Components of Loam Soil

Sand Component

• Loam soil has a sand content ranging from 23 to 53 percent of the total mixture. Sand grains range from 0.05 mm and 4.75 mm, are easy to see with the naked eye and feel gritty if you rub them between your fingers. Sand particles often include the minerals quartz, magnetite, olivine, feldspar and hornblende. You can subdivide sands into fine, medium and coarse varieties. Find-grained sands are similar to powdered sugar, with grain sizes between 0.075 mm and 0.42 mm. Medium-grained sands are between 0.42 mm and 2 mm in size, which is similar to that table salt. The largest particle size, coarse-grained, is between 2 and 4.75 mm, which resembles water softener salt.

Silt Component

• Loam's silt component generally ranges from 28 to 50 percent of the total mixture. Silt particles are between 0.002 mm to 0.05 mm and are too small to see without a microscope. However, you can sometimes feel the small, gritty grains between your fingers. These small grains have a greater ability to hold water in the soil than the larger sand particles. Silt particles are contain quartz, feldspar, micas and other silicate minerals.

Clay Component

• A loamy soil mixture is often 7 to 27 percent clay particles. Smaller than 0.002 mm in size, clay particles are the smallest of loam soil's inorganic components, which you can only see using a microscope. Clay particles feel sticky when they're wet and will hold water and nutrients for vegetation. Clay particles are actually a family of minerals that form from the degradation of micas and feldspars in various rock types. Loam soil can include a variety of clays such as kaolinite, smectite, illite and chlorite.

Organic Matter Component

• Organic matter in loamy soil includes fresh or decomposed animal or plant material. The content of organic matter in loamy soil is generally between two and four percent. Although its percentage is small, organic matter is an important part of loam soil because it helps to aerate the soil, retain moisture, control and reduce erosion and provide important nutrients such as sulfur, nitrogen, phosphorous to nearby plants.