Memoirs of the Geological Survey of Great Britain, and the Museum of Practical Geology in London Volume 23

Memoirs of the Geological Survey of Great Britain, and the Museum of Practical Geology in London Volume 23

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1860 edition. Excerpt: ...to be found out and taken hold of by the plant. These alkaline salts are invariably found in the ash of the cane, and the table shows how the incessant cropping of the exhausted soils has reduced their proportions by one-half; hence the necessity of adding alkalies under some form, if these so called "exhausted" lands are to be restored to fertility. The proportion of oxide of iron is considerable in the red soils, and it is believed those examined contain less than is usually characteristic. Some chemists have attributed a useful effect to this substance, as it is supposed to absorb ammonia from the atmosphere, fixing that alkali in the soil for the use of the plants; but it would be important to know whether very large per-centages of that substance are equally beneficial when associated with stiff clay soils, as the natural vegetation on the surface occupied by the red variety is not at all indicative of rich or fertile lands. All the soils examined contain lime and magnesia, both of which are essential to the growth of the cane; but the modes of combination of these bases, a matter of great interest, can only be vaguely indicated, as their precise nature could not be fully determined in the limited time allotted to the examination. Where there is so much carbonate of lime as occurs in the marls or subsoils of the black, one would expect to find abundance in the soil itself; but this is not the case, it seems the high temperature of this climate induces its rapid removal, wherever the carbonated surface waters can penetrate, so that in place of 20 per cent., the average content of the marl, only 136 per cent. of lime, equal to about 2 per cent. of carbonate exists in the virgin soil, and of this only a small proportion is...show more

Product details

  • Paperback | 78 pages
  • 189 x 246 x 4mm | 154g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236795768
  • 9781236795762