Agricultural Development 

 May — before the dry season acquires its cutting- 

 edge. For these reasons a crop of ripe barley can 

 be made with an annual rainfall of ten inches, well 

 distributed from December to March. The practice 

 of bare-fallowing and alternate year cropping, with 

 its saving of moisture by tillage, has also prevailed 

 in California for half a century. 



But great as are the advantages of tillage in the 

 effort to grow a crop with a scant precipitation, 

 it is an interesting fact, which is not sulficiently 

 well known, that the supreme efficacy of tillage in 

 moisture conservation was demonstrated in the west 

 upon irrigated areas and not upon dry lands, and 

 that tillage as a substitute for irrigation was an 

 incidental, though immensely valuable, suggestion 

 from experience in irrigation. The popular under- 

 standing of the matter is probably otherwise. It 

 can be safely claimed that farmers operating by 

 irrigation are more diligent and thorough culti- 

 vators than those operating by rainfall. In an 

 investigation made by the writer for the Irrigation 

 Investigations of the United States Department of 

 Agriculture, and published in Bulletin 108 of the 

 Office of Experiment Stations, the experience of 

 about 225 individual fruit growers is given in detail 

 and the following conclusion is drawn: "Very 

 diligent cultivation is practiced both by those who 

 rely upon local rainfall and by those who irrigate. 

 Irrigators cultivate more frequently. Frequency of 

 irrigation is in itself not desiraole if it can be 

 avoided; frequency of cultivation with irrigation 

 simply indicates that so often as the soil is thrown 

 out of good condition for moisture retention, so 

 often must such good condition be restored." 



The efficacy of tillage in moisture retention, 

 which is the secret of arid land production, either 

 from rainfall or irrigation, has been accurately 

 determined. Dr. Samuel Fortier, who has charge 

 of the Irrigation Investigations of the United States 

 Department of Agriculture, has recently shown by 

 actual test on the University Farm, Davis, Califor- 

 nia, that land allowed to become compacted by 

 drying after irrigation lost by evaporation more 

 than one-third of the w^ater applied within a month 

 after the application, while land which received 

 good tillage to the depth of nine inches lost less 

 than 1 per cent by evaporation. Nine inches depth 

 of finely pulverized surface layer is greater than 

 desirable in orchard or vine5^ard practice, but it 

 is desirable to know what it will accomplish. Sim- 

 ilar experiments conducted by Dr. Fortier at 

 Wenatchee, Washington, in June, 1908, showed the 



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