Pedobiologia最新文献

Soil plays a crucial role in the provision of ecosystem services, particularly in mountain areas that are frequently regarded as delicate and vulnerable systems. The alteration of vegetation cover is known to impact the various fractions of organic matter and other soil properties, subsequently influencing the activities of microbes and enzymes that play a role in nutrient cycling. However, there is not much information available regarding the effect on soil properties in semi-arid mountain landscapes. Here, we studied different soil features under woodland (dominated by Carpinus orientalis Miller.), shrubland (dominated by Berberis integerrima Bunge.) and grassland (dominated by Festuca ovina L., Dactylis glomerata L. and Bromus danthoniae Trin.) in the north of Iran. In the summer, a total of eighteen soil (0–10 cm depth) samples were collected from each vegetation type. In addition, to investigate the dynamics of soil microclimate and biota population, the same number of soil samples were collected in the fall season. Results indicated that woodland had a more fertile soil and a higher biological activity than the other vegetation types. Soil earthworm groups showed higher densities in the fall season, whereas soil biota population and microbial processes were enhanced in the summer season. In addition, the study area presented hot spots of soil fertility and biological activities in woodland compared with shrubland and grassland. As a conclusion, distinct soil properties are influenced by various types of vegetation (particularly woody species in contrast to grass covers). With the aim of increasing soil functioning or rehabilitating degraded areas, natural resource managers are suggested to establish wood covers (trees or shrubs) rather than grasslands, whenever possible.

Soil fungi are essential in the degradation of crop residues in natural systems. However, how long–term continuous cropping combined with residue incorporation (CCRI) affects the fungal communities in reclaimed saline soils is still unclear. In this study, CCRI was implemented in a reclaimed salinized farmland for 0 (control group), 5, 10, 15, 20, and 25 years to explore the effects on soil properties and fungal communities. The results showed that CCRI reduced soil pH, electrical conductivity (EC), and available potassium (AK) by 2.6–8.3%, 24.0–71.4%, and 9.1–59.4%, respectively, and increased soil organ carbon (SOC), total nitrogen (TN), available phosphorus (AP), and microbial biomass carbon (MBC) by 36.0–117.2%, 84.2–173.4%, 18.5–344.8%, and 16.0–206.8%, respectively, compared with the control group (0–yr treatment). CCRI increased soil fungal species richness, but this effect decreased after 15–yr CCRI treatment; Ascomycota had the highest relative abundance (75.8–90.9%) in the CCRI soils. CCRI treatments significantly reduced the relative abundance of symbiotroph, saprotroph, and pathotroph; Especially, the relative abundance of plant pathogen fungi was significantly reduced by (25.5–36.7%), and that of arbuscular mycorrhizal fungi (AMF) was significantly increased (0.01–0.07%), compared with the control group. Besides, the main soil properties affecting soil fungal community were pH and AK. Overall, the 10 – 15 years CCRI treatment was most beneficial for soil nutrient accumulation and maintaining the richness and diversity of fungal communities. However, it also decreased the abundance of some beneficial fungi and increased soil pathogenic fungi. Therefore, the duration of CCRI can not exceed 15 years, and attention can be paid to maintaining the stability of soil fungal community by regulating soil pH and AK content to reduce the negative impact of long term CCRI. This study will have important guiding significance for soil health improvement in arid areas.

Frequent soil cultivation in intensive vegetable production is detrimental to soil quality. Combining several sustainable management techniques, such as increasing organic matter input and plant diversity, and reducing soil cultivation, could benefit biological soil quality. We designed a crop rotation with a system approach, combining plant-based fertilisers, cover crops and reduced tillage, while growing more crops (sustainable intensification, SI). We compared this approach to common practice (CP), where animal manure fertilisers, no cover crops and ploughing were employed in a standard organic crop rotation on sandy loam in Denmark. Treatments were initiated in 2017, and two sets of contrasts, each comparing across cropping systems and specific crop rotations, were investigated in the second and third year of implementation: lettuce-leek double-cropping (SI) vs. leek sole-cropping (CP), and onion-lettuce intercropping (SI) vs. lettuce-lettuce double-cropping (CP). Soil microbial activity was assessed by β-glucosidase and dehydrogenase activity and potential N mineralisation over 28-days incubation. Root growth was investigated using minirhizotrons. The risk of N leaching was estimated from soil mineral N content at 0–2.5 m depth in autumn. β-glucosidase and dehydrogenase activity increased by 27–107% under SI compared to CP in the third year after implementation. SI improved potential N mineralisation by 12–52 kg N ha⁻¹ before and after spring fertilisation both years. Increased soil fertility under SI contributed to 1.3 to 2.3 times higher plant N uptake (except for lettuce/onion first year), and 1 to 2.7 times higher marketable yields, but only minimally affected root depth. Despite higher N fertilisation, risk of N leaching did not rise under SI. The beneficial effects of SI were attributed to the combination of higher N fertilisation (53–144 kg N ha⁻¹ more) as organic matter addition (2–3 Mg carbon ha⁻¹ more), growing cover crops, and reducing soil tillage. Combining these techniques is promising for improving soil microbial activity in a sustainable way for highly intensive organic vegetable production.

