66 



1916 ANNUAL REPORT 



main branches that 

 do not rebranch until 

 they reach a consider- 

 able height, forming 

 a poor shaped tree 

 from which it is dif- 

 ficult to pick the fruit 

 and which lacks stur- 

 diness. This character 

 is apparently entirely 

 due to the fact that 

 the tree was not shap- 

 ed when young. 



Judging from his 

 study of branching, it 

 seems to the writer 

 that the tree should 

 Figure 7.— Large, budded tree of Challenge avocado, \)q Iq throw out 



branching very low, but satisfactory. (Photo by 



H. J. Webber) some branches rather 



low down, probably not 



more than 2 feet from the ground, and that the trunk should be headed 

 at a height of not over 6 feet. 



It would appear also to be important, as in citrus trees, to develop 

 the branches so far as possible from points on the trunk at different 

 heights, no two branches being opposite each other, in order to give 

 greater strength. 



Cultivation and Irrigation. — Little can be said regarding cultivation 

 and irrigation, as we are here again confronted with inexperience. I 

 have introduced this subject primarily to bring out one factor of the 

 problem. The spread of the trees is such that in a mature orchard a 

 large part of the surface will be covered and shaded. The land under 

 such wide spreading trees must in a dry country receive attention. It 

 would seem certain that it must be irrigated if good results are to be 

 obtained. It cannot well be cultivated, as the limbs would interfere, and 

 furthermore experience seems to show that it is far better not to 

 mutilate and disturb the roots. It thus seems to the writer that orchards 

 should be planted with the expectation of irrigating under the trees by 

 the basin method, keeping the soil mulched instead of cultivated. The 

 falling leaves from the tree provide naturally a considerable amount of 

 mulch, which probably may profitably be supplemented by the addition of 

 some other material, such as, alfalfa hay. The practice of mulching 

 in citrus groves is rapidly gaining in favor, as a method of soil treat- 

 ment, and judging from preliminary studies it apparently serves to 

 keep the soil in excellent physical condition. It is a practice especially 

 adapted to the avocado and can probably be recommended for trial as 

 safely as can any other practice with avocados. 



If the method of mulching under the tree, with basin irrigation, is 

 to be used, it may be desirable to know this when the grove is being 

 planted, in order that the arrangement of the basins may be considered 



