THE USE OF SEWAGE SLUDGE IN CROP CULTIVATION

Purpose: to study the structure of sewage sludge, as well as to reveal the possibility of its use in agriculture in order to increase moisture reserves in the soil. Materials and methods. The object of research is sewage sludge from the Volzhsky wastewater treatment plant. The structure of the sewage sludge was investigated by scanning electron microscopy. The field experiment was set up in accordance with generally accepted methods. Results and discussions. The investigated sewage sludge has a high fertilizing value with an increased content of nitrogen (3.30 %), ammonia nitrogen (0.19 %), phosphorus (4.27 %), potassium (0.31 %) and an optimal content of organic matter (32 %), which indicates the broad possibilities of its application in agriculture. Analysis of micrographs of sewage sludge showed that it is a nanostructured material, the presence of a porous structure which proves the presence of adsorption properties in the sludge and the ability to retain moisture when applied as a fertilizer was found. Data have been obtained confirming that sewage sludge contributes to an increase in the amount of moisture and its retention in soil by the example of the cultivation of dyeing safflower in the absence of irrigation. The maximum accumulation of moisture was observed with the introduction of sewage sludge at a dose of 10 t/ha, as well as with the use of deep tillage with the “Rancho” working body and amounted to a layer of 0–0.4 m when sowing dyeing safflower 88.5 mm, in the phase of full ripeness – 4.4 mm. Conclusion: it is advisable to use sewage sludge, which is a nanostructured material with a porous structure and adsorption properties to increase moisture reserves in soil.