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Open access

Gunārs Bremanis and Solveiga Maļecka

Influence of waste liquors of mildronate production on yield and quality of winter rapeseed

The effect of mother liquors obtained in one production stage of the popular medicinal preparation Mildronate on yield and quality of winter rape (Brassica napus L.) grown for biofuel was tested. The mother liquors contain quaterine-type compounds, which are known to stimulate growth of lupines. In the three-year study, Mildronate mother liquors were sprayed on winter rape. The yield and fat content of rape was determined. Mother liquor contains small amounts of methyl acrylate. However, this compound was not found in rapeseed, stalks and soil. Mother liquors spray had a positive effect on soil microorganisms. In the period from initiation of flowering to maximum flowering stage, spraying with mother liquors, as well as with quaterine-M and isopropanol (basic substance of mother liquor), in most cases had a low (around 10%) positive effect on rape yield and a very small impact on the fat content in rape grain. The effects differed among years, suggesting interaction with weather conditions. The determined optimal mother liquors dosages were quite wide, from 0.4 to 10 L ha-1.

Open access

Gunārs Bremanis, Maris Klaviņš, Oskars Purmalis, Raitis Ziemelis and Solveiga Maļecka

Extracts for agricultural use were prepared using cavitation method at 45 oC and at 95 oC from peat and earthworm biohumus. Samples of all studied extracts had similar dry-matter content. Peat humic substances and earthworm biohumus extracts were analysed using UV-Vis, FT-IR, and fluorescence spectrometry. Trace element analysis was performed with atomic absorption spectrometry. Extracts were tested for acidity, conductivity, humic acid concentration, and carboxyl group concentration. Hydrophobicity was assessed using a water-polyethylene glycol twophase system and calculation of the partition coefficient. Total nitrogen and phosphorus concentration was determined. Concentration of the humic substances slightly changed during the heating process. Significant changes in total phosphorus concentration was observed both in earthworm humus and peat extract. Thermal treatment caused decrease of hydrophobicity and lower concentration of organic matter in extracts, while carboxyl group concentrations in isolated humic substances practically did not change. The calculated ratio from UV-Vis spectra showed significant difference in humification degree of samples.