RU2807297C2 - Parametric system of mineral fertilizers with controlled dissolution and release of nutrients - Google Patents

Abstract

FIELD: chemical production; agriculture; mineral fertilizers.

SUBSTANCE: agrochemical complex includes a set of mineral fertilizers of one or different types, consisting of traditional U1 and several fertilizers U2, U3, U4, U5, U6, U7 encapsulated with polymer coatings with specified kinetic parameters of controlled dissolution and release of nutrients U1(t), U2(t), U3(t), U4(t), U5(t), U6(t), U7(t) and a computer program for controlling the dissolution of fertilizers. Control of the dissolution of fertilizers is carried out by changing the amount, composition and ratio of the components of the compositions, which are combinations of fertilizers in the set, adjusting and kinetically matching their dissolution parameters with the growth parameters of a particular plant, and selecting an agricultural plant. The measured values of the kinetic parameters of plant growth are converted into relative values - mass fractions, and brought to a measurement scale from 0.00 to 1.00. The relative values of the growth parameter of the selected plant are approximated and the kinetic curve of its growth is calculated using the equation: where: P - plant mass in relative values, mass, proportion; t - time, days; a, b, c, k, l, m are the coefficients of the equation. A set of fertilizers is selected, the kinetic parameters of the dissolution of the fertilizers in the set are converted into relative values - mass fractions, the dissolution curves of the compositions are calculated, the kinetic parameters of which are compared with the parameters of the plant growth curve. The approximation error is calculated as an integral indicator of the deviation of the curves and, based on its minimum value, the fertilizer composition whose dissolution curve most closely matches the growth curve of the selected plant is determined.

EFFECT: complex allows you to optimize the nutrition of agricultural plants and increase the efficiency of using nutrients from mineral fertilizers by synchronizing the processes of dissolution of the fertilizer system and plant growth.

1 cl, 7 dwg

Description

The invention relates to the areas of chemical production B01J, C05, C08, C09 and agricultural (hereinafter - agricultural) application of mineral fertilizers A01C 21/00 according to the International Patent Classification.

A parametric system of mineral fertilizers with controlled dissolution and release of nutrients (hereinafter referred to as the System) is an agrochemical complex for controlling plant nutrition and development, which includes:

- dynamic set, a set of several mineral fertilizers of the same or different types with certain, precisely specified dissolution parameters (speed, duration, kinetics);

- a computer program for dissolution control (hereinafter - the Program), which, by varying the composition and ratio of fertilizers of the dynamic set, calculates and composes the composition, dissolution and release of nutrients (hereinafter - IR) which ensures optimal nutrition and development of a particular plant under given growing and exposure conditions environment.

The dynamic set includes fertilizer systems of 3 levels:

1. General system.

2. Operating systems.

3. Fertilizer compositions.

The set is called dynamic because when using the System, which consists in the formation of various combinations of composition and ratio of fertilizers, there is a movement from the general system to a specific composition (final product): from the fertilizers of the general system, the Program compiles operational systems, on the basis of which compositions are calculated and selected one that provides the optimal nutrition regime for a particular plant under given growing conditions.

1. General system (1st level system) - a basic element, which is a set of several (at least 4) fertilizers with certain, precisely specified parameters for the dissolution and release of nutrients.

For example, a set of 6 polymer-coated modifications of the nitrogen fertilizer urea U2, UZ, U4, U5, U6, U7 with S-shaped kinetics U2(t) (2), U3(t) (3), U4(t) (4 ), U5(t) (5), U6(t) (6), U7(t) (7) and the duration of complete dissolution at 20°C in the range from 30 to 110 days. The additional 7th element of the kit is traditional (non-encapsulated) urea U1 with linear dissolution kinetics V1 (t) (1) and a duration of complete dissolution of 10-15 days, expanding the capabilities of managing the dissolution of the Fertilizer System in the early stages of the growing season, as well as reducing the cost of final compositions with her participation (Fig. 1).

The unit of measurement for the dissolution process of mineral fertilizers is the amount of released nutrients (hereinafter referred to as CPR), the natural values of which (U*) are expressed as the concentration of the dissolved substance in g/l, mol/l, etc. Values of quantitative parameters of the processes of fertilizer dissolution and plant growth in actual units of measurement may differ significantly from each other, making them difficult to compare and reconcile. For accurate and correct kinetic coordination of processes, their quantitative parameters must be compared on the same scale, on the same measurement scale. To do this, the process parameters are brought to one dimensional scale - converted into relative values by dividing the intermediate natural values of the parameter by its maximum value Par=Par*/Par* _max and expressed in mass fractions, on a measurement scale from 0.00 to 1.00. The natural values of the CPV of fertilizers in the general system are converted into relative values Y = Y * / Y * _max and are expressed in mass fractions.

