380 THE SMALL GRAINS 



that in Utah the store of nitrogen is drawn upon in grain 

 farming from considerable depths. This condition, to- 

 gether with the addition of humus from straw returned 

 to the soil, permitted either continuous cropping or wheat 

 cropping alternating with summer tillage, without de- 

 crease of nitrogen or humus in the surface foot of soil. 

 The second foot of grain-cropped land contained less nitro- 

 gen and humus than the second foot of adjacent virgin 

 soil. 



409. Increasing the humus and thereby the supply of 

 nitrogen, by any practicable means, is the most impor- 

 tant soil improvement to be made in this area. As before 

 stated, the simplest, cheapest, and most effective means 

 is usually the application of barnyard manure but, to 

 date, this method is here not practicable at present, any 

 more than in the Great Plains, because of the lack of live- 

 stock. Long-time experiments with barnyard manures in 

 the Western area have been few or none, but the prob- 

 ability of their beneficial effects is strong, judging from 

 conditions and the results of experiments elsewhere. 



Probably the most important benefit of manuring, next 

 to the supply of nitrogen, is the greater utilization of the 

 rainfall thus made possible. The drier the season, the 

 more marked is the influence of the organic matter in this 

 respect, and the influence appears to extend below the 

 level at which the manure is applied. While the mois- 

 ture content of the first three feet is increased over that 

 in soils not manured, it is slightly decreased in the next 

 three feet, indicating that the manure is effective in bring- 

 ing more water from below to the surface soil. Both 

 stable and green-manures, unless the soil is wet at the time 

 of turning under, will have an opposite tendency at first 

 to dry out the surface soil by breaking the connection of 



