Assessment of the impact wastewater of dairy farms on soil microbiota

Abstract

In the production of milk on cattle-breeding farms and complexes large amount of wastewater is formed containing significant numbers of chemicals and is ecologically hazardous source of pollution of water and soil resources. Wastewater of dairy farms contain natural animal excretions, exhaust solutions of cleaning and disinfecting agents, milk residue which is washed off from internal surfaces of milking equipment, residues of feed, litter, dirt, which is washed off during washing of walls and floor of dairy cow house. Since such wastewater contain valuable organic substances they are used to fertilize plants. There are technologies of safe use of wastewater from cattle-breeding farms to fertilize pastures. Also wastewater used as fertilizer in cultivation of sugar beets, tomatoes, cucumbers, spinach, cabbage and the like. It is expedient determination of the influence of wastewater used for the fertilizer of agricultural cultures, on the soil microbiota. After all, soil fertility is inextricably linked with microorganisms that inhabit her. The aim of the work was carrying out of an assessment of influence of wastewater from dairy farms on the soil microbiota. Samples of soil for microbiological studies were selected in 20 centimetre thickness of top layer after application of wastewater of dairy farms. The total microorganism number was determined the method of sowing of soil suspension of corresponding dilutions on nutrient medium of meat-and-peptone agar (MPA). Micromycetes on Chapek medium. The state of soil microorganisms after application in her different doses of wastewater of dairy farms was investigated. It is established, that the total number of microorganisms in soil when accounting 12 days later after application of wastewater in quantities of 500 l/ha exceeded control by 7.4%. At doses of 600 l/ha and 700 l/ha by 9.8% and 12.4% accordingly. 30 days later after application of waste-water the number of microorganisms almost did not differ from control. It was observed that after application of wastewater increase the total number of micromycetes. 12 days later after application of dose 500 l/ha, of number of micromycetes was increased on average by 14,6%; in dose of 600 l/ha by 18.0%; in dose of 700 l/ha — by 19.6%. 30 days later after application of wastewater the total number of micromycetes exceeded control by 1.5%. It is defined, that wastewater of dairy farms in doses of 500–700 l/ha do not exert negative effect on soil microbiota.