Subsoiling to Conserve Moisture 137 



amount of water in the two cases is practically the 

 same. 



In a fourth experiment to show the effect of sub- 

 soiling in the spring on the water content of the soil 

 in the fall, one of the small areas already described was 

 allowed to stand exposed from June until September, 

 75 days, without in any way disturbing the surface, 

 except to keep it free from weeds by shaving them off 

 with a sharp hoe. The results were these : 



Here, again, the results have the same general char- 

 acter as they did when the subsoil period was from 

 October to April, the surface foot of subsoiled ground 

 being the dryest, while the next 3 feet are more moist. 

 When the effect of subsoiling in this case is expressed 

 in inches of rain, the gain in the saving of soil moisture 

 amounts to 1.64 inches, which is a very important 

 amount. 



The effects of subsoiling probably do not last much 

 longer than a single season, unless there has been but 

 little rain, so that the ground has never been thoroughly 

 saturated, permitting it to again settle together. In 

 the case of the field trial here reported, samples of soil 

 were taken on the same ground April 8, April 16, and 



