BettewFruit 



The Pioneer HorHculiural Jourtih of the Pacific Northwest 



Entered as second-class matter April 22, 1918, at the Postoffice at Portland, Oregon, under act 



of Congress of March 3, 1879 



\o\.. XVI 



Portland, Oregon, June, 1922 



Number 12 



Suggestions on Orchard Irrigation 



METHODS by which irrigation 

 water should be applied to 

 orchard lands vary considerably 

 under the influence of the systems of crop- 

 ping, slope and physical characteristics of 

 the land. Shallow furrows, deep furrows 

 and borders are well suited for moderately 

 sloping land while deep contour furrows, 

 flooding through thick stands of alfalfa or 

 clover and in extreme cases, sprinklers 

 should be used on steep land. 



Since the shallow furrow method of ap- 

 plying water is in common use it requires 

 no explanation. It is at present used prac- 

 ■ tically on all types of soil and slopes ol 

 land. The practice, however, can be 

 abandoned to advantage in some instances 

 for better methods. 



Shallow furrows are necessary for the 

 most efficient distribution of water in 

 row crops, for irrigating coarse, sandy soils 

 under clean cultivation, and for moisten- 

 ing the surface of land sown to clover and 

 similar crops. In coarse soil the spread and 

 rise of moisture is not extensive. This 

 renders it necessary to apply the water near 

 the surface by means of shallow furrows 

 placed close together to insure even and 

 thorough distribution of the moisture in 

 the soil. 



Under such conditions the water should 

 be run for a much shorter time than on 

 finer soils. If this is not done heavy losses 

 result from deep percolation near the 

 flumes. It is important to have the fur- 

 rows short. For sandy land^ 200 feet is 

 a desirable length and 4U0 feet is the ex- 

 treme limit. On heavy soils, in which loss 

 of water by deep percolation does not take 

 place readih', the furrows should be much 

 longer. 



Use of Deep Furrows — Deep furrows, 

 for a number of reasons, are preferable to 

 shallow furrows for orchard use. They 

 should be extensively employed for land 

 under clean cultivation and for steep slopes. 

 By using deep furrows in clean cultivated 

 orchards, the irrigation water can be used 

 without wetting a great amount of the 

 surface of the soil. Cultivation can be 

 practiced immediately following irrigation, 

 thus filling the furrows and covering the 

 wet soil, a practice which is necessary to 



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I Methods of afflying irrigation \ 



I water to orchards have imfortant | 



I hearing on results the grower in an | 



I irrigated section may obtain. All too | 



I frequently the orchardist lacks de- | 



I fendable infornuition on the subject. | 



I In such cases he usu-atly accepts the | 



I practices of his neighbors without | 



I particular thought to basic fwida- \ 



I mentals. While superintendent of \ 



I the Hood Ri-:-er Experiment Station, | 



I R. W. Allen made an excellent | 



1 report on orchard irrigation practices. | 



i The article folUjwing is taken from \ 



I this report. The suggestions and af- \ 



I plications, though based on practices | 



I in Hood River Valley, apply in large | 



I measure to other irrigated fruit sec- \ 



I tions. I 



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prevent baking. This can not be done 

 where shallow furrows are used and the 

 surface of the land becomes wet. 



Deep furrows do not need to be as nu- 

 merous as shallow ones, and the water can 

 be permitted to run longer in them with 

 desirable results on all but coarse soils. The 

 length of time the water is permitted to 

 run, however, should be very closely 

 watched for it differs materially with the 

 character and condition of the soil. Three 

 to five deep furrows for each space will 

 give satisfactory results in irrigating most 

 orchards. The number can be varied from 

 a maximum of five to a minimum of two 

 or three when the organic content of the 

 soil is increased and its physical condition 

 improved, for under such conditions the 

 water will be found to enter and spread 

 rapidly through the soil. Furrows of this 

 character can be made with an ordinary 

 turning plow, with a single shovel plow, 

 or with multiple shovel furrowing im- 

 pl-emcnts. 



APPLICATION of water by means of 

 deep furrows is claimed by some 

 authorities to cause deep rooting. Whether 

 or not this result actually occurs it is evi- 

 dent that by using deep furrows on the 



finer soils, they become well moistened and 

 will meet the demands of deep or shallow 

 rooted trees or other plants and establish 

 conditions favorable for the growth of 

 roots at considerable depth. 



Serious objection to the use of deep fur- 

 rows is frequently voiced on account of 

 numerous roots being destroyed in mak- 

 ing them. It is, or soon will be recognized 

 that plowing is necessary in most all 

 orchards where the practice of shallow cul- 

 tivation has been followed. It is evident, 

 therefore, that deeper cultivation will be 

 introduced, under which conditions there 

 can be no objections to the use of deep 

 furrows for irrigating. 



Numerous observations of plowmg m 

 orchards not previously given to deep cul- 

 tivation have shown that many small and 

 medium sized roots were destroyed. Where 

 such orchards have been properly irrigated 

 and otherwise cared for, however, no detri- 

 mental influences appear to have resulted. 

 It is not advised that deep plowing should 

 be practiced the first year the plow is 

 introduced in the orchards, but by gradually 

 deepening the operation, a final state ot 

 cultivation that will permit of deep and 

 effective irrigation can be accomplished 

 without injury to the trees. When laid out 

 on steep land in such manner as to modify 

 the fall, furrows six to nine inches in 

 depth will carry the water and render con- 

 tour irrigation possible while it is not feas- 

 ible with shallow furrows. 



Time to Irrigate — To determine the 

 time at which water should be applied a 

 close study is necessary in order to know 

 the approximate amount of moisture the 

 soil cont.iins. A superficial examination of 

 the soil or an endeavor to judge from the 

 appearance of the trees as to when they 

 require water, does not convey a correct 

 understanding of the conditions under 

 which the trees are working. The first 

 practice might result in the irrigation being 

 applied prematurely, thus resulting in the 

 waste of water and time. The second prac- 

 tice invariably results in a measure of 

 drouth existing before the trees show signs 

 of distress. 



Ordinarily, irrigation should be applied 

 before the soil begins to fall apart after be- 



