RU2726561C1 - Hydrogel preparation for anti-pathogenic soil protection - Google Patents

Abstract

FIELD: agriculture.SUBSTANCE: invention relates to the agriculture. Hydrogel preparation is a highly cross-linked hydrophilic acrylic copolymer containing filler in the polymer matrix in the form of finely ground peat and silver ions in the following ratio, wt. %: hydrophilic acrylic copolymer - 70–82; turf filler - 14–23; silver ions - 0.5–1.0; residual water is balance.EFFECT: invention provides effective inhibition of growth of pathogenic microorganisms, including late blight.1 cl, 1 tbl, 7 ex

Description

The invention relates to agriculture and can be used as a plant protection agent in the root zone of plants.

Currently, agriculture uses a wide variety of plant protection products for anti-pathogenic soil protection. Most of them are toxic to humans and animals. Washing out plant protection products from the soil leads to pollution of environmental objects (primarily groundwater) and a decrease in the duration of the drugs used. One of the most effective and least toxic components of plant protection products is silver in ionic or colloidal form.

There are a large number of preparations based on colloidal silver and methods for their preparation (Patents RU 2584198 from 09/10/2014, 2463757 from 05/05/2011, 2459403 from 03/14/2011, etc.). Some of them are used as plant protection products.

Known composition "Agritos Agro", which is a concentrate of a colloidal solution of silver nanoparticles (99.99%) with an average nanoparticle size of 1-5 nanometers (aqueous solution) and 10 nanometers (in propylene glycol solution) with a wide range of antimicrobial, antiviral, antifungal and algicidal validity period 1-2 months.

Known drug Zerebra Agro (Patent RU No. 2419439 dated 05/27/2011), the active ingredient of which are 500 mg / l of colloidal silver and 100 mg / l polyhexamethylenebiguanide hydrochloride.

The main disadvantage of all these drugs is their leaching from the soil, which leads to a reduction in the period of action.

Known drug Zerox, the active substance of which are nanosized particles of colloidal silver, surface modified with a biodegradable amphoteric surfactant harmless to humans, animals and the environment, which allows it to be used as a fungicide. The disadvantages include rapid leaching from the soil.

Known preparations based on silver dihydrogen citrate (EAPO patent No. 018283 dated 04/30/2013, US patent No. 6583176 dated 10.10.1997). The main disadvantage is also rapid leaching from the soil.

Fixation of protective agents in the root zone of plants significantly increases their effectiveness.

Known biocidal composition based on bentonite powder intercalated with silver ions (Patent RU No. 2407289 dated 05/13/2009). The use of this composition as a plant protection agent in the root zone of plants is limited by the partial inactivation of silver during its sorption by bentonite, as well as the impossibility of protecting the roots not in direct contact with the bentonite surface in the entire volume of the rhizosphere.

One of the most effective methods for fixing biologically active substances in the soil is the introduction of hydrophilic lightly crosslinked polymers into a polymer matrix. The use of a hydrogel with a half-life of more than the active substance allows the latter to be kept in the root zone for the entire service life of the hydrogel without being washed out of the soil. In addition, the hydrogel helps to optimize water retention capacity, soil structure, mineral root nutrition, etc.

The closest in technical essence to the claimed invention are compositions obtained by swelling of rarely crosslinked hydrophilic acrylic copolymers in solutions of silver salts (Smagin et al. Gel compositions for anti-pathogenic protection and optimization of edaphic properties of the potato rhizosphere / Achievement of science and technology of the agro-industrial complex, 2018, vol. 32 , No. 3. pp. 54-63; Smagin et al. Gel-silver compositions for the rhizosphere: laboratory testing of antimicrobial properties / Agrochemistry, 2018, No. 5. pp. 27-34). The polymer base is a copolymer of acrylamide, sodium acrylate and N, N-methylene-bis-acrylamide as a crosslinking agent. The composition is obtained as a result of swelling of the copolymer in a solution of silver nitrate of a given concentration. Time to obtain the composition is 5-12 hours.

The main disadvantage of this composition is the loss of silver during polymer swelling. Part remains on the surface of the polymer and is easily washed off, and part can be lost when preparing a solution of silver nitrate due to its precipitation in the form of insoluble compounds when using fresh water of unknown composition. Also, the disadvantages of these compositions include the presence of two components, which is not very convenient in practice and can lead to errors.

