RU2636945C1 - Method for biological soils reclamation - Google Patents

Abstract

FIELD: ecology.

SUBSTANCE: method consists in application of ground clay according to the invention, the clay is preliminary analyzed for toxicity, and according to its results, clay waste is uniformly mixed with a peat-sand mixture in the proportion (40-60):(60-40)%, mineral fertilizers and seeds of perennial frost-resistant herbs, for example ryegrass, and applied to the surface as a layer of 8 to 10 cm on the planned drained area after snow cover melting in spring. Gray dense clays with interlayers of Upper Kotlin subsuite sandstones are used as clay. When using this method, ecological clean waste of excavation works for laying deep underground tunnels is used.

EFFECT: costs of the biological stage of reclamation are lowered, the protective properties of the reclaimed surfaces are increased from the physical impact and a stable fertile soil layer is created.

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Description

The invention relates to agriculture, in particular to soil restoration, increasing its fertility and use for the improvement of urban plantings.

A known method of reclamation of contaminated land (RF patent No. 23239882, published July 27, 2008), which is based on the sequential coating of a site contaminated with toxic substances with layers - first a zeolite-containing rock, then carbonate clay, a mixture of soil with AK-639 grade B polyacrylamide polymer -415K in a volume ratio of 100: 1, as well as a layer of soil. Subsequent surface tinning is carried out using rhizome perennial grasses of rind and wheat grass in a weight ratio of seeds 1: 1 and a sowing rate of 20 kg / ha.

The disadvantages of this method is the multi-stage process, the lack of decoding of the composition of the soil, as well as the use of artificial polymers.

A known method of reclamation of dumps of cement production (RF patent No. 2338355, publ. November 20, 2008), which consists in introducing as an organic fertilizer sapropel mixed with grass seeds in an amount of 25-30 t / ha and smelling it to a depth of 4-6 cm.

The disadvantages of this method is the insufficient depth of the fertile layer for the possibility of using it for agricultural purposes and growing crops with developed root structure.

A known method of biological reclamation of disturbed permafrost soils (RF patent No. 2599836, publ. 10/20/2016) consists in uniformly applying pre-harvested organomineral soil with a layer of at least 10 cm, then the required amount of lime and mineral fertilizers are successively applied, forming a layer of plant soil; Next, a layer of plant soil is planned, rolled and sown and mixed, and the soil composition and mixture selected depending on the type of soil being cultivated, and the seeds are sown immediately after lime and mineral fertilizers are added to the soil.

The disadvantage of this method is the high complexity of the method, the multi-stage method and the long term for obtaining results.

A known method of biological reclamation of man-made disturbed lands (RF patent No. 2512171, publ. 04/10/2014), including sowing perennial grasses with mineral fertilizers, consisting in the fact that vermiculite substrate with granules up to 2-4 is scattered on the ground with a layer of up to 1 cm mm and pH from 6.5 to 7.2, grass seeds are sown on the surface of the substrate and irrigated with an aqueous solution of mineral fertilizers, then the surface of the substrate is covered with a polymer film, which is removed on the 5-7th day.

The disadvantage of this method is the complexity of the method and the complexity of manufacturing a vermiculite substrate.

A known method of increasing the fertility of sandy soils (RF patent No. 2265980, publ. 12/20/2005), adopted as a prototype, which includes the introduction and smelling of clay containing 30-31% of silty particles in the soil in an amount of 25-50 t / ha. Before applying and smelling clay into the soil, it is crushed. Adding and smelling clay is carried out in the fall.

The disadvantage of this method is the multi-stage process, the long term for obtaining results and the lack of information on the composition of the soil intended for use.

The technical result of the invention is the minimization of time and resource costs for carrying out biological restoration of the soil and the use of available soil components for urban environments.

The technical result is achieved by the fact that clay is preliminarily analyzed for toxicity, and according to its results, clay waste is uniformly mixed with a peat-sand mixture in the proportion (40-60) :( 60-40)%, mineral fertilizers and seeds of perennial frost-resistant herbs, for example ryegrass , and is applied to the surface with a layer with a thickness of 8 to 10 cm on the planned drained territory after the snow cover has melted in the spring.

The method is as follows.

The clay used in the proposed method is a clay waste of earthmoving when laying underground tunnels. Initially, with the use of a screw conveyor, the development of clay waste located in the lower part of the chamber of the rock-breaking organ occurs. The auger conveyor is coupled with a belt conveyor that extends as it penetrates, with the help of which the developed clay waste is delivered to the surface.

