Work quality indicators tillage unit with application flexible working body in systems "Organic farming"

. The relevance of the research lies in the use of a flexible working body in the form of a cable as part of a soil-cultivating ripping-separating machine. It has been experimentally proven that a flexible working body in the form of a cable as part of an experimental machine provides a more rational redistribution of agronomically valuable soil lumps along the depth of the cultivated layer. When tilling the soil to a depth of 0.03 m, an additional leveling of the soil surface occurs. The combined working body allows for a single pass of the unit to provide high quality tillage and effective control of weed growth. The destruction of dicotyledonous weeds by a machine with an additional flexible working body exceeded the result by 13% obtained without using a flexible working body.


Introduction
Surface tillage provides crumbling of the surface layer of soil, crushing of crop residues, control of weed growth and levels the sowing surface.The quality of loosening the soil is most relevant when sowing small-seeded vegetable crops.The mechanical soil composition is determined by the ratio of the four main fractions [1][2][3]: Dusty (particle size less than 0.002 mm).Sandy (particle size 0.05 ... 2 mm).
Coarse-grained sandy loam (particle size 2…25 mm).Lumps (with a particle size of more than 25 mm).The use of a traditional tillage system (stubble peeling, plowing, pre-sowing cultivation) is rational with a low weed infestation and good soil condition [4][5].Often pre-sowing tillage is combined with sowing [6][7].This combination of operations leads to a reduction in energy costs and time savings [8][9].
Immediately (the first 6 hours) after treatment, chernozem soils (in a loosened state) are characterized by high water permeability (120-142 mm/h).With an increase in density, the water permeability decreases by more than 2 times (50-62 mm/h).In virgin areas, water permeability is relatively stable (65-93 mm/h) [10].
Structured soil absorbs moisture well after rain and minimizes evaporation of soil moisture by placing it in internal aggregate pores [11].If the number of water-resistant lumps larger than 0.25 mm is at least 40-45%, then the indicators of soil density and its aeration porosity are within the optimal limits.In chernozems, the plow layer contains about 55-60% of such lumps [12].Oversaturation of the soil composition with large lumps leads to an increase in the degree of aeration, and oversaturation with dust contributes to wind erosion, drying out of the soil and loss of humus [13].
The most favorable mechanical composition of the soil for providing plants with nutrients and moisture contains 20 ... 25% of soil lumps 5 ... 20 mm in size, 60 ... 65% of agronomically valuable lumps 0.25 ... no more than 15% of lumps smaller than 0.25 mm [14].This ratio of structural particles allows plants to effectively use soil moisture.Equal sizes of seeds and soil particles of the seed layer ensure maximum crop yields.At the same time, the top layer of soil (depth less than 4 cm) can have large particles 5-20 mm in size [15].
The development of plants during the growing season is affected by the density of the surface layer of the soil, which deviates from the optimal boundaries in dry years by 0.08 g/cm 3 upwards and in wet years by 0.05 g/cm 3 downwards [16][17].To maintain optimal soil density in the surface layer, it is advisable to compact or loosen the soil [18][19].Thus, the most favorable conditions for plants are created when the cultivated soil layer is differentiated according to its structural composition.
It was noticed that in drought conditions the working bodies, even with a blunt blade, well destroyed tender shoots of weeds.This suggested the replacement of working bodies with a blunt blade with a cable [20].
The advantages of a flexible working tool (rope) are: simplicity of design; low metal consumption and energy intensity; minimum friction surface; high availability even of small peasant farms.However, the wire working body has not received wide application in production conditions.The disadvantages of a flexible working body are: the possibility of breaking the cable; the complexity of regulating the depth of the cable; leaving smallgrowing weeds uncut; clogging of racks with plant residues.This requires additional research to improve the reliability of the flexible working body for medium-depth tillage in combination with other tillage tools.
The aim of the study is to determine the quality of the work of a flexible working body as part of a soil-cultivating ripping-separating machine in the field.
The scientific novelty of the work is to increase the coefficient of soil structure with a simultaneous decrease in the number of weeds without the use of herbicides through the use of a flexible working body as part of a soil-cultivating cultivator-separating machine.The authors substantiated the quality indicators of the soil-cultivating machine using a flexible working body in the system of "Organic farming", taking into account environmental safety and balanced environmental management of the soil.

