On‐site soil analysis in the framework of precision agriculture is gaining significant importance to achieve improved crop productivity, increased soil health and reduced fertilizer application. In ...situ sensing techniques can provide the information required for decision support systems immediately on the field, for example, to control fertilization and liming. Shifted excitation Raman difference spectroscopy (SERDS) pilot investigations for on‐site soil analysis are presented using a portable SERDS sensor system specifically developed for in‐field studies. The SERDS sensor includes a dual‐wavelength diode laser at 785 nm integrated in an in‐house realized turnkey laser system and an optical power of 36 mW at the sample was chosen for our experiments. Outdoor pre‐investigations with the device and polystyrene as test sample show the capability of SERDS for qualitative and quantitative analysis under changing daylight conditions. On‐site soil analysis is carried out and SERDS extracts Raman signals from disturbing background interference with a 15‐fold improvement of the signal‐to‐background‐noise ratio. Beside others, closely neighboured Raman signals of calcite and dolomite are identified and even mixtures of both soil carbonates are discriminated using SERDS. The number of accumulations for generating an averaged SERDS spectrum of soil with a sufficient signal stability and signal‐to‐background‐noise ratio is evaluated to optimize the overall exposure time for such in situ experiments. The presented results demonstrate the large capability of the developed portable SERDS sensor system for on‐site soil investigations as promising tool for precision agriculture.
Shifted excitation Raman difference spectroscopy (SERDS) pilot investigations for on‐site soil analysis are presented using a portable SERDS sensor system specifically developed for in‐field studies. SERDS extracts Raman signals from disturbing background interference with a 15‐fold improvement of the signal‐to‐background‐noise ratio enabling identification of soil minerals, even those with closely neighboured Raman signals, for example, calcite and dolomite. The presented results demonstrate the large capability of the portable SERDS sensor system for on‐site soil investigations as promising tool for precision agriculture.
A global atlas of the dominant bacteria found in soil Delgado-Baquerizo, Manuel; Oliverio, Angela M; Brewer, Tess E ...
Science (American Association for the Advancement of Science),
01/2018, Letnik:
359, Številka:
6373
Journal Article
Recenzirano
Odprti dostop
The immense diversity of soil bacterial communities has stymied efforts to characterize individual taxa and document their global distributions. We analyzed soils from 237 locations across six ...continents and found that only 2% of bacterial phylotypes (~500 phylotypes) consistently accounted for almost half of the soil bacterial communities worldwide. Despite the overwhelming diversity of bacterial communities, relatively few bacterial taxa are abundant in soils globally. We clustered these dominant taxa into ecological groups to build the first global atlas of soil bacterial taxa. Our study narrows down the immense number of bacterial taxa to a "most wanted" list that will be fruitful targets for genomic and cultivation-based efforts aimed at improving our understanding of soil microbes and their contributions to ecosystem functioning.
Methanol extracts of stem, leaf, and seed obtained from
Pistacia terebinthus
which are rich in phenolic compounds were used for the first time to produce chitosan-based antioxidative and ...antimicrobial films. All the produced films were characterized by FT-IR, TGA, DSC, SEM, contact angle measurements, and UV-Vis spectroscopy and mechanically. As was expected, incorporation of the plant extracts into chitosan films enhanced the antioxidant and antimicrobial activities effectively. Also, the elasticity of chitosan-seed and chitosan-stem films was improved. The eco-friendly nature of the produced blend films was determined through soil and water degradation analyses. All these findings lead to the conclusion that the produced blend films with
Pistacia terebinthus
extracts can be applied as alternative food packaging material.
Chitosan films blended with stem, leaf and seed extracts of
Pistacia terebinthus
for active food packaging.
This study evaluates the use of visible and near infrared spectroscopy (Vis-NIRS) combined with multivariate regression based on random forest to quantify some quality soil parameters. The parameters ...analyzed were soil cation exchange capacity (CEC), sum of exchange bases (SB), organic matter (OM), clay and sand present in the soils of several regions of Brazil. Current methods for evaluating these parameters are laborious, timely and require various wet analytical methods that are not adequate for use in precision agriculture, where faster and automatic responses are required. The random forest regression models were statistically better than PLS regression models for CEC, OM, clay and sand, demonstrating resistance to overfitting, attenuating the effect of outlier samples and indicating the most important variables for the model. The methodology demonstrates the potential of the Vis-NIR as an alternative for determination of CEC, SB, OM, sand and clay, making possible to develop a fast and automatic analytical procedure.
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•Analytical methodology based on Vis-NIRS spectroscopy and random forest•Determination of quality soil parameters as CEC, SB, organic matter, clay and sand•Random forest was statistically superior to PLS regression.•Random forest attenuates the effect of outlier samples.•Fast and automatic alternative methodology for soil analysis
Abstract
Soil is the largest terrestrial reservoir of organic carbon and is central for climate change mitigation and carbon-climate feedbacks. Chemical and physical associations of soil carbon with ...minerals play a critical role in carbon storage, but the amount and global capacity for storage in this form remain unquantified. Here, we produce spatially-resolved global estimates of mineral-associated organic carbon stocks and carbon-storage capacity by analyzing 1144 globally-distributed soil profiles. We show that current stocks total 899 Pg C to a depth of 1 m in non-permafrost mineral soils. Although this constitutes 66% and 70% of soil carbon in surface and deeper layers, respectively, it is only 42% and 21% of the mineralogical capacity. Regions under agricultural management and deeper soil layers show the largest undersaturation of mineral-associated carbon. Critically, the degree of undersaturation indicates sequestration efficiency over years to decades. We show that, across 103 carbon-accrual measurements spanning management interventions globally, soils furthest from their mineralogical capacity are more effective at accruing carbon; sequestration rates average 3-times higher in soils at one tenth of their capacity compared to soils at one half of their capacity. Our findings provide insights into the world’s soils, their capacity to store carbon, and priority regions and actions for soil carbon management.