Comparison of the kinetic characteristics of the processes of fertilizer dissolution and plant growth is carried out in real time, therefore process graphs are given in the coordinate system:

ordinate axis - a quantitative parameter of the process, expressed in natural* (g, kg, g/l, etc.) or in relative quantities (mass, fraction) on a measurement scale from 0.00 to 1.00;

The abscissa axis is the time of the process in real units of measurement (t, days), in increments of 5 days.

The dissolution kinetics and duration of release of PV of encapsulated fertilizer are determined by many factors or their combination, for example, the thickness of the polymer shell of the capsule δ, microns. The thickness of the polymer coating of particles and, accordingly, the duration of dissolution of fertilizers increase from U2 to U7.

Fertilizers of the general system form a kinetic region of dissolution control, the boundaries of which are the curves of the fastest soluble fertilizer Y1(t) (1) and the slowest soluble fertilizer Y7(t) (7) of the set. Nutrition of a large number of crops, the duration and kinetic growth curve of which fits into the dissolution control area of the general system, can be optimized using such a kit.

Each of the 6 encapsulated fertilizers U2, U3, U4, U5, U6, U7 of the general system can be used as an individual fertilizer with controlled release of PV, but not every encapsulated fertilizer can be an acceptable element of the System. The general system is a set of fertilizers with specific, precisely defined dissolution parameters, various operational combinations of which allow the nutrition of as many different crops as possible to be optimized as accurately as possible in a wide range of growing conditions and environmental influences.

2. From the set of fertilizers of the general system, operational systems (2nd level systems) are compiled as combinations of 2, 3 or more components to optimize the nutrition of specific agricultural crops in certain growing conditions.

3. Varying the composition, i.e. based on the dissolution parameters of the operating system fertilizers and the weight ratio of the components in the combination, the dissolution control program calculates possible compositions (3rd level systems) and selects one, the dissolution of which is most accurately kinetically matched with the growth of a specific agricultural crop.

A fertilizer composition is several fertilizers mixed in a certain proportion with different dissolution parameters from the general system kit.

nK - composition of n-fertilizers;

h - index of the component in the composition, h=1, 2 ... n;

n is the number of components in the composition (operating system);

U ₁ , U ₂ ... U _n - components of the composition, individual fertilizers from the general system kit;

w ₁ , w ₂ ... w _n - weight fractions of components in the composition, w ₁ +w ₂ +...+w _n =1.00.

The dissolution parameters of the n-fertilizer composition are determined by the dissolution parameters of each component of the composition, the ratio of the components (their weight fraction) in the combination and the number of components. Dissolution parameters include the rate, duration and kinetics of dissolution and release of the PV fertilizer.

The optimal number of components for operational systems and compositions, from a functional, economic and technological point of view, are combinations of 2 or 3 fertilizers.

For a general system of 7 fertilizers, the total number of two-component compositions (hereinafter referred to as 2K-composition) is 2121. Any agricultural enterprise or farmer can independently calculate, compose and apply 2K-compositions for their crops and growing conditions, having the appropriate instructions and documentation.

The total number of three-component compositions (hereinafter referred to as the 3K-composition) is 180,285. In this case, the calculation and selection of the composition for optimal plant nutrition is carried out by the chemical company that produces the Fertilizer Systems based on the technical specifications from the customer.

The main components of the System are fertilizers with controlled dissolution and release of PV. The method for producing such fertilizers is microencapsulation - these are chemical, physicochemical and physical methods of enclosing dispersed particles in polymer shells and capsules [1, 2], such as:

- coacervation (phase separation);

- solvent evaporation;

- interfacial polymerization or polycondensation;

- extrusion, electrostatic and other methods.

These methods consist of creating a physical barrier on the surface of encapsulated particles by applying organic polymer film coatings of different thicknesses, with different chemical natures, structures and physical properties, to different types of mineral fertilizers of different granulometric compositions.

Note. Inorganic, mineral and other natural and synthetic materials are also used as capsule shells. Only organic film-forming polymers are considered here.

Fertilizer systems can be of two types:

1. A combination of one type of simple or complex particle fertilizer with different dissolution parameters. For example, a composition of nitrogen fertilizer urea from non-encapsulated (traditional) and encapsulated particles of different sizes and shapes, coated with polymer membrane films of different nature, structure and physical properties, with different coating thicknesses in one or several layers.

2. A combination of several types of fertilizers of different chemical natures with different dissolution parameters in different weight ratios. For example:

- a triple combination of encapsulated particles of ammonium nitrate (N), potassium chloride (K) and unencapsulated particles of traditional superphosphate (P);

- double combinations of encapsulated particles of urea (N) and ammophos (NP) or of encapsulated particles of ammonium nitrate (N) and azophosphate (NPK), etc.

