20 THE FUTURE OF ARID LANDS 
and the capillary fringe, and no water could be secured from the 
water table by capillarity. 
It was also thought that a dust mulch maintained by repeated 
cultivation would prevent water loss and therefore provide a 
solution of the water problem. Again it was easily proved that a 
dust mulch provided no more protection to the moisture below 
than the same amount of hard soil (3), that the only advantage of 
the repeated cultivation was in keeping down the weeds which 
would otherwise pull the water out of the soil. This same effect 
was accomplished in Australia by overpasturing the land with 
sheep. But the dust mulch had two very serious, harmful results. 
In a heavy rain, and many of the rains are of this character, the 
soil sealed over, prevented water penetration, and caused a heavy 
runoff. The dust mulch was also subject to wind erosion and was 
a predisposing cause of dust storms. A cloddy surface was much 
more desirable for preventing blowing and for increasing water 
penetration. 
Another bad practice was introduced by the advocates of loosen- 
ing up the subsoil by blasting, deep plowing, and by the subse- 
quent use of a sub-soil packer. Closely allied to these harmful 
practices was the deep planting of fruit trees. The roots of such 
trees came promptly to the surface where and where only could 
they find moist soil. The use of manure and nitrate fertilizer had 
to be abandoned for they caused the loss of the crop by drought. 
In the short grass the nitrates released in fungus fairy rings killed 
out the short grasses. 
The conservation of moisture transcends all other arid land 
problems. All precipitation should be absorbed by the soil and 
held there until needed by the crop. Weeds should never be 
allowed to compete with the crop, even before the land is seeded. 
The moisture should be used as soon as practicable by short season 
drought evading crops which are thinly seeded or widely spaced 
to allow a large amount of moist soil to each plant. 
In eastern Colorado maize was the crop used by the earlier dry 
farmers. Now wheat has crowded out most of the other crops and 
as a result of the sustained price about 70% of the land is devoted 
to this crop. 
