Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

Soil Sampling and Methods of Analysis

Abstract: SOIL SAMPLING AND HANDLING, G.T. Patterson and M.R. Carter Soil Sampling Designs, D. Pennock, T. Yates, and J. Braidek Sampling Forest Soils, N. Belanger and K.C.J. Van Rees Measuring Change in Soil Organic Carbon Storage, B.H. Ellert, H.H. Janzen, A.J. VandenBygaart, and E. Bremer Soil Sample Handling and Storage, S.C. Sheppard and J.A. Addison Quality Control in Soil Chemical Analysis, C. Swyngedouw and R. Lessard DIAGNOSTIC METHODS for SOIL and ENVIRONMENTAL MANAGEMENT, J.J. Schoenau and I.P. O'Halloran Nitrate and Exchangeable Ammonium Nitrogen, D.G. Maynard, Y.P. Kalra, and J.A. Crumbaugh Mehlich 3 Extractable Elements, N. Ziadi and T. Sen Tran Sodium Bicarbonate Extractable Phosphorus, J.J. Schoenau and I. P. O'Halloran Boron, Molybdenum and Selenium, G. M. Hettiarachchi and U. C. Gupta Trace Element Assessment, W.H. Hendershot, H. Lalande, D. Reyes, and D. MacDonald Readily Soluble Aluminum and Manganese in Acid Soils, Y.K. Soon, N. Belanger, and W.H. Hendershot Lime Requirement, N. Ziadi and T. Sen Tran Ion Supply Rates Using Ion Exchange Resins, P. Qian, J.J. Schoenau, and N. Ziadi Environmental Soil Phosphorus Indices, A.N. Sharpley, P.J.A. Kleinman and J.L. Weld Electrical Conductivity and Soluble Ions, J.J. Miller and D. Curtin SOIL CHEMICAL ANALYSES, Y.K. Soon and W.H. Hendershot Soil Reaction and Exchangeable Acidity, W.H. Hendershot, H. Laland,e and M. Duquette Collection and Characterization of Soil Solutions, J.D. MacDonald, N. Belanger, S. Sauve, F. Courchesne, and W.H. Hendershot Ion Exchange and Exchangeable Cations, W.H. Hendershot, H. Lalande, and M. Duquette Non-Exchangeable Ammonium, Y.K. Soon and B.C. Liang Carbonates, T.B. Goh and A.R. Mermut Total and Organic Carbon, J.O. Skjemstad and J.A. Baldock Total Nitrogen, P.M. Rutherford, W.B. McGill, C.T. Figueiredo, and J.M. Arocena Chemical Characterization of Soil Sulphur, C.G. Kowalenko and M. Grimmett Total and Organic Phosphorus, I.P. O'Halloran and B.J. Cade-Menum Characterization of Available P by Sequential Extraction, H. Tiessen and J.O. Moir Extractable Al, Fe, Mn, and Si, F. Courchesne and M.C. Turmel Determining Nutrient Availability in Forest Soils, N. Belanger, David Pare, and W.H. Hendershot Chemical Properties of Organic Soils, A. Karam SOIL BIOLOGICAL ANALYSES, E. Topp and C.A. Fox Cultural Methods for Soil and Root Associated Microorganisms, J.J. Germida and J.R. de Freitas Arbuscular Mycorrhiza, Y. Dalpe and C. Hamel Root Nodule Bacteria and Symbiotic Nitrogen Fixation, D. Prevost and H. Antoun Microarthropods, J.P Winter and V.M. Behan-Pelletier Nematodes, T.A. Forge and J. Kimpinski Earthworms, M.J. Clapperton, G.H. Baker and C.A. Fox Enchytraeids, S.M. Adl Protozoa, S.M. Adl, D. Acosta-Mercado, and D.H. Lynn Denitrification Techniques for Soils, C.F. Drury, D.D. Myrold, E.G. Beauchamp, and W.D.Reynolds Nitrification Techniques in Soil Systems, C.F. Drury, S.C. Hart, and X.M. Yang Substrate-Induced Respiration and Selective Inhibition as Measures of Microbial Biomass in Soils, V.L. Bailey, J.L. Smith, and H. Bolton Jr. Assessment of Soil Biological Activity, R.P.Beyaert and C.A. Fox Soil ATP, R.P. Voroney, G. Wen, and R.P. Beyaert Lipid-Based Community Analysis, K.E. Dunfield Bacterial Community Analyses by Denaturing Gradient Gel Electrophoresis (DGGE), E. Topp, Y.