CALIFORNIA AVOCADO ASSOCIATION 



85 



All young trees should have a stick for the first couple of years placed to 

 the south or south-west side to act cis part shade for the trunk. A lean-to shade 

 made out of burlap about 5 feet square and fastened to 5 or 6 foot stakes can be 

 used as means of shade for t!he first few months after planting. 



4. IRRIGATION 

 S. W. JAMIESON AND WM. HERTRICH 



The irrigation of the Avocado, like every other subject in connection there- 

 with, occasions wide diversity of opinion. The planter must study his soil and 

 other conditions, and adopt a system that will meet his requirements and limita- 

 tions. At one time it was considered impossible to over-irrigate, but it has been 

 found that too much water is as bad as too little, and for this reason the drop 

 system has been practically discarded. 



There are three systems of irrigation in general use; furrow, basin, and 

 overhead. In the first, furrows are made between the tree rows, usually with a 

 team and cultivator; water is then turned into the furrows or rills, cutting down 

 the flow when it has reached the end of the furrow and allowing it to run until 

 sufficient water has been applied. The drawback to this system is that it requires 

 the use of a horse or team at exactly the right time, which is not always possible 

 on a place not large enough to warrant owning such equipment. 



To use this system of irrigation it is very important to have the distance 

 of the pipe lines correctly spaced. In light open sandy or gravelly soil the 

 irrigating lines ought not to be more than two hundred feet apart; if the soil 

 is of the light silty type the distance can be increased to about three hundred and 

 fifty feet, while in heavy soil as much as four hundred and fifty feet between 

 irrigating lines has been found to be satisfactory. 



The length of time the water should run in the furrows is governed by the 

 type of soil as well as the lay of the land. In a light open soil, with a one to 

 two per cent grade, less time is necessary to accomplish the required results 

 than would be in a heavy soil under the same grade conditions. However, to 

 keep the water in the furrows from twelve to forty-eight hours, according to the 

 conditions, should give satisfactory results. 



The basin system consists in making a more or less permanent baism around 

 each tree, which is filled with water at stated intervals. This basin is some- 

 times cultivated and sometimes kept filled with a mulch. Opponents of this 

 system claim that it brings all the roots to the surface with ultimate injury to the 

 trees. 



The overhead system involves the piping of the entire orchard with water 

 under pressure, together with sprinklers, either portable or permanently placed. 

 The largest type of these sprinklers consists of an upright pipe of any height up 

 to sixteen feet, with a revolving cross arm at the top, each end of which has a 

 nozzle. It can be arranged that one end throws the water in a wider circle 

 than the other, thus giving an even distribution over a circle of about sixty feet 

 diameter. Where tall uprights are used as portables, they must be guyed to 

 the four corners of a wooden platform. If sufficient sprinklers are used, the 

 entire orchard can be irrigated at once, which would be of benefit in case of frost 

 or excessive heat. The washing the trees receive, has some value in removing dust 



