) in situations where there were extremely low numbers of Soil Nematodes. Results showed that the effect of heavy metal contamination on Soil Nematodes might be strongly influenced by plants. Although the abundance of plant-feeding Nematodes did not reflect the heavy metal conditions in the Soil, it might be used as an index for assessing the Soil remediation potential of pioneering plants. Patrinia villosa seems superior to Viola baoshanensis as a pioneer plant species for Soil remediation based on analysis of rhizosphere nematode community.
Wenju Liang - One of the best experts on this subject based on the ideXlab platform.
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Soil Nematodes of Grasslands in Northern China
2017Co-Authors: Wenju Liang, Xiaoke ZhangAbstract:Soil Nematodes of Grasslands in Northern China presents research on China's temperate grasslands, providing the findings and results of a large field survey along a transect across the northern temperate grassland. It examines nematode distribution patterns along the transect from trophic group and family, to genus level, also evaluating their relationship with climatic conditions, plant biomass and Soil parameters. The book then presents detailed taxonomy information of Nematodes to genus or species level, providing keen insights into nematode diversity along the grassland transect in north China. Final sections review the advances and perspectives for the research of Soil ecology on Soil Nematodes in China, including recent major discoveries of Soil microbial diversity and eco-function during this field survey. This work will help researchers predict the impact of global change drivers on below ground Soil biota and better understand the functioning and services they provide in terrestrial ecosystems.Features previously unavailable information on nematode diversity and distribution along a large geographic region of ChinaDescribes the relationship of nematode assemblage composition with climatic conditions, plant and Soil characteristicsCovers nematode genera and species descriptions along the grassland transect
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tillage and rotation effects on community composition and metabolic footprints of Soil Nematodes in a black Soil
European Journal of Soil Biology, 2015Co-Authors: Zhiyong Zhang, Xiaoke Zhang, Jiasiang Jhao, Xiaoping Zhang, Wenju LiangAbstract:Abstract Understanding the response of Soil biota to tillage and rotation practices is useful for evaluating the effect of agricultural management. We investigated Soil physiochemical properties, nematode community structure and composition and their metabolic footprints in different tillage and crop rotation systems in a 12-year old field experiment in a black Soil. The experiment was based on a split-plot design with conventional tillage (CT) and no-tillage (NT) as main plots and corn-soybean rotation (CS) and continuous corn (CC) treatments as subplots. Soil samples were taken at 0–5 cm and 5–15 cm depths. The results showed that in comparison with CT, NT increased total Soil organic carbon, Soil moisture and microbial biomass carbon at 0–5 cm depth regardless of rotation system. Rotation effect on total nematode abundance was significant. The abundance of fungivores was significantly influenced by the tillage effect, with higher abundance found in CT systems. In total, fifty-eight nematode genera were identified. Acrobeloides dominated under CS and Filenchus under CC. In NT system, a bacterial-dominated decomposition pathway was dominant under CS, and fungal-based channel under CC at 0–5 cm depth. The interactive effect of tillage and rotation changed the decomposition channel. Under CS system, lower structure index (SI) and higher channel index (CI) were found in CT than in NT at 0–5 cm depth. At both depths, functional metabolic footprint was greater under CS than under CC in both tillage systems. Footprint of fungivores also suggested a greater flow of resources into the food web through fungivorous channels under CC. Redundancy analysis (RDA) showed that tillage and rotation influenced Soil Nematodes by changing Soil physiochemical properties. Nematode community analysis indicated that corn-soybean rotation system increased nematode abundance and their functional metabolic footprint, and favored a more diverse residue resource entry into Soil food webs.
