inch hole and well tamped in, the hardpan will be broken to a depth 

 of six or seven feet from the surface and sideways six or seven feet 

 in all directions. Under these conditions holes at fifteen feet centers 

 will probably be close enough because of the considerable volume of 

 loose compact soil above the hardpan. 



As hardpan frequently runs under the surface soil irregularly, the 

 depth of the holes will have to be varied to suit the conditions in 

 different parts of the field that is being subsoiled. The man putting 

 down the holes can easily decide the necessary depth by the amount 

 of resistance that the soil offers to the auger or bar. 



The main thing to guard against is the location of a charge beneath 

 a thin section of hardpan, as such a charge may break up the soil under- 

 neath the hardpan but may not break the hardpan. When the hardpan is 

 thin it is better to place the charge a little too high than a little too low. 



In parts of California and in a few other sections of the country, 

 the hardpan is so thick and hard as to have the characteristics of 

 stone. In such soil the charge should never be less than a whole 

 cartridge at fifteen-foot spacing, and owing to the high cost of putting 

 down the holes, it is often more economical to use twenty-foot spac- 

 ing with two or three cartridges per hole. The high value of Cali- 

 fornia land when under cultivation warrants the high cost of such 

 subsoiling. 



In rocky hardpan running near the surface a whole cartridge every 

 ten feet will probably produce better results than four cartridges every 

 twenty feet. While the holes for ten-foot spacing need not be quite 

 so deep as for twenty-foot spacing there will be four times as many 

 holes. 



Opinion of a Distinguished Citizen 



A pioneer in subsoiling with dynamite was General Samuel J. 

 Crawford, ex-Governor of Kansas. Below is a letter from him that 

 tells of his experience : 



"I am glad the good work of blasting the compact subsoil and hardpan is 

 moving along in the east as well as in the west, whether it be for the planting of 

 trees, grain or anything else that grows from the ground. If the subsoil is 

 loosened so that the rainfall can penetrate the earth, the roots of grain, grasses, 

 trees, etc., will follow the water to their natural depth and draw their nourish- 

 ment from five or six feet of soil instead of five or six inches of surface soil, as 

 heretofore. Besides, the blasting creates sub-reservoirs in which to store the 

 surplus rainfall which will supply the roots of the growing products with mois- 

 ture when the dry season is on. Again, if the ground is loosened so the water 

 can pass down into sub-reservoirs, there will be no standing water on the surface 

 to damage the crops or keep the farmers back with their work. Such treatment, 

 properly applied, will revolutionize the agricultural and horticultural industries 

 throughout the country. 



"The government is spending millions of money for irrigation purposes in 

 isolated places, which, from the nature of things can only benefit a few people, 

 while the blasting process will benefit all the farmers and fruit growers at com- 

 paratively a nominal expense. By this process most of the worn-out farms in 

 New England and throughout the country can be reclaimed and made to produce 

 good crops. All that is necessary is for the producers to grasp the idea and learn 

 how to handle explosives." 



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