RU2484613C2 - Method of creation of vegetative ground cover in recultivation of disturbed soils - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to the field of recultivation of disturbed soils, in particular technogenic wastelands. The method comprises application on the soil surface of wastes, mineral fertilisers, and sowing of perennial grasses. At that, on the soil surface the mining wastes are applied with the layer not less than 5 cm, containing calcite and/or hydrous magnesium silicate. Compound fertilisers N₇₀P₇₀K₇₀ are applied, then exfoliated vermiculite is spread with a layer of up to 1 cm with granules of up to 4 mm, a mixture of seeds of perennial plants is sown, watered and covered with a polymer film which is removed at the 5-7^th day. As mining wastes the carbonatite wastes are also used, or screened olivinite ore or serpentinite magnesite. As the seeds of perennial plants the red fescue, timothy, awnless brome, European dune wild ruttishness is used in the amount of 50-100 g/m². Watering is carried out at the rate of 5 l/m².

EFFECT: method reduces complexity of technical and biological works on recultivation of disturbed soils and planting of urban areas, wastes recycling of mining and processing complex, increasing the efficiency of formation of sowing culture phytocoenoses and their durability, accelerating the process of recultivation with creation of conditions for accelerated accumulation of elements of fertility in the disturbed layer.

4 cl, 1 tbl

Description

The invention relates to methods for biological reclamation of disturbed lands and can be used to restore lands that have become barren as a result of human activities, including for the restoration of man-made disturbed acidified lands (man-made wastelands).

The main factor in the digression succession of ecosystems located in the zone of influence of enterprises emitting heavy metals (HM) and acid-forming substances, primarily sulfur dioxide, is the acidification of the territory. The difficulty of solving the problem is exacerbated by the constant ongoing over time high level of air pollution. The traditional method of reducing soil acidity is liming. As calcareous materials, in addition to the original calcareous rocks, the main component of which is calcite CaCO ₃ and, to a lesser extent, magnesium carbonate MgCO ₃ , industrial wastes of complex composition are used [1]. For example, in shale ash, most of the calcium and magnesium is in the form of silicates. Shale ash when added in equivalent amounts of CaO + MgO is more effective than carbon dioxide forms of lime. Silicic acid in calcareous materials can reduce the amount of mobile aluminum in soils and contribute to better absorption of phosphorus by plants. At the same time, in accordance with GOST 17.5.1.03-86 “Classification of overburden and host rocks for biological land reclamation” in case of pronounced soil toxicity in the reclaimed territories, “radical chemical reclamation is necessary; creating a screen of neutralizing toxic properties of rocks; overlapping by potentially fertile rocks with a thickness of the layer that ensures the normal development of plants in these climatic conditions. " When carrying out restoration work on technologically disturbed areas, it is recommended to remove contaminated soil and replace it with a new fertile layer, which leads to the need for landscape disturbance in other territories to remove large volumes of the fertile layer, to the problem of disposing of the removed layer and to a significant increase in labor costs and the cost of restoration works. During physicochemical treatments of the removed layer with its return to the former territory, a number of concomitant problems also arise: increasing mobility and bioavailability of pollutants, redistributing them into fractions, changing the overall physicochemical characteristics of the substrate, which significantly reduces the effectiveness of its further use as ordinary soil.

Organomineral fertilizers containing various components are also used for deoxidation of soils (for example, organomineral fertilizer consisting of a mixture of bedded manure, peat and lime according to USSR author's certificate No. 1395618, organomineral fertilizer according to patent No. 2263651 of 05/13/2004, obtained by mixing bird litter with a calcium-containing component - defect of beet sugar production, etc.). However, the agrochemical effectiveness of such fertilizers is low, and their production is associated with significant energy consumption.

Various formulations or compositions for land reclamation are known, including various organomineral additives and sorbents (patents for inventions of the Russian Federation No. 1730742, 2193590, 2277326, 2293103, etc.), for example, peat-sand mixture, sapropel, aluminum powder, lignin, etc. . derived from local wastes. It is known to use expanded vermiculite as additives for soils and soils in an amount of 25 to 70% to improve their composition and increase crop yields, as well as in soil mixtures consisting of vermiculite and peat in a ratio of 1: 1 or vermiculite with soil or soil in a ratio 1: 2.

A known method of restoring disturbed lands, including creating grass cover from lawn strips grown hydroponically on a vermiculite substrate according to the RF patent for invention No. 2393665 of July 13, 2007. However, the vegetation created by this method does not develop well on acidified lands, since vermiculite is screened from acid a layer of one cm was not enough. The roots of plants are concentrated in this layer and penetrate into the soil only 2-4 cm.