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Soil Nematode Responses to Increases in Nitrogen Deposition and Precipitation in a Temperate Forest
PloS one, 2013Co-Authors: Xiaoming Sun, Xiaoke Zhang, Shixiu Zhang, Guanhua Dai, Shijie Han, Wenju LiangAbstract:The environmental changes arising from nitrogen (N) deposition and precipitation influence Soil ecological processes in forest ecosystems. However, the corresponding effects of environmental changes on Soil biota are poorly known. Soil Nematodes are the important bioindicator of Soil environmental change, and their responses play a key role in the feedbacks of terrestrial ecosystems to climate change. Therefore, to explore the responsive mechanisms of Soil biota to N deposition and precipitation, Soil nematode communities were studied after 3 years of environmental changes by water and/or N addition in a temperate forest of Changbai Mountain, Northeast China. The results showed that water combined with N addition treatment decreased the total nematode abundance in the organic horizon (O), while the opposite trend was found in the mineral horizon (A). Significant reductions in the abundances of fungivores, plant-parasites and omnivores-predators were also found in the water combined with N addition treatment. The significant effect of water interacted with N on the total nematode abundance and trophic groups indicated that the impacts of N on Soil nematode communities were mediated by water availability. The synergistic effect of precipitation and N deposition on Soil nematode communities was stronger than each effect alone. Structural equation modeling suggested water and N additions had direct effects on Soil nematode communities. The feedback of Soil Nematodes to water and nitrogen addition was highly sensitive and our results indicate that minimal variations in Soil properties such as those caused by climate changes can lead to severe changes in Soil nematode communities.
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residue incorporation and n fertilization affect the response of Soil Nematodes to the elevated co2 in a chinese wheat field
Soil Biology & Biochemistry, 2009Co-Authors: Wenju Liang, Shuang Zhong, Xunhua Zheng, Jianguo ZhuAbstract:The interplay between the carbon and other nutrient cycles is the key to understand the responses of Soil ecosystems to climatic change. Using the free-air CO2 enrichment (FACE) techniques, we carried out a multifactorial experiment in a Chinese rice–wheat rotation system, to investigate the response of Soil Nematodes to elevated CO2 under different application rates of N fertilizer (225.0 kg N ha �1 (HN) and 112.5 kg N ha �1 (LN), respectively) and residue incorporation (0 kg C ha �1 (ZR), 1000 kg C ha � 1 (MR) and 2000 kg C ha �1 (HR), respectively). This study was conducted during the wheat growing season of 2007 after expose to the elevated CO2 for three years. The results in our study indicated that seasonality is an important factor in determining changes in the nematode abundance and diversity. The residue addition effects were more obvious than the elevated CO2, which significantly influenced the abundance of total Nematodes and plant-parasites, and some ecological indices. The interactions between residue addition and CO2 significantly influenced nematode dominance and structure indices. High level of N fertilization was found to decrease the nematode diversity, generic richness and maturity indices at wheat jointing stage. There are significant interactions between N fertilization and elevated CO2 for abundance of total Nematodes and different trophic groups.
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vertical distribution of Soil Nematodes in an age sequence of caragana microphylla plantations in the horqin sandy land northeast china
Ecological Research, 2007Co-Authors: Deming Jiang, Qi Li, Yong Jiang, Wenju LiangAbstract:The vertical distribution of Soil Nematodes down to a depth of 50 cm was studied in an age sequence of 0-, 5-, 10-, and 22-year-old Caragana microphylla plantations (treatments) in the Horqin Sandy Land, Northeast China. The abundances and generic compositions of nematode fauna in five Soil layers (0–10, 10–20, 20–30, 30–40, and 40–50 cm) were analyzed. 42 genera were observed in the nematode suspensions, and Acrobeles was the dominant genus in all treatments. The results showed that the total number of Nematodes and the generic diversity in an age sequence of C. microphylla plantations decreased with increasing Soil depth. Significant differences in the numbers of total Nematodes, bacterivores (BF), plant parasites (PP), and omnivores–predators (OP) were observed between treatments and depths. BF was the most abundant trophic group in our study, followed by OP. The numbers of OP showed an obviously increasing trend with increasing age of C. microphylla plantation. The vertical distribution of the Soil nematode communities was related to gradual changes in Soil chemical properties, and it indicated that C. microphylla plantations have played positive roles in improving Soil environmental conditions and restoring desertified ecosystems in the Horqin Sandy Land. The ecological indices selected were influenced by plantation chronosequence but not by Soil depth.
