ON MANURES. 



II39 



provide in addition an abundance of all forms of available 

 plant-food at the times needed for the development of the trees 

 and fruit, apply annually chemical fertilisers in the following pro- 

 portions per acre : 



Nitrate soda . . . . . . . . . . . . loolb. 



Superphosphate . . . . . . . . . . lOolb. 



Bone-meal . . . . . . . . . . . . 20olb. 



Potash 20olb. 



The amounts to be applied must depend upon the character 

 of the soil, the kind of fruit to be grown, and the age and vigour 

 of the trees." 



Guano. — Most horticulturists favour guano as a manure, and 

 until within recent years this was certainly one of the most 

 important nitrogenous fertilisers in the market. True guano is a 

 substance found upon certain almost rainless islands along the 

 coast of Peru, which has resulted from the slow decomposition 

 of the dung and other refuse of sea-birds. 



The wonderful plant results obtained with small quantities ot 

 this very concentrated manure produced the utmost astonishment 

 among both farmers and gardeners, and greatly stimulated the 

 constant inquiry into the action of manures generally, which has 

 resulted in the addition of a great number of artificial fertilisers, 

 and in the greater knowledge of the action of manures which 

 we now possess. 



The guano which is procurable at the present date is dis- 

 tinctly inferior to that which was formerly imported, and buyeis 

 should protect themselves by asking for some guarantee as to 

 the quality of their purchases. It is in the nitrogenised com- 

 pounds of guano that its value is to be chiefly attributed. In 

 the best descriptions of guano, the nitrogen may range from 

 10 per cent, to 17 per cent., the phosphoric acid from 12 per 

 cent, to 15 per cent., and the potash from 2 per cent, to 8 per 

 cent. The classes of guano now to be obtained will probably 

 not contain more than from 4 per cent, to 8 per cent, of 

 nitrogen, 9 per cent, to 12 per cent, of phosphoric acid, and 

 from I per cent, to 3 per cent, of potash ; but even with this 

 composition it is a powerful manure. 



Considered as a general manure, the phosphates predominate 

 over the other constituents, and guano is therefore very useful 

 as an adjunct to farmyard or stable manure, which are poor 

 in phosphates. It is poor in potash, consequently on soil and 

 crops requiring a large supply of this ingredient, it should be 

 used in conjunction with potash-salts, kainit, or wood-ashes. 



About one-third of the nitrogen present in guano is in the 

 condition of ready-formed ammonia, which acts very quickly 

 on plant-life ; the remaining two-thirds are present in a variety 



4 D 2 



