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ABSTRACT This paper presents an innovative solution for a distributor head equipped with a deflector (controlled plate)—intended to change the tilt angle (realignment) of the pneumatic seed

drill distributor head cover. We compared two qualitative parameters of seed sowing, coefficient of variation and coefficient of lateral unevenness of seed sowing (_δ_). Values were obtained

on the test stand with an innovative deflector built into the distributor head at three angles of inclination (0°, 5° and 10°). Statistical analyses revealed a significant effect of airflow

velocity and deflector angle, which corrects the deviation from the vertical plane of the distributor head, on the uniformity of seed sowing. In addition, regression equations were

determined to predict the quality of the seed sowing process. The developed and manufactured innovative distributor head with a deflector that tilts in two planes, designed to improve the

distribution evenness of the air stream transporting seed to individual coulters in pneumatic seed drills, received a positive review. The use of a deflector with automatic control of its

position angle, correcting the deviation of the distributor head from a vertical plane in pneumatic seed drills improves the uniformity of seeding. Therefore, it is reasonable to use this

solution for new pneumatic seed drills and those in use on soils with different relief (undulating surface). Moreover, the solution fits in with modern agricultural manufacturing in

accordance with the ideas of precision agriculture. SIMILAR CONTENT BEING VIEWED BY OTHERS DESIGN AND EXPERIMENT OF AIR-SUCTION DRUM-TYPE SEEDLING SEEDER FOR IRREGULAR-SHAPED VEGETABLE SEEDS

Article Open access 08 February 2025 INVESTIGATION OF THE PERFORMANCE OF A CYLINDRICAL HOPPER AND METERING DEVICE OF A CARROT SEEDER Article Open access 16 January 2023 DESIGN AND

EXPERIMENT OF A SOYBEAN SHAFTLESS SPIRAL SEED DISCHARGE AND SEED DELIVERY DEVICE Article Open access 25 November 2023 INTRODUCTION Pneumatic seed drills are equipped with a primary air

system that transports the seed from the main seed tank to the seed conduits that end in coulters. Distribution of the main seed stream to the individual seed conduits takes place in a

separation device, called a distributor head. The head should be designed to divide the main seed stream into equal unit streams, which travel to the rows in the soil through seed tubes and

coulters. The distribution principle of the heads is based on the vortex interaction of the turbulent air stream with the seed and the resulting stochastic distribution of the seed1.

Pneumatic seed drills, despite their numerous advantages including high efficiency, maneuverability, easy and fast loading of seed2,3,4, have disadvantages. The most important of them is low

lateral sowing evenness5,6, especially in terrain with varied terrain (hills)1. In the literature there are many papers concerning the causes of unevenness of seed sowing performed with

pneumatic seed drills7,8. There are also studies which prove that uniform distribution of seeds in the soil has a positive effect on the crop quantity and quality by improving utilization of

sun rays and water by growing plants9. Moreover, intraspecific competition is reduced as plants have a similar life space. Authors of these studies use various indicators, test

procedures10,11 and methods of seed uniformity assessment10,11,12,13,14 to evaluate the process of machine seeding. Pippig has analyzed the influence of technical parameters of pneumatic

seeding system units and found that the diffuser tube length should be about 350 mm to maintain acceptable uniformity of seeding15. Subsequent studies indicate the distribution of air flow

velocities at the outlet of the seed (pneumatic) tube, which is necessary to validate the mathematical model of two-phase flow mechanics in pneumatic seed drill systems5, and proposes

minimum seed transport velocities8,16. From the analysis of the literature, it appears that the uniformity of seed distribution is also influenced, though minimally (2°–3°), by inclination

of the seed-air stream distributing head17. There is also research whose results are mathematical models describing evenness of the seed distribution in the distributor head5,18. Other

researchers work on improving or developing new sowing system designs5 as well as using electronic optical systems to control the sowing process19. Xiaolong et al.20 designed and tested a

new pneumatic precision centralized seed dispenser with internal seed loading, which sows six rows simultaneously. The authors explored the influence of design and operational parameters on

sowing evenness. Karayel et al.21 developed a new helicoidal seed tube where falling seeds move along a seed spiral which improves seed distribution uniformity. The tests were conducted for

two species of wheat and barley grains. The values of variability coefficient for the grain species changed from the level of 118.4% and 139.5% to the level of 77.2% and 70.6%21,

respectively. In another study the authors developed and tested in field conditions a contactless, self-priming system for wheat seed injection. The value of seed distribution uniformity

