13 
Soils boundaries were delineated on the photographs by photo-interpretation 
methods, then verified and checked by field investigations. Detailed reports were 
prepared by the soils scientists, and the soils laboratory was established in 
Santiago to process and test the soils samples. In addition, numerous soils were 
taken for the purpose of crop yield and fertility investigations. 
Whenever possible the Project incorporated into the mapping the names of 
soils series appearing in previous maps or reports prepared by the Chilean 
Ministry of Agriculture. The soils symbol was divided into two parts, the first 
portion, usually two letters, designating the soils series and the second in the 
form of a fraction. The first number in the numeration of the fraction indicates 
the stage of pedogenic profile development and degree of weathering of the parent 
material. The second number defines the drainage class or wetness and the third 
number designates the texture of the surface soil. The denominator of the fraction 
indicates the limiting factors applicable to the mapping unit. This is illustra 
ted in Figure 5. The designation PH 522 states that this is Pudahuel soil found 
rrd 
about 12 km. west of Santiago. The 5 indicates a moderately mature soil having 
(2) optimum drainage and (2) being moderately coarse, actually a silicious taff 
that is high in content of pumie. The rrd indicates that the surface of the hard- 
pan is generally between 40 and 80 cm below the surface and the area is moderately 
acid. 
The soil boundary together with its identifying symbol was delineated on the 
mosaic sheets. All soils lab reports, soil scientists'notes and field observa 
tions are a part of the basic information provided. 
Forestry 
This portion of the Project was undertaken to provide quantitative informa 
tion to indicate the relative capabilities of certain agricultural soils with 
respect to forest plantations. Experienced foresters and agriculturists studied 
and sampled 280 plantations and measured more than 11,000 trees for height, dia 
meter and age. 
Field crews ran strips from recognizable points on the aerial photographs