Today, in many countries around the world, the development, industrial production and use of controlled-release fertilizers (CRF) are actively underway [3, 4, 5, 6]. The growing popularity of such products is due to the fact that their use leads to increased efficiency in the use of PV compared to traditional fertilizers, improved plant nutrition, increased yield of agricultural crops, which results in increased profitability of agricultural production and preservation of the environment. A particularly powerful impetus for the development of mineral fertilizers encapsulated with polymer coatings was given by the creation in the early 2000s by the Canadian company Agrium Advanced Technologies of the ESN product “Intelligent Nitrogen” (Polymer Coated Urea, polyurethane encapsulated urea), which is currently the most widespread nitrogen fertilizer with controlled release PV with a production volume of more than 500,000 tons per year [7, 8, 9, 10, 11].

The parametric system of mineral fertilizers with controlled dissolution is a continuation and development of the theme of “smart” encapsulated fertilizers with controlled release of PV (CRF), with the aim of enhancing their functional and economic efficiency, improving nutritional conditions and development of plants, increasing the yield of agricultural crops and environmental safety environment.

To ensure optimal nutrition and development of an agricultural crop, it is necessary that the processes of fertilizer dissolution and plant growth be kinetically coordinated in quantitative and time parameters, i.e. their curves expressed in relative values and on the same measurement scale must coincide.

Plant growth is a process of biosynthesis, the process of creating its shape and mass, which proceeds according to a certain program embedded in its genetic memory. Graphically, the kinetics of this process usually takes the form of an S-shaped curve (sigmoid), for example, the growth curve of a corn plant P*(t) (8) (Fig. 2.1). The unit of measurement for growth (P*) is usually the dry mass of the whole plant (hereinafter referred to as DM), which in natural quantities is expressed in grams or kilograms. Further and everywhere the abscissa axis is t, days.

As was said earlier, for an accurate and correct comparison and kinetic coordination of the processes of fertilizer dissolution and plant growth, their quantitative parameters must be compared on the same scale and on the same measurement scale. Therefore, the natural values of plant dry mass (P*), as well as the amount of released fertilizer nutrients (V*), are converted into relative values P _OB =P*/P* _max and are expressed in mass fractions, on a measurement scale from 0.00 to 1.00. The growth curve of a corn plant in relative values P _OV (t) (9) (Fig. 2.2) is kinetically completely identical to the plant growth curve in natural values P * (t) (8).

Traditional nitrogen fertilizers, such as ammonium nitrate, urea, ammonium sulfate, etc., have high solubility and dissolution rate in water and aqueous media. Depending on the temperature, composition and humidity of the soil, water regime and other external factors, the dissolution of such fertilizers occurs quite quickly and ends within 1.5-2 weeks after their application. The dissolution curve of a traditional nitrogen fertilizer, for example, urea U1(t), is almost linear (1), which, both in the shape of the curve and in time parameters, is absolutely incomparable with the S-shaped plant growth curve, for example, corn P _OB (t) ( 9), when comparing the relative values of quantitative parameters of processes (U, R _OV ) on the same scale, on a measurement scale from 0.00 to 1.00 (Fig. 3). Due to the discrepancy between the kinetic parameters of plant growth and the dissolution of traditional nitrogen fertilizers, the efficiency of using their nutrients does not exceed 20-30%. The dissolution process of traditional nitrogen fertilizers cannot be controlled or modified. All this causes high losses of PV of traditional nitrogen fertilizers, irrational plant nutrition and, as a consequence, low yields of agricultural crops and pollution of the soil and the environment.

Unlike the traditional one, the dissolution of a mineral nitrogen fertilizer encapsulated with a polymer coating proceeds through a more complex mechanism, which, in addition to the heterogeneous chemical reaction between the capsule core and soil water, includes the processes of mass transfer of the liquid phase through the film coating, i.e. diffusion membrane processes. This mechanism reduces the dissolution rate and radically changes the kinetics of solute release compared to traditional mineral fertilizers. A “lag period” dissolution delay appears at the initial stage and a smooth exponential deceleration at the final stage, which forms the S-shaped dissolution kinetics of the encapsulated nitrogen fertilizer. The S-curve of dissolution, for example, of the encapsulated nitrogen fertilizer urea U5(t) (5) both in shape and in time parameters is comparable to the S-curve of plant growth corn P _OB (t) (9) when comparing the relative values of the quantitative parameters of the processes ( U, R _OV ) on the same scale, on a measurement scale from 0.00 to 1.00 (Fig. 4). The correspondence of the kinetic parameters of plant growth and the dissolution of encapsulated fertilizers determines the high, up to 70-80%, efficiency of the use of PV, which can significantly improve the nutrition and development of agricultural crops, reduce losses of PV and reduce the chemical impact on the soil compared to traditional fertilizers [6 ].

