The twelve tons of oranges per acre. If the plantation be capable 



Cultivation of o a neav ier yield, on account of its maturity or from the 



3 variety being a prolific one, or owing to the nature of the 



16 soil, the advantages of the site, facilities for irrigation, the 



climate, etc., the quantities of the several fertilizers may 



be judiciously increased until the limit of production is found 



to have been reached. 



On the other hand, if the plantation is naturally one 

 capable of producing only moderate yields, the trees of me- 

 dium size and facilities for irrigation absent, the same com- 

 bination of fertilizers must be employed, but the applica- 

 tions must be less in quantity; and in determining that 

 quantity the skill and judgment of the grower will come in. 



Superphosphate of lime, containing not less than 14 to 

 1 6 per cent, of phosphoric acid, is to be preferred as the 

 phosphatic element in the fertilizer on account of its ready 

 solubility and relative cheapness. In soils distinctly deficient 

 in lime Thomas Phosphate (basic slag) may in many cases 

 be substituted with advantage. If basic slag be used, a 

 somewhat larger quantity of it should be applied than is 

 prescribed in the case of the employment of superphosphate 

 of lime. 



Of potash salts, it is advisable to use only the sulphate; 

 it being the opinion of many experienced growers that the 

 sulphate communicates to the fruit the greater delicacy and 

 aroma. 



Exact experiments carried out during the past few years 

 have shown that Nitrate of Soda is the best source of nitrog- 

 enous food for the orange tree. And here it must be borne 

 in mind that Nitrogen, from whatever source derived, must 

 be in the form of a nitrate to be assimilable by the vegetable 

 organism. Thus, if manures containing organic nitrogen, or 

 sulphate of ammonia which yields ammoniacal nitrogen- 

 be employed, the nitrogen which they contain has to undergo 

 in the soil a natural process known as Nitrification, in con- 

 nection with the action of minute organisms which convert 

 the ammoniacal or organic nitrogen of the manures into 

 nitric acid and nitrates. For this conversion more or less 

 time is required, and, whilst the processes last, losses occur 

 by the giving off of free nitrogen, which the plants are unable 

 to utilize and which is lost in the atmosphere. 



