CULTIVATION OP THE ORANGE TREE IN SPAIN. 635 



variety of produce, and the richness of this fortune-favored district. 

 The color of the earth in the parts where there is no irrigation is, in 

 general, red, but this changes to gray when irrigation commences 

 and manure is employed. In parts where vegetable refuse and abun- 

 dance of farm manure form the greater portion of the soil, the color in- 

 clines to black. 



The soil should be at least one meter in depth and should be subject 

 to irrigation. It should further be of a middle consistence, silicious- 

 argillaceous, or argillaceous-calcareous, rather damp, but without being 

 humid. Chalky soils, more or less pure, those completely silicious, and 

 those which are compact argillaceous, with constant humidity, are use- 

 less. In the two first the manures decompose rapidly before being of 

 service to the roots, and they require excessive irrigation, which weak- 

 ens the soil and exhausts it. In the latter the excessive humidity which 

 is constantly retained deprives the roots of atmospheric influence and 

 causes putrefaction. A soil composed of clayey marl or a light clay 

 mixed with sand is most suitable for the cultivation on a large scale of 

 orange, lemon, and other trees of the same family. The soils where 

 the orange-tree thrives well are of very distinct composition, as there 

 are as many orangeries on sandy as on clayey ones, but those most com- 

 pact should not contain more than 65 per cent, of fine earth (with less 

 than 0.005 millimeter diameter), and on reaching this limit they should 

 have a sandier earth for subsoil. The same extreme limits which the 

 orange-tree admits in its physical composition are also admitted by the 

 soil with regard to the quantity of lime contained in it, for while in cer- 

 tain districts (Benifay6) the earth contains no carbonate of lime, in 

 other parts 18.29 per cent, is found, and recently a calcareous earth has 

 been examined, the same being of great depth, and has been found to con- 

 tain 57.22 per cent, of said carbonate ; notwithstanding the same, the 

 orange-trees thrive well. These earths are also rich in potash, and con- 

 tain this matter in an exceedingly large quantity in a form that may be 

 considered as assimilable with the tree, so that in such districts there 

 is no necessity of employing potash for manure. Of the other alimental 

 principles of the plants, there is in general a limited quantity of phos- 

 phoric acid, and in some parts an addition of magnesia. 



The extraordinary foliage acquired by the orange-tree in a loose soil, 

 which at the same time contains what is necessary for its proper develop- 

 ment, may be fully appreciated in the districts of Alcira and Garcagente, 

 in this province, which districts are the center of production, and the 

 soil in which is loose and of great depth. A simple analysis of a sam- 

 ple of earth taken from Garcagente showed that it did not eflfervesce 

 with acids, whilst a sample from Mcira did, and abundantly. The anal- 

 ysis of 100 grams of earth from Alcira gave, salt of lime (carbonate), 

 20 per cent. ; sand (silicate), 70 per cent. ; clay, 10 per cent. This an- 

 alysis, which was lightly made, is sufacient to give an idea of the soil 

 iu which the orange-tree thrives to perfection. 

 156a 10 



