CHAPTER XV 



IRRIGATION OF FRUIT TREES AND VINES 



Whether fruit shall be grown with irrigation or not is a local and 

 specific question, and it must be answered with due regard for 

 several conditions, among which are : First, the minimum local rain- 

 fall ; second, the depth and character of the soil and subsoil ; third, 

 the situation and environment of the ground on which the fruit is 

 to be grown ; fourth, the kind of fruit which it is desired to produce. 



These conditions are all correlated, and a knowledge of them all 

 is necessary to an intelligent decision as to correct practice in any 

 given locality. For example, the amount of rainfall which is ade- 

 quate in one locality, or in one situation, even, may be quite in- 

 sufficient in another, because, first, one soil may be deep and fairly 

 retentive, into which roots can penetrate and find abundant mois- 

 ture ; second, another soil may have sufficient depth, but be so porous 

 as to lose its moisture by evaporation, or so leachy as to lose it by 

 drainage ; third, still another may be shallow, and quickly dried out 

 under a fervid sun, or quickly drained by reason of a sloping sub- 

 stratum of rock or hardpan, while another similar soil, differently 

 situated, may receive abundant moisture from the drainage of the 

 slope above it ; fourth, possibly in all the soils cited there might be 

 adequate moisture for deciduous fruits, but citrus fruits would re- 

 quire irrigation ; or enough for young, but not for bearing trees. 



Thus it appears that even to decide whether a location has suffi- 

 cient rainfall for the growth of fruit without irrigation, one must 

 pass judgment upon all conditions first mentioned. It is hardly 

 worth while, then, to discuss such a topic upon theoretical grounds, 

 or to attempt to answer the general question, Shall irrigation be 

 employed in the growth of fruit? The true guide is enlightened local 

 experience, and the true test is the growth of the tree and the ex- 

 cellence of its fruit. So long as the grower is able to secure every 

 year a generous amount of good-sized and excellent fruit by natural 

 rainfall, he need concern himself very little about irrigation ; if his 

 tree shows distress, and his fruit, even when properly thinned out, 

 is not up to market standards every year, he may do well to provide 

 himself with irrigation facilities, either for constant use or to supple- 

 ment rainfall when it is occasionally deficient. 



Of course it is not commended that the grower wait until the tree 

 shows signs of distress before applying water. This is a very bad 

 plan of proceeding, but the visible language of the tree is mentioned 

 as indicating that the tree needs help, either at regular intervals or 

 occasionally, and after such a warning the grower should be able 

 to tell by examination of the soil and by study of the local rainfall 

 record when this need will occur, and apply water in advance of 

 the need. 



