CALIFORNIA AVOCADO ASSOCIATION 



87 



5. CULTIVATION 

 WM. HERTRICH 



It is a well known fact that the Avocado tree is inclined to make a great 

 number of surface or near surface roots, if permitted to do so. which is against 

 proper methods of establishing an orchard of any kind in a country where summer 

 irrigation has to be applied as the only source of moisture available. Intelligent 

 tilling of the soil will avert the condition mentioned above and will encourage the 

 roots to seek deeper levels, which is manifold in its benefits. 



First, a four to six inch mulch can be maintained which aids to hold the 

 moisture and permits air to work into the soil, both of which are very essential. 

 Second, the root system, which is forced to seek lower levels, is better for anchor- 

 ing a tree and holding it in an upright position. Third, in case the main supply 

 of water, for some reason or other, breaks down in mid-sum.mer, just at the time 

 when your turn for irrigation comes; if your soil is in good physical condition, 

 with a six inch mulch on top, your trees will withstand the water shortage much 

 better than a non-cultivated orchard with most of its fibrous feeding roots near the 

 surface. 



Two methods of tilling the soil are practiced, one of which is plowing and 

 cultivating, and the other is just cultivating mostly by means of discing. Either 

 of these methods is satisfactory, if intelligently done, but the first is preferable 

 to the second. Plowing ought to be done about once a year with either a disc 

 or mold-board plow not less than eight inches deep and should be followed imme- 

 diately with a disc or tooth harrow as required by prevailing conditions. If 

 cover crop has been plowed in, discing will have to follow plowing, but in case of 

 no cover crop either one of the tools mentioned will do satisfactory work. 



The proper time to plow an Avocado orchard is a hard question to decide as 

 not enough experiments have been made along this line to form definite conclu- 

 sions. If no cover crop has been planted and deep cultivation has been prac- 

 tised it won't matter materially whether the plowing is done in the winter or early 

 spring months as only a small percentage of the roots will be cut; on the other 

 hand, it takes six months to mature a cover crop, during which time no cultivation 

 has been done and perhaps a little more water has been applied with the result 

 that a large number of feeding roots have crept near the surface. All of 

 these accumulated feeders, as well as a few more below will be cut during plow- 

 ing, consequently it is not advisable to perform this work during blooming time 

 as a certain amount of check will follow and very likely would affect the setting 

 of the fruit. This method, however, is only practical when the orchard is 

 planted with one or a few varieties which bloom at the same time, but as the 

 blooming season of the various Avocados ranges from early fall to late spring it 

 is very difficult to specify the proper tim.e to do the work, especially so when 

 several varieties are interset, which method of planting is frequently practised. 



In heavy or near heavy soil plowing or discing practised for some time often 

 causes a hard crust below the depth or reach of the tool used. This formation 

 called plow sole finally gets hard enough to resist water penetration; to avoid 

 this condition, plowing two different de^Dths at different times is advisable, 

 also, use of subsoil plow once or twice through the center of the rows both length- 

 wise and crosswise from twelve to sixteen inches deep according to the require- 

 ments, but not when the trees are in full bloom. If subsoiling is practised dur- 

 ing the summer months it should be followed immediately by irrigation. Culti- 

 vating and irrigating should be used in conjunction and must be practised 



