Soil Colloids

Soil Colloids

 

tiny particles of soil, from 0.2 to 0.001 micrometers. In soil water they form colloidal solutions (sols), and in this form they are carried from one soil layer to another and settle, forming horizons that are compacted to various degrees (for example solonets horizon in the soils of the arid steppes and forest-steppes and illuvial horizon in the podzolic soils of the northern taiga). In different soils the colloidal fraction ranges from 2 percent (light soil) to 30–50 percent (heavy soils).

Soil colloids are very important in agronomy: they absorb ammonium, potassium, calcium, magnesium, and phosphate ions from soil solutions, prevent the ions from leaching out, and promote the formation of soil structures. Soil colloids consist of three groups of compounds—organic, mineral, and organomineral (complex). Most of the organic matter in the soil is in dispersed colloidal form. Mineral colloids consist primarily of clayey minerals. The composition of the colloidal mineral fraction is different in different types of soil. The organomineral soil colloids are represented primarily by compounds of humus substances with clayey and other secondary minerals. Under natural conditions colloidal particles form in two ways—condensation and dispersion.

I. N. ANTIPOV-KARATAEV

References in periodicals archive ?
In the soil DNA molecules adsorb to soil colloids and minerals that prevent its enzymatic degradation particularly from DNases (Romanowski et al.
Changes in soil pH, solution ionic strength, and the types of ions in the soil solution can promote the dispersion or flocculation of soil colloids, consequently potentially interfering in the aggregation of soil particles (Seta and Karathanasis 1996).
2+]) compared with the clayey soil, which may have contributed even more to the permanence of K in the solution of the sandy soil, due to the preference of soil colloids to retain [Ca.
The phase distribution of pesticides in soils is determined by the nature of adsorptive soil colloids and the physiochemical characteristics of the pesticides [4].
The consulting firm will be required to provide the following: The Hydrology of the "Bowmanston Caves"; The possible sources of soil colloids intrusion and recommendations to prevent/reduce these intrusions; Technical Review of the Three (3) Best Methods of Resolution; Desk Level life-cycle cost, economic and Environmental Analysis of the Three (3) Best Methods of Resolution; Conceptual Designs, Specifications and Implementation Plan for each method.
No significant activity of this herbicide in soil and is absorbed by soil colloids [7].
It is well established that the surface charge of soil colloids plays an important role in nutrient availability, and that surface charge can be classified as either permanent or variable.
Paraquat adsorbs easily to predominantly negatively charged soil colloids.
However, in case of Pendimethalin and Benthiocarb absence of their residues in the lower layers could be attributed to the strong adsorptive nature of dinitroaniline group of herbicides on soil colloids.
Describe two ways by which soil colloids develop charge.
For example, the size of clay and other soil colloids is best described by using micrometers or nanometers (nm).