RU2673671C1 - Method for determination of an environmental safety and biological efficiency of soils based on sewage sediments in field conditions - Google Patents

Abstract

FIELD: ecology.

SUBSTANCE: invention relates to ecology and can be used in the complex determination of ecological safety and biological effectiveness of soils created on the basis of urban sewage sludge in the field. For this, shallow trenches with an area of at least 10 m² are created at test sites with a natural soil cover in triplicate, interleaving them with sections of natural soil of the same area. Trenches are filled with 0–20 cm layer, which is in accordance with the content of heavy metals and sanitary and hygienic parameters, with the requirements of SanPiN 2.1.7.573-96. After pre-seed treatment of the test site, a test culture is planted, and oats for green mass are used as a test culture. Further, when the plants reach the harvesting phase of development, a planking determination of the above-ground biomass and a statistical assessment of the reliability of the difference in the above-ground biomass between the plots with soil and natural soil. Good condition of oat stalk and a high level of above-ground biomass in variants with soil testify to the absence of its negative influence on the growth and development of plants.

EFFECT: invention provides a definition of the biological properties of soils on the basis of sewage sludge.

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Description

The invention relates to methods for determining the environmental safety and biological effectiveness of soil created on the basis of urban sewage sludge and used for road construction, urban gardening, in forest and decorative nurseries, while restoring disturbed lands, solid domestic and industrial waste landfills subject to compliance environmental standards and regulations.

A known method of comparing the environmental safety of soil by chemical analysis and comparing the data with environmental safety standards of soils.

However, the known method does not take into account the complex bioecological characteristics of the soil due to the impossibility of determining their integrated effect on plants grown at the sites of reclamation.

There is also a way to determine the fertility of soils by conducting vegetation experiments, when various soils with seeding of test cultures are laid in the vegetation vessels. But vegetative experiments can only serve for a preliminary reconnaissance assessment of soil properties. Our laboratory and vegetation experiments with sewage sludge and soil showed that precipitation when the content of heavy metals in them does not exceed the normative indicators for the Sanitary Rules and Norms SanPiN 2.1.7.573-96. Hygienic requirements for the use of wastewater and its rainfall for irrigation and fertilizer. M .: Ministry of Health of Russia, 54 pp., Did not adversely affect the growth and development of test plants, as shown in the article: G.E. Frozen G.A. Zyabkina, I.A. Nesterovich, T.P. Fomkina. “Agroecological assessment of the use of sewage sludge” // Agrochemistry. 1995. No5. - S. 102-108.

From a methodological point of view, the main one for determining the effectiveness of plant growing methods is considered to be field experience, which completes exploratory research, as only field experience allows us to quantify the complex effect of a new method or technology of plant cultivation and gives objective reasons for the introduction of scientific achievement in production. This methodological position is described in the work (B. A. Dospekhov. “Methods of field experience (with the basics of statistical processing of research results).” 4th ed., Revised and enlarged M .: Kolos, 1979. - 415 pp.).

A method for determining the environmental safety and biological effectiveness of soil based on sewage sludge in the field has not yet been developed. Our studies showed that the most rational methodological solution to the problem is to determine the environmental friendliness of soils produced on the basis of urban sewage sludge by comparing the biomass of test plants grown on the studied soil and uncontaminated soil in a field experiment.

The proposed method is as follows.

The studied soil in the experimental plot is placed in shallow, about 20 cm, trenches (plots) specially dug with a bulldozer, with a total number of at least three, each with an area of at least 10 m ² , alternating with undisturbed areas of the same area that are control in comparison with plots with soil. After pre-sowing treatment of the plots according to generally accepted technology, they are sown with a test culture, and when the plants reach harvesting readiness, their above-ground biomass is determined sub-plot. The results of determining the aboveground biomass are subjected to statistical processing by the method of analysis of variance to identify the complex effects of soil on the test culture in comparison with natural soil.

Example

The soil was created from thermophilically fermented mechanically dehydrated sewage sludge, according to SanPiN 2.1.7.573-96, by mixing with sand and peat in a ratio of 1: 1: 1 and composting for a month. Agrochemical, toxicological and sanitary-hygienic indicators of the soil are shown in table 1. The soil was a homogeneous mass of dark brown, had a favorable chemical composition.

According to the actual content of toxicants, the activity of natural and technogenic radionuclides, bacterial and parasitic indicators, the soil did not exceed the corresponding environmental standards.

The soil test was carried out by generally accepted methods in the Ramensky district of the Moscow region in a field experiment.

The field experiment scheme included two options: 1. Control, natural soil. 2. The soil.

The experimental plot area is 15 m ² (3 × 5 m). Repeat options - three times. The soil was poured in a layer of 20 cm in trenches to the subsurface horizon, i.e. instead of arable horizon (Figure 1). The soil of the control variant — natural soil — sod-podzolic loamy soil, was characterized by a poor supply of nutrients, contained 0.79% of organic carbon (1.36% of humus according to Tyurin), 0.09% of total nitrogen, 70 mg / kg of mobile phosphorus (P ₂ O ₅ ), 60 mg / kg potassium (K ₂ O) (according to Kirsanov) at a pH of _kcl 4.6.

Pre-sowing treatment in all variants of the experiment consisted of milling and harrowing.

As a test culture in all plots oats were sown on green mass. Seeding rate of 200 kg / ha. Oats were sown in June 2016.

By the time the aboveground biomass was taken into account, oats were in the exit phase into the tube (Figure 2). In this case, the soil, as studies have shown, had a positive effect on the aboveground biomass of plants, as evidenced by the data in table 2.

Statistically from the use of soil, a reliable increase in the elevated oat biomass was obtained. The collection of aboveground oat biomass in the case with soil was 24.0 t / ha, which is 18.8 t / ha more than in the control.

Thus, the use of soil based on precipitation of urban wastewater when mixing them with sand and peat in a ratio of 1: 1: 1 and composting for a month was an effective technique, providing a significant increase in the collection of aboveground biomass of plants compared to natural soil. The good condition of the oat stalk and the high level of above-ground biomass in the options with soil indicate its negative influence on the growth and development of plants, which confirms the environmental safety and biological effectiveness of the claimed method, as well as the possibility of its use for the integrated assessment of biological properties of soil based on precipitation Wastewater.

Claims (1)

A method for comprehensively determining the environmental safety and biological effectiveness of soil based on sewage sludge in the field, including comparing them from the aboveground biomass of the sown test culture with natural soil in at least three replicates of the comparison options, characterized in that the soil is created by mixing dehydrated sewage sludge with sand and peat in a ratio of 1: 1: 1 and composting for a month, then the resulting soil is applied in a layer with a capacity of 20 s m in the experimental plot with a homogeneous soil cover on plots with an area of at least 10 m ² , which are trenches 0-20 cm deep, interspersed with control plots of the same area with natural soil, followed by pre-sowing preparation of the entire plot for sowing, sowing test culture, and as a test culture, oats for green mass are used, followed by a subsection determination of its aboveground biomass when the plants reach the harvesting phase of development and a statistical assessment of the reliability of the difference in aboveground th biomass between plots with the ground soil and natural soil; At the same time, the good condition of the oat stalk and the high level of aboveground biomass in the options with soil indicate the absence of its negative effect on the growth and development of plants, which confirms the environmental safety and biological effectiveness of soils based on sewage sludge.

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