The use of organic compost associated with nitrogen (N) fertilization has been intensively studied, revealing the promotion of changes in soil microbial properties. However, few studies have reported the effect of N application in soil amended with organic compost in the long-term on soil microbial communities. This study assessed the responses of bacterial and archaeal communities to N application in soil with a long-term amendment of organic compost obtained from tannery sludge. The application of high and low rates of compost increased the abundance of Actinobacteria and Thaumarchaeota, respectively, while the application of N did not change the relative abundance of bacterial and archaeal groups. The long-term application of compost promoted an increased abundance of specific bacterial groups, including Solirubrobacter, Microvirga, and Geodermatophilus. Regardless of the application of N, higher microbial complexity and interconnection were observed with the application of compost. This study showed a small effect of N fertilization on the microbial community, which suggests that N may not be a limiting factor for microorganisms in soil under long-term amendment of organic compost. Our findings showed that compost application has a stronger impact on soil microbial communities than N fertilization, and it could be useful in agricultural productivity.

Springtails (Hexapoda: Collembola) play a key role in biological community in glacial ecosystems and represent important ecological indicators in such threatened habitats. An effective sampling protocol for springtail community that optimizes sampling effort in the peculiar conditions of glacial lithosols is not available. We tested three sampling methods on the Sforzellina glacier (Central Italian Alps) in 21 sampling points. For each sampling point, we performed: 1. Tullgren funnels; 2. Flotation method; 3. Pitfall trapping. The potential effect of different sampling methods on species detection was evaluated by ANOVA and by N-mixture models for Flotation method and Tullgren funnels. The incidence coverage estimator (ICE) was used to test the performance of each sampling method comparing the observed vs estimated species richness. Our analysis showed that the sampling method affected the number of species and individuals recorded. Tullgren funnels collected the highest number of species, pitfall trapping the highest average number of species, but did not detect soil species. The observed/estimated species ratio was higher for pitfall trapping and Tullgren funnels than for flotation. The combination of pitfall trapping with Tullgren funnels or flotation method resulted optimal in terms of number of species and functional types recorded. Flotation method collected more than twice the number of specimens obtained with Tullgren, indicating a higher ability to extract springtails from mineral soil. Flotation method and Tullgren funnels detected the same community, from a functional point of view, but only flotation method collected all the most abundant species. These results indicate that a combination of pitfall trapping and flotation should be evaluated in order to maximize the obtained information in terms of specie assemblage composition and functional categories.

Straw returning and nitrogen (N) fertilizer application are important agricultural measures to improve soil carbon pool. However, the combined effect of various straw-returning amounts and N-fertilizer application rates on soil carbon pool is still unclear. Therefore, a field experiment with three straw-returning amounts and three N-fertilizer application rates was conducted for 4 years in central China. The results revealed that the addition of N fertilizer clearly enhanced the contents of soil organic carbon (SOC) by 2.2%− 2.7%, dissolved organic carbon (DOC) by 20.1%− 39.2%, microbial biomass carbon (MBC) by 37.9%− 44.2%, and easily oxidizable carbon (EOC) by 18.4%− 23.6%. Moreover, it also enhanced the activities of invertin by 33.4%− 46.4%, cellulase by 23.5%− 32.4%, and polyphenol oxidase by 20.5%− 27.1%, as well as the carbon pool management index (CPMI) by 21.3%− 27.6%. The CPMI increased gradually as the N-fertilizer application rate increased. However, straw returning did not significantly change the contents of SOC, EOC, and MBC; invertin activity, or CPMI. Based on the structural equation model, it was observed that N fertilizer application enhances MBC and subsequently improves CPMI by increasing EOC. This highlights the vital role of soil microorganisms in the soil carbon cycle and the significance of supplementing N to improve and sustain agricultural soil carbon reservoirs. Additionally, this study indicates that the combined application of N fertilizer and straw returning has a more positive effect on improving the soil carbon pool.

