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The tonne (/ t ʌ n / ⓘ or / t ɒ n /; symbol: t) is a unit of mass equal to 1,000 kilograms.It is a non-SI unit accepted for use with SI.It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the short ton (United States customary units) and the long ton (British imperial units).
If the soil has more than 15% by weight retained on a #4 sieve (R #4 > 15%), there is a significant amount of gravel, and the suffix "with gravel" may be added to the group name, but the group symbol does not change. For example, SP-SM could refer to "poorly graded SAND with silt" or "poorly graded SAND with silt and gravel."
The initial weight dropping has the most impact, and penetrates up to a greater depth. The following drops, if spaced closer to one another, compact the shallower layers and the process is completed by compacting the soil at the surface. Most soil types can be improved with dynamic compaction. Old fills and granular soils are most often treated.
The original Proctor test, ASTM D698 / AASHTO T99, uses a 4-inch-diameter (100 mm) by 4.584-inch-high (116.4 mm) mold which holds 1/30 cubic feet of soil, and calls for compaction of three separate lifts of soil using 25 blows by a 5.5 lb hammer falling 12 inches, for a compactive effort of 12,375 ft-lbf/ft 3.
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Harbour ton, used in South Africa in the 20th century, was equivalent to (2,000 pounds (907 kg)) or 1 short ton. Assay ton (abbreviation 'AT') is not a unit of measurement but a standard quantity used in assaying ores of precious metals. A short assay ton is approximately 29.17 g (1.029 oz) and a long assay ton is approximately 32.67 g (1.152 oz).
The metric ton is the name used for the tonne (1000 kg, 2 204.622 62 lb), which is about 1.6% less than the long ton. The US customary system also includes the kip , equivalent to 1,000 pounds of force, which is also occasionally used as a unit of weight of 1,000 pounds (usually in engineering contexts).
Sustainable techniques attempt to slow erosion through the use of cover crops in order to build organic matter in the soil. The United States loses almost 3 tons of topsoil per acre per year. [16] 1 inch (2.5 cm) of topsoil can take between 500 [17] and 1,000 years [18] to form naturally, making the rate of topsoil erosion a serious ecological ...