The Nitrogen 85 pounds 



Cultivation of Phosphoric acid 102 " 



Citrus Fruits Potash 85 " 



14 It will be necessary, then, to restore these elements to 



the soil, in one form or another, if the trees are not to suffer 

 from want of nourishment and to cease to produce maximum 

 crops of good quality. 



On the basis of the foregoing figures, the typical for- 

 mula of chemical manures, per acre of orange trees, will be : 



Nitrate of Soda 560 pounds 



Superphosphate of lime (i 6% soluble phosphoric acid) 6l2 " 

 Sulphate of potash I 70 " 



Obviously, however, this general formula must not be 

 adopted without reference to specific conditions; it must be 

 modified to meet the requirements of each particular case, 

 according to the nature of the soil and the state of vegetation 

 in the plantation. 



It may be well to mention here that in the opinion of 

 some of the most experienced and successful growers of 

 oranges in Spain, all formulae of manures for the orange 

 tree should contain sulphate of lime and sulphate of iron, 

 the quantity varying according to the composition of the soil. 

 If the land is poor in lime, only gypsum (sulphate of lime) 

 is employed; if lime is moderately abundant, both sulphates 

 are used, and if the soil is distinctly calcareous, only the 

 sulphate of iron. 



The formulae which are indicated later on are based 

 upon that given above, modified in accordance with the par- 

 ticular requirements of the plantation. 



In the first place, the composition of the soil has to be 

 taken into account. To ascertain this requires a delicate 

 analysis, which only a chemist can make; but the certainty 

 which such an analysis affords in the application of manures 

 renders it of the first importance to the horticulturist. The 

 cost of it will be repaid in a single season by economies 

 following upon a close determination of the nature and quan- 

 tities of the fertilizers to be employed. 



In default of an analysis, however, a knowledge of the 

 physical qualities of soils is of much utility. A clay soil 

 may be assumed to be rich in potash and poor in phosphoric 

 acid; a calcareous or limey soil is, on the other hand, gener- 



