Studies on the Effects of Soil Moisture upon the Growth and the Oil Content of Lemon-grass.

摘要

Experimental plots were divided into five classes soil moistures of which were kept at 100 %, 80 %, 60 %, 40 %, and 25 %, respectively of the water capacity, and the effects of the soil moisture upon the growth and the oil content of lemon-grass were investigated in 1952. 1. At 80 %, the growth of the plant was best, and at 60 %, it was somewhat inferior. But at 100 % and 40 %, the remarkable obstruction of the growth due to excess or deficiency of soil moisture was recognized. And at 25 %, the effects of drought were found serious recognized. 2. The water content of the fresh leaves was highest at 80 % soil moisture, and the effect was more conspicuous in leaf-sheaths than in leaf-blades. 3. The oil content of the fresh leaves was highest at 100 % moistened soil, slightly decreasing with the soil moisture. At 25 %, the decrease of the oil content by the drought was remarkable. 4. Among three plots of 100 %, 80 %, and 60 %, the specific gravity of the oil was highest at 100 %, the excess of the soil moisture being found to make it higher. 5. The reflactive index of the oil was lowest at 60 %, and both the excess and the deficiency of the soil moisture made it higher. 6. The citlal content of the oil was highest at 80 % and both the excess and the deficiency of the soil moisture made it lower. (Received April. 4, 1954)