Soil and crop microbiome under soil amendment with poultry manure compost

Abstract

The aim of the study. The aim of the study was to review publication about microbiome of chicken manure, chicken manure compost, as well as soil and crop microbiome after compost addition to soil as a fertilizer. Methodology. A search in the bibliographical data bases PubMed and elibrary.ru was performed using the keywords pertaining to the topic of the article. Main results. The results about the chicken manure microbiome, obtained by high throughput sequencing, showed that the chicken gut microbiome is dominated by bacteria of the Firmicutes and Bacteroidetes phyla; some regional chicken populations were found to have Clostridium, Lactobacillus, Eubacterium, Bacteroides, Escherichia coli, Prevotella, Selenomonas, Streptococcus, Megasphaera, Fusobacterium и Bifidobacterium as the main representatives of the gut microbiome. However, chicken manure can contain bacteria with antibiotic resistance genes, as antibiotics are increasingly used in the poultry industry to stimulate production. In general manure composting can be regarded as environmentally safe method for transforming various organic wastes into organic fertilizers. As increasing output of the poultry industry, which inevitably includes manure, increased the interest to its composting, and recent years have seen unprecedented number of research, dealing with various details of manure composting, such as duration, hydrothermal conditions, added bulking materials, microbiological preparations, abundance of the antibiotic resistance genes, and so on. However, the studies of soil and crop microbiome after soil fertilization with chicken manure compost have so far been rather scarce, resulting in ambiguous conclusions, i.e. about positive or no effect of the compost addition. The effect is determined by species, breed, age, rearing and manure composting technology, as well as by crop and its cultivar, agricultural practices and soil specifics. Conclusions. Chicken manure contains taxonomically diverse microbiome that can be changed during composting. Microbiota of chicken manure and its compost with their great microbial species richness can contain bacteria, carrying antibiotic resistance genes. Dispersal of such components of the compost resistome in environment via compost addition to agricultural soils should be regarded as a growing biological hazard, threatening the efficient use of antibiotics for treating bacterial infections in in veterinary and medicine. Therefore increasing poultry production urges for assessing the risks and evaluating the scope of the threat, as well as estimating and establishing permissible limits of pathomicrobiotic load of the poultry litter manure and compost, using up-to-date metagenomic techniques. The greatest concern is about spreading antibiotic resistance genes into the marketable crop components, consumed raw; consequently, alongside with studying microbiota of the compost-receiving agricultural soil as a source of dust, microbiome research should be also focused crop phytobiome where crops are produced under addition of composts, obtained with manure of the antibiotic-treated poultry during industrial production.