Student Scholarship

Document Type

Research Paper

Abstract

This study investigates the chemical and physical properties of various soil types in St. Charles County, Missouri, with a primary focus on their cation exchange capacities. The author examines how plants obtain essential nutrients through an exchange process where root hairs release hydrogen ions in trade for metallic cations like calcium, magnesium, and potassium held on the surface of clay and humus colloids. To provide a comprehensive assessment of soil productivity, the research utilizes a photoelectric colorimeter to measure seven key components: organic matter, extractable phosphorus, pH, and exchangeable hydrogen, potassium, magnesium, and calcium. 

The experimental phase involved analyzing samples from three distinct locations representing different geological histories: a Memphis silt loam from a South Main Street quarry, a Wabash silt loam from the Boerding farm, and a forested Memphis silt loam on Droste Road. Results indicate significant variations in fertility based on management and origin. The South Main samples, derived from loess over limestone, showed a fair nutrient balance but required lime due to acidity. The Droste Road forest soil exhibited high organic matter but lower exchange capacities, suggesting it is best suited for timber rather than cropland. In contrast, the Boerding river-bottom soil demonstrated nearly ideal chemical fertility and high exchange capacity, though its high clay content—locally known as gumbo—makes it difficult to till. 

The study concludes that ion exchange tests provide a vital scientific basis for predicting soil productivity. By correlating these chemical profiles with physical textures and geological data, land managers can make informed decisions regarding fertilization and lime requirements to maintain the soil in its highest state of productivity.

Research Highlights

  • The Problem: The research addresses the need for a more complete understanding of the chemical and physical characteristics, nutrient availability, and ion exchange capacities of different soil types to ensure high productivity and prevent mineral depletion. 

  • The Method: Soil samples were collected from three locations in St. Charles County (Memphis silt loam at a limestone quarry, Wabash silt loam at Boerding farm, and forested Memphis silt loam on Droste Road) and analyzed for texture, mineral content, pH, organic matter, and exchangeable hydrogen, phosphorus, potassium, calcium, and magnesium using sedimentation, microscopy, and photoelectric colorimetry. 

  • Quantitative Finding: Average Missouri soil fertility levels range from very low to very high across factors including organic matter (1.0% to 4.0%+), phosphorus (30 to 191+ lb/A), potassium (75 to 281+ lb/A), and pH (4.9 to 6.4+); the Wabash silt loam (Boerding site) exhibited the highest total exchange capacities recorded at 28.02 and 28.13 ME. 

  • Qualitative Finding: Soil fertility and ion exchange capacity are influenced by five primary factors: parent material, climate, vegetation, topography, and time; Wabash silt loam (gumbo) is identified as highly productive but difficult to till due to high clay content, while Droste Road forest soils are best suited for timber due to low exchange capacity and high acidity in subsoil layers. 

Publication Date

5-1954

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Faculty Sponsor

Archive

Download

Included in

Soil Science Commons

Share

COinS