Materials and methods
Experimental studies were carried out in the Kharkiv region in 2019 in order to assess the feasibility of using a flexible working body in the form of a cable with a diameter of 4 mm as part of a rotary tillage cultivator-separating machine.The experiments were carried out E3S Web of Conferences 463, 01001 (2023) EESTE2023 https://doi.org/10.1051/e3sconf/202346301001 at different speeds of the rotary soil-cultivating ripping-separating machine and at different working depths, at a constant rotor speed of 130 rpm.
Before the field experiments, the field area was plowed in autumn, and in the spring, early spring harrowing and cultivation with lancet paws to a depth of 0.12 m were carried out.The experiment was carried out at a soil moisture content of 23%, a hardness of 130 N/m 2 , a working depth of 0.08 m, and a travel of the flexible working body of 0.035 m.
Qualitative indicators of work were evaluated by the coefficient of soil structure at the depth of processing of the lower and upper layers.Within the framework of each experiment, three soil samples were taken in the zone of passage of the working bodies at a distance of 15 m from each other.Each sample included samples of the top and bottom layers.To assess the effect of a flexible working body on the quality indicators of tillage, soil samples were taken when working with and without it.
Field studies were carried out on a tillage machine with a flexible working body based on a rotary cultivator KPR-1, designed for soil stratification by separating lumps according to the depth of processing.The experimental machine was aggregated with an agricultural general-purpose tractor MTZ-80 (Figure 1).The machine for surface tillage is a rigid frame with a hinged device.On both sides of the frame there are support wheels with mechanisms for adjusting the depth of tillage.
The frame 6 of the tillage machine has 3 sections.Flat free-rotating disks 1 with a diameter of 300 mm are rigidly mounted on the front of the frame.A plowshare 2 is fixed to the ends of the rack 3. The knives of the rotary working body 4, fixed on the axis of rotation 7, loosen the soil and move it along the bars of the separating grid 5.The disks 1 are located on both sides of the plowshare 2 and create a uniform supply of soil to the rotary working body 4 (Figure 2).Visual studies revealed that during the operation of a flexible working body, a swath is formed in the soil, during the movement of which on the field, micro-roughnesses of the soil fall asleep (Figure 3).The height of the roll significantly exceeds the dimensions of the cross section of the flexible working body.Loosening the surface layer of the soil with a flexible working body with a round cross section simultaneously ensures the compaction of the lower soil layers.The best leveling quality of the field surface was obtained during the movement of the flexible element along the ridges.The difference in the quality of field surface alignment when the flexible element moves along and at an angle to the ridges is so great that it is easily determined visually.The stability of the resistance force of the flexible working body in the soil ensures its steady movement along the ridges.This creates good prerequisites for using it together with other types of working bodies.
The use of a flexible working body as part of a soil-cultivating loosening-separating machine [21] will allow cutting weeds simultaneously with loosening the soil (Figure 4), which is the most effective way to deal with them [22].The structural-aggregate composition of the soil was determined by sifting.The experiment was repeated three times with a soil mass of at least 2.5 kg.The soil was brought to an air-dry state and sifted through a sieve with round holes.The soil separated on sieves was weighed and the relative mass of each fraction was calculated using the formula: Where m is fraction mass (kg); M is mass of soil sample (kg).The coefficient of soil structure was determined by the formula [23]:

Influence of movement speed
The experimental values of the coefficient of soil structure depending on the speed of movement are given in Table 1.At a speed of 3.55 m/s, the coefficient of soil structure when using the machine without a flexible working body in the upper and lower layers was the same and amounted to 0.70.When using a flexible working body, the difference in the structural coefficient in the upper and lower layers was 20%.
At a speed of movement of the machine without a flexible working body of 1.73 m/s, the difference in the structural coefficients of the upper and lower layers was 21%.The use of a flexible working body as part of the experimental machine increased this difference to 23%.Checking the data obtained using the Fisher criterion showed their reliability with a probability of 95%.The smallest significant difference is 0.125.Increasing the speed of movement reduces the coefficient of soil structure in the upper and lower layers of the soil (Figure 5).

