Jeehwan Bae : Paper of the week & Book of the month

Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland Juan Jia     Zhenjiao Cao     Chengzhu Liu     Zhenhua Zhang     Li Lin     Yiyun Wang     Negar Haghipour     Lukas Wacker     Hongyan Bao     Thorston Dittmar     Myrna J. Simpson     Huan Yang     Thomas W. Crowther     Timothy I. Eglinton     Jin‐Sheng He     Xiaojuan Feng Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here, we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized ( 14 C‐enriched) carbon in ...

The concurrent decline of soil lead and children’s blood lead in New Orleans Howard W. Mielke ,  Christopher R. Gonzales ,  Eric T. Powell ,  Mark A. S. Laidlaw ,  Kenneth J. Berry ,  Paul W. Mielke  Jr. , and  Sara Perl Egendorf PNAS  first published October 14, 2019  https://doi.org/10.1073/pnas.1906092116 Significance The inextricable link between topsoil lead (Pb) and children’s blood lead (BPb) has not been widely accepted. Pb is associated with multiple health adversities. Urban residents are at risk from exposure to legacy Pb dust in topsoil resulting from smelting, industrial discharges, leaded gasoline emissions, leaded paint, and incineration. In New Orleans, topsoil median Pb decreased in ∼15 y from 99 mg/kg to 54 mg/kg, or ∼2.4 mg⋅kg⋅y −1 . In ∼12 y, children’s median BPb declined from 3.6 μg/dL to 1.3 μg/dL, or ∼0.2 μg⋅dL⋅y −1 . We argue that depletion of topsoil Pb is an important factor in the continuous dec...

Kelly S. Ramirez1 , Jonathan W. Leff4,5, Albert Barbera´n5 , Scott Thomas Bates6 , Jason Betley7 , Thomas W. Crowther8 , Eugene F. Kelly2 , Emily E. Oldfield8 , E. Ashley Shaw3 , Christopher Steenbock4 , Mark A. Bradford8 , Diana H. Wall1,3 and Noah Fierer4,5 Soil biota play key roles in the functioning of terrestrial ecosystems, however, compared to our knowledge of above-ground plant and animal diversity, the biodiversity found in soils remains largely uncharacterized. Here, they present an assessment of soil biodiversity and biogeographic patterns across Central Park in New York City that spanned all three domains of life, demonstrating that even an urban, managed system harbours large amounts of undescribed soil biodiversity. Despite high variability across the Park, below-ground diversity patterns were predictable based on soil characteristics, with prokaryotic and eukaryotic communities exhibiting overlapping biogeographic patterns. Further, Central Park soils harboured nearly ...

Author  :  Milind Bunyan, Shibu Jose, Robert Fletcher Year  : 2019 Title  :  Edge Effects in Small Forest Fragments: Why More Is Better? Journal  :  American Journal of Plant Sciences Comment   :   They investigated the response of microenvironment and edaphic variables to distance from a tropical montane forest (locally known as shola)-grassland edge using one-edge and multiple-edge models.   The edpahic variables did not show any differences between the grassland and shola soils. The conventional one-edge models sufficiently explained variation trends in micro environment along the edge to interior gradient in large fragments.   As with other studies on small fragments though, they observed no edge effects with the use of a conventional one-edge model. However, the inclusion of multiple edges in small fragments significantly improved model fit. Thus, small fragments dominated by edge habitat may ...

Author  :  Ian A. Smith, Lucy R. Hutyra, Andrew B. Reinmann1, Jonathan R. Thompson, David W. Allen Year  : 2019 Title  :  Evidence for edge enhancements of soil respiration in temperate forests Journal  :  Geophysical Research Letters Comment   :   Forest fragmentation impacts carbon uptake and storage, however, the magnitude and direction of fragmentation impacts on soil respiration remain poorly characterized. They quantify soil respiration rates along edge-to-interior transects in two temperate broad-leaf forests in the eastern US that vary in climate, species composition, and soil type. They observe average soil respiration rates 15-26% higher at the forest edge compared to the interior, corresponding to large gradients in soil temperature.  These results suggest that estimates of soil respiration in the temperate forest region may be underestimating biological emissions of carbon dioxide.