D. A. Crossley - One of the best experts on this subject based on the ideXlab platform.
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Short-term impacts of aboveground herbivory (grasshopper) on the abundance and 14C activity of Soil Nematodes in conventional tillage and no-till agroecosytems
Soil Biology and Biochemistry, 2001Co-Authors: Keith W Kisselle, David C. Coleman, Paul F. Hendrix, D. A. CrossleyAbstract:Abstract This study was designed to monitor the responses of Soil Nematodes to different levels of aboveground herbivory and to test the hypothesis that the low level of aboveground herbivory facilitates Soil nematode activities and high herbivory suppresses Soil nematode activities. Three herbivory levels were established by introducing four pairs, two pairs and no grasshoppers to graze on corn plants ( Zea mays ) for 2 h. The experiment was conducted in conventional tillage (CT) and no-till (NT) agroecosystems at Georgia piedmont. In NT, bacterivorous and fungivorous nematode numbers were more abundant 24 h after herbivory treatment at high grazing level compared to controls, but this was not observed at low grazing level. In NT, the 14 C activity of Soil Nematodes was significantly higher at both low and high grazing levels than the controls. In CT, however, we did not observe any effects caused by aboveground herbivory on the abundance and 14 C activity of Soil Nematodes. The abundance of other trophic groups of Soil Nematodes (phytophages, predators and omnivores) was not affected by aboveground herbivory treatments under either NT or CT regimes. The curvilinear relationship between the nematode activity and the grazing intensity was not found in this study, we suggested that a grazing gradient of leaf area loss ranging from 0 to 100% might be more desirable for future research. We hypothesized that root associated materials might be more important to Soil organisms in NT than in CT since the effect of aboveground herbivory on Soil Nematodes was only observed in NT.
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Responses of trophic groups of Soil Nematodes to residue application under conventional tillage and no-till regimes
Soil Biology & Biochemistry, 2000Co-Authors: David C. Coleman, Paul F. Hendrix, D. A. CrossleyAbstract:A laboratory and a field study were conducted to monitor the increase in numbers and 14C uptake of different trophic groups of Soil Nematodes in response to residue addition and to examine the relative importance of bacterivorous and fungivorous Nematodes in conventional (CT) and no-till (NT) agroecosystems. In general, Soil nematode numbers increased more rapidly in response to residue addition and became much more abundant (greater than five-fold) under laboratory conditions than in the field. Our results showed that bacterivorous Nematodes responded to residue addition earlier than fungivorous Nematodes under both CT and NT regimes in the laboratory and field studies. A depth effect was observed in NT, but not in the CT treatment; this reflected the vertical residue distribution in both tillage regimes. Soil Nematodes were more abundant under NT than under CT in the field. The same pattern was observed at the beginning of the laboratory study but it reversed later. The ratios of fungivorous-to-bacterivorous Nematodes (FN-to-BN) were not significantly different between CT and NT treatments at the beginning of the experiment. They were very low (less than 0.2) in both tillage regimes, indicating that bacterivorous Nematodes were relatively more important than fungivorous Nematodes in both tillage agroecosystems. However, the FN-to-BN ratios increased with time after residue decomposition started, particularly in the CT treatment. This suggested that the relative importance of fungivorous Nematodes increased with the progress of residue decomposition. It was more pronounced in the CT treatment during the short period after residue application. In both the laboratory and field studies, the 14C specific activity of Soil Nematodes and the ratio of 14C bound in nematode biomass to total 14C decayed in the experiment (reported elsewhere) were significantly higher under CT than under NT, suggesting that Soil Nematodes use carbon more efficiently under CT than under NT. No significant difference of 14C specific activity of Soil Nematodes was found between the two depths under CT in both the studies; however, 14C specific activity was significantly higher in the 0–2.5 cm than in the 2.5–5.0 cm layer under NT in the laboratory study.
Xiaoli Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of experimental nitrogen and or phosphorus additions on Soil nematode communities in a secondary tropical forest
Soil Biology & Biochemistry, 2014Co-Authors: Faming Wang, Zhian Li, Jian Li, Xiaoli Wang, Shenglei FuAbstract:Abstract In tropical forest ecosystems, highly weathered Soils are often considered as relatively nitrogen-rich but phosphorus-poor. Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, little is known about how nitrogen and/or phosphorus additions affect the conditions of Soil food web which is an important component of belowground ecosystems. In the present study, Soil nematode communities were monitored and served as indicators of Soil food web conditions under experimental nitrogen and phosphorus additions in a secondary forest in tropical China. The principal response curves of Soil nematode community structure revealed same tendency of changes under nitrogen and/or phosphorus additions compared with control, in terms of nematode functional guild compositions: apparent successions from communities dominated by He3 and Ba1 to communities dominated by Ba2 and Fu2 occurred after nitrogen and/or phosphorus additions. The diversity of Soil nematode genera was not sensitive to either nitrogen or phosphorus addition. Phosphorus addition significantly suppressed total nematode density, density of omnivore-predators, and four nematode faunal indices (i.e. MI25, EI, SI, and SFI), but increased two faunal indices (i.e. CI and BaI). However, nitrogen addition did not induce remarkable changes of these variables in the present study. Our results suggest that nitrogen and/or phosphorus additions suppress Soil Nematodes in tropical secondary forests, which was inconsistent with our expectation that nitrogen addition was detrimental to and phosphorus addition was conducive to Soil Nematodes in this nitrogen-rich but phosphorus-poor Soil. Furthermore, the effects of phosphorus addition are more powerful than the effects of nitrogen addition. Moreover, phosphorus addition degrades the structure and trophic links of the Soil food web, reduces the carbon utilization of Soil Nematodes, and leads to a more fungal dominated decomposition pathway. The alterations of Soil food web conditions might result in altered ecosystem functioning. Our findings could provide a better understanding of the responses of Soil food web to nitrogen and phosphorus additions in nitrogen-rich but phosphorus-poor Soils.
