首页期刊导航|Geoderma: An International Journal of Soil Science
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Geoderma: An International Journal of Soil Science
Elsevier Science Publishers
Geoderma: An International Journal of Soil Science

Elsevier Science Publishers

0016-7061

Geoderma: An International Journal of Soil Science/Journal Geoderma: An International Journal of Soil Science
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    Determining water content and bulk density: The heat-pulse method outperforms the thermo-TDR method in high-salinity soils

    Peng W.Lu Y.Wang M.Ren T....
    7页
    查看更多>>摘要：? 2021 Elsevier B.V.Heat-pulse (HP) and thermo-time domain reflectometry (thermo-TDR) methods have been used to determine soil thermal properties, water content (θ) and bulk density (ρb) simultaneously. Their performances on salt-affected soils, however, remain unknown. This study investigated the effect of salinity on HP signals and thermo-TDR measured electromagnetic waveforms, and the derived θ and thermal property values of packed soil columns with various textures, saturations and bulk electrical conductivities (σa). The thermo-TDR and HP-based methods for estimating ρb values were also evaluated. The results showed that: (1) at σa values lower than 1.0 dS m?1, the TDR method provided reliable θ with relative errors within 5%; salt effects became apparent at σa values greater than 1.0 dS m?1 due to the distortion of TDR waveforms; the TDR method failed to estimate θ at σa > 2.71 dS m?1 because the 2nd reflection point on the waveform was undetectable; (2) salinity had negligible effects on soil thermal property values in the studied range (σa < 7.59 dS m?1), and the HP-based approach was able to derive θ and ρb values from thermal property measurements, with root mean square errors within 0.02 m3 m?3 for θ and within 0.12 Mg m?3 for ρb. Thus, the HP-based approach outperformed the thermo-TDR approach for determining θ and ρb values in soils with σa > 1.0 dS m?1.
      原文链接:
    • NSTL
    • Elsevier

    Response of methanotrophic activity and community structure to plant invasion in China's coastal wetlands

    Wang W.-Q.Wu H.-S.Liu J.-Q.Shen L.-D....
    9页
    查看更多>>摘要：? 2021 Elsevier B.V.Coastal wetlands are critical in the global carbon budget while vulnerable to plant invasion. Spartina alterniflora (S. alterniflora), a typical invasive plant species, has rapidly expanded in China's coastal area since 1979, which disturbed the carbon cycle of the coastal wetland ecosystems. However, until now, the effect and underlying mechanisms of S. alterniflora invasion on methanotrophs are poorly known in coastal wetlands. Here, a large-scale investigation of the activity, abundance and community structure of methanotrophs was conducted in seven wetlands under both native (dominated by Phragmites australis, Kandelia candel or Avicennia marina) and invasive plants (dominated by S. alterniflora) across the southeast coast of China. Compared with the native community, S. alterniflora invasion led to a significant (p < 0.05) increase in activity and abundance of methanotrophs, which increased by 62.1% and 64.0% in average, respectively. The invasion of S. alterniflora did not greatly alter the methanotrophic community structure in most of the examined wetlands. However, the relative abundance of type I methanotrophs decreased under P. australis community, while type II methanotrophs (Methylocystis) increased after S. alterniflora invasion. In addition, the soil organic carbon content, ammonium content and salinity were identified as important environmental factors affecting the activity and community structure of methanotrophs. Overall, our results demonstrated that the activity and abundance of methanotrophs responded positively to S. alterniflora invasion, suggesting the important role of methanotrophs in reducing methane emissions from China's coastal wetlands.
      原文链接:
    • NSTL
    • Elsevier

    Molecular transformation of dissolved organic carbon of rhizosphere soil induced by flooding and copper pollution

