LT6335B - Polymer composites for the preparation of mulch coatings - Google Patents

Abstract

The invention is related to the application of polymer composites for the preparation of mulching coatings on the growing media, which lower evaporation of water and improve the properties of the growing media. The grained waste of the processing of horns (horn meal) and crude glycerol which is the by-product of the production of biodiesel are used for the preparation of the composites. Glycerol is used as the plasticizer and as the source of the soluble organic carbon. Poly(vinyl alcohol) is used as a binder. The composites contain the nutrients useful for plants, i.e. nitrogen and phosphorus. The invention is related to the mulching of plants cultivated in pots and containers. The liquid mulching composition is spread out on the surface of the growing media. After drying up the mulch coating is obtained. The application of the certain amount of the composite with the certain size of the particles of the horn meal enables to form on the growing media the coatings of the required thickness. The coating obtained can be easily removed. Therefore, it can be named as the mulch mat or mulch carpet.

Description

Field of the invention to which the invention relates

The present invention relates to the use of polymeric composites to form mulch coatings on a growing medium to reduce water evaporation and improve the properties of the growing medium.

Existing level

The soil surface is mulched to preserve soil moisture, maintain a more consistent temperature and reduce weeds. Natural organic mulch is especially useful - compost, chopped grass, straw, peat, tree leaves, wood chips and so on. This mulch improves the physical properties of the soil, enriches it with nutrients and humus. However, the most widely used mulching films are non-degradable polyethylene and biodegradable mulch films made from polyhydroxybutyrate, polylactic acid, starch or mixtures thereof. Polyethylene film microorganisms do not decompose. After use, they must be removed from the soil and found suitable for their disposal. Biodegradable mulch film does not have this disadvantage. By the end of the vegetation period, the plants are decomposing and the waste can be plowed. However, these films are more expensive than polyethylene films [Subrahmaniyan Kasirajan & Mathieu Ngouajio Polyethylene and biodegradable mulches for agricultural applications: a review Agron. Sustain. Dev. (2012) 32: 501-529].

In order to reduce the mulching process, it is suggested to replace the biodegradable mulch films with liquid mulch when the biodegradable polymer solution or polymer solution with various additives is sprayed onto the soil surface. Once dry, a coating is formed that functions as a mulch film.

The patent [US6672001 (B1)] proposes the use of solutions of plant or animal protein materials for spray application of a mulch coating. By the end of plant vegetation the coverings are decomposing.

A known mulch composition is composed of polymer hydroxyethyl cellulose, water, clay and other components such as gypsum, paper. Spraying it creates a protective coating on the soil surface [US5082500 (A)].

Also known is a product for spray mulch coating. It is composed of cellulosic fiber 2 and recycled wood waste of different geometric shape with biodegradable components [US2007186463 (A1)].

The mulching mixture proposed in the patent [US2002129544 (A1)] is composed of a solution of polyvinyl alcohol and of vegetable origin dispersed therein.

The known mulch blend consists of a natural polymeric polysaccharide and various additives: vegetable and fruit processing residues, cotton, hemp, flax and other fibers, as well as waste paper production [EP2558548 (A1)].

[U.S. Pat. No. 4,297,710 A] discloses a mulch composition based on various size hay particles, shredded paper and binder.

In horticultural farms, seedlings and sprouts are grown in containers and pots. The water evaporates from them faster than when growing in soil, so the surface of the substrate is mulched to protect the plants from lack of moisture and to maintain the required and constant moisture in the root area. Organic mulch is often used for sapling of plants grown in containers or pots - crushed tree bark, pine or spruce needles, sawdust, wood chips, etc. However, in order to achieve the desired result, they must be several centimeters thick and also loose, which causes problems in transportation.

Nowadays, various companies offer coatings known as rugs or mats. They are made of wool, jute, coconut fibers.

There is a known method of making mulch mats consisting of two layers. The lower layer is made of rubber or other degradable material and the upper layer is made of chopped used tires [US7082713 (B1)].

The patent [US6293045 (B1)] proposes the use of composites consisting of cellulosic, proteinaceous fibers, ground corn stalks, nut shells, seeds, seed husk, tree bark and minerals: sand, perlite, vermiculite, etc. for the production of mulch mats. Binders may contain polysaccharides, polyglycosides, waxes or hardened oils.

Mulching mats or mats are easy and convenient to use, but the cost of producing and transporting them increases the cost of mulching and production. If coatings are made of non-degradable materials, problems arise with their collection and disposal, and the environment is polluted.

The agricultural, processing industries generate various types of animal waste. Appropriately treated, this waste is used in the organic farming system. One such waste is cattle horns. It is a keratin-containing waste which, when specially treated, is used in the manufacture of haberdashery. Poor horns and waste from the manufacture of these articles are crushed into chips or flour. They contain about 15% nitrogen, 1.5-2.0% phosphorus and other elements, so the shavings are used for fertilization and soil improvement. Since these nutrients are organic, they cannot be directly absorbed by plants. They must first be broken down by soil microorganisms into simple mineral compounds. As a result, nutrients are released gradually, reducing leaching to the environment and improving their efficiency [KornittowiczKovvalska Teresa, Bohacz Justyna. Biodegradation of keratin waste: Theory and practical aspects. Waste Management 31 (2011) 1689-1701; Jong-Myung Choi and Paul V. Nelson Developing a Slow-Release Nitrogen Fertilizer from Organic Sources: II. Using Poultry Feathers. J. AMER. SOC. HORT. SCI. (1996) 121 (4): 634-638]. We suggest using horn flour to make mulch coatings. These coatings would perform several functions: reduce moisture loss and provide a nutrient source for plants; release nutrients gradually throughout the vegetation period of the plant and improve the properties of the growing medium.

