INFLUENCE OF WATER 25 



pact sub-surface and the granulated top. For this reason 

 it is better to have the lower portion of the soil compact 

 and the layer on the surface coarse and granular than to 

 have it all finely pulverized. 



When a farmer desires to plant a field infested with 

 cutworms, grubworms, wireworms, or some other pest 

 which can be eradicated by plowing, he wants to know 

 whether it is best to plow for the express purpose of kill- 

 ing the insects, for the conservation of moisture, or at a 

 time of the year when plowing can be easier done. He 

 must decide which is the most important and plow ac- 

 cordingly. The number of times that one would run 

 into difficulty with moisture when plowing to kill insect 

 pests would be very few because the ideal time to plow 

 to kill insect pests is during their larva state, which for 

 the most part is in the fall of the year. 



If one plans on plowing sod with the expectation of 

 growing a crop it is better to fall plow for the moisture 

 conservation process and also for the killing of insect 

 pests. The small profit that may be made in pasturing 

 such fields is much less than the total accruing from 

 plowing in the fall previous to planting. This has been dem- 

 onstrated sufficiently to be stated as a fundamental fact. 



If one studies carefully the conditions mentioned it is 

 evident that the damage done during dry periods can 

 be minimized by having the soil kept in the proper 

 physical condition by the right kind of tillage to save 

 moisture for use at this time. 



From the foregoing it is obvious that soil moisture 

 very often determines whether a yield will be large or 

 small. The same needs for moisture are present, 

 north, east, south and west, and the same laws for con- 