Thus, the object of the invention is to eliminate these disadvantages and to create a highly effective one-component hydrogel preparation for antigenic soil protection in the root zone of plants, which has a prolonged biocidal effect and the possibility of optimizing the water-holding capacity and structure of the soil, mineral root nutrition (additives of microelements during the preparation process) etc.

The task is solved by simultaneously obtaining a hydrophilic acrylic copolymer containing peat filler and silver ions in a ratio,% wt:

hydrophilic acrylic copolymer - 70-82;

peat filler - 14-23;

silver ions - 0.5-1.0;

residual water - the rest.

The inventive drug is prepared as follows.

An aqueous solution of acrylamide (AA) and a crosslinking agent N, N'-methylene-bis-acrylamide (MBAA) in an amount of 0.05 ÷ 0.20 mol. Are loaded into a vertical cylindrical reactor equipped with a rising stirrer. % of the amount of monomers, mixed for 5 ÷ 25 min until the crosslinking agent is completely dissolved. Further, with stirring, aqueous solutions of salts of acrylic acid (AA) are introduced: ammonium acrylate (AkAm) or sodium acrylate (AkN). The ratio of acrylamide and acrylic acid salts is 25/40 ÷ 75/60 (mol%). Then, when the mixer is running, a solution of silver nitrate (demineralized or distilled water) is added in an amount of 0.5-1.0% (in terms of silver ions) of the total mass of monomers and peat filler, mixed for 1-10 minutes and then finely ground peat filler ( MTN) in the form of a powder (the degree of grinding is not more than 0.3 mm) in the amount of 15-25 wt. % of the amount of monomers in terms of dry weight. The components are mixed until a homogeneous dispersed system is formed (temperature is not more than 27 ° C, mixing time is 3 ÷ 20 min). Then, solutions of initiators (demineralized or distilled water) are introduced ammonium persulfate (PSA) and after 1 ÷ 10 min sodium sulfite (CH) in an amount of 0.10 ÷ 0.40 mol. % of each of the amount of monomers. After 3-25 minutes of stirring after the beginning of the gelation process, the stirrer is turned off and removed from the reaction mass. The duration of the polymerization process is 60 ÷ 300 min. Then the resulting polymer block is discharged from the reactor, it is cut, crushed, dried, crushing and screening by known methods.

The resulting preparation in finished form is black irregular granules with a size of 0.2 to 2.0 mm (depending on the degree of crushing and sieving, other fractions can be obtained).

Finely ground peat filler is obtained by grinding lowland peat dried at a temperature of not more than 70 ° C by any known method to a value of not more than 0.3 mm. The presence of a peat filler in a polymer hydrogel makes it possible to reduce its biodegradation rate, thereby increasing the service life of the entire composition due to an increase in the retention time of silver ions in the hydrogel and, accordingly, in the soil.

The resulting preparation is capable of absorbing from 450 to 650 grams of water per 1 gram of its dry weight, which facilitates the access of plant roots to the active substance of the composition (Ag), increases the water-holding capacity of the soil, improves its structure, mineral root nutrition, etc.

When the content of silver ions is below 0.5% of the mass. the effectiveness of anti-pathogenic soil protection decreases, and an increase of more than 1.0% of the mass. leads to overspending of the active substance and, accordingly, to an increase in the cost of the drug.

The advantage of the proposed drug over the prototype is the absence of loss of silver in preparation for application to the soil, a longer period of action and ease of transportation and preparation for application to the soil (swelling for 1-3 hours in fresh water).

Thus, the resulting hydrogel preparation for anti-pathogenic soil protection provides protection of plants from diseases transmitted with planting material and localized in the rhizosphere, has a high anti-pathogenic activity and a broad spectrum of action, a simpler and less laborious method of application to the soil compared to the prototype.

