78 



1917 ANNUAL REPORT 



SYMPOSIUM ON IRRIGATION 

 Discussion Led by Dr. Lester Keller, Yorba Linda 



Dr. Lester Keller: I have 9 acres in avocados, 300 feet wide by 

 1400 to 1500 feet long, being planted in six rows. The source of water 

 is approximately in the center of this tract, at the highest point. Irrigation 

 pipes consist of a 2-inch main reduced to 1 1/4 inch which runs through the 

 center of the tract, the long way. Coming off at right angles to this main, 

 every 25 feet, are %-inch pipes, this %-inch pipe supplying the first two 

 rows of trees. This is then reduced to i/2-inch pipe supplying the second 

 row, and to %-inch pipe supplying the third row. Uprights extend above 

 ground lYl feet from the tree. This distance should be corrected as it is 

 sometimes too close. On top of this pipe I have placed a gas-cock instead 

 of a faucet as it is more convenient. Pressure at the lowest point is about 

 40 pounds, and at the highest point is probably one-half of this amount. I 

 always have plenty of pressure. 



The first year I basined the trees and turned on the faucet with a 

 slow stream, every ten days. The second year the basins were leveled, and 

 the drip system started, watering the trees every two weeks. The drip runs 

 for 48 hours, amounting to about two to three barrels of water per tree. 

 The water goes on so slowly that it does not run off. A J/? -inch pipe ex- 

 tends down from the faucet to one side or the other of the tree for distribut- 

 ing the water as it is required. About 36 hours after the water is turned 

 off, the soil is cultivated lightly with a hoe rake to about 1 Yi inches, mak- 

 ing a dust mulch. With this treatment, the soil kept quite moist all summer. 



Some of my land is too steep to plow. I simply dug holes for the 

 trees, and have had the water running on this from the 1 5th of June al- 

 most continually. I have thus far discovered no sign of root rot or gum 

 disease. These trees have made more growth than any others I have, and 

 since these hillside trees are doing so well, I turned on the water on all the 

 other trees for a run of about two weeks. The "norther" pushed over some 

 of these latter trees which did not have stakes to protect them. This was 

 on account of the soft ground. 



I believe that the avocado needs water often, and lots of it. On a 

 different type of soil, this amount of irrigation might give a water-soaked 

 soil, but not in my case. I have had the water standing on my soil but 

 have not been able to discover any disease or injury of any kind. 



G. W. Beck: I have 10 acres in lemons interplanted with avocados, 

 eveiy fourth tree being an avocado. The oldest trees I have are five years 

 old. I have always irrigated in furrows and find that they have taken the 

 same amount of water as lemon trees. Occasionally the smaller trees get 

 water once in two weeks and they have done pretty well under this treat- 

 ment. Nursery stock, during the hot weather, received water once a 

 month. I have a heavy clay soil, and by watering the trees once a month 

 and with proper cultivation, they are doing well. 



I am afraid Mr. Keller is laying the foundation for trouble in the 

 future by the use of too much water. Mr. Keller has a more porous soil 

 but even that can have too much water. I think Mr. Keller will have 

 trouble later on. I have seen trees planted in similar soil on hillsides which 

 were drowned out by winter rains. With a light top, cind clay subsoil, the 



