European Journal of Soil Science最新文献

Fine-grained hypermonosulfidic sediments are widespread on the coastal plains of the northern Baltic Sea that when drained, cause the formation and dispersion of acid and toxic-metal species. In this study, a 30-month laboratory oxidation experiment with such a sediment was performed in incubation cells. To minimize or prevent acidification, limestone was applied in two grain sizes: agricultural limestone with particles that were all <3.15 mm and half of them <0.80 mm, and fine-grained limestone with a median grain size of 2.5 μm. The amount of limestone applied corresponded to the theoretical acidity contained in the sulfides, as well as four times that amount. Another treatment included addition of peat to the low limestone dose to test its effects on immobilizing sufhur and metals. The pH of the drainage water and solid phase decreased to pH <4.0 in the control, and to pH <5.0 in the coarse-grained low-limestone treatment, but remained near-neutral in the other treatments. Hence, the fine-grained limestone effectively hindered acidity formation in contrast with the coarse-grained limestone when applied in amounts corresponding to the potential acidity held in the sulfides. The limestone treatments further overall decreased the rate of pyrite oxidation, slowed down the movement of the oxidation front, strongly minimized the formation of dissolved and solid-phase labile Al, and caused formation of gypsum as well as more labile secondary Fe(III) phases than corresponding Fe phases formed in the control. The limestone and peat treatments also caused shifts in the 16S rRNA gene-based microbial communities, where the control developed acidophilic iron and sulfur oxidizing communities that promoted acidity and metal release. Instead, the limestone-treated unacidified incubations developed acid tolerance to neutrophilic communities of iron and sulfur oxidizers that promoted sulfate formation without acidity release. The results showed that limestone treatments have several biogeochemical effects, and that using a fine-grained limestone as amendment was favourable in terms of minimizing acidity formation and metal release.

There is increasing recognition that the application of fine-grained silicate rock granulates can improve soil productivity by increasing its fertility and ameliorating its physical properties. Although the former has been extensively studied, empirical information on the latter is scarce. Pot and field experiments were conducted at the University of Ghana's Forest and Horticultural Crops Research Centre (FOHCREC), Kade, Ghana, from May 2020 to December 2021 to quantify the short-term effect of the application of Greenlandic glacial rock flour (GRF) on the physical properties of three benchmark arable soils in Ghana, namely an Acrisol (sandy clay loam), a Haplic Ferralsol (sandy loam), and an Arenosol (sand). The pot experiment included three GRF treatments (0, 10, and 20 t ha⁻¹) and the three soil types, while the field experiment was conducted on only the sandy clay loam soil where GRF rates of 10 and 50 t ha⁻¹ were compared to the control. Intact 100 cm³ soil cores were sampled from the soil surface in the field and pot experiments to assess the soil bulk density. We also quantified soil water retention, air and gas transport, and pore morphological characteristics over a range of matric potentials. Both the pot and field experiments showed that adding GRF did not improve soil water retention. Still, the response of gas transport and pore characteristics to changing matric potential was significantly (p < 0.05) modified by GRF in some soil types. The results suggested that the effectiveness of the use of GRF to ameliorate soil physical conditions for plant growth may depend on soil type and the soil water matric potential. We concluded that the application of GRF cannot be relied upon as a short-term strategy to significantly improve the structural quality of the tropical soils studied. Rather, GRF should be considered for application to the soils for its other beneficial effects. We recommend that the effects of repeated applications and further build-up of the material in the soil should be investigated to determine the effect of higher relative GRF concentrations on soil hydro-physical properties.

Grapevine (Vitis vinifera L.) is a traditional crop cultivated in Navarre (NE Spain). However, in some areas, it is grown without harnessing land suitability for its cultivation. This research was conducted to approach the pedological recognition of viticulture zoning (on the farm scale) in a traditional and distinct viticultural region: Olite (Navarre). As grape yield and grape quality in a given field are generally variable and do not coincide one way or another, 13 soil profiles were selected for pedological description and analysis in an attempt to recognise the importance of soil properties. For that purpose, 45 soil samples (corresponding to the different pedogenetic horizons of the 13 soil profiles) were collected to improve zonal vineyard estimations. The most notable characteristics of the studied soils were the presence of petrocalcic horizons, high stone fragments content, mainly loamy textures, high pH (between 8.24 and 9.24), high carbonate (between 19.1% and 90.0%), and active limestone contents (between 5.7% and 26.1%), and relatively low organic matter contents (<3.34%). Appreciable soil properties variability was detected from the results of this study and, therefore, variability in production and grape composition was expected. These results emphasise the spatial variability of the study area soils in a way that allows for the delineation of homogeneous viticultural zones. The results also provide the necessary information not only for viticultural zoning in the Navarre wine-growing region, but also in wine-growing regions with a Mediterranean continental climate. Hence, our findings will allow future viticultural management zones to be developed and specific practices to be implemented.