The closest is the method of reclamation of disturbed lands according to the RF patent for invention No. 2336684 dated November 13, 2006, which includes introducing waste onto the surface of acidified soil contaminated with toxic substances, plowing, introducing activated sludge from sewage treatment plants and sowing plant seeds. Sludge waste from soda production in the amount of 10-40 kg / m ² is used as a neutralizing reagent, and activated sludge is used as organic fertilizer in the amount of 4-5 kg / m ² . The sludge from the soda plant contains, wt.%: Calcite (CaCO ₃ ) - 79-97, aragonite (CaCO ₃ ) - 1-2, dolomite - up to 1, quartz - 1-8, water - the rest. The activated sludge of the treatment plant of a chemical plant contains, wt.%: Mineral substances - 53-78, organic substances - 22-47, including total nitrogen up to 3.6%, phosphorus up to 4.8%. As the seeds of plants, cane reeds, meadow clover, sowing alfalfa and creeping wheatgrass are preferably used. The method allows you to create a sustainable vegetation cover on disturbed lands, neutralize the toxicity of land and utilize waste from chemical industries. The disadvantage of this method is the plowing of waste along with contaminated land, the increase due to this the complexity of the formation of the fertile layer and the duration of the process of reclamation of disturbed soils.

The inventive method, as well as known, includes applying to the soil surface waste, fertilizers and sowing perennial grasses.

The problem solved by the invention was to restore vegetation in urban and technologically disturbed areas without creating a fertile layer of scarce materials (soil, peat, etc.) in a short time.

The technical result consists in reducing the complexity of technical and biological work on the restoration of disturbed lands and greening urban areas, in the utilization of waste from the mining and processing complex, increasing the efficiency of the formation of planting crop phytocenoses and their durability, in accelerating the process of restoration with creating conditions for accelerated accumulation of fertility elements in the disturbed layer.

A technical result is achieved by the fact that mining wastes containing calcite and / or magnesium hydrosilicate are applied to the soil surface with a layer of at least 5 cm, complex fertilizers N ₇₀ P ₇₀ K _{70 are} applied, then expanded vermiculite with granules up to 4 is scattered with a layer of up to 1 cm mm, they sow a mixture of seeds of perennial plants, watered and covered with a polymer film, which is removed on the 5-7th day. Carbonatite waste, or screening of olivinite ore, or serpentinite magnesite are used as mining waste. As seeds of perennial plants, red fescue, timothy grass meadow, beechless rind, sandy screech and others in the amount of 50-100 g per square meter can be used. Watering can be carried out at the rate of 5 liters per sq.m. The introduction of mining waste containing calcite and / or magnesium hydrosilicate directly on the soil surface with a layer of at least 5 cm ensures a reduction in the laboriousness of technical and biological work on the restoration of disturbed lands and landscaping of urban areas, the utilization of waste from the mining and processing complex, and the creation of conditions for accelerated accumulation of elements fertility in the disturbed layer. The use of bulk shielding, neutralizing the fertile layer from industrial waste from the mining and processing complex instead of traditional soils, peat and other natural materials can significantly reduce the cost of materials and, therefore, the cost of the work on the formation of vegetation on disturbed lands.

The application of complex fertilizers N ₇₀ P ₇₀ K ₇₀ to the waste layer, application of expanded vermiculite with granules up to 4 mm on a soil layer of up to 1 cm, sowing grass seeds on the surface of the substrate and watering them with water at a rate of 5 l / m ² provides optimal conditions (large the amount of moisture, air, nutrients) necessary for initiating the processes of seed germination and further growth and development of herbaceous plants, and, accordingly, increasing the efficiency of the formation of planting phytocenoses and their durability, accelerating the process of recul ivatsii with the creation of conditions for accelerated storage elements impaired fertility layer.

The use of prepared swollen vermiculite with weak alkalinity (with pH up to 7.2) for reclamation of disturbed lands provides the possibility of sowing various types of herbaceous plants, protects them from freezing in severe frosts due to good thermal insulation properties, and also reduces the complexity of the technical reclamation work due to low weight vermiculite. The substrate is an independent carrier of valuable macro- and microelements, which increases the durability of grass cover. Expanded vermiculite is an active absorber (sorbent) of chemical compounds, ions of heavy metals and radionuclides and forms, together with the waste in heavily contaminated areas of the soil, a soil-like layer due to which plants of the created cover can grow and develop over a long period of time. This layer of vermiculite protects both sown seeds and plants grown from them from the influence of these pollutants.

Shelter of crops with a polymer (polyethylene, for example) film preserves the temperature and moisture of the substrate with seeds in the initial, starting period of seed germination and seedling growth, which also provides initiation of seed germination processes, reducing the formation time of phytocenosis cultures to 7-10 days.

The combination of the above distinguishing features, combined, provides the claimed technical result.

