Experiments on the effects of fertilizer elements upon the growth of geranium (Pelargonium denticulatum JACQ.)

Abstract

Five experimental plots namely, (1) with complete fertilizers, NPK, (2) without nitrogen, PK, (3) without phosphoric acid, NK, (4) without potassium, NP, and (5) without any feitilizers, O, were planted with geranium (Relargonium denticulatum Jacq.). Results obtained are summerized as follows: 1. Generally speaking, between the plots of NPK and NP and also between the PK and O plots, the growth of the plant resembled each other, but in the latter two plots it was remarkably inferior to that in the former two ; and in the NK plot it was at an intermediate level between the two groups. Therefore the effect of nitrogen was recognized to be the strongest, followed by the effect of phosphoric acid, while that of potassium was hardly recognizable. 2. Generatly the top growth was best in the NPK and NP plots, the difference between them was small ; and in the NK plot, it was inferior a little to the formers. In both PK and O plots, it was inferior conspicuously to the others. 3. The raw weight of the top was maximum in the NP plot, while in the NPK plot, it was inferior slightly to that in NP, though the difference besween them is not remarkable ; and in the NK plot, it was inferior a little to the formers ; and in PK and O plots, it was inferior conspicuously to the others. As to the raw weight of the leaves and the stem and branches, the similar tendency as the above-mentioned results was also found. 4, The root weights, both raw and dry, were maximum in the NPK plot, and decreased in in order of the NP to NK plots, and they were conspicuously small in the PK and O Plots. 5. The size of the mature leaves was maximum in the NPK plots, and in the NP and NK plots, it was inferior slightly to the former, and in the PK and O plots, it was consp-icuously small. As to the raw weight of a single mature leaf, the similar tendency was recognized ; but the dry matter content ratio of the mature leaves was very high in the PK and O plots, and it decreased in order of NK, NPK to NP. 6. The percentage of the oil content of the leaves was higher in the NPK and NP plants, and gradually decreases in order of PK, NK to O plots, but the differences among each plot were not remarkable. The amount of the oil per plant was maximum in the NP plot and it slightly lower in the NPK plot, and decreased further in the NK plot, and was very small in the PK and O plots. 7. The oil contents in the stems and branches were so slight in each plot that it was difficult to compare them. 8. The specific gravity and the refractive index of both the oil in the PK and O Plots were slightly higher than those of the other plots.