Author  :  Moura-Bueno, J. M. Dalmolin, R. S. D. ten Caten, A. Dotto, A. C. Dematte, J. A. M. Year  : 2019 Title  :  Stratification of a local VIS-NIR-SWIR spectral library by homogeneity criteria yields more accurate soil organic carbon predictions Journal  :  Geoderma Comment   :    The aim of this research was to  i) characterize and identify differences among spectra obtained for subtropical soils samples, ii)  evaluate different pre-processing techniques and multivariate methods to propose SOC prediction models from  the spectral data and iii) evaluate the performance of SOC prediction models calibrated from the stratification of  a local library.  Spectral reflectance measurements were performed in the  laboratory with a spectroradiometer in the range of 350–2500 nm. Six pre-processing techniques were applied to  the spectra (including derivatives, normalization and non-linea...

Author  :  Tümsavaş Zeynal,  Tekin Yücel,  Ulusoy Yahya,  Mouazen Abdul M Year  : 2019 Title  :  Prediction and mapping of soil clay and sand contents using visible and near-infrared spectroscopy Journal  :  Biosystems engineering Comment   :    The aim of this research was to examine the potential of visible and near infrared (Vis -NIR) spectroscopy for the prediction and mapping of sand and clay fractions of soils.  This study demonstrated that soil sand and clay can be successfully  measured and mapped using Vis-NIR spectroscopy under both laboratory and  on-line scanning conditions.  A partial least squares  (PLS)  regression with leave-one-out  cross-validation analysis was carried out using the calibration set, and the resulting  model prediction ability was tested using the prediction set.   Models developed were used  to predict sand and ...

Author  :  Soltani, I.  Fouad, Y.  Michot, D.  Breger, P.  Dubois, R.  Cudennec, C. Year  : 2019 Title  :  A near infrared index to assess effects of soil texture and organic carbon content on soil water content Journal  :  European Journal of Soil Science Comment   :   Characterization of soil hydrodynamic properties is important for assessing the soil water regime. Over the last decades, diffuse reflectance spectroscopy (DRS)  techniques have been used increasingly. Methods based on DRS  offer several advantages compared with conventional ones because  they are rapid, cost-effective and non-destructive. Therefore, the  spread within the soil science community of soil spectroscopy in  the visible (vis), near (NIR) and mid-infrared (MIR) spectral ranges  enabled various physical, chemical and biological soil properties to  be assessed.  Spectra were con...

Author  :  Chongfeng Gonga, Shixiao Yua, Heather Joesting, Jiquan Chen Year  : 2013 Title  :  Determining socioeconomic drivers of urban forest fragmentation with historical remote sensing images Journal  :  Landscape and Urban Planning Comment   :  To quantify the land-use change during this rapid urbanization process and explore the underline drivers, nine sets of Landsat images from 1973 through 2005 were used to calculate the landscape metrics of forest patches.   They found that the forest in Shen-zhen had been restored to 85.85% of pre-urbanization coverage by 2005, but was characterized with smaller, isolated patches across the landscape.   The changes in patch density, distribution, and shape during the 30-year study period were nonlinear and defined by episodic periods. The stepwise multiple regression models with socioeconomic drivers provided further explanation for fragmentation rates in pa...

Author  :  Meihua Yang, Dongyun Xu, Songchao Chen, Hongyi Li  and Zhou Shi Year  : 2019 Title  :  Evaluation of Machine Learning Approaches to  Predict Soil Organic Matter and pH Using  vis-NIR Spectra Journal  :  Sensors Comment   :   Visible-near infrared (vis-NIR) spectroscopy with multivariate calibration can be used to effectively estimate soil properties. In this study, 523 soil samples were collected from paddy fields in the Yangtze Plain, China.  Four machine learning approaches—partial least squares regression (PLSR), least squares-support vector machines (LS-SVM), extreme learning machines (ELM) and the Cubist regression model (Cubist)—were used to compare the prediction accuracy based on vis-NIR full bands and bands reduced using the genetic algorithm (GA). The coefficient of determination (R2), root mean square error (RMSE), and ratio of performance to inter-quartile distance (RPIQ) we...

Author  :  Wenjuan Sun, Xinju Li, Beibei Niu Year  : 2018 Title  :  Prediction of soil organic carbon in a coal  mining area by Vis-NIR spectroscopy Journal  :  PLOS one Comment   :   Visible-near infrared (Vis-NIR) spectroscopy has been shown to be a rapid, timely and efficient tool for the prediction of soil organic carbon (SOC).   In this study, 104 soil samples were collected from the Baodian mining area of Shandong province. Vis-NIR reflectance spectra and SOC content were then measured under laboratory conditions.   The spectral data were first denoised using the Savitzky-Golay (SG) convolution smoothing method or the multiple scattering correction (MSC) method, after which the spectral reflectance (R) was subjected to reciprocal, reciprocal logarithm and differential transformations to improve spectral sensitivity.   Finally, regression models for estimating the SOC c...