128 



DRY FARMING CONGRESS. 



The conclusions are, in part at least, based on theory rather than on 

 actual observation or experiments. They are of sufficient importance to 

 warrant serious consideration until effectually disproved. 



To summarize these conclusions briefl}^. it might be said that the 

 present indications are that summer fallowing with alternate year crop- 

 ping, applied to grain production in the Great Basin, makes it possible 

 to grow profitable crops with a rainfall so light that cropping every 

 year would be impossible; also, that the practice of summer fallowing 

 as applied in this region, particularly when it includes the plowing iinder 

 after each crop of a large amount of organic matter, results in keeping 

 up, if not in actually increasing, the prodticing capacity of the soil. 

 There are one or two minor features in connection with this practice 

 that need further emphasis. It has been found, for instance, on some 

 soils, particularly those rich in lime, that continuous shallow cultivation 

 in summer fallow results in the formation of a thin hardpan at a depth 

 of about two or three inches in the furrow slice, just below the dust 

 mulch. This condition can be avoided, or at least its injurious effect 

 reduced, if the depth of cultivation in maintaining the dust mulch is 

 varied with each operation; that is, in using the disc harrow, for instance, 

 if it can be run deep one time and shallow the next the formation of 

 this hardpan can be nearly, if not quite, avoided. This hardpan is in- 

 jurious, not only because it prevents the read}' penetration of the first 

 autumn rain following the season of summer fallow, but it also excludes 

 the air from the lower part of the furrow slice, where it is needed to 

 carry on the humification of the organic matter previously plowed under. 

 It is needed also by the bacteria that live in the organic matter and 

 elaborate the nitrogenous compotmds. Furthermore, it is desirable that 

 when the organic matter is plowed under, it should be plowed under 

 deeply. This is on account of the well known fact that there is little or 

 no humification of organic matter in very dr}^ soil, such as that in the 

 dust mulch. An ideal condition for humification and for moisture con- 

 servation is produced when the summer fallow is made by plowing under 

 the wheat straw to a depth of seven or eight inches, and then following 

 this with a surface tillage that establishes a dust blanket to the depth 

 of three inches. There remains, then, below the dust blanket a layer of 

 four or five inches of soil, rich in organic matter, well aerated, and with 

 sufficient moisture to promote the rapid Intmification of the organic 

 matter and the growth of soil bacteria to elaborate nitrogenous plant 

 food. With these conditions provided, it is reasonable to believe that 

 dry farming on the semi-arid and non-irrigable lands of Utah may "be- 

 come as firmly established a feature of western agriculture as the irriga- 

 tion farming which has made this region so popular and so famous. 

 It should not be taken for granted, however, that the problems of dry 

 farming are as yet all solved, or even' all appreciated. In the campaign 

 for the subjugation and untilization of these semi-arid lands the same 

 optimism, the same perseverance, and the same ingenuit}^ that have char- 

 acterized this work up to the present stage must be continued many 3-ears 



