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1. Comparison of conventional methods with Haney H3A version 4 for available phosphorus and potassium in southern Manitoba soils.

Author

Crittenden, Stephen, Molina, Oscar, Sager, Steve, Cavers, Curtis, Xing, Zisheng, St. Luce, Mervin, and Lawley, Yvonne

Subjects
AMMONIUM acetate, SOIL testing, PLANT nutrients, SOIL sampling, SOILS
Abstract

The H3A-4 extraction is a new method to determine plant available nutrients but has not been compared with standard soil tests or calibrated to crop response in Manitoba, Canada. Olsen P and ammonium acetate K were related to H3A-4 P and K for 961 soil samples. Significant relations were found between Olsen P and H3A-4 (R2 = 0.74, P < 0.01) and ammonium acetate K and H3A-4 (R2 = 0.83, P < 0.01). New thresholds were established for fertilizer recommendations with H3A-4 as 24 mg kg–1 for P and 32 mg kg–1 for K. [ABSTRACT FROM AUTHOR]

Published
2024
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2. The effect of four tillage systems on agronomic properties and soil health indicators in southern Manitoba.

Author

Crittenden, Stephen, Cavers, Curtis, and Xing, Zisheng

Subjects
SOIL ripping, SOIL management, SOILS, SOYBEAN, RAPESEED, TILLAGE, NO-tillage
Abstract

Soil health encompasses the collective functioning of chemical, physical, and biological properties in soil. The extent to which soil management affects soil health and the links with agronomic outcomes remain unclear. This project aimed to understand the interrelations of tillage systems, soil health, and agronomic properties in Portage la Prairie, MB, Canada. Tillage systems were cultivation, deep tillage, raised beds, and vertical tillage. Soybean (Glycine max (L.) Merr), corn (Zea mays L.), and canola (Brassica napus L.) were all grown in 2020, 2021, and 2022. Crop yield, seed protein content, and seed oil content were measured each year. Soil samples were taken in spring 2021, fall 2021, and fall 2022 and analyzed for nitrate-N, ammonium-N, total N, ACE protein, water extractable organic N, water extractable total N, water extractable ammonium N, soil organic matter, soil organic carbon, calcium carbonate equivalent, CO2 burst, permanganate oxidizable carbon, water extractable organic C, pH, salts, Olsen P, K, S, sand, silt, and clay. Tillage system had a significant impact on agronomic properties in seven crop by sampling combinations. Tillage system effected soil nitrate-N concentration at five crop by sampling combinations, three more than any other soil property. Soybean agronomic properties correlated with soil health indicators more frequently than for corn and canola. This suggests that the utility of soil health indicators may be crop specific. Further research is needed to understand the mechanisms underpinning the ability of soil health indicators to predict agronomic outcomes and to benchmark soil health indicator values with time. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Characteristics of Red River clays pertaining to vertisolic criteria and macropore flow

Author

Cavers, Curtis G. and Cavers, Curtis G.

Abstract

Clay soils predominately composed of montmorillonite possess a high shrink-swell potential that has taxonomic and practical implications. The presence of slickensides and evidence of high shrink-swell in these soils may meet revised criteria which would place these soils under a Vertisolic Order, or as vertic intergrades of Chernozemic, Gleysolic, Luvisolic or Solonetzic Orders in the Canadian System of Soil Classification. The presence of large cracks and biological pathways in these soils may result in higher rates of water flow and potential for pollutant transport than previously expected. Several analyses were conducted on three clay soils with contrasting hydrologic regimes. The purpose was to identify features and processes which may serve as diagnostic criteria for classification, and which may affect the permeability of the soil. Visual analysis of contiguous cores from two sites identifred physical features such as texture, structure, carbonates, salts, mottles, slickensides, roots, cracks, and biopores and mapped their location according to depth. Micromorphological analysis of the soil fabric, tritium analysis of groundwater, and 14 C analysis of root material were conducted to aid in assessing the potential for downward movement of water and dissolved materials in these soils. Saturated flux versus hydraulic gradient relationships were examined in the laboratory using a liquid bubble flow meter and pressure transducer on four contiguous core samples. At hydraulic gradients less than 1.2 m/m, there is a deviation from the straight-line relationship of Darcy's Law, with saturated fluxes at low hydraulic gradients about one order of magnitude lower than predicted by Darcy's Law. This non-Darcian flow occurs due to a portion of the water molecules in the pores immobilized by the attractive forces of the clay. Samples with pathways conducive to macropore flow follow Darcian behavior but saturated flux may be an order of magnitude higher than expected for sam

Published
1996

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