    Chen L.Han L.Ma C.Zhang B....
    9页
    查看更多>>摘要：? 2021 Elsevier B.V.Dissolved organic carbon (DOC) in rhizosphere soil is critical for multiple geochemical processes. Soils that suffer from heavy metal pollution accompanied by flooding are present worldwide, while little research has explored their effects on rhizosphere DOC structures, especially at the molecular level. Therefore, this study was designed with the aim of improving the understanding of rhizosphere DOC fate in copper (Cu) amended and/or flooded soils. A 180-day laboratory incubation including soils with different Cu levels with and without flooding was conducted. Fourier transform ion cyclotron resonance mass spectrometry analysis showed that the number of formulas detected only in the rhizosphere DOC of flooded and Cu-treated soil was as high as 528–1375. Flooding and Cu pollution reduced molecular weight, aromaticity and compounds containing CHON2 and CHON3 of rhizosphere DOC, but increased its oxidation degree. Furthermore, Cu pollution resulted in DOC with more abundant lignin-, carbohydrate- and protein-like components but less condensed aromatic-like components. Overall, due to Cu pollution and flooding, the rhizosphere DOC pool contained more chemically and biologically labile components. Structural equation modeling indicated that this change in DOC structure was partly explained by soil enzyme activities (decrease in invertase, cellulase, urease activity and the increase in polyphenol oxidase and peroxidase activity). The findings highlighted the ecological risk of Cu pollution and flooding to soil health from the perspective of rhizosphere carbon.
      原文链接:
    • NSTL
    • Elsevier

    Nitrate leaching and N accumulation in a typical subtropical red soil with N fertilization

    Yang J.-L.Zhao X.-R.Dong Y.Yang S.-H....
    12页
    查看更多>>摘要：? 2021 Elsevier B.V.Nitrate (NO3?) leaching in agroecosystems has caused much concern worldwide due to its negative environmental and health impacts. To evaluate the effect of fertilization on NO3? leaching and soil N accumulation, a two-year 15N tracing study was conducted in subtropical China with field lysimeters packed with non-destructive sampling red soil. 200 kg N ha?1 yr?1 urea (15N abundance of 10%) was applied for maize crops. Fertilization promoted NO3? leaching by 91.5 ± 6.1 and 57.9 ± 15.2 kg N ha?1 yr?1 at 20 and 100 cm depth, respectively. Soil organic nitrogen (SON) pool was the main NO3? source (>60%), especially at surface soil. Fertilizer contributed 19.4 ± 2.0 and 32.8 ± 1.9% to NO3? leaching. At 20 cm depth, besides NO3? leaching accelerated by fertilization during the crop growth period (51.8%), mineralization of SON also resulted in abundant NO3? leaching during the fallow period (48.2%). At 100 cm depth, NO3? leaching significantly increased with the fertilization year due to the continuous NO3? leaching and the delay of NO3? leaching by soil NO3? adsorption. After two-year fertilization, 55.3 ± 2.2% of the applied N accumulated in the soil, leading to a soil N pool increase of 110.0 ± 10.1 kg N ha?1 yr?1. If the fertilization was maintained, the continuous N accumulation poses a potential threat to groundwater quality or drinking water safety. In subtropical red soil regions, to reduce NO3? leaching, NO3? leaching during both the crop growth and fallow period should be taken seriously, and effective management practices, such as cover crops and intensive tile drainage systems, should be carried out to reduce the fertilizer N accumulation and the contribution of SON.
      原文链接:
    • NSTL
    • Elsevier

    Allocation of foliar-P fractions of Alhagi sparsifolia and its relationship with soil-P fractions and soil properties in a hyperarid desert ecosystem

