RU2807744C1 - Biodegradable container mixture - Google Patents

Abstract

FIELD: forestry.

SUBSTANCE: mixture for a biodegradable container includes wood waste in the form of sawdust and a binder. Portland cement and mineral and organic components are used as a binding material in the following ratio, wt.%: Portland cement “ПЦ400 II/А-Ш 32.5Б (ПЦ 400-Д20)” - 20, softwood sawdust, 3...5 mm in size - 20, sand, fineness modulus 1...2.5 mm – 27, aluminium sulphate – 4, sodium liquid glass – 3, beet molasses – 2, water – 24.

EFFECT: preservation of the seedling and its root system is ensured.

1 cl, 4 tbl

Description

The invention relates to forestry. A mixture recipe has been proposed for the manufacture of a biodegradable forest planting container based on a wood-cement composite. The invention can be used for reforestation of cleared areas, protective afforestation, and cultivation of large-sized seedlings using technology with a closed root system.

A biocontainer for planting plants is known (patent RU 2423036 C1, published on 10/07/2011), containing a shell made of material obtained by pressing from one or a mixture of several formative, biologically digestible substances, with a cavity for planting material and additionally containing granules. a swelling, biodegradable absorbent in soil of water and/or aqueous solutions, the swelling rate of which in the presence of soil moisture and absorption capacity exceed, respectively, the swelling rate and absorption capacity of the biocontainer shell material.

The disadvantage of this biocontainer is its low mechanical strength and the inability to use it for growing large seedlings.

A known method of reforestation [RF Patent No. 2744178 C1, IPC A01G 23/00 publ. 03.03.2021], including a silvicultural area, planting material with a closed root system in substrate biocontainers with a protective shell, which are laid out individually on the surface of the silvicultural area or locus without placement in the soil in coordination with the microrelief of the area and fixation from possible displacement. For dimensional stability, the biocontainer is equipped with a protective moisture-permeable biodegradable shell made of cellulose-containing material (GOST 53207-2008 “Cardboard for flat layers of corrugated cardboard”).

The disadvantage of this method is the high cost of the original cellulose material (cardboard) from which the container is made and the low mechanical strength of such a container, which does not allow the production of a container of large size and sufficient strength intended for large-sized crops.

A known composition for producing a biodegradable pot [RF Patent No. 2723724 C1, IPC A01G 9/029, A01G 24/00, C12N 1/20 publ. 06/17/2020], consisting of plant waste with a percentage of 80-85% of the finished product, and a binder - a cultural liquid containing a polysaccharide.

This solution is closest to the stated one and is accepted as a prototype.

The disadvantage of the prototype is the limited availability, high cost of the culture liquid containing polysaccharides, as well as the insufficient mechanical strength of the biodegradable pot, which is not suitable for growing large plants.

The invention solves the problem of high-quality reforestation using seedlings with a closed root system, including large ones, due to the capabilities of a biodegradable container, as well as reducing the cost of the claimed product.

The technical result from the use of the invention is the preservation of the seedling and its root system, even if the latter is large in size.

This is achieved by the fact that the formulation of the biodegradable container allows it to be destroyed during the growth of the seedling without impeding the development of its root system; the need to remove the seedling from the biodegradable container before planting in the soil is also eliminated. The initial high strength of the formulation makes it possible to produce a large-sized biodegradable container, providing favorable conditions for growing large seedlings.

The claimed biodegradable container is thus distinguished by the use of Portland cement and mineral components as a binding material - sand, sodium water glass, aluminum sulfate, and if it is necessary to accelerate the destruction of the material of the biodegradable container, beet molasses is added to the recipe.

- The mixture recipe for molding a biodegradable container has been established experimentally (wt.%):

Portland cement PC400 II/A-Sh 32.5B (PC 400-D20) 20 Softwood sawdust, size 3...5 mm 20 Sand, fineness modulus 1…2.5 mm 27 Aluminum sulfate 4 Sodium liquid glass 3 Beet molasses 2 Water 24

Beet molasses can be added to the recipe in a volume of 1.5...2.5% by weight. Moreover, with an increase in the percentage of molasses, the rate of destruction of the biodegradable container increases.

Preliminary research has established (Dolmatov, S.N. Containers for reforestation from wood-cement composites / S.N. Dolmatov, P.G. Kolesnikov // Bulletin of the Volga State Technological University. Series: Forest. Ecology. Nature management. – 2021. – No. 2(50). – P. 52-60. – DOI 10.25686/2306-2827.2021.2.52. – EDN ODZQIY), the effect on the recipe of adding beet molasses if it is necessary to accelerate the destruction of the material of a biodegradable container.