In the future, the waste is checked according to existing methods for toxicity (chemical composition, particle size analysis, biotesting). If clay waste belongs to hazard classes I-IV (from extremely hazardous substances to low-hazard substances), the waste cannot be used for the biological stage of reclamation and is sent for storage to dumps. If clay waste corresponds to hazard class V (almost non-hazardous), it is mixed with a peat-sand mixture in the proportion (40-60) :( 60-40)%, mineral fertilizers and seeds of perennial frost-resistant herbs on a special site.

Peat-sand mixture is used in the following composition: peat bottom and top - 60%, sand - 40%. The addition of mineral fertilizers was carried out in the following ratio: N - 350 mg / kg, P ₂ O ₅ - 400 mg / kg, K ₂ O - 500 mg / kg. The ryegrass grass was chosen as a test culture. Mixing is carried out by milling cutters and is carried out immediately before the biological stage of reclamation. The resulting mixture is delivered to a site designed for biological reclamation by road.

The mixture is applied on a flattened and compacted surface with a layer with a thickness of 8 to 10 cm using special spreaders. The application is carried out immediately after the snow cover has melted in spring (when the temperature passes through + 5 ° C). In the future, produce regular watering of crops with water.

A feature of the method is that it is proposed for use for biological reclamation the main waste of earthmoving when laying underground tunnels in the city of St. Petersburg. They are clays of the Upper Kotlinsky subformation. Verkhnekotlinskaya subformation is represented by clays developed on a vast territory. Clays are gray, dense, with interbeds of sandstones. Depth, increasing southward, reaches 50 m.

The method is illustrated by the following examples.

Initially, clay samples were taken from three points - the places of laying tunnels under construction in St. Petersburg.

The chemical composition of the samples was studied using an XRF-1800 Shimadzu wave X-ray fluorescence spectrometer; the analysis of particle size distribution by laser diffraction was carried out using a LA-950V2 Horiba laser particle size analyzer. To establish the toxicity of the waste, we used a method for determining the change in optical density of a chlorella algae culture.

The studies were carried out in an accredited CCU of the Mining University, St. Petersburg.

The results of laboratory analyzes of all samples are presented in tables 1, 2, 3.

This waste has a hazard class V and can be used for the improvement of urban plantations, for example, for landscaping near the construction site.

Subsequently, the clay waste was delivered to the surface by a screw conveyor and mixed in various proportions with a peat-sand mixture. The peat-sand mixture was used in the following composition: peat bottom and top - 60%, sand - 40%.

Mineral fertilizers were added to the mixture in the following ratio: N - 350 mg / kg, P ₂ O ₅ - 400 mg / kg, K ₂ O - 500 mg / kg and lawn grass.

As a test culture, a lawn grass mixture of the following composition was selected:

- Perennial ryegrass “Henrietta”, 30%,

- Perennial ryegrass “Romeo”, 30%,

- Perennial ryegrass Fancy, 30%,

- Perennial ryegrass Roadrunner, 10%.

The ryegrass tolerates temperatures well below minus 15 ° C without the presence of snow, does not require frequent watering and additional fertilizers. Life expectancy is 3-5 years.

Mixing was carried out mechanized way immediately before the biological stage of reclamation. The resulting mixture was transported to a site intended for biological reclamation by road.

The prepared mixtures of various compositions were applied on a flat and compacted surface with an area of 30 × 30 cm with a layer of thickness from 8 to 10 cm by hand. The application is carried out immediately after the snow cover has melted in spring (when the temperature passes through + 5 ° C). In the future, produce regular watering of crops with water.

To assess the fertility of the proposed soil mixture for use at the biological stage of reclamation, experiments were set up, the purpose of which is to establish the optimal ratio of waste / soil. The optimal ratio is determined by indicators of germination, growth, survival, color of the sown test culture (Table 4).

Table 4 presents the bioproductivity values of various compositions for biological soil remediation:

From table 4 it is seen that the optimal ratio of the components to obtain the highest bio-productivity have compounds No. 3, 4 of the mixture. A further increase in the thickness of the layer of plant soil does not give a significant increase in germination and the process of plant growth.

When using this method of biological soil remediation, the ecological clean waste of earthmoving is used when laying deep underground tunnels, which significantly reduces the costs of the biological stage of restoration and improvement of urban plantings, and also increases the protective properties of reclaimed surfaces from physical impact (water and wind erosion) and creates a stable fertile soil layer.

Claims (1)

A method of biological soil remediation, including the application of crushed clay, characterized in that the clay is pre-analyzed for toxicity, and according to its results, clay waste is uniformly mixed with a peat-sand mixture in the ratio (40-60) :( 60-40)%, mineral fertilizers and seeds of perennial frost-resistant herbs, such as ryegrass, and is applied to the surface with a layer of 8 to 10 cm in the planned drained area after the snow cover has melted in the spring.