Evaluation of phytotoxicity of disinfectants used for manure disinfection

Abstract

Manure as an organic fertilizer in practice of agriculture is allowed to use only if it does not contain pathogenic microorganisms. Upon detection in manure and chicken droppings of pathogens of infectious diseases is carried out their disinfection. Choosing method of disinfection is carried out at the direction of veterinary service taking into account danger of arising of epizootic situation, type of pathogen of disease, presence and type of chemical reagents and technical means. For disinfection of animal by-products by chemical method we use a large number of disinfecting agents potentially hazardous for the environment which is associated with the content in their composition of xenobiotics, in particular aldehydes, chlorine, phenols, etc. The paper presents results of biotesting of soils polluted by disinfecting agents used for disinfection animal by-products, in particular, bioethanol, Novochlor-Extra (contain such active substances how inorganic chlorine compounds and alkali) and Dezaktin (organic chlorine compounds, anion SAS and sodium tripolyphosphate). The assessment was carried out under laboratory conditions through biotesting with the use of spring barley (Hordeum vulgare L.). It is established, that after five-day cultivation of barley seeds in soils containing 1.0, 10.0 and 100.0 mg/kg of such agents as bioethanol, Novochlor-Extra and Dezaktin there was gradual reduction of mass of stem to 10.2% compared to a control. When the content in soils was 1.0, 10.0 and 100.0 mg/kg of investigated disinfectants gradual reduction of length of stem of barley by an average of 12.2% was observed. At pollution of soil investigated agents in the number of 1.0, 10.0 and 100.0 mg/kg we observed the small increase of length of longest of root by an average of 7.8%, which indicates to stimulating influence on the growth of root system and absence of phytotoxicity. When the content of disinfectants bioethanol and Novochlor-Extra in soils was in a quantity of 1000 mg/kg, there was reduction of mass, length of stem and longest root of an average of 19.1, 30.5 and 16.8%, respectively. At pollution of soil at the level of 1000 mg/kg agent of Dezactin we observed reduction of mass of stem to 61.8%, its length on 72.0% and length of longest of root to 67.4% that demonstrated to phytotoxic influence. At the hit of disinfectants with disinfected animal by-products in soils in a quantity of ≥1000 mg/kg it is possible to predict negative impact on morphometric indicators of plant what probably will lead to worsen of their development. The method of determination of pollution of soils by delay growth of root of plants is informative express method for ecological assessment of content in them the disinfectants used for disinfection of animal by-products.