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Effects of experimental nitrogen and/or phosphorus additions on Soil nematode communities in a secondary tropical forest
Soil Biology and Biochemistry, 2014Co-Authors: Jie Zhao, Faming Wang, Bi Zou, Xiaoli WangAbstract:Abstract In tropical forest ecosystems, highly weathered Soils are often considered as relatively nitrogen-rich but phosphorus-poor. Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, little is known about how nitrogen and/or phosphorus additions affect the conditions of Soil food web which is an important component of belowground ecosystems. In the present study, Soil nematode communities were monitored and served as indicators of Soil food web conditions under experimental nitrogen and phosphorus additions in a secondary forest in tropical China. The principal response curves of Soil nematode community structure revealed same tendency of changes under nitrogen and/or phosphorus additions compared with control, in terms of nematode functional guild compositions: apparent successions from communities dominated by He 3 and Ba 1 to communities dominated by Ba 2 and Fu 2 occurred after nitrogen and/or phosphorus additions. The diversity of Soil nematode genera was not sensitive to either nitrogen or phosphorus addition. Phosphorus addition significantly suppressed total nematode density, density of omnivore-predators, and four nematode faunal indices (i.e. MI25, EI, SI, and SFI), but increased two faunal indices (i.e. CI and BaI). However, nitrogen addition did not induce remarkable changes of these variables in the present study. Our results suggest that nitrogen and/or phosphorus additions suppress Soil Nematodes in tropical secondary forests, which was inconsistent with our expectation that nitrogen addition was detrimental to and phosphorus addition was conducive to Soil Nematodes in this nitrogen-rich but phosphorus-poor Soil. Furthermore, the effects of phosphorus addition are more powerful than the effects of nitrogen addition. Moreover, phosphorus addition degrades the structure and trophic links of the Soil food web, reduces the carbon utilization of Soil Nematodes, and leads to a more fungal dominated decomposition pathway. The alterations of Soil food web conditions might result in altered ecosystem functioning. Our findings could provide a better understanding of the responses of Soil food web to nitrogen and phosphorus additions in nitrogen-rich but phosphorus-poor Soils.
F R Wanless - One of the best experts on this subject based on the ideXlab platform.
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the effects of forest disturbance on diversity of tropical Soil Nematodes
Oecologia, 1997Co-Authors: G Bloemers, M Hodda, P J D Lambshead, John H Lawton, F R WanlessAbstract:We provide the first account of the effects of forest disturbance on species richness of Nematodes in tropical forest Soils, from 24 sites along gradients of disturbance and regeneration in the Mbalmayo Forest Reserve, Cameroon. Species richness was very high. Samples of 200 Nematodes from individual Soil cores contained a maximum of 89 and an average of 61 species; in total we recorded 431 species and approximately 194 genera. The model of Siemann et al. (1996), predicting that species richness scales as the number of individuals I0.5, underestimates nematode diversity 4–6 fold in these samples. Over 90% of specimens cannot be assigned to known species. Although nematode species richness declined with forest disturbance, statistically significant effects were detectable only under the most extreme conditions (active slash-and-burn agriculture and complete mechanical forest clearance) and even here remained at 40% of the richness of near primary sites. Impacts on trophic structure were also small, and there were no significant changes in the maturity index (MI) (Bongers 1990) with disturbance (mean MI across all treatments was very high, at 3.58). In the light of this study, the problems of completing reliable all-taxon inventories in tropical forests are briefly discussed.