572 FRUIT CULTURE IN FOREIGN COUNTRIES. 





 are some very fine prolific orchards in the rear of Tarifa, on the Straits 



of Gibraltar, as well as ou the delta and the lower reaches of the Gua- 

 dalquivir. On hillsides or uplands the trees thrive well, provided 

 the altitude is not such as to act virtually in the sense of latitude. 

 It is not common, I believe, to find productive orchards in this sec- 

 tion at an altitude exceeding 250 meters above sea-level. It is also con- 

 sidered desirable to have the trees sheltered from very strong winds 

 from any quarter. In Andalusia winds from the north and east are 

 the most prejudicial, the first as being cold and raw, and the east 

 wind as having a desiccating, withering eifect. Very steep hillsides 

 are an undesirable location on account of the insufficient retention 

 of moisture; very low grounds are open to the contrary objection, and 

 though large yields are frequently made in such localities, the trees 

 are liable to suffer in wet seasons, and expensive drainage is usually 

 imperative. Of more importance far than* the merely topographical 

 features of the soil is its composition, which will be treated further on, 

 as also its stratification. It should be borne in mind that the orange 

 tree extends its roots primarily in a vertical direction, thus requiring a 

 permeable subsoil. Whenever an impervious stratum is reached whilst 

 this vertical development of the roots is still going on, the trees suffer, 

 and in many cases perish. Fine orchards, composed of trees of from 

 thirty to forty years of age, have been known thus to waste away. 



These few remarks are sufficient to show that categorical information 

 as to the influence of topography upon yields is most difficult to give. 

 Vicinity to the sea seems to be anything but injurious, though I do not 

 recollect ever having seen orchards in immediate proximity to the sea 

 without some natural or artificial shelter. In the valley of the Guadal- 

 quivir, both above and below Seville, very fine orange crops are raised, 

 the altitude probably not exceeding 80 meters above sea-level. The 

 soil of one of the best orchards of that section, on being subjected to 

 levigation. was found to be composed as follows : 



Per cent. 



Sand 43 



Clay 31 



Calcareous salts : 15 



Organic matter 11 



1 100 



Soil of this character, or of somewhat similar type, when accompanied 

 by permeability of the subsoil, may be looked upon as well adapted to 

 orange culture. Soils having impervious subsoil, or such as are water- 

 soaked or difficult to drain, are especially to be avoided j in such situa- 

 tions the upper layer of soil is frequently very rich, and on that account 

 an orchard may appear to thrive luxuriantly at first, but as soon as the 

 roots strike deeply, disaster will overtake the trees. 



Irrigation and cultivation. Orange groves in Western Andalusia re- 

 quire irrigation during the hot season at intervals varying from ten to 



