ON MANURES. 



II35 



It is believed that the beneficial effects of artificial fertilisers 

 are due as much to the timely supply of plant-food as to the 

 actual amount of assimilable ingredients they may contain. 

 Food given at the right time, and in judicious quantities, 

 enables the plant to extend its roots, whereby it is able to secure 

 more nourishment from the soil, over and above that furnished 

 by the manure, than it could have secured without such help. 

 If this is so, it shows that the use of commercial fertilisers in 

 small but frequent quantities may not only largely increase the 

 total yield of crops, but may also produce a greater abundance 

 of flowers and of fruit. It must be remembered, however, that 

 one and the same description of manure will not be equally 

 efficient on all classes of soils. 



Reference has been made to complete fertilisers, that is, 

 those manures which contain, as it has been aptly described, the 

 " golden tripod of plant-life " — namely, nitrogen, phosphoric acid, 

 and potash, in the proportions found in the plants to be grown. 

 But plants vary widely in their amounts and proportion of 

 nitrogen, phosphoric acid, and potash. The variations are due 

 to many causes, such as an abundance or lack of moisture, 

 sunshine, and inherited power of the plants. Then, too, the 

 soil varies more widely in the percentage of plant-food and its 

 availability than the plants do. 



In general terms it may be stated that, in the garden, when 

 it is desired to increase the leaves and stalks — the vegetative 

 system — of plants where luxuriance and succulency are required, 

 as in the cultivation of the various Cabbage and Broccoli tribe. 

 Celery, Asparagus, Lettuce, Spinach, Rhubarb, and foliage plants, 

 this can be accomplished by supplying them with plenty of 

 nitrogen ; while, on the other hand, the production of flowers, 

 seeds, fruits, tubers, and roots, where maturation rather than 

 luxuriance is the end in view, is best secured by using moderate 

 quantities of nitrogen and liberal amounts of available phosphoric 

 acid and potash, and sometimes of lime also. 



Artificial manures may be divided into {a) phosphatic manures, 

 including the nitrogenous guanos ; (b) nitrogenous manures 

 proper ; {c) potassic manures, some of which also contain 

 nitrogen ; {d) other mineral manures, like gypsum, lime, &:c. ; {e) 

 special mixed manures. 



Phosphatic Manures. — Phosphate of lime is a chemical 

 substance, which has acquired great commercial importance in 

 recent years, and has been found to be a manure of considerable 

 value in the garden, in the orchard, and in the conservatory. 

 There are several varieties of this manure, which includes such 

 fertilisers as raw bones, bone-meal, bone-ash, superphosphate of lime, 

 phosphatic rocks, and basic slag, as well as the phosphatic guanos. 



Raw bones are true phosphatic manures, although they contain 

 a small percentage of nitrogen. They decompose slowly in the 



