Microorganisms and Soil Structure

Authors

T. M. McCalla, University of Nebraska-Lincoln
F. A. Haskins, University of Nebraska-Lincoln

Date of this Version

1961

Citation

Journal Series / Nebraska Agricultural Experiment Station (1961?) paper no. 1007.

Comments

Copyright 1961, the authors. Used by permission.

Abstract

SUMMARY

Good stable soil structure is valuable for promoting the growth of plants and micro-organisms by permitting enhanced aeration and water penetration and by decreasing erosion under some conditions.

Micro-organisms influence water percolation through the soil. They may plug up soil pores with byproducts of growth and reduce water percolation. On the other hand, if a soil containing a large amount of microbial products is stirred and allowed to dry, then the percolation may be high.

Micro-organisms are involved in stabilizing soil structure by their products of decomposition and their cellular binding material, such as mycelia. Microorganisms differ greatly in their ability to stabilize soil structure. Restricting the microflora to superior soil structure stabilizing micro-organisms materially increases soil structure stability. This restriction is accomplished under laboratory conditions by first eliminating the indigenous soil flora and then introducing the desired micro-organisms. Indigenous flora can be eliminated by autoclaving or by the use of a soil fumigant such as chloropicrin. Some fumigants, such as urea-formaldehyde and biuret-urea-formaldehyde at certain critical concentrations, selectively eliminate soil micro-organisms, leaving only effective soil aggregators. Physical and chemical factors, such as temperature, moisture, and amount and nature of energy material, affect the growth and effectiveness of soil structure stabilizing micro-organisms.

The use of superior micro-organisms for changing nutrient availability, nitrogen fixation, and soil structure stabilization may permit a. degree of control over plant growth which heretofore has been impossible.