    Gao Y.Tariq A.Zeng F.Zhang Z....
    11页
    查看更多>>摘要：? 2021 Elsevier B.V.Desert vegetation in the juncture of the Qira oasis and the Taklamakan Desert typically grows on phosphorus (P)-poor soils. Alhagi sparsifolia Shap. (A. sparsifolia), as widely distributed natural vegetation in this area, not only has crucial ecological effects of wind sheltering and sand fixation, but also is an excellent forage resource. Researchers are increasingly interested in the foliar-P utilization strategy of A. sparsifolia that allows it to survive in extremely P-impoverished soils. Therefore, A. sparsifolia growing in four different soil sites with differing availability of P in this area were studied, and leaves and 0–100 cm soils were collected. Foliar total nitrogen (N), total-P and P fractions (metabolic-P, nucleic acid-P, structural-P, and residual-P) were determined. Soil labile-P (resin-P, NaHCO3-Pi, and NaHCO3-Po), moderately labile-P (NaOH-Po and NaOH-Pi), stable-P (HCl-P and residual-P), and basic soil properties were determined. Our findings showed that A. sparsifolia growth was highly likely to be limited by soil-P in this area, and the concentrations of foliar total-P and young leaf metabolic-P increased with increasing soil-P availability, while foliar-N was relatively constant. Comparatively, A. sparsifolia allocated a higher proportion of foliar-P to nucleic acid-P and a lower proportion to structural-P, as soil-P availability decreased. Moreover, foliar metabolic-P, nucleic acid-P, and structural-P had the strongest positive response to soil labile-P in topsoil. Furthermore, soil electrical conductivity (EC), labile-P, and moderately labile-P influenced foliar-P fractions. Comprehensively, variation in foliar-P allocation patterns of A. sparsifolia varied across the four soils with differing available-P and were closely related to soil-P fractions and properties. These results will help us better understand A. sparsifolia foliar-P utilization strategy and their potential responses to environmental nutrients.
      原文链接:
    • NSTL
    • Elsevier

    Oxygen matters: Short- and medium-term effects of aeration on hydrolytic enzymes in a paddy soil

    Wang C.Dippold M.A.Dorodnikov M.Blagodatskaya E....
    9页
    查看更多>>摘要：? 2021 Elsevier B.V.Rapid exposure of anoxic microbial communities to oxygen (O2) can have unpredictable effects, including strong suppression of their enzymatic activity. Nonetheless, most medium- and long-term incubation studies on soil organic matter transformations fail to consider aeration effects during sample post-processing and/or assays. Moreover, it remains unclear whether anoxic enzymatic systems are adapted to quick switch to oxic conditions. We evaluated the effects of short-term (2-h oxic (+O2) vs. anoxic (–O2) assays) and medium-term aeration (after 10-day oxic vs. anoxic pre-incubation) on the kinetic parameters (Vmax, Km) of phosphomonoesterase, β-glucosidase, and leucine aminopeptidase in top bulk, rooted, and bottom bulk paddy soil of flooded rice mesocosms. We hypothesized contrasting short- and medium-term responses of hydrolytic enzyme activities to aeration (i) a negative short-term effect caused by reactive O2 species toxicity and/or other mechanisms, and (ii) adaptation of anoxic microbial communities to medium-term aeration reducing the impact of ongoing O2 exposure. Overall, 2-h aeration suppressed Vmax values by 7–43% and catalytic efficiency Ka (Vmax/Km) by 3–22%, and extended the substrate turnover time Tt (7–33%) of three tested enzymes in all soil compartments pre-incubated without O2. In contrast, no short-term suppressive effect of O2 was observed on three tested enzymes after oxic pre-incubation. Medium-term aeration increased Vmax (by 12–253%) and Ka (by 3–78%) of the enzymes and shortened Tt (4–42%) as compared to the anoxic counterpart. These findings support our hypothesis about anoxic microbial community adaptation over the medium-term aeration. Accordingly, the sensitivity of anoxic hydrolytic enzymes to a short-term O2 exposure and the O2 adaptation mechanisms require strong consideration (i) for enzyme assays of anoxic soils and (ii) for understanding the soil organic matter dynamics in environments with O2 fluctuations.
      原文链接:
    • NSTL
    • Elsevier

    Land use conversion and soil moisture affect the magnitude and pattern of soil-borne N2, NO, and N2O emissions

