2 BULLETIN 454, U. S. DEPARTMENT OF AGRICULTURE. 



EFFECT OF SOIL AND CLIMATE ON THE COMPOSITION OF PEPPERMINT 



OIL. 



Henderson states 1 that peppermint plants grown on a river bank 

 on heavy loam and on deep sandy, loam yielded oils which showed 

 distinct differences in composition. According to Umney, 2 soil and 

 chmatic conditions are responsible for the higher content of esters in 

 some peppermint oils than in others. Charabot and Hebert 3 have 

 shown that the formation of certain constitnents of the oil, and 

 especially the esters, is favored by treating the soil with sodium chlo- 

 rid and sodium nitrate. Mossier 4 has also observed that certain fer- 

 tilizers, such as saltpeter, superphosphate, and potash, tend to favor 

 the growth of the plant and the production of oil therein. 



In order to study the effect of various types of soil and chmatic 

 conditions upon the general composition of peppermint oil, plants 

 were grown at Webster, S. Dak., on rich black loam soil; at Glenn 

 Dale, Md., on light sandy soil; and at Arlington Farm, Va., on heavy 

 clay soil. The yields of oil distilled from these plants and also the 

 physical and chemical properties were determined, and the results are 

 given in Table I. 



Only very slight differences are noted in the yield of oils obtained 

 from the plants grown on the different soils. The physical proper- 

 ties — color, odor, and taste — likewise show only slight variations. 

 The specific gravity of the Arlington oils distilled during two seasons 

 are lower than the South Dakota or Maryland oils. The rotation 

 and refraction of the various oils differ considerably. The Arlington 

 oils are slightly more soluble in 80 per cent alcohol than either of the 

 other oils. 



Comparing the chemical composition of oil distilled from the 

 plants grown at Arlington with that from the South Dakota plants, 

 it will be seen that the latter is richer in both esters and total menthol, 

 while the ester content of the oil from Maryland plants is much 

 greater than in either of the other oils. 



From these results and from results obtained by other observers it 

 may be inferred that light soils of either a sandy or loamy nature are 

 more conducive to the production of esters and menthol in the oil 

 than soils of heavy texture. In the case of the oils first compared it 

 is probable that the chmatic conditions during the growing period 

 acted jointly with the soil conditions to bring about the difference in 

 the oils. This relation, however, did not apply to the oils produced 



1 Henderson, H. J. An experiment in peppermint culture. In Pharm. Jour., v. S7 (n. s., v. 33), no. 2 193, 

 p. 175-176. 1911. 



2 Umney, J. C. The effects of climate and soils on oils of peppermint. In Pharm. Jour., v. 57 (s. 4, v. 

 3), no. 1362, p. 103-104. 1S96. 



3 Charabot, Eugene, and Hubert, Alex. Influence de la nature de milieu extdrieur sur l'dtat d'hydra- 

 tation de la plante. In Compt. Rend. Acad. Sci. [Paris], 1. 136, no. 3, p. 160-163. 1903. 



1 Mossier, Gustave. Uelicr den Einfluss verschiedener Kulturbedingungen auf das atherische Oel von 

 Mentha piperita. In Pharm. Post, Jahrg. 45, no. 1, p. 2-5. 1912. 