The parameters of the process of dissolution and release of PV of an individual encapsulated fertilizer are fixed, but can be changed by changing the chemical nature or type of film-forming polymer, its density, porosity and permeability, film thickness and/or number of layers, etc. Changing the dissolution parameters of an individual encapsulated fertilizer can be performed only in the factory, at the stage of its production or at the stage of research work when developing the formula and actually means the creation of a new product. The kinetics of the dissolution process of individual encapsulated fertilizers with controlled release of PV is comparable, but not synchronized with the kinetics of plant growth/nutrition. Complete coincidence of the kinetic curves of these processes is possible only by chance, because the number of combinations “plant - growing conditions” is huge, and it is technologically and economically infeasible to develop and produce a separate encapsulated fertilizer for each such combination.

The main difference between a parametric fertilizer system and the selected prototype, an individual polymer-coated controlled-release nitrogen fertilizer, such as the ESN product, is the OPERATIONAL CONTROL of the dissolution and release of the PV.

- OPERATIONAL is the ability to easily and quickly, anywhere and at any time, “on the spot”, for any agricultural crop, in a wide range of growing conditions and environmental influences, to change the dissolution parameters of the Fertilizer System: speed, duration and dissolution kinetics.

- MANAGEMENT of fertilizer dissolution is the ability to adequately respond to changes in the type of agricultural crop, growing conditions and environmental influences, accordingly changing the parameters of the dissolution process of the System, fine-tuning, synchronizing them with the parameters of the plant’s nutrition and growth processes.

The fertilizer system allows you to quickly calculate and create a composition whose kinetic dissolution parameters most accurately correspond to the growth/nutrition parameters of a particular plant under given growing conditions and environmental influences. For example, the composition of 2 encapsulated modifications of nitrogen fertilizer urea 2K=w ₁ ⋅U ₁ +w ₂ ⋅U ₂ , where: U ₁ =U5, U ₂ =U6 from the general system kit (Fig. 1). Fertilizers U5, U6 form an operational 2K system, including in steps of 1% weight. 101 compositions, and the dissolution curves U5(t) (5), U6(t) (6) form the area for controlling the parameters of the compositions. By varying the ratio of components U5, U6, possible 2K compositions are compiled within the operating system and one 2K _KS =0.7⋅U5+0.3⋅U6 is selected, the dissolution of which is most accurately kinetically synchronized (KS) with the growth of a particular plant. The S-curve of the dissolution of the fertilizer composition 2K _KS (t) (10) almost completely coincides with the S-curve of the growth of the corn plant (9), 2K _KS (t) ≈ P _OV (t), when comparing the relative values of the quantitative parameters of these processes (2K _KS , R _OV , U) on the same scale, on a measurement scale from 0.00 to 1.00 (Fig. 5). With such a degree of coordination of the processes of dissolution of the optimal composition of fertilizers and plant growth, the efficiency of PV use is as high as possible and amounts to more than 90%, which ensures the most rational diet and development of the plant throughout the entire growing season. The dissolution parameters of this 2K fertilizer composition can be easily and quickly changed or adjusted by changing the weight ratio of the components w ₁ / w ₂ , for example, when switching to another agricultural crop or when changing growing conditions (temperature, humidity, water regime, composition and soil structure, etc.).

As stated earlier, a custom controlled release encapsulated fertilizer such as ESN has fixed dissolution parameters (rate, duration and kinetics) that are set and can only be changed by the chemical manufacturing company during the product development or factory production phases. .

The parametric fertilizer system, unlike individual encapsulated fertilizers, has two levels of dissolution control.

1. Strategic management - changing the dissolution parameters of individual fertilizers of the general system set; development, adjustment and optimization of the composition, quantity, properties of fertilizers and parameters of the dissolution control area of the general system; improvement and development of the Fertilizer System dissolution management program. Performed by the chemical manufacturing company of the System at the stages of research development and industrial production.

2. Operational management - quick, adequate and accurate response to changes in growing conditions and environmental influences and/or during the transition from one agricultural crop to another, by changing the composition and ratio of fertilizer compositions. Performed by an agrochemical company or agricultural manufacturer at the stages of preparation and application of the Fertilizer System in the field.

The essence of the operational dissolution control of the System is that, unlike an individual encapsulated fertilizer, the dissolution kinetics of which is determined by one S-curve for each product, a system of any level is a combination of several fertilizers that form a certain kinetic dissolution region, consisting of many S- curves of various compositions, the boundaries of which are the dissolution curves of the fastest and slowest fertilizer from the general system kit. Within this kinetic region, the dissolution of a fertilizer system of a given level can be easily controlled by changing the composition and weight ratio of the components and, thus, quickly calculate and select a composition that provides the optimal nutrition regime for a particular plant. So, for example, for 2K-compositions (w ₁ U5 + w ₂ U6) of the operational 2K-system U5-U6, an increase in the weight fraction w _{1 of} the U5 fertilizer will gradually increase the integral speed (the steepness of the S-curve increases) and will reduce the total duration of dissolution of the composition, and a change in the composition of the operational 2K system to U4-U6, i.e. replacing U5 with an even faster modification U4 at a constant w ₁ /w ₂ ratio will sharply increase the speed and significantly change the slope of the S-curve of dissolution of the composition (w ₁ U4 + w ₂ U6).

