.27 



But cultivation does not benefit the soil, only by assisting in the 

 retention of moisture ; it also affords an opportunity of aerating the 

 roots of the trees, and this is a very important function. It should be 

 hardly necessary to ask any one to call to mind the appearance of an 

 orange grove where cultivation has been neglected or, perhaps, 

 scarcely ever practised. As a rule, in such cases, the leaves of the trees 

 are yellow, and often one sees the dying back of young twigs. In 

 fact, uncultivated trees usually have a sickly look, which denotes their 

 condition, and it is when in this state that they are most susceptible 

 and most readily succumb to the attacks of the numerous army of 

 insect and fungus pests to which they are subject. 



A homely illustration of retention of moisture is occasionally 

 afforded by the turning over of an old sack or bit of wood left about in 

 the garden. Whilst all around the soil may be to all appearance 

 quite dry, that immediately beneath the sack or wood is found to be 

 damp ; this is because evaporation has been prevented, or at any rate 

 hindered, just in that spot. 



The fine top soil or mulch of an orchard in a good state of cultiva- 

 tion acts in just the same way ; it prevents evaporation. The frequent 

 stirring with a cultivator prevents capillary action being set up, and 

 the mulching qualities are thus retained. 



Ieuigation. 



No citrus orchard should be laid out in Soath Africa without 

 facilities for irrigation. It is true that the same need for water does 

 not exist on the coast-line as it does on the high plateaus of the 

 interior, but that the need does exist is proven by the fact that some 

 of the largest growers on the coast have been compelled to make 

 arrangements for a supply of irrigation water. Assuming for a 

 moment that no facilities for irrigation exist — that a rainfall of forty 

 inches is present on the coast citrus belt, that precipitation occurs, as 

 would normally be the case from September or October to March or 

 April, one finds a most important period in the annual life of llie tree 

 passing without any adequate water supply. If forty inches could be 



