682 
SCIENCE 
[N.S. Vou. XXXV. No. 905 
OuTUNE OF SCHEME OF SOIL CLASSIFICATION. ~~ 
REclon-TemPERATURE| Temperate 
IMATE 
ay ee { 
Sub-Tropical Tropical 
2 Humid — Semi-Arid Arid 
eh > 
DWISION inte of Sedentary Transported 
: Formation 5 i ; 
PROVINCE ; ’ Residual Cumulose Gravity, Water ea tind, 
(oma 
4 4 pl ea f ca cae Pei aren af 
ce Sourcedt4 AcidttBasic Shale Sandstone Limestone# Muck,Peat -- d0UIce of ource of +90 i 
SOIL ceo igeousRocks Slate Quarie Marble Rock Swamp aerial Material (Material 
Color EXAMPLES oF APPLICATION oF SCHEME. f 
Organic Matter CecilClay — HaersianwiLoam Muck Oru Dunkirk SitLoam Watash loam Votusia Sift Lowes empl Sit .oam 
SERIES Drainage Recion. Tenpfate Temperate Tempera Tenpecfe Terpuce. Tempuate. Tope Temperate 
pa == Seay ted umd. tums tumd— umd =~ Turd Humid amid 
Special Chemical Properties | Owision Sedentary Sedenfary  Sedentary Transported Transporied Transported Transported Transported 
PROVINCE Residual ., Residual  Cumulose Waller (Ocean) ee Waler Gtream) [ce Giacial) Wind 
TyPE Texture GROUP Gneiss ° Limestone Sphagnum - +. Resta tLimefore SLGlacial Shale Migeeignegus 
Structure SERIES Red Brown Red Calcareous Red ‘ Brown-yéllow Dark Light ——-Yelowcalcareous 
TYPE Clay Loam , Sand Silt + Loam Sittloam — Silt loam = ~* 
cultural properties will be indicated as the 
scheme is developed. 
Climate.—The broadest agricultural divi- 
sions in soil are due to climate. Although 
the soil material were the same (if that is 
possible), if it oceurred under widely dif- 
ferent conditions of climate it would have 
a different agricultural value and should 
be differentiated. 
Climate consists of two primary ele- 
ments. These are temperature and humid- 
ity, or precipitation. 
I. The Region. Temperature.—We pro- 
pose to term the groups of soils determined 
by temperature the region and the surface 
of the earth would be divided into belts or 
zones corresponding in general to these 
commonly made, and these may be multi- 
plied if their agricultural diversity proves 
too great. The temperature has some in- 
fluence upon the type of processes by which 
soils are formed and the changes which 
they are continually undergoing. 
II. The Section. Humidity—tThe groups 
determined by humidity we would term 
the section and the temperature zones 
would be subdivided according to the de- 
gree of aridity. In the United States three 
conventional groups have been recognized, 
namely, the humid, the semi-arid and the 
arid. Humidity has an especially marked 
effect upon the processes of soil formation 
and brings about distinct physical and 
chemical differences. In a general way in 
arid regions physical processes of the decay 
of rocks are relatively more prominent 
than chemical processes, resulting in soil 
which averages coarser in texture. Alkali 
or the excess of soluble salts is chiefly iden- 
tified with aridity of climate. These are, 
therefore, broad distinctions in the proper- 
ties of soil which should be recognized. 
III. The Province. Mode of Formation. 
—The third great factor which determines 
the properties of a soil is the mode or 
process of formation. This includes all 
the processes and forces which have been 
operative in transforming rocks into soil 
and imparting to them distinctive physical 
and chemical characteristics. These are 
dynamic and, therefore, impress special 
properties upon the material handled. 
While several processes are usually opera- 
tive on the same material, they are seldom 
equally prominent, and certain conven- 
tional groupings have been adopted by 