The main task of the parametric mineral fertilizer system is to optimize plant nutrition and development. The condition for optimal plant nutrition (hereinafter referred to as OPR) is the exact kinetic coordination of the processes of fertilizer dissolution and plant growth, which is carried out using the System’s computer program for controlling the dissolution of fertilizers according to the following algorithm.

1. A plant is selected, for example, the agricultural crop corn.

2. The conditions for growing corn are set: temperature*, humidity, type and composition of soil, etc.; the defining indicator is the weighted average active soil temperature during the growing season of the selected agricultural crop, for example, Тn°=20°С.

3. Quantitative parameters for the growth of the selected agricultural crop under the given growing conditions are entered. The dry mass of the entire corn plant (P*) is measured at different arbitrary points in time from the beginning of the growing season (sowing), for example, 10 days - 0.006 kg, 20 days - 0.022 kg, 38 days - 0.074 kg, 50 days - 0.171 kg, 62 days - 0.347 kg, 75 days - 0.449 kg, 85 days - 0.459 kg, maximum value P* _max = 0.460 kg. Minimum 5 measurements.

Natural values of the measured dry mass of corn (P*) are converted into relative values P _OB =P*/P* _max , mass, fraction: 10 days - 0.012, 20 days - 0.047, 38 days - 0.161, 50 days - 0.373, 62 days - 0.754, 75 days - 0.976, 85 days - 0.998.

4. Values (R _OV ) are approximated using numerical methods. The coefficients of equation (11) are calculated and the complete growth curve of the corn plant P(t) (12) is constructed in the time interval (t) from 0 to 100 days, with a constant step Δt=5 days (Fig. 6).

Plant growth equation (sigmoid equation):

P - plant mass in relative values, mass, proportion;

t - time, days;

a, b, c, k, l, m are the coefficients of the equation.

The curves P(t) and P _OB (t) almost completely coincide when comparing the relative values of their kinetic parameters (P, P _OB ) on the same scale, on a measurement scale from 0.00 to 1.00, approximation error Ap = 0.104%. The P(t) curve is the basis for comparison and kinetic synchronization of the processes of fertilizer dissolution and plant growth.

5. Fertilizer is selected, for example, nitrogen fertilizer urea. A general fertilizer system is specified, for example, a set of traditional urea U1 and its six encapsulated modifications U2, U3, U4, U5, U6, U7 (Fig. 1) with different S-kinetics and duration of complete dissolution in the range of 10 days U1(t ) up to 110 days U7(t). Quantitative parameters for the dissolution of fertilizers in the general system are introduced, expressed in relative values, for a temperature of 20°C equal to the specified weighted average soil temperature,

6. Selection of fertilizers for the operating system and calculation of the optimal composition.

6.1. The number of components of the composition is selected, for example, a two-component fertilizer composition is calculated.

6.2. From the set of the general system, the dissolution control program makes up operational systems from combinations of 2 fertilizers, U ^j ₁ -U ^j ₂ . Number of possible operational 2K systems from a set of 7 fertilizers:

6.3. For each j-operational 2K system, compositions are calculated with different ratios of the weight fractions of fertilizers 2K _i ^j =w _1i ⋅U ^j ₁ +w _2i ⋅U ^j ₂ , from 100% modification U ^j ₁ (w _1i =1.00, w _2i =0.00) to 100% Y ^j ₂ (w _2i =1.00, w _1i =0.00). Each operational 2K system includes 101 (i) compositions, with a step of the ratio of the weight fractions of the components of 1%, Δw _i =0.01.

6.4. For each 2K-composition of each j-operational system, a dissolution curve is constructed - the change in the total amount of released PV of the fertilizer combination w _1i Y ^j ₁ and w _2i Y ^j ₂ - in the time interval of plant growth from 0 to 100 days.

i=1-101, j=1-21

6.5. The values of the quantitative parameters of dissolution and release of PV of each composition 2K _i ^j (1) are compared with the values of the complete plant growth curve P(t) at the same time points in the range from 0 to 100 days.

