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To increase crop yields by destroying weeds the separate group of pesticides exist, that is called herbicides. Among the herbicides based on chlorphen oxalcanecarboxylic acids products of sodium and ammonium salts, as well as 2,4-dichlorophenoxyacetic acid (2,4-D), are widely used. However, the production and use of pesticides affects the state of the environment and pose a potential risk for public health. In this paper the need to clarify the mechanisms of transformation and degradation of 2,4-D de-rivatives under the action of physical, chemical and biological environmental factors was showed. The preparations based on 2,4-D, registered in the Republic of Belarus is reviewed. The mechanisms of action of these xenobiotics are described, analysis of their toxicity for the environment components is performed. Particular attention is paid to the microbial degradation of pesticides, possible ways of their degradation under the action of microorganisms enzyme systems are described, the factors, that affect the biotransformation process are an alyzed. It has been shown that th e bacterial degradation of 2,4-D is carried with the formati on of 2,4-dichlorophenol by en zyme 2,4-dihlorphenoxyacetate-α-ketog-lutaratedioxygenase, and further the intermediate degrades with 3,5-dihlorocatechol formation using 2,4-dihlorphenolhydroxylase in two ways: or tho-splitting or peripheral meta-splitting.

The most important component of destruction of herbicides in soil is their degradation by soil microbiota, which occurs due to the capability of microorganisms to adapt their enzymatic systems to specific substrates and to transform them. Bioaugmentation is one of the most ecological and economical methods of remediation of natural objects. However, the use of this way provides the need to receive a comprehensive information about migration, cumulation and transformations of pesticides in the environment (about dynamics) and also about factors, which increase the efficiency of focused application of bacteria-destructors (immobilization, introduction of additional substrates). This research is focused on the study of the influence of different factors on the efficiency of degradation of pesticides of sulphonylurea group in soil. The results show that intensification of process of degradation of remaining amounts of tribenuron-methyl and metsulfuron-methyl in soil and liquid medium can be achieved by the exposure of bacteria-destructors to optimal conditions during cultivation as well as by the use of immobilized cells of microorganisms.

Studies aimed to import pharmaceuticalproducts, as well as to strengthen the food security of the Republic of Belarus, are highly relevant. In this connection an universal culture of Jerusalem artichoke is of interest, the value of which is determined due to the possibility of its use in feed, food and pharmaceutical industries. The paper presents the productivity research of Jerusalem artichoke varieties with different growing seasons, the estimation of mineral composition of tubers, the content of inulin as the most valuable component of mentioned agricultural crops was determined.

Currently in agriculture much attention is paid to development and use of low-cost and at the same time effective methods of fight against weeds. In this regard, widely purchased sulfonylurea herbicides. The paper presents the general characteristics, mechanism of action, degradation pathways (hydrolysis, photochemical transformation and microbial degradation) of metsulfuron-methyl and tribenuronmethyl. The key role of chromato-mass-spectrometry to establish the mechanisms of destruction these herbicides by soil microorganisms is shown.