Topsoil


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topsoil

[′täp‚sȯil]
(geology)
Soil presumed to be fertile and used to cover areas of special planting.
Surface soil, usually corresponding with the A horizon, as distinguished from subsoil.

Topsoil

 

the surface layer of soil that is regularly worked by tillage equipment. Topsoil 20–22 cm deep is considered normal. If it is less than 20 cm deep, it is considered shallow; if it is 22–35 cm or greater in depth it is considered deep. Between 80 and 90 percent of the roots of cultivated plants is concentrated in the topsoil. Therefore, the soil must be fertile, containing adequate amounts of the nutrients, moisture, and oxygen needed for both the roots and the soil microorganisms that break down organic remains into compounds assimilable by the plants. Organic and inorganic fertilizers are applied to the topsoil to enrich it with nutrients. The soil is loosened to increase its absorption of precipitation and its oxygen content.

topsoil

1. The surface of upper layer of soil, as distinct from the subsoil; usually contains organic matter.
2.See loam.
References in periodicals archive ?
When rainfall occurs, overland water flow can transport sediments from the upper to lower slope positions; meanwhile, it also infiltrates from the topsoil layer to the deeper soil layer with the eluviation of CaC[O.
Good q-uality topsoil contains the fibrous roots of turf stripped from the site before it was excavated.
Bulk compost made from yard waste can cost less than $20 per scoop, but expect to pay twice that much for screened, aged organic farm compost mixed with good topsoil.
Dandy's Topsoil, established in 1826 by James Dandy, now employs a team of 25 people and has a pounds 2.
Nevertheless, characterisation of topsoil moisture content at catchment and seasonal scales on Mediterranean soil surfaces are scarcely reported and few works are available concerning the effect of physiographic conditions controlling the spatial pattern of topsoil moisture in Mediterranean soils.
Dig to break up the compacted soil, add lime and organic matter and increase the depth of topsoil to achieve the most satisfactory long-term results.
The only problem with topsoil is that the water that drains through it stains the surface underneath.
Intensive fertility programs including micronutrients can improve the productivity of subsoil, but fertilizer alone cannot replace the benefits of topsoil (Mielke and Schepers 1986; Olson 1977).
If you have hollows in your lawn, provided they aren't too deep you can top-dress them a few times between spring and autumn with a mixture of topsoil, compost and sand or ready-made turf dressing to rejuvenate the area.
According to the United Nations Convention to Combat Desertification, during the Dust Bowl years, "At least five inches of topsoil were lost from nearly 10 million acres.
Sodbusters plowed up close to one hundred million acres of grassland and a drought followed by winds blew tons of topsoil across the American High Plains and as far east as Washington, DC.
Then, near the bottom of the hill, the steepness decreases and the land becomes relatively flat or forms a depression, where topsoil accumulates.