TAMING THE WILD BLUEBERRY 



143 



Six seedling blueberry plants in 4-inch 

 pots containing a good acid blueberry 

 soil were set apart from their fellows 

 and watered exclusively with ordinary 

 lime-water. The applications were of 

 such an amount that the soil in the pot 

 was thoroughly wetted each time, and 

 usually a small excess quantity ran 

 through the hole in the bottom of the 

 pot. 



For more than seven months these 

 pots received no other water than lime- 

 water. During this period the plants 

 continued to grow in a normal manner, 

 their average height increasing from \~y 2 

 to 14 inches. The lime appeared to have 

 no deterrent effect whatever on the 

 growth of the plants. An analysis of 

 the soil in one of the pots showed that 

 it contained over 8 per cent of lime, or 

 the equivalent of an application of 25 

 tons per acre, an enormously excessive 

 amount from the standpoint of agricul- 

 tural usage. 



The blueberry plants ought to have 

 been dead long before. As a matter of 

 fact they were making excellent growth. 

 A careful examination of the contents 

 of one of the pots was then made. The 

 surface of the soil was found to be 

 covered with a hard gray crust of lime. 

 Immediately underneath for a depth of 

 about half an inch the soil was black and 

 contained no live blueberry roots. Be- 

 neath this the peaty soil was dark brown 

 and filled with growing, healthy roots. 

 The lime appeared to have penetrated 

 only into the superficial portions of the 

 soil. A chemical test confirmed this, 

 showing that the black, rootless upper 

 layer was densely impregnated with lime, 

 while the brown, peaty portion contain- 

 ing the growing roots still gave the acid 

 reaction that was characteristic of the 

 whole potful of soil before the lime- 

 water applications began. 



Since all the water that the limeless, 

 root-bearing portion of the soil had 

 received during the preceding seven 

 months had come from the lime-water 

 applications, it was evident that the lime 

 contained in the lime-water had been 

 deposited in the upper half inch of the 



soil. The following laboratory experi- 

 ment confirmed this : A 2-inch glass pot 

 was filled to the depth of three-fourths 

 of an inch with the acid upland peat used 

 in growing blueberries. The peat was 

 slightly moist and of rather fine texture, 

 having been rubbed through an eighth- 

 inch sieve. Then ordinary lime-water 

 reddened by the addition of phenol- 

 phthalein — a substance giving a delicate 

 color test for alkalies such as lime — was 

 poured upon the soil. The excess water 

 that filtered through the soil and came 

 out of the hole in the bottom of the pot 

 was wholly devoid of red color and, 

 when submitted to a further chemical 

 test, showed not a trace of lime. The 

 precipitation of the lime by the soil had 

 been not only complete but practically 

 instantaneous. Only 15 seconds had 

 elapsed between the time when the lime- 

 water was added to the soil and the time 

 when the liquid, entirely free from lime, 

 began to drop from the pot. 



This experiment has a very important 

 bearing on the method of applying lime 

 to acid soils in ordinary agricultural 

 practice. A surface application of lime 

 would have no appreciable effect in neu- 

 tralizing the acidity of a soil unless the 

 soil were so sandy, or gravelly, or other- 

 wise open that the rain-water contain- 

 ing the dissolved lime could run down 

 through it practically without obstruc- 

 tion. A surface dressing of lime would 

 have little effect in neutralizing the acid- 

 ity of an old meadow or pasture. To 

 secure full action of the lime, as now 

 generally recognized in the best agricul- 

 tural practice, requires its intimate mix- 

 ing with the soil, such as is accomplished 

 by thorough harrowing, especially after 

 putting the lime beneath the surface with 

 a drill. 



where) to look FOR BLUEBERRIES 



The favorite type of acid soil for the 

 swamp blueberry is peat. The peat 

 chiefly used in the experiments was not, 

 however, a bog peat, but an upland peat 

 formed of a half decomposed mass of 

 mixed leaves of oak and laurel (Kalmia 

 latifolia). This accumulates for years 



