THE AGRICULTURAL JOURNAL. IfK. 



The Production of Ex/tortabie Oranges. 



IN a lecture on " Orange Culture and 

 Di seases," delivered at a meeting ol' 

 the Malta Archeological and Scientific 

 Society, Dr. J. Borg, ^',A., M.D., made 

 the following remarks concerning the 

 production of oranges best adapted for 

 export purposes : — 



" Too sandy and too compact soils are 

 alike unsuitable for the regular growth of 

 the orange tree. This tree, when planted 

 in a sandy soil, is very liable to suffer 

 from dry weather. A sandy soil is, 

 generally speaking, a poor soil, because 

 the nutritive compounds on which the 

 tree subsists are very readily carried away 

 by rain water, beyond the reach of the 

 roots of the orange tree, which, it must 

 be remembered, is essentially a surface 

 feeder. A too compact soil keeps the 

 water stagnant, and is one of the chief 

 causes of chlorosis. Moreover, the roots 

 are compelled to remain very near the 

 surface, and therefore must be exposed to 

 great heat in summer and to great cold in 

 winter. Also, in a compact clayihh soil 

 the root system is particularly subject to 

 dry rot. With regard to the chemical 

 composition of the soil, we may say that 

 the orange tree requires a soil containing 

 a high percentage of carbonate of lime 

 and oxide of iron, and only a moderate 

 quantity of clay (alumina). When the 

 percentage of clay is very high, or when 

 the orange tree is situated on a subsoil of 

 clay, it produces fruit having a very thin 

 rind, and a very luscious flavour, but, un- 

 fortunately, easily subject to rot, and 

 cannot be much depended upon tor ex- 

 portation. This is the case of some 

 orange groves at the Boschetto. When 

 the subsoil consists of soft porous rock, 

 the fruit is large, has a thick rind, the oil 

 glands and the aromatic properties are 

 well developed. This may be observed 

 in the orange groves of Casal Lia, Casal 

 Balzan, and Casal Attard, Malta. If the 

 subsoil is very hard and compact, and 

 therefore very dry, as the subsoil of the 

 orange groves at Musta, the fruit is small- 

 sized, the rind is thin, but the pulp is 

 very juicy and delicious. Fruit grown 

 on such a subsoil ripens early, and is in 



every way suitable for exportation. What- 

 ever the quality of the soil may be,still we 

 may grow the orange tree to advantage, 

 provided that the soil is so regulated that 

 there will be a perfect drainage. A layer 

 about two feet in thickness, and consist- 

 ing of rubble and stones, and covered by 

 two or three inches of thin rubbish, will 

 constitute by itself a perfect system of 

 drainage to favour the flow of super- 

 fluous water in winter. The layer of 

 earth which covers that of rubble should 

 be two feet in depth, and never less than 

 one foot and a half. As the rootlets will 

 hardly ever penetrate beyond the layer of 

 rubbish, and as drought prevents the 

 formation of roots within six inches from 

 the surface, we may say that the soil in 

 which the orange tree thrives is from 

 twelve to eighteen inches in thickness." 



Concerning manures. Dr. Borg said : — 

 " The orange tree does not exhaust the 

 soil very rapidly. The produce of the 

 orange tree are the fruit and the pruned 

 branches, so that, strictly speaking, the 

 soil is depauperated of its nutritive sub- 

 stances for the same amount which these 

 substances enter into the composition of 

 the fruit and the pruned branches. If 

 the nutritive elements of the pruned 

 branches are again returned to the soil in 

 the form of wood ashes, we will find 

 that, even after the lapse of several 

 years, the orange grove can hardly be 

 said to be improvished at all. In the 

 raising of crops of cereals and other annual 

 vegetables we meet with the reverse. In 

 these crops we carry off both the fruit and 

 the plant which produced it, or in other 

 words the earth loses for ever all the 

 nutritive substances absorbed by the 

 action of the roots. Now, the vast per- 

 centage of the weight of an orange con- 

 sists of water and hydrocarbons, and of a 

 few nitrogen compounds which the tree 

 receives directly from the air. The small 

 amount of phosphates and potash necessary 

 for the formation of the fruit and the 

 perfection of the orange pips is com- 

 pensated by the stable manure which is 

 supplied to the orange grove at regular 

 intervals of six or eight years. The effect 