-C. Tien, and A. Hartmann Indicators of Soil Food Web Properties, T.A. Forge and M. Tenuta SOIL ORGANIC MATTER ANALYSES, E.G. Gregorich and M.H. Beare Carbon Mineralization, D.W. Hopkins Mineralizable Nitrogen, Denis Curtin and C.A. Campbell Physically Uncomplexed Organic Matter, E.G. Gregorich and M.H. Beare Extraction and Characterization of Dissolved Organic Matter, M.H. Chantigny, D.A. Angers, K. Kaiser, and K. Kalbitz Soil Microbial Biomass C, N, P and S, R.P. Voroney, P.C. Brookes, and R.P. Beyaert Carbohydrates, M.H. Chantigny and D.A. Angers Organic Forms of Nitrogen, D.C. Olk Soil Humus Fractions, D.W. Anderson and J.J Schoenau Soil Organic Matter Analysis by Solid-State 13C Nuclear Magnetic Resonance Spectroscopy, M. J. Simpson and C. M. Preston Stable Isotopes in Soil and Environmental Research, B.H. Ellert and L. Rock SOIL PHYSICAL ANALYSES, D.A. Angers and F.J. Larney Particle Size Distribution, D. Kroetsch and C. Wang Soil Shrinkage, C.D. Grant Soil Density and Porosity, X. Hao, B.C. Ball, J.L.B. Culley, M.R. Carter, and G.W. Parkin Soil Consistency: Upper and Lower Plastic Limits, R.A. McBride Compaction and Compressibility, P. Defossez, T. Keller and G. Richard Field Soil Strength, G.C. Topp and D.R. Lapen Air Permeability, C.D. Grant and P.H. Groenevelt Aggregate Stability to Water, D.A. Angers, M.S. Bullock, and G.R. Mehuys Dry Aggregate Size Distribution, F.J. Larney Soil Air, R.E. Farrell and J.A. Elliott Soil-Surface Gas Emissions, P. Rochette and N. Bertrand Bulk Density Measurement in Forest Soils, D.G. Maynard and M.P. Curran Physical Properties of Organic Soils and Growing Media: Particle Size and Degree of Decomposition, L.E. Parent and J. Caron Physical Properties of Organic Soils and Growing Media: Water and Air Storage and Flow Dynamics, J. Caron, D.E. Elrick, J.C. Michel, and R. Naasz SOIL WATER ANALYSES, W.D. Reynolds and G.C. Topp Soil Water Analyses: Principles and Parameters, W.D. Reynolds and G.C. Topp Soil Water Content, G.C. Topp, G.W. Parkin, and Ty P.A Ferre Soil Water Potential, N.J. Livingston and G.C. Topp Soil Water Desorption and Imbibition: Tension and Pressure Techniques, W.D. Reynolds and G.C. Topp Soil Water Desorption and Imbibition: Long Column, W.D. Reynolds and G.C. Topp Soil Water Desorption and Imbibition: Psychrometry, W.D. Reynolds and G.C. Topp Saturated Hydraulic Properties: Laboratory Methods, W.D. Reynolds Saturated Hydraulic Properties: Well Permeameter, W.D. Reynolds Saturated Hydraulic Properties: Ring Infiltrometer, W.D. Reynolds Saturated Hydraulic Properties: Auger-Hole, G.C. Topp Saturated Hydraulic Properties: Piezometer, G.C. Topp Unsaturated Hydraulic Properties: Laboratory Tension Infiltrometer, F.J. Cook Unsaturated Hydraulic Properties: Laboratory Evaporation, O.O. B. Wendroth and N. Wypler Unsaturated Hydraulic Properties: Field Tension Infiltrometer, W.D. Reynolds Unsaturated Hydraulic Properties: Instantaneous Profile, W.D. Reynolds Estimation of Soil Hydraulic Properties, F.J. Cook and H.P. Cresswell Analysis of Soil Variability, B.C. Si, R.G. Kachanoski, and W.D. Reynolds APPENDIX Site Description, G.T. Patterson and J.A. Brierley General Safe Laboratory Operation Procedures, P. St-Georges INDEX

