41 8 Biochemical Stiidies of Heated Soils [Mar. 



attractiveness of the bliieberry has often led to attempts to trans- 

 plant and grow it under artificial conditions but failure usually fol- 

 lowed. This was explained by assuming that the blueberry loved 

 a peaty soil, a condition which could not be successfully imitated in 

 gardens. Hovvever, Coville^^ has recently succeeded in growing the 

 blueberry from seed and bringing it to füll size and maturity. This 

 was not done until a careful field study had shown that in nature 

 this plant flourishes upon peaty soils which are acid in character. 

 With this fact in mind Coville used well-drained acid soils, and by 

 so doing he had unusual success in raising the blueberry. In the 

 roots of the blueberry plant he discovered a mycorrhizal fungus 

 that seemed to help supply the plant with nitrogenous food. In 

 acid soils the ordinary nitrogen bacteria cannot develop, and this 

 type of fungus may take their place in plants like the blueberry and 

 the cranberry which thrive on acid peaty soils. In a later note 

 Coville ^^ reported that the Mayflower, or Trailing Arbutus, could 

 be raised from seed when sown upon such acid soils, and could then 

 be brought to a perfection of bloom seldom equalled in the wild 

 State. We feel that there is some connection between these two 

 observations that certain plants flourish upon acid soils and that 

 many of the same kinds flourish on burned-over soils. In our 

 earlier work we found that heating a soil produces in it easily sol- 

 uble substances of acid reaction. It seems likely that burning over 

 the underbrush on a soil renders it acid in reaction, and probably 

 produces an artificially acid condition nearly as agreeable to certain 

 plants as are the naturally acid peat soils. To test this point we 

 now have experiments under way with seeds and cuttings of the 

 blueberry, and also with the seeds of the Mayflower planted in soils 

 rendered acid by heating. 



ANALYTIC CHEMICAL STUDIES 



In our previous paper the data for composition of the extracts 

 of soils exposed to dry heat show that the amounts of soluble matter 

 in the extracts are from six to ten times greater than in similar 



"Coville: Experiments in blueberry culture. Bull. 193, Bur. of Flant In- 

 dustry, United States Dep't of Agriculture, Washington. 191 1. 



"Coville: The use of acid soil for raising seedlings of the Mayflower, 

 Epigcea reperts. Science, 33: 711-2. 1911. 



