184 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



where the subsoil had been shattered with dynamite. As far 

 as could be judged no difference in this respect occurred for 

 good growth was made both seasons and in the fall of the second 

 year, 1914, all of the trees appeared uniformly vigorous and 

 healthy. 



Before taking up the discussion of the injury which occurred 

 during the winter of 1914-15 a brief statement should be made 

 with regard to the character of the. soil in the orchards and 

 the method followed in dynamiting. 



The soil on the farm is a moderately heavy, reddish loam, 

 underlain by a very compact subsoil. In the orchard in ques- 

 tion the surface soil contains rather more sand and is conse- 

 quently somewhat lighter than most of the remainder of the 

 farm which is devoted to similar purposes. Regardless of the 

 presence of the sand the subsoil is quite impervious to mois- 

 ture, and according to the farm superintendent, runs only from 

 7 to 15 inches below the surface. The topography of the or- 

 chard is such that for the most part a gentle slope to the west 

 provides good surface drainage. The only soil pockets where 

 water was likely to stand or where the surface drainage was 

 poor have been underlaid with tile. 



In blowing holes for setting the young apple trees the charge 

 of dynamite was inserted at a depth of from 30 to 36 inches. 

 The material encountered toward the bottom of the holes con- 

 sisted of a resistant hardpan which was very difficult to break 

 and required one stick of extra 20 per cent dynamite. The 

 expert reported as follows regarding a test hole put down to a 

 depth of 36 inches and loaded with one cartridge. "This blew 

 but a small amount of dirt out of the hole. A man was put to 

 work digging out the loose material, and we found there was 

 very satisfactory loosening to a depth of 36 inches with lines 

 of breakage extending in all directions from the point of the 

 shot." In writing of digging into another hole on similar soil 

 on another part of the farm he said : "This shattering seemed 

 to dip slightly upward in all directions." 



In the spring of 19 15 it was evident that a considerable num- 

 ber of the young apple trees had suffered severely from winter 

 injury. Many were killed back to within 12 to 18 inches of the 

 ground while some appeared dead, nearly or quite to the soil 

 line. In the latter part of June, when it was felt that the full 