variability coefficient was 11.3%22. Xi et al23 discussed a different approach to the issue of seed distribution uniformity improvement by proposing a seed sowing system without seed

delivery tubes whose clearance is 5.0–8.8 cm. The best qualitative parameters of seed sowing were found for 7.0 cm clearance tubes—sowing accuracy was 83.84%, whereas the seed distribution

uniformity variability coefficient was 14.68%. The research, however, did not consider a varied terrain (slope). Some simulation research on the seed mixture movement and the air stream

coming out of the dispenser was conducted by Zhou et al.24, Xiaolong et al.19,25 and Bourges et al.26. That research involved distribution of the seed-air stream flow in the distributor

head. Unfortunately, the authors did not investigate evenness of the dosed air stream distribution with the head tilted from the vertical—head tilt. Kumar et al. carried out research on the

effect of the distributor head shape, outlet air stream velocity and sowing unit operation speed on seed distribution evenness. The authors indicated that sowing evenness is influenced by

the velocity of the air stream transporting the seed, sowing rate, and the seed physical properties. From the literature analysis, it can be concluded that the research results and their

scope are not conclusive and do not exhaust the subject of seed sowing evenness in machine sowing. Therefore, it may be stated that there is still a problem of even seed-air stream flow

distribution, especially when sowing seeds in soils with varying terrain—especially on slopes above 10°. According to the research conducted so far27,28, the deviation from the vertical of a

mechanical-pneumatic seed drill distributor head has a significant effect on the seed flow distribution uniformity inside its head, and the distributor head deviation from the vertical in

the range of 0°–20° significantly worsens the coefficient of lateral seed sowing unevenness, up to 14%27. Gierz Łukasz and Markowski Piotr29 achieved similar correlations for sowing oat

seeds. The distributor head deviation from the vertical by an angle of 10° resulted in a 31% evenness deterioration of oat seed sowing (evenness of seed and air stream distribution in the

distributor head) from a value of 10.36% at the vertical position of the distributor head to a value of 13.55% at the deviation by an angle of 10°. Yatskul et al.30 noticed a similar

relationship when sowing wheat seed and tilting the distribution head by an angle from 0° to 22°. For the selected orientation, the head cover tilt in relation to the diffusion tube vertical

axis, can result in more seed being carried in that direction, i.e. asymmetrical seed-air stream distribution. Distributor heads of commonly used pneumatic drills usually are not equipped

with seed direction control, and it is not possible to change the seed reflection angle. Another disadvantage of assessing the machine sowing quality noted by the authors is the use of

several methods (field and laboratory) to estimate the seed sowing evenness, which makes it difficult and sometimes even impossible to compare the results presented in the respective

articles. Therefore, it is not always possible to make an unambiguous evaluation of the influence of the sowing unit individual design and operational factors on the seed sowing evenness. It

needs, however, to be noted that regulations included in ISO (7256-1:1984) 28 norm are helpful for unification of methods used for evaluation of seed sowing quality and make it possible to

compare the results of variability coefficient (CV) for different grain species31. The authors present evaluation of lateral seed distribution evenness with a pneumatic seed drill using an

innovative method of correcting the setting of the distributor head cover of the pneumatic sowing system by means of a controlled plate (deflector), which makes it possible to control the

distribution of the seed-air stream by changing the seed reflection angle. To be able to compare the obtained results with those presented in the literature, two coefficients were used to

assess the quality of seed sowing—coefficient of variation CV and coefficient of lateral seed sowing unevenness _δ._ MATERIAL AND STUDY METHODS HEAD WITH DEFLECTOR The subject of the

research is an innovative seed-air stream distributor head with an adjustable angle deflector, made according to patent claim no. PL.23049228. The deflector's design allows it to be

tilted in two planes—in two perpendicular axes. The deflector tilt angle from the distributor head parallel plane is controlled by three screws numbered 2, 3, 4 (Fig. 1). In practice, this

solution enables the deflector to be kept parallel to the plane of the distributor head. The stream divider and diffuser rings were made using Rapid Prototyping method32,33,34. The

distributor head diffuser, which scatters the seed, is made of two diffuser rings and a spacer sleeve (Fig. 2). To carry out the tests, the diffuser was deliberately fitted with two diffuser

rings instead of the standard nine diffuser rings arranged along the entire length of the diffuser. This design measure was applied to reduce the seed distribution evenness, i.e. to

increase the value of the coefficient of seed distribution unevenness, in order to capture more clearly the effect of the deflector on the seed distribution evenness. The height of the

diffuser rings used in the diffuser was 22.27 mm, between which two spacer sleeves of 60 mm and 116 mm were fitted, allowing the diffuser rings to be distant from each other by 176 mm (Fig. 

