Page:Report of the Puerto Rico Experiment Station (IA CAT31294391015).pdf/25



A. J. Loustalot and R. Fernández Pol

The West Indian and Java varieties of lemongrass were harvested 10, 17, and 19 times, respectively, when cut at 2 feet, 2½ feet, and maximum height (about 3½ feet) over a 3-year period. The Java variety consistently outyielded the West Indian variety in terms of fresh grass produced, but the yield of oil per acre was greater in the West Indian variety cut at maximum and low heights because the percentage of oil was higher. The Java variety cut at medium height yielded more oil than the West Indian variety cut at the same time, because the percentage of oil was about the same and the Java variety yielded more grass. The yield of oil per acre of West Indian lemongrass was not appreciably increased by frequent cuttings. The average annual yield of oil from plots cut 10, 17, and 19 times over a 3-year period was 131.0, 132.3, and 110.5 pounds, respectively. Therefore, the maximum height appears to be the most economical height at which this variety should be harvested.

The Java variety of lemongrass yielded the most oil per acre when harvested at a height of 2½ feet. The average annual yield of oil per acre in this treatment (217.4 pounds) was at least 100 pounds more than when the grass was cut at maximum or low height. The cost of production per unit of oil would determine whether it is more economical to harvest this variety 17 times at 2½ feet or 10 times at maximum height over a 3-year period.

The percentage of oil was consistently higher in the West Indian variety but there was no marked or consistent differences in citral content between the two varieties or among the three harvest treatments.

The Guatemala and Java varieties of citronella grass were harvested 8, 11, and 15 times, respectively, when cut at 32, 42, and maximum height (about 6 feet) over a 4-year period. The Java variety of citronella grass consistently outyielded the Guatemala variety in all harvest treatments. The percentage of oil in the Guatemala variety was consistently higher in all treatments and the average yield of oil per acre was somewhat higher for this variety than for the Java when harvested at maximum or low heights. At the medium height, the percentage oil in the Guatemala variety was not much greater than in the Java, and consequently the yield of oil from the latter variety was considerably higher because of the higher yield of grass.

The Guatemala variety yielded the most oil per acre when it was havested 11 times over a 4-year period at a height of 4 feet. This treatment yielded 154.4 pounds of oil per acre compared to 141.6 and 136.0 pounds, respectively, for plots harvested 15 and 8 times during the same period.

The highest annual yield of oil per acre was obtained when the Java variety was cut at medium height. This treatment yielded 170.7 pounds of oil per acre per year compared to 138.6 and 119.6 pounds, respectively, from plots cut at low and maximum heights. The substantial increase in oil production obtained when the grass was cut