Conventional soil chemical analyses are time-consuming and laboratory-based. Spectroscopic techniques have been introduced to make soil measurements more rapid and cost-effective. While portable ...X-ray fluorescence spectrometry (pXRF) has been increasingly adopted for advanced soil analysis in temperate regions, comparatively few applications have been developed for tropical soils. Using PXRF, soil total elemental composition can be obtained in seconds, with properties inferred from the collected data. In the present study, pXRF was used to screen samples (n = 252) from tropical Cerrado agricultural areas under different land uses in Brazil. The objective was to determine the total elemental composition of soil samples and predict soil fertility properties using simple or multiple linear regression with pXRF data as a proxy. Air-dried and sieved soil samples (<2 mm) under laboratory conditions were screened using a pXRF, then compared to soil chemical characterization by conventional methods. pXRF data properly corroborated the known soil mineralogy and geochemical background of Cerrado soils. Based exclusively on pXRF data, clay content was successfully predicted. Also, soil organic matter and plant-available forms of Ca, Mn and Cu were reasonably predicted from pXRF results.
•Cerrado agricultural soils chemically characterized by proximal sensor.•Clay content can be accurately predicted by pXRF.•pXRF data elucidate soil mineralogy and geochemistry of Cerrado soils.•Several plant-available elements were successfully predicted by pXRF.•252 highly weathered Cerrado soils of Brazil were evaluated.
Research on microplastics in soils is still uncommon, and the existing publications are often incomparable due to the use of different sampling, processing, and analytical methods. Given the complex ...nature of soils, a suitable and efficient method for standardized microplastic analysis in the soil matrix has yet to be found. This paper proposes a critical review on the different published methods for sampling, extraction, purification, and identification/quantification of microplastics in complex environmental matrices, with the main focus on their applicability for soil samples. While large microplastic particles can be manually sorted out and verified with chemical analysis, sample preparation for smaller microplastic analysis is usually more difficult. Of the analytical approaches proposed in the literature, some are established, whereas others are a proof of principle and have not yet been applied to environmental samples. For the sake of development, all approaches are discussed and assessed for their potential applicability for soil samples. So far, none of the published methods seems ideally suitable for the analysis of smaller microplastics in soil samples, but slight modifications and combinations of methods may prove promising and need to be explored.
Nitrite plays a critical role in a variety of nitrification and denitrification processes in the nitrogen cycle. Due to the high surface energy, tendency to aggregate, and poor conductivity, current ...nitrite ZnS-based sensing platform could not meet the need of on-site nitrite detection in smart agriculture. In order to address these issues, the carboxylated carbon nanotube (CNT) was introduced to reduce the surface energy and prevented aggregation of ZnS, while ZnS-carboxylated CNT (ZnS-CNT) composite also provided excellent electrochemical conductivity. Furthermore, the introduction of phase transition BSA (PTB) created a three-dimensional porous conductive matrix without interfering with the mass transfer process of nitrite. The resulting sensing platform exhibited a linear detection range of 10 nM to 0.4 mM for nitrite, with a detection limit of 0.73 nM. And this sensing platform had the excellent antifouling ability to direct detection nitrite in real soil suspension. In addition, the sensing platform demonstrated remarkable resistance to interferences from pH variations, microbial presence, and organic pollutants that usually present in soil environment. Therefore, on-site detection of nitrite ions in soil environment was realized no needing complex pretreatments.
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•The introduction of CNT could prevent aggregation of ZnS, while providing excellent electrochemical conductivity.•The amyloid-BSA maintains stable non-specific adsorption resistance compared to the original BSA.•Based on effective recombination of ZnS/CNT and amyloid-BSA, a three-dimensional porous conductive matrix was created.•The proposed sensing platform can be effectively applied for on-site detection of nitrite in soil environment.
Little is known about the changes in soil microbial phosphorus (P) cycling potential during terrestrial ecosystem management and restoration, although much research aims to enhance soil P cycling. ...Here, we used metagenomic sequencing to analyse 18 soil microbial communities at a P-deficient degraded mine site in southern China where ecological restoration was implemented using two soil ameliorants and eight plant species. Our results show that the relative abundances of key genes governing soil microbial P-cycling potential were higher at the restored site than at the unrestored site, indicating enhancement of soil P cycling following restoration. The gcd gene, encoding an enzyme that mediates inorganic P solubilization, was predominant across soil samples and was a major determinant of bioavailable soil P. We reconstructed 39 near-complete bacterial genomes harboring gcd, which represented diverse novel phosphate-solubilizing microbial taxa. Strong correlations were found between the relative abundance of these genomes and bioavailable soil P, suggesting their contributions to the enhancement of soil P cycling. Moreover, 84 mobile genetic elements were detected in the scaffolds containing gcd in the 39 genomes, providing evidence for the role of phage-related horizontal gene transfer in assisting soil microbes to acquire new metabolic potential related to P cycling.
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