The effect of sewage sludge as a fertilizer-ameliorant in the safflower cultivation was studied. Sewage sludge from Volzhskij wastewater treatment plants prepurified by enzyme-cavitation method was used as a fertilizer-ameliorant in the safflower cultivation. It was found that prepurified sewage sludge is environmentally friendly and has a high fertilizing value. The amino acid composition of safflower seeds was studied. The obtained data indicate that sewage sludge introduction made it possible to significantly increase the safflower nutritional value and the soil microbiological activity. It was found that the greatest increase in the safflower crop yields was observed in the case of sewage sludge introduction at a dose of 10 t/ha with chisel tillage. It can be stated that the technology of safflower cultivation proposed by us, including the application of sewage sludge as a fertilizer-ameliorant in combination with the chisel tillage, significantly affects its productivity. The increase in safflower crop yields over the years of the studies was 8.4-15.3%. In general, it can be concluded that sewage sludge has a complex effect on the soil: improves its water-physical, agrochemical and physico-chemical properties, increases the activity of soil biota and the content of organic matter – one of the main indicators of soil fertility.

The findings of comprehensive studies on morphology, physico-chemical properties of sewage sludge, as well as practicalities of its application have been introduced. The sewage sludge used for the research came from the purification facilities of Volzhsky after the preliminary treated by the enzymatic-cavitation method. The morphology and structure of the processed sewage sludge have been determined by scanning electron microscope investigation and X-ray phase analysis. The chemical composition of the processed wastewater sludge have been and tested as an organic fertilizer in the cultivation of the false saffron.

The key problem of modern farming is the search for an alternative to traditional arable farming, which leads to a permanent decline in soil fertility, primarily to a decrease in organic matter and significant loss of moisture. The study was aimed at studying the effect of waste and zero tillage on the agro-physical indicators of the soil, yield, sugar accumulation dynamics and the economic efficiency of cultivation of a sugar sorghum hybrid Slavic homestead. The experience was conducted in Commercial Farmers Association “Kuznetsovskaya”, Ilovlinsky District of the Volgograd Region, on zonal subtypes of light chestnut soils in the period from 2009 to 2015. Research methods were used according to generally accepted methods and recommendations. When considering the effect of treatments on soil density, there was an increase in soil compaction due to zero tillage. When determining the state of aggregation of soil by zero tillage, the number of valuable aggregates was 69.43 % versus 65.43 % for land tillage. The coefficient of structure was zero tillage. The yield of sugar sorghum amounted to 54.7 t/ha, which showed an increase of 7 % relative to dump soil treatment. The zero tillage profitability ratio was 104 %. The transition to zero processing will provide increased productivity, reduce the need for labor and technology, reduce the time for field work, make it more optimal, increase the income of agricultural enterprises, increase the wages of workers and improve their social conditions, which is an important economic and social advantage of resource-saving technology.

Purpose: to study the chemical composition of sewage sludge and zeolite, the sludge structure and also to evaluate the spring barley yield against the background of the ameliorant application and pre-sowing seed treatment with bischofite. Materials and methods. The object of research is the sewage sludge from the treatment facilities of Volzhsky and natural limestone zeolite. The chemical composition of sewage sludge and zeolite was studied under laboratory conditions. The study of sewage sludge structure was carried out by scanning electron microscopy. The field experiment was set up in accordance with generally accepted methods. Results. The chemical composition of the sewage sludge and the quality indicators of zeolite were determined. During the study, the increased content of nitrogen (6.7 %), phosphorus (2.8 %), potassium (0.21 %) was found in the sediment, the organic matter content was 80.0 %. Zeolite analysis data showed that it is based on silica SiO₂ (60.49 %) and alumina Al₂O₃ (12.1 %). When studying the structure of sewage sludge, it was found that the sample has a porous structure, particles of various sizes are found in it, meso- and macropores are present. Data on spring barley yield indicate that when treated with worked out sewage sludge, it increases to 3.15 and 3.25 t/ha against the background of control without seed treatment and with seed treatment with bischofite, respectively. In the variant without pre-sowing seed treatment and with the ameliorant introduction (sewage sludge + zeolite), the yield was 3.88 t/ha, in the variant with seed treatment with bischofite – 4.05 t/ha. Conclusions. To increase the productivity and yield of spring barley in the arid zone of the Volgograd region, it is advisable to use non-traditional ameliorant fertilizers with an optimal chemical composition. Pre-sowing seed treatment with bischofite had a positive effect on field germination and spring barley yield, however, additional studies of its effectiveness in pre-sowing seed treatment are needed.

Instrumental methods of analysis were used to study sewage sludge formed during its processing by the enzyme-cavitation method for further water reuse. It was revealed that sewage sludge samples are multiphase porous aggregates containing both amorphous and crystalline components in their structure. X-ray phase analysis helped to determine the mineralogical composition, as well as the presence of fertilizing properties. Transmission electron microscopy showed that the studied sewage sludge has several scale structural levels of porosity from 5 nm to 6 μm. The sorption properties of sewage sludge, as well as the ability to absorb and retain water, were revealed.