62 EXPERIMENTS IX BLUEBERRY CULTURE. 



partly decomposed portions of the peat into mats or tnrfs. Their 

 appearance in the upper part of these tnrfs is shown in Plate V, 

 figure '2. Taking some of these turfs, freshly gathered, the soil was 

 ail shaken from them, leaving onh' the '" fiber," consisting entirely of 

 these fine live roots. This fiber was allowed to rot for a few days, 

 and an acidity test was then made. It proved to be 0.07 normal, an 

 acidity far in excess of that which had proved injurious to the blue- 

 berry seedlings. The excessive temporary acidity of freshly gathered 

 kalmia-peat turf and its consequent temporary injuriousness to blue- 

 berrv plants are therefore attributed to the diffusion through the 

 peat of the acids originating in the roots killed in the process of 

 gathering the turfs. 



It rshould be added here that the acidity of the uppermost layer 

 of undecomposed leaves a 3'ear or less old is very great, and that 

 care should consequently be exercised to keep these out of the soil 

 used, A test of dry, brown. ncAvly fallen sugar-maple leaves showed 

 an acidity of 0.22 normal, and a mixture of the leaves of various 

 species of oak in a similar condition, 0.4. Incidentally, attention 

 may be called to the presumable efficiency of a mulch of such leaves 

 in maintaining, by means of its leachings, under the infiuence of the 

 natural rainfall, the acidity of the un.derlying more fully decom- 

 posed lavers, which Avithout the addition of fresh organic matter 

 would ultimately become alkaline. (See the account of an alkaline 

 oak-leaf mold on p. 35.) 

 (2.5) Blueberry plants potted in peat may be made to grow more rapidly if 



THEY are watered OCCASIONALLY DURING THE GROWING SEASON WITH 

 WATER FROM A MANURE PIT. 



In the Avinter of 1907-8 pottings of seedling blueberries from seeds 

 sown in August, 1907, were grown in various greenhouses of the 

 Department. The most successful of these pottings consisted of 89 

 plants in a mixture of peat, sand, and loam in 3-inch pots. Two of 

 these plants are illustrated in figures 24 and 25, It had been sup- 

 posed that the superior growth of these plants was the result of 

 specially favorable conditions of light, temperature, and watering, as 

 indeed it was in part ; but in the following winter, during an inquiry 

 about certain details of the handling of this culture, the gardener 

 in charge of the greenhouse in which the plants were grown admitted 

 that during a portion of the spring, Avithout consultation, he had 

 given the pots an occasional watering with manure water. As 

 manure Avhen used with loam in (he winter of 1906-7 had proved 

 pobitively injurious to blueberry plants, its possible beneficial effect 

 when used in conjunction with peat seemed Avorth testing further. 

 In the spring of 1909. therefore, various cultures Avere watered Avith 

 manure Avater once a AAcek. the amoimt applied being the same as 

 that giA^en in an ordinary watering Avith tap water, about 50 c. c. for 