6.6. The values of the square deviation of the 2К _i ^j (t) and P(t) curves at each time point and the approximation error A (%) are calculated using the general formula:

y - values of the complete plant growth curve P(t);

y _x - values of the dissolution curve of the composition 2K _i ^j (t);

- arithmetic mean value of plant growth parameters P _SR ;

n is the number of time points for comparing curve values. The approximation error is an integral indicator of the deviation of the kinetic curves of the dissolution of the composition 2К _i ^j (t) and the growth of the corn plant P(t).

6.7. The program calculates the values of the integral deviation indicator for all possible 2K fertilizer compositions of all operating systems and compiles a table of values size 21x101, where the columns determine the composition of the operational 2K system and the lines show the ratio of the weight fractions of fertilizers w _1i / w _2i in the 2K-Composition.

6.8. From the table, the Program determines the minimum value of the approximation error A ₁₉ ³³ = 1.19% with coordinates (19, 33):

- column 19 (j), operational 2K system U5-U6;

- line 33 (i), component ratio U5/U6, w ₁ /w ₂ =0.68/0.32,

which determine the fertilizer composition whose dissolution curve most closely matches the plant growth curve. 2K ₁₉ ³³ =0.68⋅U5+0.32⋅U6 is a composition of optimal plant nutrition, the dissolution process of which is kinetically synchronized with the growth of corn - the dissolution curve of the 2K-composition OPR 2K ₁₉ ³³ (t) (13) almost completely coincides with the curve corn plant growth P(t) (12), when comparing the relative values of the quantitative parameters of the processes (2К ₁₉ ³³ , Р) on the same scale, on a scale from 0.00 to 1.00 (Fig. 7).

By default, the computer dissolution control program automatically calculates and composes the optimal composition based on the most accurate match between the plant growth and fertilizer dissolution parameters. The program also allows you to manually change and adjust the parameters and dissolution kinetics of an automatically calculated composition, for example, to compensate for a large deficiency or remove an excessive excess of PV at certain stages of the growing season.

Two modes for manually changing dissolution parameters:

- fine tuning - adjusting the kinetic parameters of the dissolution of the composition by changing the ratio of the weight fractions of fertilizers within the selected operating system;

- rough adjustment - changing the composition of fertilizers of the operating system, creating a new one from the set of fertilizers of the general system.

Using the same algorithm, the processes of plant growth and dissolution of compositions of 3 or more fertilizers are synchronized.

The synchronized composition of fertilizers ensures rational and continuous nutrition of the plant throughout the entire growing season, so this composition is applied to the soil only once, according to the “set it and forget it” principle. Since the chemically active substance of the encapsulated fertilizer particles is isolated by an inert polymer film, the composition can be applied to the soil during sowing along with agricultural seeds without harm to them, which allows the fertilizer to be placed in close proximity to the plant and thus reduce contact time with soil and loss of PV, and also allows you to reduce the number of production operations in the field and, accordingly, the costs of preparing and applying fertilizer.

The parametric system of mineral fertilizers with controlled dissolution and release of PV is a complex, high-tech chemical product, the development of which includes 2 stages:

1. Development of individual encapsulated fertilizers with controlled dissolution and release of PV.

2. Development of a multicomponent parametric fertilizer system with controlled dissolution.

Each stage includes the implementation of research programs (hereinafter referred to as R&D) in the fields of physics/chemistry and agronomy/soil science.

Task. To create a highly effective, competitive commercial product whose functional and performance value exceeds the added cost of its production.

Stage 1. The physical and chemical research program for the development and testing of individual encapsulated mineral fertilizers with specified controlled dissolution parameters includes sections:

1.1. Formulation of the problem. For example:

- increasing the duration of complete dissolution of the encapsulated fertilizer by several (3 to 20) times compared to the original traditional fertilizer;

- S-shaped kinetics with certain dissolution parameters and shape.

1.2. Product formula development.

The kinetic parameters of dissolution and release of PV of individual encapsulated fertilizers are determined by the following factors. 1.2.1. Parameters of the capsule polymer material:

- the type and chemical nature of the film-forming polymer, for example, polyesters, nitrogen-containing and organoelement polymers, cellulose ethers, polyolefins, synthetic and natural rubbers, etc.;

- physical properties of the polymer film-membrane (strength, density, permeability, elasticity, wear resistance, etc.);

- thickness of the coating layer and number of layers;

- the presence, nature, structure and properties of adhesive, intermediate layers at the interface between the surface of the particles and the polymer shell.

1.2.2. Parameters of the original traditional fertilizer:

- the chemical nature of the fertilizer, its chemical properties and activity;

- physical properties (density, strength, solubility, etc.);

- size and shape of fertilizer particles;

- state and structure of the particle surface (roughness, microrelief, microdefects, etc.).

