Role of Physical Properties of Clays in Soil Science

Abstract

The physical properties of clay are of extreme importance in soil science. Plant growth, and hence crop production, within any environmental condition is largely controlled by soil structure which results from reactions involving clay. The active clay material in soil, particularly in combination with small amounts of organic matter, exerts a tremendous effect on soil properties. This effect may be on structure (the arrangement of soil particles), or on consistence (the response of the soil to mechanical manipulation). Where structure is favorable soil grains are clumped together into effectively larger aggregates so that soils have a more open arrangement and water and air can move freely and roots function normally. Where structure is unfavorable, soils tend to be heavy and impervious, and both the physical and chemical properties of the soil become unfavorable for plant growth. Soils which are low in clay, such as sands and silts, exhibit a rather narrow range over which physical properties can change and may be unfavorable for plants, being droughty and lacking in fertility. Structure of soil may change through action of natural forces, management practices, or cropping systems, and it is of great importance that we understand how structure affects plants, and how it is formed and stabilized by reactions involving clay. Combination of clay with relatively small amounts of certain organic compounds greatly changes the physical properties of the system and the nature of the combination and the mechanics of the soil structure-forming process are but little understood. Such changes greatly affect soil consistence and soil-water relationships as well as soil structure. The problem is made difficult since the results of any particular combination or change in clay characteristics must be interpreted not in terms of the clay system alone but in light of the resultant effect on the complex and dynamic system which constitutes a soil. Solution of such problems, however, may be of great importance to our future ability to produce food and fiber abundantly and efficiently from our limited soil resource.

Phosphorus fixation and its relationship with physicochemical properties of soils on the Eastern flank of Mount Cameroon

“…This was clearly reflected by their corresponding total porosity values with the silty clay soil having the least porosity (0.62) and the loamy soil having the highest porosity (0.75). Clay is the most active part of the soil both chemically and physically (Page, 1952). The chemical properties of a soil are favorable when clays are abundant but its physical properties will either be good or poor depending on the arrangement of the soil particles (Page, 1952).…”

“…Clay is the most active part of the soil both chemically and physically (Page, 1952). The chemical properties of a soil are favorable when clays are abundant but its physical properties will either be good or poor depending on the arrangement of the soil particles (Page, 1952).…”

Adsorption of Pyrene from Aqueous Solution by Clay and Sandy Soil

“…Also, its sorption properties enable a large extent of organic pollutants to be retained by the soil. Also in contact, the presence of cohesive forces differentiates clay and soils from other adsorbents [6]. The adsorption isotherm and kinetics are used in describing the sorption data.…”

Grain size controls on cryoturbation and soil organic carbon density in permafrost‐affected soils

“…The overall aim of this study is to gain understanding on specific grain size distributions that control SOC storage in mineral subsoil and the development of SOC-enriched cryoturbated pockets. The results are then weighed against general paradigms in soil science stating that higher clay contents increase SOC storage [14][15][16] and in frozen ground dynamics stating that coarse silt to fine sand fractions increase frost heave and ground movement. 17,18 Finally, we briefly consider how our results can be used to improve the estimates of SOC storage of Turbels in the Northern Circumpolar Soil Carbon Database (NCSCD).…”