MAN’S AGRICULTURAL NEEDS 29 
following results for the subdivision of the earth’s land- 
surface into different classes of area: — 
Total 52-5.—Unspecified 22-5, Non-productive 13-6, 
Productive 16-4. 
Productive 16-4.—Pastures 2-8, Shrubs o-2, Forest 
7:3, Marsh 1-0, Arable 5-1. 
Arable 5-1.—Grasses 0-79, Foods 0-39, Industrial 
0-37, Seeds 0-02, Cereals 3-53. 
Thus we may say that at the present time the arable 
lands form only about one-tenth of the whole land- 
surface. The available area for the effective use of 
human beings is thus seen to be very limited. In this 
connection it is to be remarked that for different 
countries the percentages available for food-crops varies 
enormously. For example, while for Tunis it is only 
0-1, for Czecho-Slovakia it is 43-1, for the whole 
world it may be taken as somewhat under 8 per cent. 
The productivity of various areas also differs as much 
as seven times. 'Lhis matter will be dealt with more 
fully in a later chapter. 
A merely cursory glance at the above figures may at 
first suggest that the possibilities of developing the 
world’s agriculture are very great. Such an inference, 
however, is not valid. 
It would not, of course, be quite accurate to apply 
the results of a statistical survey of only 46 per cent. of 
the world’s surface to the entire area of that surface. 
[t may nevertheless be taken as a rough guide. Apply- 
ing it, we get the following results: — 
Total. Productive. Non-productive. Not specified. 
52-5 16-4 136 22-5 million square miles. 
[000 21:2 25+Q 42+9 per cent. 
How far the unspecified areas may be made to con- 
tribute to the productive or arable areas we are unable 
to say. It is, however, clear that we should recard the