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United States Department of Agriculture

Agricultural Research Service

Title: A Method for Studying the Effects of Soil Aggregrate Size and Density

Author
item Zobel, Richard

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 24, 1995
Publication Date: N/A

Interpretive Summary: Changing water supplies and land use require plants which are better adapted to changed environments. Improvement of crop adaptation requires an understanding of the way plants interact with their immediate environment. A method of producing soil structures which allow testing of hypotheses about the effect of soil density and particle size on root development was developed. A test of the method demonstrated that both partical size and density are important. The method presented will be useful for scientific studies of the effect of soil structure, and for finding cultivars which have a greater tolerance of high density soils.

Technical Abstract: It has been suggested that many of the limitations to crop growth can be explained by the physical properties of soil aggregates. To explore some aspects of this, a method to simulate soil aggregates of different sizes, and densities was developed and tested. A Collamer silt-loamy soil (Fine-silty, mixed, mesic Glossoboric Hapludalf) was dried, crushed, sieved dand compressed to different densities (1.4, 1.6 and 1.8 Mg.m- 3). The resulting 25 and 50 mm thick cylindrical soil slices were cut to two different cubical sizes (25 and 50 mm sides). Cylinders with continuous horizontal and vertical macropores were assembled from these artificial aggregates to make 6 different treatment combinations of aggregate size and density. Corn (Zea mays L.) seedlings were transplanted into the cylinders and grown in a growth chamber for 27 days. Results show that high aggregate density limits crop growth and that, at intermediate densities, aggregate size assumes more significance as a limiting factor.

Last Modified: 10/20/2014
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