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soil composed of sand, silt, clay, and organic matter in evenly mixed particles of various sizes. More fertile than sandy soils, loam is not stiff and tenacious like clay soils. Its porosity allows high moisture retention and air circulation. The popular confusion of loam with humushumus
, organic matter that has decayed to a relatively stable, amorphous state. It is an important biological constituent of fertile soil. Humus is formed by the decomposing action of soil microorganisms (e.g.
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 is probably due to the superior quality of both soils. According to the preponderance of their ingredients, loams are classified as sandy, clay, or silt loams. Most soils of agricultural importance are some type of loam.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a friable sandy and clayey sedimentary rock containing 10–30 percent (by weight) clay particles smaller than 0.005 mm. In soil science, loam with a higher clay content is called heavy loam, and that with less clay is called light loam. A distinction is made between coarse sandy, fine sandy, and silty loam, depending on the content of (1) sand grains of the corresponding size and (2) silty, or aleurite, particles.

The mineralogical composition of loam is varied: the more sandy loan has a high quartz content, whereas the more clayey type contains clay minerals, such as kaolinite, illite, and montmorillonite. Loam is sometimes rich in organic substances; in arid regions it may be rich in water-soluble salts. The origin of loam is usually continental; the corresponding ocean deposits are called sandy or aleurite clays. Loam is often used as a raw material for the production of brick.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


Soil mixture of sand, silt, clay, and humus.
Molding material consisting of sand, silt, and clay used over backup material for producing massive castings, usually of iron or steel.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


In building construction, a mixture composed chiefly of moistened clay, sand, and silt, or some mixture including these ingredients. Once used as a mortar when combined with lime, or used as a plaster with the addition of chopped straw.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.


1. rich soil consisting of a mixture of sand, clay, and decaying organic material
2. a paste of clay and sand used for making moulds in a foundry, plastering walls, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
The results of our study also indicate that it is an example of another one species which prefers loamy soil (Fig.
On the other hand, the ANAPs of pure loamy soil reached maximum (11.72%) at 10 min, then fluctuated up, and went down slightly and dropped downtrend at 80 min and 120 min apparently (Figure 4(b)).
(2002), who compacted loamy soils close to our study site to > 3,000 kPa below 10 centimeters depth and still found no significant effect of compaction on above-ground tree productivity.
Territories of water-bearing units and their slopes: 1--Residues are formed by sandy loams, brownish-ashy podzol surface-clayed soil, under arable land; 2--Slopes of water-bearing units composed by forrest-like sandy loam soils and loamy soils, with brownish-ashy surface-clayed washed-out soils, under ploughed field and construction.
Ash application at 625 Mg/ha reduced stem weight and grain yield compared with control on both soils, but the decrease was significant only on the loamy soil. In the sandy soil, however, the stem weight and grain yield were significantly lower at 625 Mg/ha than at 5 Mg/ha.
Groundnut ALR1 failed to nodulate in all the soil samples and their mixtures except on loamy soil. This may be a mutant variety referred to as rhd2 (root hair defective) mutant spoken of by [15] in their study of failed nodulation in some mutant variety of Arabidopsis.
SOIL AMENDMENT IS AFFORDABLE Food crops flourish best in neutral loamy soil, but most backyard soils are either too acid, too alkaline, too heavy, or too sandy.
This was likely due to increased levels of soil microorganism populations corresponding to deeper rooting in the forest and increased organic C content compared to the other loamy soil sites.
They also need warm soil to germinate, a long growing season (100 to 150 days) and loamy soil.
On a crisp autumn morning in Sarasota, in a two-acre garden off Central Avenue, bright green heads of cabbage burst from loamy soil like flowers emerging from a magician's black sleeve.
pH adaptable, but requires moist, loamy soil. Needs to be mulched for moisture retention.
Place them in well-drained loamy soil. Bulbs will rot if they remain too wet.