1 Nov., 1898.] QUEENSLAND AGRICULTURAL JOURNAL. 363 
A,—NATURAL FERTILISERS, 
Under this heading are included those materials of a vegetable nature 
which are obtained from the refuse of the kitchen, the excrement of animals, 
&c., and which contain the ingredients necessary for the growth of plants. 
Stable manure plays an important part in agriculture in the countries of 
the temperate zones, but in tropical regions it is very seldom available in 
sufficient quantities, owing to the fact that the ‘dairy industry in itself is not 
much developed ; also because the greater portion of animal excrement is lost, 
the animals, as a rule, not being fed in stables. The manure that is collected 
consists only of dried dung. ‘The urine, which is much richer in nitrogen and 
lime, can only be saved through absorption by means of straw and litter, and, 
of course, this method cannot be practised, unless the animals are fed in. 
stables. Well-prepared stable-manure, in addition to the large percentage of 
plant-food it contains, exerts a beneficial influence on the mechanieal condition 
of the soil, on account of the litter with which it is mixed. The addition of 
humus is of the greatest importance in increasing the productiveness of soils, 
as this substance is very rapidly consumed in tropical climates. When dung 
and urine are gathered without any litter, a mixture is obtained which contains 
the plant-food ingredients in an effective form. The application of liquid 
manure offers many advantages, but, on the other hand, the difficulty and 
expense of collecting and applying this material should not be lost sight of. 
In order to utilise all of the refuse substances, composting may be 
resorted to, and composts form a very valuable fertilising mixture. ~The 
addition of earth, mud, lime, marl, &c., ig absolutely essential, in order that 
the decomposition of the mass may be accelerated. Most planters are familiar 
with the rules for making composts; it should, however, be mentioned that 
the fertilising value of the compost can be increased by the addition of potash 
salts and phosphates—say 65 Ib. to 110 lb. of muriate of potash and 110 lb. to 
150 Ib. of some phosphate to every 35 cubic feet; these should be well mixed 
and applied between the various layers. If the compost is to be applied to 
tobacco or sugar-cane, sulphate of potash should be used instead of muriate. 
Composts are most advantageously employed in the setting of young 
trees; for this purpose 5; to 26% quarts should be put into each hole, and 
mixed with good soil. ‘This method ensures more certain growth and a more 
rapid development of the trees. 
As stable manure is not available in sufficiently large quantities in the 
tropics to make it an important factor in the fertilisation of crops, the 
preparation of composts is also only possible in few cases. The planter 
must, therefore, turn his attention to other materials, and first of all to the 
residues obtained in the manufacture of commercial products from oil-fruits. 
In this connection may be mentioned cakes made from soja-beans, from 
earthnuts, castor, palm-kernels, cocoanuts, cotton-seed, olive-oil, sesame, &c., 
which form important articles of commerce in several countries, and whose 
great importance in tropical fertilisation is evident. In their effect they 
occupy a position midway between stable-manure and artificial fertilisers. 
These cakes should really be classed as nitrogenous fertilisers, on account 
of their large percentage of nitrogen (2'5 to 7 per cent.) and small percentage 
of phosphoric acid and potash. ‘he organic nitrogen contained in these 
fertilisers is very rapidly and completely brought into use, corresponding in 
this respect to the rapid decomposition characteristie of the tropics. Other 
and similar residues are leached indigo plants, coffee-shells, &e. 
But even these materials are by no means present everywhere in 
sufficiently large quantities to satisfy the demands of fertilisation, without 
considering the fact that these substances, especially the oil-cakes, can be 
employed more rationally and advantageously in feeding cattle. It should, 
therefore, be the object of the planter to provide a substitute which has no 
limit placed upon its application, and this substitute is presented to him in the 
shape of green manuring with potash-phosphate fertilisation. 
Al 
