Loss of soil carbon and nitrogen rather than variations in soil particle size distribution decreased microbial residues during conversion of grassland to croplands

2021 ◽  
Author(s):  
Shuang Liang ◽  
Hao Zhang ◽  
Xiaoling Song ◽  
Siwen Liu ◽  
Xinyao Yun ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Soil Carbon ◽  
Size Distribution ◽  
Soil Particle ◽  
Carbon And Nitrogen ◽  
Soil Particle Size ◽  
Soil Particle Size Distribution ◽  
Soil Carbon And Nitrogen ◽  
Microbial Residues

scholarly journals Determining soil particle-size distribution from infrared spectra using machine learning predictions: Methodology and modeling

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0233242
Author(s):  
Elizabeth Jeanne Parent ◽  
Serge-Étienne Parent ◽  
Léon Etienne Parent
Keyword(s):  
Machine Learning ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Soil Carbon ◽  
Size Distribution ◽  
Soil Particle ◽  
Blue Color ◽  
Soil Particle Size ◽  
Soil Particle Size Distribution ◽  
Method R

Accuracy of infrared (IR) models to measure soil particle-size distribution (PSD) depends on soil preparation, methodology (sedimentation, laser), settling times and relevant soil features. Compositional soil data may require log ratio (ilr) transformation to avoid numerical biases. Machine learning can relate numerous independent variables that may impact on NIR spectra to assess particle-size distribution. Our objective was to reach high IRS prediction accuracy across a large range of PSD methods and soil properties. A total of 1298 soil samples from eastern Canada were IR-scanned. Spectra were processed by Stochastic Gradient Boosting (SGB) to predict sand, silt, clay and carbon. Slope and intercept of the log-log relationships between settling time and suspension density function (SDF) (R2 = 0.84–0.92) performed similarly to NIR spectra using either ilr-transformed (R2 = 0.81–0.93) or raw percentages (R2 = 0.76–0.94). Settling times of 0.67-min and 2-h were the most accurate for NIR predictions (R2 = 0.49–0.79). The NIR prediction of sand sieving method (R2 = 0.66) was more accurate than sedimentation method(R2 = 0.53). The NIR 2X gain was less accurate (R2 = 0.69–0.92) than 4X (R2 = 0.87–0.95). The MIR (R2 = 0.45–0.80) performed better than NIR (R2 = 0.40–0.71) spectra. Adding soil carbon, reconstituted bulk density, pH, red-green-blue color, oxalate and Mehlich3 extracts returned R2 value of 0.86–0.91 for texture prediction. In addition to slope and intercept of the SDF, 4X gain, method and pre-treatment classes, soil carbon and color appeared to be promising features for routine SGB-processed NIR particle-size analysis. Machine learning methods support cost-effective soil texture NIR analysis.

Measurement of soil particle-size distribution by the PARIO measurement system: lessons learned and comparison with two other measurement techniques

2020 ◽  
Author(s):  
Attila Nemes ◽  
Anna Angyal ◽  
Andras Mako ◽  
Jan Erik Jacobsen ◽  
Eszter Herczeg
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Measurement Techniques ◽  
Temperature Shift ◽  
Quantitative Information ◽  
Lessons Learned ◽  
Soil Particle ◽  
Soil Particle Size ◽  
Soil Particle Size Distribution

<p>The PARIO system is a novel technique for the measurement of soil particle-size distribution. It is a computerized sedimentation-based system that will yield a quasi-continuous particle-size distribution curve. Given that it is semi-automated, continuous and sedimentation-based, this system promises to become a good and compatible alternative to the traditional pipette or hydrometer techniques. Through hundreds of measurements we have acquired practical operational knowledge that this poster will share with potential future users. We will also present quantitative information on the technique’s sensitivity to e.g. temperature shift or intermittent vibration during measurement. We also used a set of 45 soil samples of various texture from Norway to compare particle-size distribution measured by the PARIO system, the traditional pipette technique and laser diffractometry. We discuss measurement results as well as related sample-preparation aspects.</p>

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