2). Following the studies of the head tilt effect and ring placement variants on the diffuser29 the dimensions of the stream divider were modified to incorporate a novel deflector. The new

dimensions of the stream divider are shown in Fig. 3. On a laboratory bench a deflector in the seed distributor head can be adjusted to three positions. The distribution head and deflector

angles relative to the distribution head plane are shown in Table 1. For a clear illustration of the distribution head and deflector alignment, it is further illustrated in Fig. 4. TESTING

RIG Research on the innovative distributor head of a pneumatic seed drill with a deflector tilted in two planes was conducted on a special laboratory bench built at the Department of

Mechanical Engineering of the Poznan University of Technology as part of project no. N R03 0021 06/200935 (Fig. 5). The subject of the research is an innovative deflector (2) mounted in the

upper cover of the seed-air distributor (1), with tilt angle adjustable (from 0° to 10°) through adjustment screws (10). Stream divider (1) attached to diffuser (3) built of support tube

(13) spacer sleeves (4) and diffuser rings (5), is connected to supply angle joint (9) and supply conduit (11). The distributor head with deflector is attached to a distributor head support

(14) with tilting system (8) that allows the distributor head with deflector to be tilted from − 20° to + 20° from the vertical. The seed is transported from stream divider (1) with tilted

deflector plane (2) through propulsion tube (6) and the connector with flow control sensors to the seed conduits (12). The laboratory test bench for evaluating the quality of seed sowing

(Fig. 4) was constructed on the model of a 16-coulter universal pneumatic row seed drill. It consists of the main chassis (11) on which seed box (12) is suspended on four tensometric weight

sensors (13). The accuracy of seed weighing with the tensometric weight scale is ± 0.01 kg. Mounted to the lower wall of the seed box is a dispensing unit with injector (1) driven by a 0.37 

kW AC motor with an MR40 geared motor made by Kacperek Polska with ratio i = 30 (28), designed to draw the seed into the main seed-air conduit (10) with internal diameter of 80 mm, which

transports it in the air stream through a supply angle joint made of PVC material with 15° tilt angle (5) to the distribution head with tilt deflector (2). The seeds separated and directed

in the distributor head with tilt deflector (2) are further transported through seed flow sensor connector (6) and seed conduits (27) with internal diameter of 25 mm to a collection box

divided into 16 chambers (7). Each collection box chamber (7) is opened by a cam mechanism driven by BG 65X25 SI servomotor made by Dunkermotoren (23). After opening box chambers (7), the

seeds fall down into the collection conduit (26) and are then sucked through under pressured system via the suction conduit (25) into the cyclone of the batch metering system (15). The

vacuum is generated by 2G2E0032CM suction fan made by Drainvac, Quebec, Canada (18) connected to cyclone (15) through suction (air) conduit (19) attached by suction conduit bracket (20) to

the main chassis (11). Cyclone of the batch metering system (15) is suspended on three tensometric weight sensors of batch metering system (16) with measuring accuracy of ± 0.005 kg and

closed at the bottom with a flap (17). The air stream is generated by the main fan (8) with the symbol T 378/1 manufactured by POM Augustów, Poland, which is powered by a 5.5 kW AC electric

motor capable of generating an air stream velocity from 5 to 40 m/s, with a capacity of 0.680 m3/s and a pressure of 6 kPa29 (21) The main fan (8) is connected to the dosing unit with

injector (1) via airflow supply conduit (9). The laboratory test bench is also equipped with a unit for automatic weighing of the quantity of seed sown, a 16-chamber seed collection box and

a computer with software for data collection and calculation of the coefficient of lateral seed sowing unevenness. In this study, oat seed Lion with a thousand-seed weight of 32.2 g ± 0.62

and moisture content of 9.9% was used. The research material came from Main Seed Warehouse Top Farms Seeds, Production Plant in Runów located in Greater Poland Province. Based on the

announcement of the Marshal of the Sejm of the Republic of Poland on the announcement of the uniform text of the Act on the legal protection of plant varieties of January 22, 2021 (Journal

of Laws of 2021, item 213) and the breeder's declaration that the indicated variety: Lion (oat) is law protected by the breeder, the authors have received this permission. The breeder

agrees to obtain the above-mentioned plant material, which complies with the national guidelines from Main Seed Warehouse Top Farms Seeds, Production Plant in Runów located in Greater Poland

Province. The authors, with the breeder's consent, may use its plant material only for the purposes of scientific and research activities, including carrying out tests of e.g. sowing

simulation on a laboratory stand with an innovative distributor head with a deflector. Seeds were sown at a constant rate of 250 kg/ha. Once the laboratory experiment (one measuring cycle)

is completed on the designed test rig, the 16 chambers of seed collecting box (7) are opened sequentially and their contents are weighed and returned in a closed circuit to seed box (12).

