5 1 



had been summer-fallowed the year previous so as to keep down weeds 

 and maintain a moisture conserving mulch. In the matter of ploughing 

 and fall and early spring cultivation, both areas were handled in the 

 same manner. 



Crops Grown continuously on same Land versus Crops Grown 

 after Land has been Fallowed. 



Ace rage Result* for all Years Tested. 





Kubanka 

 Spring Wheat. 



AVI 

 Hulless 



rite 



Barley. 



Sixty Day Oats. 



Sab-station. 





c 





- > 









% 1 



■ p = 





i 1 



c g 

























• C 



< 



c 









Dawson County 



15-18 



17-57 



15-97 



20-90 



3,-n 



51-00 



Bosebud County ... 



16-98 



20 -So 



15-02 



28-31 



30-21 



40-03 



Yellowstone County ... 



7-78 



19-32 



14-90 



20-33 



13-75 



17-94 



Chouteau County ... I 



14-18 



17-85 



13-29 



11-95 



28-90 



34- 56 



I 



Average ... ... 



13-52 



18-76 



14-79 



20-37 



26-01 



43-38 



In humid sections serious objection is offered to the practice of 

 summer-fallowing because of the loss of plant food by the leaching which 

 occurs. In areas of light rainfall this objection does not apply, and 

 until some crop rotation system is worked out, which includes the use 

 of inter-tilled crops at the proper time, we believe that the summer- 

 fallow will claim a place on many well managed dry-farms. The results 

 given in the table show a much higher yield of 'the crops after the 

 summer-fallow than for those grown continuously. _ A review of the 

 tables given in the reports of the sub-stations shows that the yield on 

 land continuously cropped is decreasing rapidly as the seasons advance.. 

 This suggests that after cropping has been continued over a longer 

 period the yields will come to be very much less than, half as large as 

 those produced from land summer-fallowed the previous season. In 

 connection with these tests, moisture and nitrate determinations were 

 made throughout the season to find out, if possible, just why yields after 

 a fallow should be so much higher than yields from land' cropped the 

 year previous. From accumulated data, yet unpublished, we find that 

 there is upwards of three times as much moisture present in the first 

 seven feet of a fallowed field as there is in a field on which a crop has- 

 been grown during the season. Again, nitrate determinations reveal 

 the presence of a much higher percentage of nitrogen in the nitrate form 

 in a fallowed soil than in a cropped area. This is because of the greater 

 nitrate-forming activity made possible by the presence of sufficient 

 moisture to make favourable conditions for the nitrate-forming 

 organisms. These two conditions then — higher moisture content and 

 more nitrogen in an available state — readily account for the high yields- 

 after the summer-fallow. 



