Ensuring the ecological safety of agroecosystems in conditions of increased content of heavy metals in fodder and manure of cows

Abstract

Environmental pollution with organic waste from livestock, especially cattle manure, is relevant for various countries of the world, including the United States of America and the countries of the European Union. Manure, which contains toxic heavy metals such as cadmium, lead, copper and zinc, is a much greater threat to agroecosystems and, in particular, to the soil. In the forest-steppe zone of Ukraine, a scientific and economic experiment was conducted on dairy cows for the production of ecologically safe milk. During the experiment, the research groups were fed a special mineral-vitamin premix and an injection of a biological preparation that enhanced the elimination of heavy metals with excrement. Experiments were conducted in four farms with different livestock. At the end of the experiment, 10 samples of manure mass were taken from each farm (total of 40 samples) and a chemical analysis of the concentration of heavy metals Cd, Pb, Cu and Zn was made using atomic absorption spectrophotometry (spectrophotometer AAS-30). It was established that as a result of the content in animal diets of fodder with exceeding the maximum allowable concentrations of heavy metals, they, passing through the gastrointestinal tract, fall together with excrement into manure. The average concentration of cadmium was 0.07-0.11 mg/ kg, lead 5.48-8.25 mg/kg, copper 37.71-47.42 mg/ kg, zinc 66.55-81.49 mg / kg. Litter manure is subsequently applied to agricultural land as an organic fertilizer. In order to prevent soil contamination with heavy metals, it is necessary to establish the expediency of applying organic fertilizers to vegetable and fodder crops in each specific case, especially those that are fed to dairy cows. In connection with the difficulty, in today's conditions, for farmers to purchase a sufficient amount of mineral fertilizers, to increase the use of organic fertilizers, if their quantity is sufficient in the farm, but their application to the soil should be controlled and standardized, taking into account the concentration of toxicants in the manure mass and the soil of agricultural lands with simultaneous improvement of grinding and uniformity of distribution over the field. The use of modern equipment for crushing and spreading manure, as well as scientifically based methods of its composting, growing vermiculture, synanthropic fly larvae or biogas production will contribute to the introduction of manure into the soil as an ecologically safe organic fertilizer, will positively affect its mechanical and physical chemical properties, will ensure a good economically effective yield of crops, ecological safety of agroecosystems, cows with ecologically safe feed.Keywords: average daily hopes, premix, bioprepared, cadmium, lead, copper, zinc, contaminated feeds, antidote substances. Key words: manure, heavy metals, organic waste, ecological safety, agro-ecosystem, dairy cows.