The shadow of the world's future, or The earth's population possibilities & the consequences of the present rate of increase of the earth's inhabitants

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Monograph

Identifikator:: 834285843

URN:: urn:nbn:de:zbw-retromon-29464

Document type:: Monograph

Author:: Rauer, Karl Friedrich http://d-nb.info/gnd/12122385X

Title:: Preußisches Landbuch

Place of publication:: Kiel

Scope:: 1 Online-Ressource (IV, 805 S.)

Collection:: Economics Books

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42 THE SHADOW OF THE WORLD’S FUTURE "This quantity of 300 million tons annually is, however, for the entire earth’s surface; for its land-surface it may be taken to be about 80 million tons. ‘This quantity, however, is not a simple function of the amount of rainfall. It may be added further that the necessary statistical surveys to enable one to state exactly what is available on given areas do not exist. It is seen at once that, in general, the scale of Nature’s operations are, compared with Man’s, colossal. Eighty million tons annually is, however, only about 2% times the total weight of chemical fertilisers produced annually. Only a part of the nitrogen arriving on the earth in this way is effective. Considerable loss occurs through drainage, and some return is made to the atmospheric nitrogen through the agency of anzrobic organisms, as already stated. Although a shortage of nitrogen will not occur, the same cannot be said of phosphorus or possibly of potassium. The supplies, economically exploitable, of natural phosphates, of guanos and of bones, are very limited. A shortage must occur in the near future, as those concerned in the phosphate business well realise. There may also be economic difficulties in obtaining phosphorus even where it is known to exist. The sources of potassium are the ashes of land and marine plants, sea-water, alkaline springs, saline deposits, felspars, micas, wool, etc. Already there are diffi- culties in obtaining supplies cheaply, but what the economic limits are has not yet appeared. The necessity for supplies of potassium is now better under- stood than it was even a short period ago, and it is certain that the near future will witness greater effort to solve the problem of securing sufficiently cheap supplies. At the same time it may be noted that the experience of the Chinese appears to show that very high yields can be obtained without artificial fertilisers; and it may be added that should the world’s population

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