Industrial applicability of the method is illustrated by examples.

In 2007-2010 a series of laboratory experiments was carried out using screens made of quartz and calcite-containing wastes from the enrichment of apatite-magnetite ores of the Zhelezny mine (OJSC Kovdorsky GOK), containing carbonates 40%, apatite 10-20%, magnetite 10-20%, phlogopite, mica 20-30%. As a result of the studies, active penetration of the root system of the grass cover into the shielding layer, its rapid development and further penetration into the contaminated soil, which indicates a decrease in its toxicity, were noted.

In 2010, field experiments were conducted in which waste from mining enterprises containing calcite and / or magnesium hydrosilicate (serpentine) was used as deoxidizing substrates: waste from the processing of apatite-magnetite ores from the Zhelezny mine of Kovdorsky GOK OJSC, Murmansk reg. (carbonatite waste); screening of olivinite ore of the Khabozero deposit of olivinite, Murmansk region (screening of olivinite ore); and overburden of the Khalilovsky magnesite deposit, CJSC "Litosfera", Orenburg region (serpentinite magnesite).

Carbonatite waste is waste from the tailings of the Kovdorsky GOK, which is a waste of re-deep processing after the recovery of valuable components. The average content of carbonate minerals is 40%, a significant admixture of apatite (~ 15%) is a favorable factor, since, as shown by the IPPES KSC RAS, additional introduction of nutrients enhances plant resistance under conditions of technogenic stress [2]. The waste also contains useful impurities of magnetite (~ 15%), mica and phlogopite (in the amount of ~ 30%), which are recognized as non-toxic and suitable for biological reclamation [3].

Screening of olivinite ore is obtained as a result of enrichment of olivinites of the Khabozero deposit. It has a fineness of more than 5 mm, consists mainly of serpentine minerals (70%), and also contains useful goethite (~ 10%), dolomite (~ 5%), pyroxene (~ 5%) and ~ 10% of mica minerals.

Serpentinitomagnesite is produced by CJSC "Lithosphere". The target product of the enterprise is magnesite, the yield of which is ~ 5%, the remaining 95% of the rock mass mined by the enterprise is mainly represented by serpentinite magnesite. According to OOO GEOKON, the reserves of serpentinite are practically unlimited within the Khalilovskoye ore district. The average content of minerals in the composition of serpentinite magnesite is, wt.%: Serpentine 80, magnesite 15, calcite 2, magnetite 2.5, chromite 0.5.

The content of nutrients available for plants was determined (see Table 1) in samples of the studied substrates.

As a result of experiments using all of the above wastes during the greening of urban areas and when restoring man-made disturbed lands (in wastelands), the claimed method yielded positive results.

Table 1 The content of calcium and magnesium compounds available for plants in various industrial wastes Components The content of available components, wt.% Substrates Carbonatite Waste Olivinite Ore Screening Serpentinite Magnesite CaO 6.5 0.37 0.50 MgO 1.1 2.3 5.0

The method was tested in Monchegorsk district of the Murmansk region on a man-made wasteland with soil pH less than 4.0. As a rule, under these conditions, plant roots cannot penetrate into such acidic soil and die. An expensive and labor-intensive method of creating a peaty soil fertile layer showed that such a layer under the conditions of ongoing aerotechnogenic pollution is able to quickly accumulate heavy metals and components of acid precipitation and becomes toxic after about 3 years, which leads to the gradual death of the vegetation created on it. Using the proposed method can significantly increase the thickness of the shielded layer to 5-6 cm or more, which is enough to form a powerful root system of plants and, very importantly, the sand layer formed in this way does not accumulate pollutants, as it is sand, it passes them into the ground wasteland with wash water (precipitation) and, having an alkaline reaction, neutralizes the surface layer of soil on which these wastes are applied, further increasing the thickness of the root layer.

The study of the conditions for the growth and development of herbs, the projective cover and the density of the grass stand created by this method of culture phytocenosis showed that the use of vermiculite substrate and a protective plastic film helps to initiate the process of seed germination, to produce friendly and massive green shoots in the conditions of the Murmansk region within 5-7 days. Thus, the high moisture and air capacity of the centimeter layer of vermiculite substrate saturated with moisture, despite the low air temperatures in the month of October (from -2 to + 4 ° C) in the conditions of the Murmansk region, ensured optimal humidity (70%) of the medium, stable positive temperatures (+4 to + 11 ° C), as well as favorable aeration conditions throughout the entire period of hatching, seed germination and the appearance of green shoots.