Antioxidant Activity and Total Phenolics in Selected Fruits, Vegetables, and Grain Products

Abstract: The antioxidant activities and total phenolics of 28 plant products, including sunflower seeds, flaxseeds, wheat germ, buckwheat, and several fruits, vegetables, and medicinal plants were determined. The total phenolic content, determined according to the Folin−Ciocalteu method, varied from 169 to 10548 mg/100 g of dry product. Antioxidant activity of methanolic extract evaluated according to the β-carotene bleaching method expressed as AOX (Δ log A470/min), AA (percent inhibition relative to control), ORR (oxidation rate ratio), and AAC (antioxidant activity coefficient) ranged from 0.05, 53.7, 0.009, and 51.7 to 0.26, 99.1, 0.46, and 969.3, respectively. The correlation coefficient between total phenolics and antioxidative activities was statistically significant. Keywords: Antioxidant activity; phenolics; medicinal plants; oilseeds; buckwheat; vegetables; fruits; wheat products

Improving the thiobarbituric acid-reactive-substances assay for estimating lipid peroxidation in plant tissues containing anthocyanin and other interfering compounds

Abstract: The occurrence of malondialdehyde (MDA), a secondary end product of the oxidation of polyunsatu- rated fatty acids, is considered a useful index of general lipid peroxidation A common method for measuring MDA, referred to as the thiobarbituric acid-reactive- substances (TBARS) assay, is to react it with thiobar- bituric acid (TBA) and record the absorbance at 532 nm However, many plants contain interfering compounds that also absorb at 532 nm, leading to overestimation of MDA values Extracts of plant tissues including purple eggplant (Solanum melongena L) fruit, carrot (Daucus carota L) roots, and spinach (Spinacia oleracea L) leaves were assessed for the presence of MDA and other non-MDA compounds absorbing at 532 nm A method described herein corrects for these interferences by subtracting the absorbance at 532 nm of a solution containing plant extract incubated without TBA from an identical solution containing TBA The reliability and eAciency of this spectrophotometric method was assessed by altering the relative ratios of exogenous MDA additions and/or extracts of red cabbage (Brassica oleracea L) leaves containing inter- fering compounds and then measuring MDA recovery Reliability was also validated through high-performance liquid chromatography and high-performance liquid chromatography-mass spectrometry techniques Results indicated that over 90% of exogenously added MDA could be recovered through the improved protocol If there were no corrections for interfering compounds, MDA equivalents were overestimated by up to 965% Interfering compounds were not detected in vegetables such as lettuce (Lactuca sativa L) and spinach which had low or negligible concentrations of anthocyanidin derivatives Comparisons between the TBARS method presented here and two currently accepted protocols indicated that the new modified method exhibits greater accuracy for quantifying TBA-MDA levels in tissues containing anthocyanins and/or other interfering com- pounds This modified protocol represents a facile and rapid method for assessment of lipid peroxidation in virtually all plant species that contain interfering com- pounds

SoilGrids250m: Global gridded soil information based on machine learning

Abstract: This paper describes the technical development and accuracy assessment of the most recent and improved version of the SoilGrids system at 250m resolution (June 2016 update). SoilGrids provides global predictions for standard numeric soil properties (organic carbon, bulk density, Cation Exchange Capacity (CEC), pH, soil texture fractions and coarse fragments) at seven standard depths (0, 5, 15, 30, 60, 100 and 200 cm), in addition to predictions of depth to bedrock and distribution of soil classes based on the World Reference Base (WRB) and USDA classification systems (ca. 280 raster layers in total). Predictions were based on ca. 150,000 soil profiles used for training and a stack of 158 remote sensing-based soil covariates (primarily derived from MODIS land products, SRTM DEM derivatives, climatic images and global landform and lithology maps), which were used to fit an ensemble of machine learning methods-random forest and gradient boosting and/or multinomial logistic regression-as implemented in the R packages ranger, xgboost, nnet and caret. The results of 10-fold cross-validation show that the ensemble models explain between 56% (coarse fragments) and 83% (pH) of variation with an overall average of 61%. Improvements in the relative accuracy considering the amount of variation explained, in comparison to the previous version of SoilGrids at 1 km spatial resolution, range from 60 to 230%. Improvements can be attributed to: (1) the use of machine learning instead of linear regression, (2) to considerable investments in preparing finer resolution covariate layers and (3) to insertion of additional soil profiles. Further development of SoilGrids could include refinement of methods to incorporate input uncertainties and derivation of posterior probability distributions (per pixel), and further automation of spatial modeling so that soil maps can be generated for potentially hundreds of soil variables. Another area of future research is the development of methods for multiscale merging of SoilGrids predictions with local and/or national gridded soil products (e.g. up to 50 m spatial resolution) so that increasingly more accurate, complete and consistent global soil information can be produced. SoilGrids are available under the Open Data Base License.

Soil organic carbon pools in the northern circumpolar permafrost region

Abstract: of all soils in the northern permafrost region is approximately 18,782 � 10 3 km 2 ,o r approximately 16% of the global soil area. In the northern permafrost region, organic soils (peatlands) and cryoturbated permafrost-affected mineral soils have the highest mean soil organic carbon contents (32.2–69.6 kg m �2 ). Here we report a new estimate of the carbon pools in soils of the northern permafrost region, including deeper layers and pools not accounted for in previous analyses. Carbon pools were estimated to be 191.29 Pg for the 0–30 cm depth, 495.80 Pg for the 0–100 cm depth, and 1024.00 Pg for the 0–300 cm depth. Our estimate for the first meter of soil alone is about double that reported for this region in previous analyses. Carbon pools in layers deeper than 300 cm were estimated to be 407 Pg in yedoma deposits and 241 Pg in deltaic deposits. In total, the northern permafrost region contains approximately 1672 Pg of organic carbon, of which approximately 1466 Pg, or 88%, occurs in perennially frozen soils and deposits. This 1672 Pg of organic carbon would account for approximately 50% of the estimated global belowground organic carbon pool.