8 BULLETIlsr 442, -U. S. DEPARTMENT OF AGEICULTUEE. 



Table III shows the variations in the yield of oil and the citral con- 

 tent of the oil from these various types for the season of 1915. 



Table III. — Yield and citral content of lemon-grass oils distilled from the various j)lants 



under cultivation in 1915. 



Variety. 



Yield of oil. 



Citral con- 

 tent of tlie 

 oil. 



Variety. 



Yield of oil. 



Citral con- 

 tent of the 

 oil. 



No 1 



Per cent. 

 0.24 

 .27 

 .16 

 .23 

 .15 



Per cent. 

 80 

 70 

 73 

 72 

 79 



No. 9. 



Per cent. 

 0.20 

 .23 

 .28 

 .29 

 .12 



Per cent. 

 76 



No.5 



No. 10 



80 



No. 6.- 

 No 7 





No. 11 



No. 12. 



80 

 81 



No. 8 



No. 13 



85 









It has been found year by year that there is considerable variation 

 in both the yield of oil and the citral content, yet the figures given 

 in Table III may be taken as representative of the varieties men- 

 tioned. It will be noted that the Ceylon forms, Nos. 6 and 13, are 

 very low in oU yield, and the same is true of No. 8, from India. 



Both the yield of oil and the citral content of the oil have been 

 found to be affected to a considerable degree by the type of soil on 

 which the plants are grown. Therefore, before selecting a variety 

 for commercial planting, tests should be made to determine which 

 variety will give the highest yield of oil per acre and the highest 

 citral content on the land to be used. The vigor of the plants should 

 also be considered, since there seems to be a difference in soil require- 

 ments among the varieties tested. 



FACTORS AFFECTING THE YIELD OF LEMON-GRASS OIL. 



Soil conditions. — In order to determine the effect of soil conditions 

 on the yield of lemon-grass oU, tests were made in 1908 with the West 

 Indian variety. No. 1, on soils containing various degrees of moisture. 

 On light sandy soil of the high hammock type the yield of oil was 

 0.31 per cent, and on moist bottom land 0.27 per cent. Another test 

 on sandy high pine land in a different location gave an oil yield of 

 0.35 per cent, and on moist land near the lake 0.28 per cent. Further 

 tests with this variety under other conditions of soil moisture gave 

 results which were also much in favor of the sandier and better 

 drained land. In 1915 the plat devoted to the Ceylon variety. No. 6, 

 showed a higher yield of oil from the plants grown on the high, 

 weU-drained, sandy sod than from the part of the plat which con- 

 tained slightly more moisture, 0.16 per cent being obtained from the 

 former and only 0.11 per cent from the latter. Similar results were 

 secTU'ed in 1914 with varieties Nos. 5, 8, and 9. 



The evidence thus far available indicates that for all the forms of 

 lemon grass tested, a heavy growth of herb with high oil content is 

 to be expected on light, well-drained soil of the high pine type. 