The use of waste as a fertile neutralizing layer contributed to the intensive development of grass shoots, the rapid development of the sand layer by the root system and deeper penetration of the roots into the contaminated soil compared to the control (option without using a bulk layer from the waste), as well as due to the high density of grass and projective cover, biomass growth, which is explained by more efficient drainage of this layer, its high buffering ability with respect to maintaining pH and pnostyu nutrients (Ca, Mg, Fe, Mn, N). In turn, stabilization of the hydrothermal regime, improved aeration, root secretions and litter of the created vegetation cover increase the number of microorganisms, strengthen the processes of humus formation, which mobilizes the potential fertility of the substrate, leads to the accumulation of organic matter and nutrients in a form accessible to plants. As a result, the destruction of pollutants to harmless compounds is intensified.

The invention is as follows.

On a technologically-disturbed area to be restored, or on a site intended for landscaping, a 5 cm bulk layer of industrial sand waste containing nutrient and lime elements that shield plants from contaminated soil is applied mechanically or manually (with small sizes of the area) neutralize its high acidity, increase its nutritional status and immobilize heavy metals, which reduces the phytotoxicity of the soil. The bulk layer can be larger and increased to 10 cm. It is additionally fertilized with mineral fertilizers - N ₇₀ P ₇₀ K ₇₀ . Then, manually or mechanically (for example, using seeders for sowing seeds or spreaders of solid fertilizers), the prepared expanded vermiculite is scattered on the surface of the waste layer with a layer of 1 cm. Seeding of perennial grass seeds is carried out manually with an even layer in an amount of 50-100 g / m ² . As seeds of perennial plants, red fescue, timothy grass meadow, beechless rind, sandy screech, etc. can be used. For the formation of vegetation cover, seeds of other perennial plants can be used, depending on the natural or cultural flora of a particular area, for example, creeping wheatgrass, clover meadow, etc. Crops watered with water in an amount of 5 liters per sq.m. and protect with a plastic film from the effects of extreme hydrothermal conditions and maintain optimal moisture to ensure mass germination of seeds. In a short time (5-7 days) a vegetation cover is formed from green shoots, which, thanks to the supply of nutrients and moisture in the vermiculite and shielding layers, quickly transforms into a powerful turf layer.

The inventive method:

- allows you to restore vegetation in urban and technologically disturbed areas without creating a fertile layer of scarce materials (soil, peat, etc.) in a short time;

- reduces acidity in the root layer;

- increases the supply of nutrients in the root layer;

- increases the permeability (drainage), providing a washing regime of the root layer, through which heavy metals, sulfur oxide and other pollutants easily pass, thereby reducing the content of heavy metals in the root layer and reduces their accumulation in the vegetative mass;

- increases the content of flavonoids in the aerial parts of plants;

- increases grass stand productivity;

- reduces the volume of discharged waste, solves the problem of waste disposal of the mining and processing complex;

- reduces the cost of bioremediation of technologically disturbed lands and landscaping of urban areas;

- contributes to the improvement of physico-chemical, nutritional properties of disturbed soil, the protection of plants from chemical pollution, the formation of high-quality grass stand in a short time.

The inventive method is effective in environmental, technological and economic terms and is recommended for the accelerated creation and reproduction of soil and vegetation cover near industrial enterprises in the conditions of aerotechnogenic pollution, at municipal facilities (the creation of lawns, arrangement of construction sites) and on technologically disturbed lands (chemical industry, metallurgical complex, mining and processing complex).

Bibliography

1. Agrochemistry // Ed. Klechkovsky V.M. and Petersburg A.V. M .: Kolos, 1967.584 s.

2. Lukina N.V., Nikonov V.V. Biogeochemical cycles in the forests of the north under aerotechnogenic pollution. Part 1. Apatity: Publishing House of KSC RAS, 1996.

3. Gorbunov N.I., Zarubina T.G. Theoretical and practical issues of land reclamation, disturbed by industry in the southern taiga and forest-steppe zones // Development of disturbed ... - M .: Nauka, 1976. - P.82-98.

Claims (4)

1. A method of creating a land cover during the restoration of disturbed lands, including applying waste, mineral fertilizers to the soil surface and sowing perennial grasses, characterized in that mining waste containing calcite and / or hydrosilicate is applied to the soil surface with a layer of at least 5 cm magnesium, produce inclusion complex fertilizers N ₇₀ K ₇₀ P _70, then a layer of 1 cm scatter expanded vermiculite granules with up to 4 mm, the inoculated mixture perennial plant seeds watered and covering by a polymer film, which is removed on the 5-7th day. 2. The method according to claim 1, characterized in that carbonatite waste, or screening of olivinite ore, or serpentinitomagnesite are used as waste from the mining industry. 3. The method according to claim 1, characterized in that the seeds of perennial plants use red fescue, timothy meadow, beetless boneless beetroot, sandy sand in an amount of 50-100 g per sq.m 4. The method according to claim 1, characterized in that the watering is carried out at the rate of 5 liters per square. m