    Wei Z.Shan J.Yan X.Well R....
    11页
    查看更多>>摘要：? 2021 Elsevier B.V.In this study, soil-borne N2, NO, and N2O emissions induced by land use conversion and water management were investigated in intact soil cores under a helium/oxygen atmosphere by a robotized incubation system in combination with the N2O 15N site preference signature and molecular-based microbial analysis. The experiment consisted of five treatments: i) paddy-flooded (PF); ii) orchard-wet (OW, 70% WFPS); iii) orchard-dry (OD, 43% WFPS); iv) vegetable-wet (VW, 70% WFPS); and v) vegetable-dry (VD, 43% WFPS). The vessels of each treatment received 200 mg urea-nitrogen (N) (equivalent to 210 kg of urea-N ha?1), and soil moisture in the OW and VW treatments was adjusted to a higher constant moisture to simulate a scenario after irrigation or rainfall. The results showed that total gaseous N losses during the incubation period were 25.33 ± 0.33 kg N ha?1 in the PF treatment, whereas smaller losses were recorded in the OD and VD treatments (4.28 ± 2.04 and 9.75 ± 3.75 kg N ha?1, respectively). The potential contribution of bacterial denitrification to N2O emissions in the OD and VD treatments was 11.1% and 15.4% higher, respectively, than that in the PF treatment (58.8% ± 0.5%). Furthermore, the corresponding N2O/(N2O + N2) ratio in the OD and VD treatments decreased by 50% and 73.8%, respectively, relative to the ratio in the PF treatment (0.42 ± 0.01). Such changes indicated the crucial role of altered soil properties caused by land use conversion in regulating the production and consumption of N2O. Relative to the normal moisture (dry) condition, enhanced soil moisture increased total gaseous N losses in the orchard and vegetable soils by 386.9% and 67.4%, accompanied by a higher N2O/(N2O + N2) product ratio, but decreased the share of bacterial N2O by 11.1% and 15.4%, respectively. The changes in the abundance and community composition of soil denitrifiers caused by land use conversion from rice paddies to orchards and vegetable fields could partly explain the differences in gaseous N loss therein. These findings highlight the influence of land use conversion on soil gaseous N emissions and demonstrate that increased moisture in upland soils reduced the dominance of bacterial denitrification in N2O production.
      原文链接:
    • NSTL
    • Elsevier

    Berken plow and intercropping with pigeon pea ameliorate degraded soils with a hardpan in the Ethiopian highlands

    Fenta H.M.Hussein M.A.Tilahun S.A.Steenhuis T.S....
    13页
    查看更多>>摘要：? 2021 The Author(s)Closing the yield gap and enhancing efficiency in rainfed maize production systems in Ethiopia requires urgent action in increasing the productivity of degraded agricultural land. The degradation of land through continuous compaction and decline in the organic matter has resulted in a wide-spread formation of a hardpan that restricts deep percolation, prevents plant root development, and, ultimately can lead to increased erosion. Studies exploring practical low-cost solutions to break the hardpan are limited in Ethiopia. The main objective was to evaluate soil mechanical (i.e. modified plow or Berken plow) or biological intervention (i.e. intercropping with pigeon pea) effectiveness to enhance soil water management and crop yield of rainfed maize systems whilst reducing soil erosion and runoff. Five farm fields, each including four plots with different tillage treatments, were monitored during two rainy seasons in 2016 and 2017. The treatments were: (i) farmers practice under conventional (CT) tillage; plots tilled three times using an oxen driven local plow Maresha, (ii) no-till (NT), (iii) Berken tillage (BT), plots tilled three times using an oxen pulled Berken plow, and (iv) biological (CT + Bio), tap-rooted pigeon pea intercropped with maize on plots conventionally tilled. Results showed that mean tillage depth was significantly deeper in the BT (28 cm) treatment compared to CT and CT + Bio (18 cm) treatments. Measured soil penetration resistance significantly decreased up to 40 cm depth under BT and maize roots reached 1.5 times deeper compared to roots measured in the CT treatment. Under BT, the estimated water storage in the root zone was estimated at 556 mm, 1.86 times higher compared to CT, 3.11 times higher compared to NT and 0.89 times higher compared to CT + Bio. The positive effects on increased water storage and root development resulted in an average increase in maize grain (i.e. 15%, 0.95 t ha?1) and residual above ground biomass (0.3%, 6.4 t ha?1) leading to a positive net benefit of 138 USD ha?1 for the BT treatment compared to the CT treatment. The negative net benefit obtained under CT and CT+Bio was mainly related to the high labor cost related to plowing, weeding, planting, and fertilizer application whilst in the NT this was related to the significantly lower maize yields. The positive effects in the BT treatment, and to some extent the CT+Bio treatment show great potential for smallholder rainfed maize systems where degraded soils with hardpans and high variability in rainfall prevail.
      原文链接:
    • NSTL
    • Elsevier

