104 



THIRD ANNUAL SESSIONS 



English investigations had concluded thrs class of experiments, it became 

 evident that the practice is wasteful for a section with an average pre- 

 cipitation as high as thirty inches. 



Summer Fallow. 



"Summer fallowing has been identified with dry land culture almost 

 from the beginning. That this should be the case is natural for in many 

 dry farming sections the crops are light when grown every year, and 

 the light rainfall eliminates one of the objectionable features by lessen- 

 ing the amount of leaching in uncropped soils. The number of carefully 

 conducted experiments designed to throw light on the real effects of 

 summer fallowing on the dry farm has not been large and much remains 

 to be undertaken by investigators identified with dry farm experi- 

 mentati-on. 



Moisture Tests. 



"During the seasons of 1907 and 1908 the Montana Experiment Sta- 

 tion has been conducting some moisture and nitrate investigations on 

 one of the dry farming sub-stations, and it is the purpose at this time to 

 use some of the data accumulated on these tests. These data are yet 

 unpublished as it is the purpose to continue the work over another sea 

 son in order that safe conclusions may be indicated. 



Plant Foods. 



"When the work was begun it was the plan to conduct moisture tests 

 only. Before the first season had progressed very far it became evident 

 that the plant food merited some study and n'trate investigations were 

 arranged. 



Moisture Tests. 



"Turning to the relation of summer fallowing and moisture con- 

 servation, moisture determinations were made to a depth of five feet in 

 all cases with one exception when the depth of nine feet was investigated. 



Moisture Tests. 



"Determinations made every ten days during the summer of 1908 on 

 land that had been continuously cropped for three years in spring wheat 

 showed that this soil contained on an average of 7.7 per cent, moisture 

 with a range of from 5 to 12 per cent, during the season. Allowing that 

 this soil, an average loam, will retain 7 per cent, of moisture that the 

 growing plant cannot use, we are not surprised when we find a yield of 

 four bushels of wheat per acre produced on this plot. 



Result of Summer Fallow. 



"Investigations in 1908 on similar land producing the same kind of 

 crop but which had been summer fallowed the previous season showed a 

 moisture content ranging from 16.5 down to 6 per cent, with a seasonal 

 average of 11.5 per cent, for the first five feet. While this increase is 

 only 4 per cent., yet when we remember that the first 7 per cent, of the 

 moisture is of no use in growth we see that the amount of available 