Based on the task and the factors that determine the dissolution parameters of the encapsulated fertilizer, the following are selected and justified:

- initial traditional fertilizer for encapsulation (chemical nature, formula, size, shape of particles, etc.), for example, nitrogen fertilizer urea (urea), CO (NH) ₂ , granular spherical particles with a diameter of 2-4 mm;

- film-forming polymer (type, nature, properties, quantity, etc.), for example, polyurethane (hereinafter referred to as PU) elastomers, from 3 to 20% wt. to the weight of the fertilizer.

1.3. Development of encapsulation technology [1,2].

Effective technologies for encapsulating solid powdered mineral fertilizers of different granulometric compositions are physical and chemical methods of applying polymer film coatings from solution, such as coacervation and solvent evaporation.

1.3.1. Selection and justification of the technology for applying PU elastomeric film coatings to particles of granular powdered urea.

1.3.2. Testing the technological modes of the selected method:

- number and duration of stages of the technological process of applying a polymer coating;

- sequence of stages;

- temperature and pressure at the stages of the technological process;

- methods and modes for creating adhesive and intermediate boundary layers;

- modes of auxiliary processes, etc.

Taking into account the properties of the original traditional fertilizer, varying the parameters of the polymer coating and the modes of the stages of the technological process of its application, the dissolution parameters of an individual encapsulated fertilizer with controlled release of PV are set. For example, when the thickness of the polymer shell of the capsule or the number of coating layers changes, the duration and dynamics of the change in the rate of dissolution of the encapsulated fertilizer changes. Controlling the elastic properties of the polymer shell is necessary to ensure a constant slow and diffusion mechanism for the release of dissolved PV fertilizers from the capsule without its destruction; the elongation coefficient of the polymer must be at least 100%. The adhesion of the coating to the surface of the particles, the presence and properties of the boundary layers determine the dissolution delay time (lag period parameters) and the dissolution kinetics of the encapsulated fertilizer.

1.4. Primary physical and chemical tests of encapsulated products:

- obtaining accurate, objective qualitative and quantitative characteristics of the process of dissolving encapsulated fertilizer in water and aqueous media using electrochemical methods such as conductometry, potentiometry;

- analysis, comparison with the dissolution parameters of the original fertilizer;

- selection of encapsulated fertilizer for agronomic and soil tests. In the field of agronomy/soil science, joint

research program with agricultural scientific organizations and agricultural enterprises, which includes:

1.5. Determination of types of agricultural crops and growing conditions for testing and industrial use of individual encapsulated fertilizers.

1.6. Laboratory research and field testing of samples and batches of encapsulated fertilizers for various soils, agricultural crops, and growing conditions. Based on agronomic and soil tests, versions are determined

encapsulated products for industrial production and use as individual fertilizers with controlled dissolution and/or as a component of a parametric system.

Stage 2. Development and testing of a multicomponent parametric system of mineral fertilizers with controlled dissolution.

The physical and chemical research program includes sections:

2.1. Formulation of the problem. For example:

- creation of a set of general system fertilizers with a wide time interval for the control of dissolution parameters, into which the kinetic parameters of the growing season of a large number of agricultural crops fit.

2.2. Development of the primary product formula, System prototype:

- selection of agricultural crops and determination of the area of kinetic parameters of their growth;

- determination of the time interval of the dissolution control area of the Fertilizer System based on the area of growth parameters of selected agricultural crops;

- determination and selection of the optimal amount of fertilizers in the general system kit;

- determination of the range and time step of the duration of complete dissolution of the fertilizers of the general system kit;

- calculation of kinetic parameters of dissolution of individual fertilizers of the prototype set of the general system;

- calculation of kinetic parameters of the dissolution control area of the prototype general fertilizer system;

- determination and selection of the final composition and quantity of fertilizers for the System. 2.3. Development of individual encapsulated fertilizers for the general system kit according to calculated kinetic dissolution parameters:

- product formulas: type of coating, layer thickness, intermediate layers, etc.;

- encapsulation method, technological modes, etc.

2.4. Development of an algorithm for controlling plant nutrition and development through controlling the dissolution of a parametric fertilizer system:

- development of a computer program for controlling the dissolution of the System;

- development of an algorithm for optimizing the nutrition of agricultural crops, synchronizing the processes of dissolution/supply of PV compositions of the Fertilizer System and plant growth/nutrition.

2.5. Primary physical and chemical tests of the Fertilizer System.

- obtaining accurate, objective qualitative and quantitative characteristics of the process of dissolution of various systems and compositions of fertilizers in water and aqueous media using electrochemical methods;

- determination of the functional dependence of the dissolution parameters of the fertilizer composition on the composition and ratio of the components.

In the field of agronomy/soil science, the 2nd stage research program includes:

2.6. Laboratory studies and field tests of calculated fertilizer compositions for various agricultural crops, soils and growing conditions.