Rock fragments (RFs) are abundant soil constituents, but are routinely excluded from soil analyses. Hence, their contribution to soil properties, and in particular to the microbiome, is incompletely understood. Therefore, shifts in microbial colonisation along the rock-to-soil continuum of topsoils from three agricultural sites with different sedimentary parent rock materials were investigated with particular attention to RFs. Microbial biomass and community composition were quantified using phospholipid fatty acid (PLFA) analysis for unweathered and weathered parent rock materials, two RF fractions (8–16 mm and 2–8 mm) and the fine earth (FE; <2 mm). Trends in biogeochemical weathering, nutrient availability and soil organic matter (OM) development were assessed using mineralogical, geochemical and physical analyses. Actinobacterial PLFA was particularly abundant in parent rocks, where Actinobacteria likely contribute to rock weathering and the initiation of OM accumulation. Conversely, bacterial PLFAs were most abundant in the FE under nutrient- and OM-rich conditions. The integral role of RFs as a microbial habitat is demonstrated by a distinct fungal colonisation, which is enabled by the specific physical features of RFs in combination with the provision of inorganic nutrients. Our findings indicate that RFs are colonised by microbes and that differences in the community structure depend on mineralogical properties and chemical weathering status. We document that RFs are microhabitats with a significant potential to host microbial life in cultivated soils, and thus, could play an important role in biogeochemical cycling and the provision of soil functions in agroecosystems.

Despite the critical role of soil microbial communities in biomass production and ecosystem functioning, previous research primarily focussed on microbial structure without functional insights, especially for rare species. This study addresses this gap by exploring the functional potential of both abundant and rare bacterial communities across various land uses and soil groups in the Lower Namoi Valley, Australia. By integrating plant-beneficial bacteria (PBB) and Functional Annotation of Prokaryotic Taxa (FAPROTAX) databases, we show that rare species exhibited higher alpha diversity and multifunctionality than abundant species. Cropping enhanced the biodiversity of abundant functional bacteria in fine-textured soils, which promoted crop growth through increased PBB and carbon cycling. Conversely, rare functional bacteria exhibited consistently lower biodiversity in croplands. Random forest models and linear regression analyses identified land use as a significant factor influencing the biodiversity of rare functional bacterial communities, likely through plant–soil feedback systems. These findings underline the importance of land use in shaping bacterial community functionality and call for conservation strategies to protect soil biodiversity, especially rare species, to ensure sustainable soil ecosystems and support future food production.

The chemodiversity and thermodynamic stability of dissolvable organic matter (DOM) in paddy soil under different crop residue managements remain unclear. Using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis, we explored the molecular composition of DOM in paddy soil 4 years following incorporation of maize residue in different forms (air-dried straw, manure and biochar). Compared to the control without amendments, manure increased the pool size of DOM but reduced its chemodiversity, while the straw and biochar amendments reduced the pool size but increased the chemodiversity of DOM by 0.22 and 0.05, respectively. Though approximately 60% of the compounds were shared among the treatments, those distinct among the treatments were shaped by residue-derived lignin-like compounds. Moreover, the nominal oxidation state of carbon (NOSC), which corresponds to the energy content in organic carbon, decreased with the maize residue amendments, regardless of the forms. Thus, crop residue amendments could lead to higher DOM persistence in the short-term, potentially slowing carbon turnover in paddy soil.

The local adaption of soil microbial communities to native litter inputs, the so-called home field effect (HFE), is well established, though this phenomenon has yet to be demonstrated for agriculturally relevant inorganic nutrient sources. Using compound-specific ¹⁵N-stable isotope probing of proteinaceous amino acids (AAs), we investigated if continuous long-term grassland fertilisation with either ammonium or nitrate resulted in preferential assimilation by the soil microbial community of the ‘home’ N fertiliser. Relative ammonium uptake was maximal in historic ammonium treated soils and previously unfertilised soil, confirming a general microbial preference for ammonium likely due to biochemical transformation efficiencies. Assimilation of nitrate and ammonium into AAs was comparable for the historic nitrate fertilisation, indicating that microbial adaptive processes governed by historical land use can dictate the immobilisation efficiency of different fertilisers. This is the first observation of the HFE in long-term fertilised grassland soils, with further work required to investigate abiotic or biotic mechanisms underpinning this phenomena.

Vegetation restoration processes significantly affect near-surface characteristics, thus affecting soil detachment. Existing research has primarily focused on analysing soil detachment via root morphological parameters and soil physical and chemical properties. However, few studies have focused on analysing the variation in soil detachment with restoration age from a mechanical parameter perspective. Natural, undisturbed soil samples were collected from five grasslands restored for 1–22 years and from one bare plot (0 years of restoration, employed as the control). The collected samples were subjected to flow scouring in hydraulic flume experiments under six stream powers. The relationship between the soil detachment rate (SDR) and the mechanical parameters of the root–soil composites, namely root cohesion and soil shear strength (τ₂₀₀), were quantified to reveal the mechanical mechanism underlying soil detachment during vegetation restoration. The results indicated that the SDR decreased, whereas root cohesion increased with increasing vegetation restoration age. The dominant factors influencing the SDR changed from hydrodynamics at the early restoration stage to the mechanical properties of the root–soil composites at the late stage. An SDR model with a high prediction accuracy (Nash–Sutcliffe efficiency = 0.96 and R² = 0.96) was developed based on mechanical parameters, and the fitting effect was greater than that of the SDR prediction model developed based on root morphological parameters and soil physical and chemical properties. This study aimed to analyse the SDR variation mechanism from the perspective of mechanics and could provide reference for the study of the erosion reduction effect of roots.