The use of the obtained drug in agriculture will reduce the incidence of plants, increase yields and improve the quality of grown products, and reduce the cost of watering crops. Preliminary field trials were carried out when growing various varieties of potatoes in open and closed ground with watering and natural precipitation against a natural infectious background and using pre-infected planting material in experimental farms in Moscow, Perm, Krasnodar and Uzbekistan, according to Smagin et al. Gel compositions for anti-pathogenic protection and optimization of edaphic properties of the potato rhizosphere // Achievements of science and technology of the agro-industrial complex. 2018.Vol. 32. No. 3. S. 54-63. DOI: 10.24411 / 0235-2451-2018-10311; Smagin AV, et al. Tests of the effectiveness of rhizosphere gel compositions for potato growing in arid irrigated agriculture // Coll. Waste, reasons for their formation and prospects for use. Krasnodar: KubGAU, 2019.S. 162-167. ISBN 978-5-00097-843-6. The tests confirmed 92-100% protection of the root layer of the soil and tubers of the new crop from the main pathogens of potatoes, including late blight, with 1.3-2 times saving of water resources and increasing the yield up to 6-15 t / ha.

This invention is represented by the following examples.

Example 1.

In a plastic reactor with a volume of 2 dm ³ , 315.5 cm ^{3 of a} 36% solution of acrylamide (113.6 g) and 1.23 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 768 cm ^{3 of a} 29.4% aqueous solution of sodium acrylate (225.6 g) is introduced. Further, when the mixer is running, 49.3 cm ^{3 of a} 5% solution of silver nitrate (demineralized water) are added, i.e. 1.565 g in terms of Ag ⁺ ion. Then, after 2 minutes with vigorous stirring, finely ground peat filler is introduced in the amount of 180.8 g. After 3 min of vigorous stirring, 2% aqueous solutions of 91.2 cm ³ PSA (1.824 g) and 50.4 cm ³ CH (1.008 g) are introduced. After 4 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 60 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the obtained preparation are shown in Table 1.

Evaluation of the anti-pathogenic properties of the drug was carried out by testing the suppression of the growth of phytophthora (Phytophthora infestans (Mont.) De Bary) and blackleg of potatoes (Pectobacterium atrosepticum (van Hall 1902)) on a nutrient medium (potato agar with a hydrogel preparation in a ratio of 1: 1 with differentiated doses of silver ), according to Smagin et al. Gel-silver compositions for the rhizosphere: laboratory testing of antimicrobial properties / Agrochemistry, 2018, No. 5. from. 27-34.

Biodegradation time was determined by carbon dioxide emissions from incubation experiments, according to Smagin et al. Biodegradation of Some Organic Materials in Soils and Soil Constructions: Experiments, Modeling and Prevention. / Materials, 2018, 11 (10), 1889: 1-22. doi: 10.3390 / malll01889.

Water absorption was determined in distilled water.

Example 2.

Obtaining the copolymer is carried out similarly to example 1, except for the use of ammonium acrylate instead of sodium acrylate.

Mixing is carried out in a plastic reactor with a volume of 2 dm ³ , 315.5 cm ^{3 of an} aqueous 36% solution of acrylamide (113.6 g) and 0.62 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 932.8 cm ^{3 of} 22.9% aqueous solution of ammonium acrylate (213.6 g) is introduced.

Further, when the mixer is running, 36.3 cm ^{3 of a} 10% solution of silver nitrate (demineralized water) are added, i.e. 2.305 g in terms of the Ag ⁺ ion. Then, after 2 minutes, with vigorous stirring, finely ground peat filler is introduced in an amount of 55.96 g.

After 3 minutes of vigorous stirring, 2% aqueous solutions of 91.2 cm ³ PSA (1.824 g) and 50.4 cm ³ CH (1.008 g) are introduced. After 5 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 300 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1.

Example 3

Getting the copolymer is carried out analogously to example 1. The difference is the use of a larger amount of silver ions and a different ratio of monomers.

Mixing is carried out in a plastic reactor with a volume of 2 dm ³ , 208.2 cm ^{3 of an} aqueous 34.1% solution of acrylamide (71 g) and 0.31 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 952.7 cm ^{3 of a} 29.6% aqueous solution of sodium acrylate (282.0 g) is introduced.

Next, 65.1 cm ^{3 of a} 10% solution of silver nitrate are added, i.e. 4.13 g in terms of the Ag ⁺ ion. Then, after 2 minutes with vigorous stirring, finely ground peat filler is introduced in an amount of 60.3 g.

