Intraspecies chemical variability of the essential oil of Ledum palustre
The compositions of the essential oils of marsh tea,Ledum palustre L., from the southern regions of Tomsk, Transbaikalia and Amur province, and also from the southern part of the island of Sakhalin have been analyzed in detail. The results obtained indicate the sharply pronounced intraspecies chemical variability of this plant. In addition to the chemotype of march tea with myrcene as a macrocomponent which is widely distributed in the European part of the USSR, another three chemotypes with the macrocomponents limonene, sabinen, and p-cymene have been revealed.
[Chemical composition of the essential oil from melissa].
Different oil-samples of Melissa officinalis L. were analysed by capillary GC/MS, using fused silica columns and E.I.-Mass-spectrometry. Comparing the observed mass-spectra with those of a spectral collection, 70 compounds of the oil were identified. Geranial, neral, 6-methyl-5-hepten-2-one, citronellal, geranyl-acetate, beta-caryophyllene, and beta-caryophyllene-oxide comprise about 96%. The fingerprint of the capillary gas-chromatogramm permitted differentiation of the essential oil of Melissa officinalis, Cymbopogon winterianus and Nepeta cataria var. citriodora., as well as a standardisation of pharmaceutical preparations containing Melissa oil.
PRECISION FARMING APPROACHES TO SMALL-FARM AGRICULTRUE
Precision farming implies a management strategy to increase productivity and economic returns with a reduced impact on the environment. It is based on the application of information technology to a description of variability in the field, variable-rate operations and the decisionmaking system. There are three technology levels and three strategies in the development of precision farming. Precision farming practices can be used on small farms as well as big ones, and they play a core role in rural development programs which are integrated with industry. A real-time soil spectrophotometer was developed to describe soil variability in farmers' fields, to be used in precision farming.