SUMMARY OF THE INVENTION The object of the present invention is to provide biodegradable, multifaceted mulch coatings for plants grown in pots and containers, directly on the surface of the growing medium.

The essence of the invention

For the mulching of plants grown in pots and containers, it is suggested to use composites made from the biodegradable polymer polyvinyl alcohol (PVA), horn flour and glycerol. The liquid composite mixture is applied to the surface of the growth medium. It dries to form a coating. The use of a certain amount of filler particles and composite content allows the coating medium to form a coating as a single unit. The resulting coating is easy to remove and can be called a mulching mat or mat. The present invention is directed to reducing the rate of evaporation of water from the culture medium and improving the properties of the culture medium. Coatings are biodegradable.

Description of Embodiment of the Invention

Polymeric composites are made from horn meal, a waste product from the processing of ground horns containing nitrogen, phosphorus and sulfur, and a raw glycerol byproduct of biodiesel production. Glycerol is used as a plasticizer and a source of soluble organic carbon. The binder used is a biodegradable polymer, polyvinyl alcohol (PVA) JF-17, having a viscosity of 98.0-99.0% at 20 ° C - 28-32 mPa-s (Kuraray America Ine. & Japan Vam & Powai). Other manufacturers' products with similar features can be used. The concentration of PVA in the polymeric composition should be 4-6%. Higher concentrations of solutions are unacceptable due to their viscosity, especially when sprayed.

example

Procedure: Dissolve 4 g of polyvinyl alcohol and 9 g of glycerol in 81 ml of water at 80-85 ° C, add 6 g of horn flour with a particle size of 0.4 to 0.25 mm and mix. The cooled mixture is poured onto the surface of the growth medium in which the seedling jar is filled. 0.8 ml of the composite is taken per 1 cm ^{2 of} surface. Dry at ambient temperature. Neutralized peat substrate for seedling growth was used in the growth medium tests.

Examples 2, 3, 4

Same procedure as in the first example, except that horn flour of different degrees of grinding is used here:

example - horn meal particle size 0.25 to 0.16 mm;

example - horn meal particle size from 0.16 to 0.09 mm;

an example is a horn meal particle size of 0.09 mm and smaller.

The vessels are watered with an equal volume of water and stored at 20-22 ° C in a 55% humidity environment. After 14 days, the moisture content of the substrate is determined. Study data are shown in Table 1.

table. Composite coatings thickness and substrate moisture in jars

For example, N r. Composite coatings thickness, mm Substrate Humidity,% Unpolluted substrate - 80.5 1 1.7 180 2 1.8 176 3 2.2 183 4 4-6 179

When the composite (eg No. 1, 2 or 3) layer dries, the resulting coating does not absorb into the substrate and forms as a single unit on the substrate surface and can therefore be referred to as a mat or mat. This coating can be removed.

There is no clear boundary between the coating and the substrate surface when mulching composites with a particle size of horn flour of 0.09 mm or less. The filler particles diffuse into the deeper layers of the substrate, resulting in a composite-substrate mixture - the crust that shrinks as the edges of the coating separate from the sides of the pan.

All coatings reduce evaporation of water from vessels up to 2.2 times.

Example 4 Dissolve 4 g of polyvinyl alcohol and 3 g of glycerol in 1 ml of water at 80 to 85 ° C, add 6 g of horn flour with a particle size of 0.4 to 0.16 mm and mix. As in Example 1 below.

Example 4 Dissolve 4 g of polyvinyl alcohol and 6 g of glycerol in 1 ml of water at 80-85 ° C, add 6 g of horn flour with a particle size of 0.4 to 0.16 mm and mix. As in Example 1 below.

Example 4 Dissolve 4 g of polyvinyl alcohol and 9 g of glycerol in 1 ml of water at 80-85 ° C, add 6 g of horn flour with a particle size of 0.4 to 0.16 mm and mix. As in Example 1 below.

All jars are watered with an equal volume of water and stored at 20-22 ° C in a 55% humidity environment. After 21 days, the organic carbon and nitrogen content in the aqueous extract was measured at a substrate / water ratio of 1:10. The concentration of organic carbon and nitrogen in the aqueous extract was determined using a TPC-V CSH TOTAL ORGANIC CARBON ANALYZER. Study data are presented in Table 2.

table. Properties of substrate for unmultified and mulched composite coatings

Example # Properties of substrate Soluble organic carbon, mg / l Soluble nitrogen, mg / l C: N Unpolluted substrate 151 34 4.4 5 216 18th 6.4 6th 542 19th 26.2 7th 1172 12th 97.6

By varying the glycerol content of the composite, it is possible to change the C: N ratio in the substrate. The size of this ratio determines the activity of soil microorganisms in their ability to degrade organic matter [P. Dalias, P. Polycarpou Decomposition of Biodiesel By-Product, Crude Glycerol, in Soil (2014) Res. Agr. Eng. Vol. 60, No. 1: 1723],

Claims (2)

1. A method of mulching plants grown in pots and containers by applying a liquid polymeric composite composition to the surface of the growing medium which, when dried, forms a mulch coating, wherein the composite material used is milled bovine horn processing waste - horn meal with a particle size of 0.4 0.16 mm, a by-product of biodiesel production - green glycerol and polyvinyl alcohol, which is a binder; Polyvinyl alcohol content in liquid polymer composition should be 4-6%, horn flour not less than 6%, glycerol 3-9%, water - up to 100%. 2. The method of mulching plants grown in pots and containers according to claim 1, characterized in that the coating can be formed both by spraying the composite mixture and applying it to the surface of the growing medium; 0.6-0.8 ml of the composite is required to cover 1 cm ^{2 of} culture medium.