The hospital area is an important component of the urban ecosystem and a densely populated place. Hospital garden soil may act as a potential pool of keratinophilic taxa, which are the common skin disease-causing microorganisms in humans. However, the community diversity, co-occurrence properties and keratinophilic groups of soil microorganisms in hospital gardens remain poorly understood. Here, Illumina MiSeq high-throughput sequencing after the addition of a keratin-rich substrate (i.e., chicken feathers) to hospital garden soils was used to assess keratinophilic taxa in hospital (i.e., people’s hospital, traditional Chinese medicine hospital, and orthopedic hospital) garden soils from southern China (i.e., Jiangsu Province, Guizhou Province, and Hainan Province). Feather addition significantly decreased the soil microbial diversity, but increased the relative abundance of the dominant phyla. Keratinophilic microorganism such as Paenibacillus, Paenisporosarcina, Sporosarcina, Lysobacter, and Cellulosimicrobium, increased through feather enrichment. The relative abundances of Bacillus and Streptomyces (keratinophilic bacteria) and Chrysosporium (keratinophilic fungi) increased by 51–98 % in feather enrichment compared to control soils. However, Arthrobacter (keratinophilic bacteria) and Trichoderma (keratinophilic fungi) decreased by 76 % and 90 %, respectively. Co-occurrence network analysis revealed that the number of nodes, edges, average degree, and clustering coefficients of bacterial and fungal were decreased after feather enrichment treatment. The feather enrichment significant decreased the pH and C:N rates, but increased the carbon, nitrogen, and phosphorus contents of the hospital garden soil. Linear mixed model and correspondence analyses showed that pH, total nitrogen and soil organic carbon were the main factors responsible for changes in community diversity and structure. We then speculate that the keratinophilic microbial taxa are enriched by exposure to higher concentrations of keratin substrates such as human hair and skin surfaces. We suggest that future research should focus on keratinophilic taxa in some specialized habitats, particularly in hospitals.

Sampling of soil mesofauna has been traditionally carried out with Berlese/Tullgren extractions, a century old technique. However, sampling methods involving the extractions of soil are becoming increasingly difficult to implement and standardise due to the lack of commercially available equipment. Moreover, they are poorly suited to repeated sampling in the same locations and underestimate more mobile taxa.

Below-ground (hypogean) pitfall trapping is a promising new technique that up to now was only attempted with bulky custom-manufactured tools. In the present work we test a cheap and easily deployable setup made using standard pipe fittings.

The new design was compared across different environments with Berlese/Tullgren extractions in order to ascertain whether they produce similar species lists and detect the same environment-induced changes in communities. The two trap types were found to yield structurally different assemblages, with the new design producing significantly higher abundance and diversity of springtails and larger taxa. Beta-diversity profiles resulted however perfectly comparable, characterising the same pattern of dissimilarities. In addition, a new method is proposed to use the two sampling types in combination to estimate the dispersal of soil organisms.

Below-ground pitfall traps have the potential to complement Berlese extractions for reliable and standardised monitoring of soil arthropods, thanks to their effectiveness, low cost and ease of operation.

Information about the response of soil enzymes to field warming in permafrost regions is scarce, and the potential mechanisms by which warming combined with biotic and abiotic factors affect soil enzyme activities in alpine grasslands remain unclear. A 3-year in situ experiment with two warming levels (2.7 °C and 5.3 °C) was conducted in an alpine swamp meadow to investigate the effects of experimental warming on 5 soil enzyme activities involved in soil carbon and nitrogen cycling, and the relationships between soil enzyme activities and soil variables related to physicochemical properties and nutrient levels were examined. Results showed that warming had obvious positive effects on soil moisture (SM), soil organic carbon, total nitrogen, and NH₄⁺-N contents, especially in the surface soil layer. Soil NO₃^--N tended to decrease under moderate warming, while it significantly increased under high warming. Meanwhile, during the entire growing season, warming strongly enhanced invertase and amylase activities by 39.2–49.0% and 109.9–191.0%, respectively. In contrast, urease activities were significantly decreased by 36.8–55.7% in warming plots and there were no significant differences in catalase or cellulase activities among treatments during the whole growing season, while catalase activities in warming plots were significantly decreased by 2.6–4.0% in June. These inconsistent responses of soil enzyme activities to experimental warming could be partially explained by warming-induced changes in soil variables. Redundancy analysis showed that soil NO₃^--N and SM were the most important factors, which explained 29.8% and 19.7% of the variations in soil enzyme activities, respectively, suggesting that the warming-induced increase in SM could weaken the soil aeration status and enhance enzyme and substrate diffusion, strongly affecting soil nitrification and microbial enzyme production.