34 EXPERIMENTS IN BLUEBERRY CULTURE. 



Maryland peat is composed. The lower portions of it reach a some- 

 what greater degree of decomposition than is here shown. 



In a rich woods of the trillium-producing type, such as a fertile 

 sugar-maple forest, one may observe that the leaves in rotting sel- 

 dom retain their form longer than two years and that the line of de- 

 marcation between the thin leaf litter of the forest and the underlying 

 w^oods mold is sharp and clear. 



In the sugar-maple woods the decomposition of the leaves is rapid. 

 In the Maryland or kalmia peat, as it ma}" be called with more exact- 

 ness, the decomposition is slow. The cause of this difference in the 

 rate of decomposition is the difference of acidity in the two cases, and 

 this in turn is dependent on the nature of the leaves and of the under- 

 lying soil, particularly whether the soil is acid or alkaline. A slight 

 alkalinity in a soil greatly favors the decomposition of the leaves 

 overlying it. An acidity as strong as that shown to occur in newly 

 fallen oak leaves (see p. 62) can not help having a pronounced effect 

 in maintaining the aciditv of the lower leaf lavers; for it must be 

 remembered that these acids are soluble in rain water, and are there- 

 fore continually leaching down from the upper through the lower 

 layers of rotting leaves. 



These upland leaf deposits, in which decomposition is retarded for 

 many years, the writer regards as essentiall}^ peat, and to distinguish 

 them from bog peats he would call them upland peats. An upland 

 peat may be described as a nonpaludose deposit of organic matter, 

 chiefly leaves, in a condition of suspended and imperfect decompo- 

 sition and still showing its original leaf structure, the suspension of 

 decomposition being due to the development and maintenance of an 

 acid condition which is inimical to the growth of the micro-organisms 

 of decay. 



The use of the name '' leaf mold," sometimes applied to this upland 

 peat, should be restricted to the advanced stages in the decomposition 

 of leaves, in which leaf structure has disappeared. True leaf mold, 

 furthermore, is neutral or alkaline, so far as tested. 



When kalmia peat is to be used for growing blueberries it should 

 be piled and rotted for several months. An experience which empha- 

 sizes the need of this treatment is given on page 60. If stacked 

 as soon as it is dug it usually retains sufficient moisture to carry the 

 rotting forward, even if the stack is under cover. 



Kalmia peat has proved to be a highly successful soil for grownng 

 blueberries. It has been tried both pure and in many mixtures, as 

 will be described in the paragraphs beginning on page 51. 



An upland peat formed of the leaves of scrub pine {Pinus virgin- 

 iana)has also been tried for blueberry seedlings. They grow well in it. 



Oak leaves, it is believed, rotted for one or two years would make a 

 good blueberry soil. In the Arlington National Cemetery is a ravine 



193 