In table 1. presents the results of testing samples made from the proposed formulation during compression and water absorption, where beet molasses can be added to the formulation in a volume of 1.5...2.5% by weight. In table 2, 3, 4 show the dynamics of strength reduction when in natural soil conditions.

Table 1 Proportion of molasses in the mixture, % R, MPa average W,% average Shapiro-Wilk R Shapiro-Wilk W View
distribution Statistic P-Value Statistic P-Value 0 3.4 47 0.933 0.3451 0.949 0.3676 Normal 1.5 2.9 53 0.901 0.296 0.856 0.3242 Normal 2.0 2.5 56.7 0.802 0.227 0.976 0.322 Normal 2.5 2.1 77 0.891 0.201 0.833 0.3402 Normal

table 2
Strength indicators, molasses 0% Molasses in the mixture - 0%
Time spent in the ground, months R, MPa average Shapiro-Wilk W View
distribution Statistic P-Value 0 3.41 0.949 0.3676 Normal 6 3.12 0.912 0.3432 Normal 12 2.89 0.871 0.3432 Normal 24 2.35 0.978 0.3737 Normal 36 1.77 0.912 0.3860 Normal 42 1.65 0.978 0.3921 Normal

Table 3
Strength indicators, molasses 2.0% Molasses in the mixture - 2.0%
Time spent in the ground, months R, MPa average Shapiro-Wilk W View
distribution Statistic P-Value 0 2.5 0.832 0.320 Normal 6 1.91 0.912 0.2814 Normal 12 1.4 0.921 0.3265 Normal 24 0.72 0.876 0.3782 Normal 36 - sample collapsed - - -

Table 4
Strength indicators, molasses 2.5% Molasses in the mixture - 2.5%
Time spent in the ground, months R, MPa average Shapiro-Wilk W View
distribution Statistic P-Value 0 2.1 0.912 0.2719 Normal 6 1.55 0.983 0.3689 Normal 12 1.21 0.903 0.3589 Normal 24 0.52 0.803 0.3471 Normal 36 - sample collapsed - - -

The final recommended mass ratio for molasses was 2%. With this ratio, the strength of the initial mixture is sufficient to form the walls of the container, and the dynamics of strength loss allows us to conclude that the material loses strength and breaks down after 36 months of being in the ground.

A biodegradable container made of wood-cement composite, located in natural soil conditions, is exposed to precipitation, freezing-thawing phenomena, and the action of mineral salts contained in the soil. In this case, the cement shell that envelops the wood particles is destroyed. These phenomena occur quite intensely due to the high porosity of the material. As soon as excess moisture during the destruction of cement stone becomes available for absorption by the wood particles that make up the wood-cement composite, the process of intensive water absorption begins. And under the influence of cycles of freezing and thawing of a sample with high humidity and under the influence of sugars in beet molasses, the bonds between wood and cement stone and the cement stone itself are destroyed. This causes a rapid decrease in the strength of the biodegradable container. It was experimentally established that the tensile strength of the wall material of a biodegradable container decreases from 3.41 to 1.65 MPa (when in the ground for 42 months) (Table 2). The final strength of 1.65 MPa corresponds to the indicators of heavy sandy loam (1.4 - 1.7 MPa). Such low strength will allow the root system of the developing seedling to easily overcome the walls of the container and go beyond its boundaries. When making the wall of a biodegradable container from a recipe containing 2% beet molasses (Table 3), the initial tensile strength of 2.5 MPa drops to 0.72 MPa after 24 months, and after 36 months the container is completely destroyed.

The material of the biodegradable container, after its destruction, enters the soil. Particles of mineral origin (sand, products of the destruction of cement carbonate stone due to their granulometric composition, contribute to loosening and saturation of the soil with oxygen. The nutrients contained in wood and beet molasses are processed by soil microorganisms and serve as a nutrient medium for the development of the root system of the cultivated plant. When used These components reduce the cost of the declared product.

Claims (2)

A mixture for a biodegradable container, including wood waste in the form of sawdust and a binder, characterized in that Portland cement and mineral and organic components are used as the binder material in the following ratio, wt.%: Portland cement PC400 II/A-Sh 32.5B (PC 400-D20) 20 softwood sawdust, size 3...5 mm 20 sand, fineness modulus 1…2.5 mm 27 aluminum sulfate 4 sodium liquid glass 3 beet molasses 2 water 24