Loam, in agriculture, a species of earth, less cohesive than clay, but more compact than chalk.

There are several varieties of loam ; the most common of which we shall enumerate.

1. The clayey, that is likewise called string, stiff, cold, and heavy loam : it consists of a mixture of clay and coarse sand; is distinguished by the name of Windsor loam, and is much used for making bricks, building furnaces, etc.

2. The chalky loam ; the constituent parts of which are chalk, clay, and coarse sand.

3. The sandy loam, consisting of the same ingredients as the preceding kind, though the sand prevails in a larger proportion. The two latter varieties are frequently blended, and compose what is called a deep crumbly loam. This was formerly supposed to be unfit for vegetation, till it had been exposed for several years to the influence of the sun, air. frost, etc. Experience, however, has evinced the contrary ; and it is certain, that though the vegetative powers of this barren earth (as some have disdainfully called it) remain latent for a longer time than in soils which have undergone a proper degree of fermentation ; yet, after its surface is broken up and properly stirred, it will, at the expiration of one year, be well adapted to the production of crops.

A deep crumbly loam is particularly calculated for the growth of fruit-trees; and, if it be laid in ridges during one winter, and the succeeding summer, it will afford ample nourishment to such trees ; even though it should have been turned up from the depth of 6 feet in the ground.