50 
more accurate work accomplished has become paramount, This has led to the provision of 
money on estimates for their purchase and thus a more ready supply of aerial photographs 
either as contact prints or as enlargements where these are necessary for the proper re- 
cording of field data, Photographs are no longer regarded as too valuable to mark and in 
fact for some years photographs with matte and semi-matte surfaces were specified so as to 
facilitate such marking, More recently pencils of several colors which will clearly and 
easily mark glossy photographs and stand up to the vagaries of weather in the field have 
become available, Every Soil Survey undertaken is made with the aid of aerial photographs 
which are regarded as a prerequisite, 
As well as being used for formal soil mapping aerial photographs have been used 
extensively for recording field studies of land-use, soil erosion and surface hydrology, 
especially where these studies have been associated with soil surveys, Many features of 
land use show clearly on photographs of appropriate scale, including health and vigor of 
fruit trees and vines, variation in crop and pasture growth, forest plantation vigor, and 
some aspects of the use of fertilizer such as the method of application of superphosphate 
to pastures e.g. the rotating type of spreader leaves an irregular pattern of response 
readily detected on the photographs, The various forms of water erosion and deposition 
such as gully, rill, sheet and tunnel forms, wind erosion sealds and blow-outs, and drift 
sand deposits are all readily identified and mapped on aerial photographs, Land-slips in 
various stages also show as characteristic markings on the photographs. 
In several areas, ranging from closely to sparsely settled country where soil 
surveys have been undertaken, lack of cadastral surveys has resulted in an absence of the 
usual base plans on which to publish soil data, In these cases base plans have been com- 
piled from controlled slotted template lays of the photographs or, less accurately, by the 
use of uncontrolled photo mosaics at a scale of approximately h miles to 1 inch, In the 
latter case photographs of a scale of 1 in 50,000 have been used to first record the field 
work which under these circumstances is always of a reconnaissance type. In a number of 
cases base plans based on early land surveys have been found inaccurate or incomplete in 
some portions, Aerial photographs have been used to remedy these defects, 
In a number of instances vertical aerial photographs have yielded information of 
direct value in pedological studies as distinct from formal soil mapping, For example in 
County Victoria north of Adelaide, S.A. the erosional geretic relationship between the 
clay-loam and other members of the Belalie and Canowie series was initially postulated 
from the pattern and topographic positions of these soils revealed on the photographs, 
(Stephens et al 1945), The prior streams theory for the origin of certain soil patterns 
in the Riverine plains of N,S,W, and Victoria was clearly defined from photographs (Butler, 
1950), There are numerous other cases which could be quoted, 
In one particular project an attempt was made to use trimetregon photographs but 
the two obliques in each set of three, while not useless, proved difficult and exasperating 
to use because of their changing scale and lack of definition with distance from the fore- 
ground, However a number of obliques taken as opportunity offered during airline flights 
have proved useful for demonstrating pedological and geomorphic relationships of different 
parts of various landscapes, It is interesting to note too that the only recorded recog- 
nition of barchanoid type dunes in Australia followed observation from a civilian airliner, 
So far the cost of general unavailability of vertical color photographs have pre- 
cluded their use in soil survey. However, an inspection of a limited number of examples 
clearly indicates that they would have considerable advantages, 
REFERENCES 
Butler, B,E, (1950), A theory of prior streams as a causal factor in soil occurrence in 
the Riverine plains of S,E, Australia, Aust... Jd. Ag, Res, 1. 231. 
Marshall, T.dJ. and Hooper, P.D. (1932). A Soil Survey of Blocks A, B, C, D, and PF, Ren- 
mark Irrigation District, South Australia, ¢.8.I.R,- (Aust. ). Bull, No. 56. 
Prescott, J.A. and Taylor, J,K, (1950). The Value of Aerial Photography in relation to 
Soil Surveys and Classification, Jour, 6.8. 1.R. (Aust... Yo1. 3. No. h. Dp. 
229-232, L plates, 
Stephens, C.G., Herriott, R.I., Downes, R.G., Longford Smith T,, and Acock, A,M, (1945), 
A Soil Land Use and Erosional survey of Part of County Victoria, South Australia, 
G.S, T.R. (Aust, ). Bull. No. 188, 
  
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