    Plant species and plant neighbor identity affect associations between plant assimilated C inputs and soil pores

    Zheng H.Guber A.K.Kravchenko A.N.Kuzyakov Y....
    13页
    查看更多>>摘要：? 2021 Elsevier B.V.Greater plant diversity is known to facilitate soil C gains, yet the exact mechanisms of this effect are still under intensive discussion. Whether a plant grows in monoculture or in a multi-species mixture can affect allocation of plant assimilates, belowground exudation, and microbial stimulation. The goal of this study was to examine the effects of inter-cropping on a previously overlooked aspect of plant-soil interactions, namely, on locations where plant assimilated C is allocated within the soil pore system and its subsequent fate in relation to soil pore size distributions. The soil for the study originated from a greenhouse experiment with switchgrass (Panicum virgatum L.) (var. Cave'n'Rock) (SW), big bluestem (Andropogon gerardii Vitman) (BB), and wild bergamot (Monarda fistulosa L.) (WB) grown in monocultures and in inter-cropped pairs and subjected to species specific 13C pulse labeling (Kravchenko et al., 2021). Intact soil cores (8 mm ?) were collected from the experimental pots, subjected to a short-term (10 day) incubation, X-ray computed micro-tomography (μCT) scanning, and soil 13C micro-sampling “geo-referenced” to μCT images. Results indicated that in the plant systems with demonstrated interplant C transfer soil 13C was positively correlated with < 10 μm ? pores immediately after plant termination and with 20–80 μm ? pores after the incubation. In the systems without marked interplant C transfer soil, 13C was positively correlated with 20–30 μm ? pores, however, the correlations disappeared after the incubation. Soils from the systems with demonstrated belowground C transfer displayed lower losses of root-derived C during incubation than the systems where interplant C transfer was negligible. Factors facilitating interplant C transfer appear to also lead to placement of root-derived C into smaller pores and to its greater protection there.
      原文链接:
    • NSTL
    • Elsevier

    Water treatment residuals for ameliorating sandy soils: Implications in environmental, soil and plant growth parameters

    Ribeiro P.L.dos Santos Pereira I.Monteiro A.B.de Lima C.L.R....
    13页
    查看更多>>摘要：? 2021 Elsevier B.V.Water treatment residuals (WTR) application may improve the quality of sandy soils; however, nutrient deficiency to plants and potentially toxic elements (PTEs) may be limiting. In contrast, adjusting the WTR pH, soil pH and WTR application rate might prevent adverse effects. This study aimed to evaluate the environmental safety and agronomic effectiveness of limed WTR for application in sandy soils. The tested treatments were increasing rates (0, 15, 30 and 60 Mg ha?1 of dry mass) of ground, dried and limed WTR in sandy soil under field conditions. Soil samples with disturbed and undisturbed structure were collected to determine selected soil physical, hydraulic and chemical parameters related to fertility, as well as the soil concentration of PTEs. Nutrients and PTEs content in plant tissue and the agronomic performance of maize and ryegrass were also evaluated. WTR were beneficial as they increased the content of fine and reactive particles (clay and silt). In general, WTR rates did not spoil soil chemical parameters related to soil fertility; did not increase aluminium saturation; and did not change soil PTE contents which were below the limits indicated by environmental legislations. The tested WTR rates did not cause negative effects on the agronomic variables of maize and ryegrass plants. Thus, waste application rates up to 30 Mg ha?1 are recommended. Liming WTR and soil makes this material safe and suitable for application in sandy and acidic agricultural soils.
      原文链接:
    • NSTL
    • Elsevier