The value of mineralogical examination in determining soil types, with a method of examination and a comparison of certain English and Scottish soils

Abstract

Accounts have already been published by this department of investigations made as to the origin, nature and properties of the glacial drift soils of the north-east of Scotland; in particular, the soil as found at the Experimental Farm of Craibstone, near Aberdeen, has been studied by means of mechanical analysis and the determination of the chemical composition of the fractions resulting therefrom (4). The results obtained have brought out some characteristic features of the Craibstone soil, and have indicated that important differences may exist between a glacial drift soil, derived mainly from rocks of granitic nature, and such a soil as that of Rothamsted, arising from the “Clay with flints” formation.

Soil Components

“…Additional information ean be obtained by separating the sand minerals into three SG group s (HENDRICK and NEWLANDS [1923]; HART [1929aHART [ , b, 1941; ELDER and MCCALL [1936]; JEFFRIES and WHITE [1940]; MARSHALL and JEFFRIES [1945]). Vari ou s SG values have been used, but the most useful are about 2.62 and 2.88, giving a lightest group eharaeterized by potash feldspars, an intermediate group containing quartz and plagiodase, and a heavy group containing the usual heavy mineraIs.…”

A study in the mineral composition of the soils of South Ayrshire

“…(1) less than 2-63 (orthoclase crop); (2) 2-63-2-89 (quartz crop); (3) greater than 2-89 (ferro-magnesian crop). The method of separation is detailed by Hendrick and Newlands (12), bromoform of S.G. 2-89 being the heavy liquid used.…”

The reaction, exchangeable calcium, and “lime requirement” of certain Scottish soils

“…The greater part of the cultivated land in Scotland is covered with glacial drift and to determine, even approximately, the origin of the matrix of this drift would involve a detailed mineralogical examination of the soils. Such examination has been carried out by Hendrick and Newlands (23) and is at present being carried out in this department. The results so far obtained indicate that, although boulders are frequently far-travelled, the matrix of the drift-at any rate where the drift is comparatively thinis largely derived from the underlying rock.…”