The The removal from the soil of the constituents of a 



Cultivation of success i on o f crops brings about sooner or later, sterility or 

 - exhaustion of the soil from default of nitrogen, phosphoric 

 IZ acid and potash; and this sterility or exhaustion cannot be 



prevented or remedied by any system of cultivation. Field 

 operations carried out with thoroughness do, indeed, re- 

 store to the surface soil the elements of fertility which 

 the rains wash down into the sub-soil, they hasten their solu- 

 bility and prepare them for assimilation by the plant, but 

 they replace nothing. It is indispensible therefore to make 

 good the deficit, and, by means other than cultivation, to 

 restore to the soil what the crops have removed from it. On 

 this fact is based the use of manures, and in manuring skil- 

 fully and adequately lies the secret of successful fruit grow- 

 ing. 



Barn-yard manure used in moderate quantities will re- 

 store to the soil, to some extent, the elements removed from 

 it by continuous cropping, but in the case of citrus fruits it 

 will be inadequate to increase production; employed in 

 greater quantity and to an excessive extent, its effects are 

 rather injurious than favourable, since it gives rise to all 

 the evils attendant upon the application of organic nitrogen 

 in too large proportion. 



Moreover, although barn-yard manure is, in a general 

 sense, termed a complete manure, it does not, when em- 

 ployed alone, satisfy the requirements of citrus trees, inas- 

 much as the quantity of some of its constituents needs to be 

 supplemented if heavy yields and healthy vegetation are to 

 be maintained. 



Fortunately, the rational application of manures is daily 

 becoming better understood, and the grower is now in a 

 position, by the aid of chemical fertilizers, to raise the yield 

 of his plantation to a maximum^and, at the same time, to 

 secure for his trees that vigour of growth which enables 

 them to resist unfavourable climatic conditions and parasi- 

 tic attacks. 



Liberal and judicious fertilization is essential to profit- 

 able results in the culture of citrus fruits; and the grower 

 should be the less inclined to stint outlay in the purchase 

 of fertilizers, because he may be certain of obtaining highly 

 remunerative returns in the yield and quality of the crop. 

 The orange tree, in particular, is one that responds gener- 