Influence of tillage depth
The results of the experiment to study the influence of the depth of tillage on the quality of its crumbling are given in Table 2.The coefficient of soil structure at a depth of 0.03 m when processed using a flexible working body was 2.7.The coefficient of soil structure decreases with a decrease in the depth of the soil layer.In the soil layer at a depth of 0.1 m it was 1.4.This is explained by  Checking the data obtained by the Fisher criterion showed their reliability with a probability 96%.The smallest significant difference is 0.12.The dependence of the coefficient of soil structure on the depth of its processing is shown in Figure 6.
The use of a flexible working body affects the coefficient of soil structure in different ways.With a working depth of 0.03 m, the coefficient of soil structure increased by 50% due to the use of a flexible working body.The increase in the coefficient of soil structure at a tillage depth of 0.07 m was only 14%.The use of a flexible working body when tilling the soil at a depth of 0.1 m led to a decrease in the coefficient of soil structure by 43%.

Effect on weedinfestation
The most common weeds were: upturned amaranth, white gauze, field mustard, ragweed, gray foxtail and chicken millet.The total weediness of the field was in the range of 55…118 pieces/m 2 .The use of a flexible working body as part of a tillage machine can reduce the number of weeds (Table 3).The use of a flexible working body as part of a tillage machine makes it possible to reduce the weed infestation with dicotyledonous and cereal weeds by an average of 63%; when using strip processing by 56%; with the use of herbicide by 81%.
Double processing with repetition in 35 days without a flexible working body reduced the number of dicotyledonous weeds by 66.6%.When using a flexible working body, this figure increased by 29% and reached 95.7%.
Systematic tillage of the field made it possible to reduce the infestation of the field with dicotyledonous weeds before harvesting to 85.5%.Additional processing with a flexible screed reduced clogging to 98.5%, which is 13% higher.

Conclusions
It has been experimentally proven that the use of a flexible working body as part of an experimental tillage machine has a positive effect on the quality indicators of processing.The coefficient of soil structure in the lower layer increases from 1.2 to 2 times due to the use of a flexible working body during machine operation.
The use of a flexible working element in the composition of a rotary tillage cultivatorseparating machine allows you to reduce the number of lumps and effectively control the growth of weeds even without the use of herbicide.

Fig. 1 .
Fig. 1.Soil tillage machine for surface tillage with a flexible working body based on a rotary cultivator KPR-1.

Fig. 2 .
Fig. 2.The device of the machine for surface tillage: 1 is flat discs; 2 is plowshare; 3 is rack; 4 is rotary working body; 5 is rods of the separating grid; 6 is frame; 7 is axis of rotation.Between them, at the bottom of the part, a flexible element was stretched in the form of a cable with a cross-sectional diameter of 4 mm.During pre-sowing preparation of the soil,

Fig. 3 .
Fig. 3. Scheme of the expected impact of the flexible working body on the soil.

E3SFig. 5 .
Fig. 5. Dependence of the coefficient of soil structure on the speed of movement of the experimental tillage machine.

E3S
Web of Conferences 463, 01001 (2023) EESTE2023 https://doi.org/10.1051/e3sconf/202346301001 the fact that the flexible working body levels the field surface and increases the average soil structure factor by 13%.

Fig. 6 .
Fig. 6.The dependence of the coefficient of soil structure on the depth of its processing.

Table 1 .
Coefficients of soil structure depending on the speed of the tillage machine.

Table 2 .
Coefficient of soil structure depending on the depth of its processing.

Table 3 .
The influence of the use of a flexible working body as part of an experimental tillage machine on the weediness of table beet.