Based on physicochemical and agronomic tests and research, the dissolution parameters of individual encapsulated fertilizers are adjusted, the composition of the prototype System is optimized, and the final set of fertilizers of the general system is determined with a given range, step and shape of the kinetic region of dissolution control. The criterion for choosing fertilizers for a set of general systems is the synergistic, mutually reinforcing and complementary effect of their joint use, which in this case is expressed in the ability of a parametric fertilizer system to optimize with high accuracy the nutrition and development of as many different types of agricultural plants as possible in a wide range of growing conditions and environmental impacts.

An important factor in the development of the world economy today is the introduction of new resource-saving technologies, one of the basic elements of which in agriculture is “Precision agriculture”, which is an integrated process of managing plant growth in accordance with their needs [12, 13, 14]. Accurate and quick adjustment of the dissolution parameters of a parametric system of mineral fertilizers, especially when used as part of such a modern resource-saving technology as “Precision Agriculture”, will ensure high efficiency in the use of PV fertilizers, optimal nutrition and development of the plant throughout the growing season, and ultimately high yields agricultural crops, high quality products and environmental protection.

Literature and sources of information.

1. Solodovnik V.D. Microencapsulation. - M: Chemistry, 1980.

2. Microencapsulation: Methods and Industrial Applications, Second Edition. 1996.

3. US 6358296 Patent. 2003. Slow-release polyurethane encapsulated fertilizer using oleo polyols.

4. US 7267707 Patent. 2007. Polyurethane encapsulated fertilizer.

5. US 6663686 Patent. 2003. Controlled release fertilizer and method for production thereof.

6. M.E. Trenkel. "Slow- and Controlled-Release and Stabilized Fertilizers: An Option for Enhancing Nutrient Use Efficiency in Agriculture)". International Fertilizer Industry Association (IFA). Paris, France, 2010.

7. https://smartnitrogen.com

8. https://landmark.com.au>...2018-07...ESN_Polymer_Coated_Urea...

9. https://cdfa.ca.gov>is/ffldrs/pdfs/Ellison_Eric.pdf

10. https://www.slideserve.com/carol/performance-of-polymer-coated-urea-esn-as-a-nitrogen-source-for-corn

11. https://agproducts/nutrient.com>en_US>

12. http://mcx-consult.ru/d/77622/d/tochnoe-zemledelie.pdf

13. http://www.agrophys.ru/precision_agro

14. https://www.agroinvestor.ru/technologies/article/28123-precision-farming-dlya-rossiyskikh-agrariev/

15. "Agrochemistry". Agropromizdat. Moscow. 1989.

PARAMETRIC SYSTEM OF MINERAL FERTILIZERS WITH CONTROLLED DISSOLUTION AND RELEASE OF NUTRIENTS

BRIEF DESCRIPTION OF DRAWINGS AND GRAPHICS

Fig. 1. Dissolution curves of general system fertilizers.

Fig. 2. Corn plant growth curve.

Fig. 3. Comparison of kinetic curves of traditional nitrogen fertilizer dissolution and plant growth.

Fig. 4. Comparison of kinetic curves of dissolution of encapsulated nitrogen fertilizer and plant growth.

Fig. 5. Comparison of kinetic curves of dissolution of a synchronized 2K-composition of encapsulated nitrogen fertilizers and plant growth.

Fig. 6. Complete growth curve of a corn plant.

Fig. 7. Dissolution curve of a 2K OPR composition synchronized with the growth of a corn plant.

Claims (3)

An agrochemical complex for managing plant nutrition and development, including a set of mineral fertilizers of one or different types, consisting of traditional U1 and several fertilizers encapsulated with polymer coatings U2, U3, U4, U5, U6, U7 with specified kinetic parameters of controlled dissolution and release of nutrients U1( t), U2(t), U3(t), U4(t), U5(t), U6(t), U7(t) and a computer program for controlling the dissolution of fertilizers, characterized in that the dissolution of fertilizers is controlled by changing the amount , composition and ratio of the components of the compositions, which are combinations of fertilizers in the kit, by adjusting and kinetically matching their dissolution parameters with the growth parameters of a particular plant, an agricultural plant is selected, the measured values of the kinetic parameters of plant growth are converted into relative values - mass fractions, they are brought to a measurement scale from 0.00 to 1.00, approximate the relative values of the growth parameter of the selected plant and calculate the kinetic curve of its growth using the equation: where: P - plant mass in relative quantities, mass, proportion; t - time, days; a, b, c, k, l, m - coefficients of the equation, a set of fertilizers is selected, the kinetic parameters of the dissolution of the fertilizers of the set are converted into relative values - mass fractions, the dissolution curves of the compositions are calculated, the kinetic parameters of which are compared with the parameters of the plant growth curve, the approximation error is calculated as an integral indicator of the deviation of the curves and based on its minimum value, the fertilizer composition is determined, the dissolution curve of which most accurately coincides with the growth curve of the selected plant.