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ANNUAL REPORT 1918 AND 1919 



irrigation method and those obtained by a more modern system. I walked 

 into this young grove, knee deep in alfalfa, and began to examine the 

 fruits. Immediately I was struck by their superior size and the uniformly 

 heavy crop over the entire grove. I hunted up the caretaker and talked to 

 him. He told me that they irrigated every three weeks; a good stream 

 ran by the edge of the grove, and water was always available. 



The impression which this grove made upon me has not yet com- 

 menced to fade from my memory. The system of cultivation was cer- 

 tainly the best I have seen in Mexico, judging by the results. Unfortunately, 

 I have seen no groves here which are cleaoi cultivated, or irrigated and 

 tilled, as in California. I cannot, therefore, compare the effect of this 

 system of combining avocados and alfalfa with clean cultivation, but when 

 compared to the method usually followed in Mexico the results strike one 

 as nothing less than marvelous. The alfalfa was planted close up around 

 the trees ; combined with the foliage of the latter the ground was effectively 

 shaded. The trees were all branched low, and were fruiting right down 

 to the ground. 



As to the question of mulching versus tillage, I have as yet had no 

 opportunity to make any comparisons, as tillage is rarely practiced in 

 Mexican avocado orchards and the only mulching done is that accomplished 

 by Nature. I do not believe the litter which results from fallen leaves 

 and the accumulation of weeds is sufficient to mulch the trees effectively, 

 but this is all they ever get. 



Many of the old groves are so crowded that it is not possible for the 

 trees to perform creditably. This crowding forces the crown to form high 

 above the ground, unquestionably a bad feature. Rarely are any branches 

 given off lower than eight to ten feet from the ground. In groves where 

 there is not so much crowding the crown is formed lower and is of better 

 shape. 



No pruning seems to be done, nor are the trees encouraged to develop 

 in any particular form. It seems to be left to Nature to take care of such 

 matters, and where she has the slightest opportunity she usually succeeds 

 in getting pretty good results. The great obstacle which prevents most of 

 the trees from developing broad, well branched tops is the crowding to 

 which they are subjected. 



The interesting custom of tree renewal, practiced with various fruit 

 trees in the American tropics, Ccin often be observed in the avocado groves 

 of Mexico. I have noticed it particularly at Orizaba and Queretaro. 

 When the trees become old and decadent, sprouts develop around the base 

 of the trunk. Several of these are allowed to grow, so that when the old 

 trunk has finally to be cut away one or more vigorous young sprouts are 

 ready to take its place. Sometimes these sprouts grow to considerable size 

 before the original trunk is destroyed. Often as many as three or four of 

 them are allowed to develop. It would seem better if only one were per- 

 mitted to each tree, to replace the original. I have not yet been able to 

 learn that anything is done to produce these sprouts; they seem to appear 

 naturally and are simply allowed to remain. 



Avocado culture is too young in California for this method of tree 

 renewal to be of much value to us, but the day will come when it can be 

 tried out with profit. Apparently the new tree which develops has a 

 considerable life, and is as productive as the original. 