After 3 minutes of vigorous stirring, 2% aqueous solutions of 45.6 cm ³ APS (0.912 g) and 25.2 cm ³ CH (0.504 g) are introduced. After 8 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 240 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1.

Example 4

Getting the copolymer is carried out analogously to example 3. The difference is the use of ammonium acrylate instead of sodium acrylate.

Mixing is carried out in a plastic reactor with a volume of 2 dm ³ , 208.2 cm ^{3 of an} aqueous 34.1% solution of acrylamide (71 g) and 0.31 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 1390.6 cm ^{3 of a} 19.2% aqueous solution of ammonium acrylate (267.0 g) is introduced.

Further, 62.4 cm ^{3 of a} 10% solution of silver nitrate are added, i.e. 3.96 g in terms of the Ag ⁺ ion. Then, after 2 minutes, with vigorous stirring, finely ground peat filler is introduced in an amount of 57.7 g.

After 3 minutes of vigorous stirring, 2% aqueous solutions of 45.6 cm ³ APS (0.912 g) and 25.2 cm ³ CH (0.504 g) are introduced. After 10 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 240 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1

Example 5

The copolymer is obtained analogously to example 4. The difference is the use of a different ratio of monomers and crosslinking agent.

Mixing is carried out in an enameled reactor with a volume of 100 dm ³ , 7.59 dm ^{3 of an} aqueous 36.0% solution of acrylamide (2.73 kg) and 16.94 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 28.8 dm ^{3 of a} 22.1% aqueous solution of ammonium acrylate (6.36 kg) is introduced.

Then 1929.0 cm ^{3 of a} 10% solution of silver nitrate are added, i.e. 122.49 g in terms of the Ag ⁺ ion. Then, after 5 minutes with vigorous stirring, finely ground peat filler is introduced in an amount of 2.99 kg.

After 7 minutes of vigorous stirring, 5% aqueous solutions of 1003.2 cm ³ PSA (50.16 g) and 554.4 cm ³ CH (27.72 g) are introduced. After 8 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 300 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1

Example 6

Getting the copolymer is carried out analogously to example 5. The difference is the use of more silver ions.

Mixing is carried out in a glass reactor with a volume of 10 dm ³ , 0.759 dm ^{3 of an} aqueous 36.0% solution of acrylamide (273.0 g) and 1.694 g of MBAA are mixed, stirring for 10 minutes until the powder is completely dissolved. Next, 2.88 dm ^{3 of a} 22.1% aqueous solution of ammonium acrylate (636.0 g) is introduced.

Next, 247.7 cm ^{3 of a} 10% solution of silver nitrate are added, i.e. 15.73 g in terms of Ag ⁺ ion. Then, after 5 minutes, finely ground peat filler in an amount of 299 g is introduced with vigorous stirring.

After 7 minutes of vigorous stirring, 5% aqueous solutions of 100.3 cm ³ PSA (5.01 g) and 55.4 cm ³ CH (2.77 g) are introduced. After 10 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 300 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1

Example 7

Getting the copolymer is carried out similarly to example 5. The difference is the absence of silver ions and filler.

Mixing is carried out in a plastic reactor with a volume of 2 dm ³ , 276 cm ^{3 of an} aqueous 36.0% solution of acrylamide (99.4 g) and 0.616 g of MBAA are mixed, stirring for 7 minutes until the powder is completely dissolved. Next, 1072.4 cm ^{3 of a} 22.1% aqueous solution of ammonium acrylate (231.4 g) is introduced.

After 3 minutes of vigorous stirring, 2% aqueous solutions of 91.2 cm ³ APS (1.824 g) and 50.4 cm ³ CH (1.008 g) are introduced. After 10 minutes, after the start of the gelation process, the stirrer is turned off and raised from the reaction mass. Polymerization time 60 min. Then cutting, crushing, drying, crushing and sieving into fractions is carried out, after which samples are taken to study the properties of the resulting composition.

The characteristics of the resulting composition are shown in table 1

Claims (2)

Hydrogel preparation for anti-pathogenic protection of soil with prolonged action, containing organic compounds and ionic silver, characterized in that hydrophilic acrylic copolymers filled with peat and ionic silver with the following ratio of components, wt% are used as organic compounds: hydrophilic acrylic copolymer 70-82 peat filler 14-23 silver ions 0.5-1.0 residual water rest