Changes in the composition of guano during storage

Abstract

The term “guano” is applied almost wholly to the excrement of sea-birds and, since it contains a high proportion of nitrogen and phosphorus, guano forms a very valuable fertilizing material. The Union of South Africa has a large number of small islands scattered round the coast which are used as breeding grounds by various sea-birds. The deposits of guano from different islands vary considerably and are therefore systematically mixed to obtain an approximately uniform grade of material. The average analytical results for the years 1921–8 were: 10·0 per cent nitrogen, 11·2 per cent phosphoric oxide, 2·0 per cent potash.