Sliders are installed in the chamber bottoms of collection box (7) and are opened and closed by a cam mechanism driven by toothed belt through servomotor (23). A special program for the

laboratory rig written in Embarcadero's RAD Delphi 2010 environment controls the servomotor (23), the main fan supply motor (21), suction fan (18), and dispenser drive motor (28).

Collector pipe is located along the sixteen-chamber box, into which the seeds enter when the sliders are opened. The seeds then are transported by air stream through the suction conduit from

the collector pipe to the separating cyclone located above seed box (12). The conical bottom of separation cyclone (15) is closed from below by flap (17). It relies on three tensometric

sensors, which measure separately the weight of seeds from each chamber in collection box (7) with an accuracy of ± 0.005 kg. Cyclone flap (17) is closed by the vacuum in the system with a

force of approx. 500 N during the seed transport from collection box (7), then after suction blower (18) is switched off, the conical bottom of the cyclone drops onto the strain gauges.

Cyclone flap (17) is locked electromagnetically by the control system29,35. The whole measurement cycle of the sown seed weight is completely automated and after weighing the seed in all

sixteen chambers of the collection box, a test report is generated, and the results are stored in .txt files. The laboratory test bench with the innovative deflector is equipped with a

control system, in which the measurement cycle is programmed according to the following scheme: * 1. Read the test parameters written into the control system interface: airflow rate, sowing

time; * 2. Turn on the main fan motor and wait for its speed to stabilize; * 3. Make sure that the cam mechanism is before chamber 1; * 4. Regulate the fan shaft speed so that the assumed

airflow speed is achieved at the inlet of the seed dosing unit; * 5. Start the sowing (dosing) unit and set the desired speed of the sowing (dosing) shaft; * 6. Wait 5 s. for the sowing

conditions to be established; * 7. Direct the seed into the distribution head with the innovative deflector; * 8. Keep sowing for a set time—according to the test plan, about 10–600 s. * 9.

Switch off the sowing unit drive and after 5 s switch on the main fan motor; * 10. Start the suction fan; * 11. Check the vacuum value in the batch measuring system cyclone; * 12. Open

another collection box slider; * 13. Wait 30 s; * 14. Turn off the suction fan; * 15. Read the weight of the seed sown from a tensiometer weight scale measuring the weight of seed batch; *

16. Read the weight of all the seed from the tensiometer weight of the seed box; * 17. Open the flap that closes the seed outlet in the cyclone; * 18. If the extreme position of cam

mechanism carriage is reached, return to chamber no.1; * 19. Compile the measurement results and save them in a database. LABORATORY BENCH CONTROL SYSTEM The most important component of the

laboratory bench for studying the effect of using a deflector in the seed distributor head is a dedicated control system. The base of the control system is a computer with an operating

system, equipped with a written program created in RAD Delphi 2010 environment made by Embarcadero company, using measurement libraries provided by Advantech company. The computer program

communicates with the environment through USB 4711A measurement interface made by Advantech and through additional coupling systems, including electromagnetic relays and optocouplers35. The

measuring interface is equipped with a terminal block, where serial transmission conduits (USB2), four digital outputs (DO0…DO3) and six analogue inputs (AI0…AI6) are used to control the

device (Fig. 6). A modified position sensor for the tank-opening trolley was used during the tests. The control computer communicates with the seed-counting unit by RS485 serial link during

the tests. The software uses a proprietary graphics and mathematics library, graphics_v3, which complement the control system29. The software sets out to divide the entire measurement cycle

into two stages: 1—the seed sowing procedure, 2—the procedure of weighing seed sown into individual chambers of the collection box. Both stages are fully automated. Measurement procedure 1

(seed sowing) consists of inputting fixed parameter values in accordance with the test plan after the main dialogue form appears i.e. sowing time. The sowing speed is read from working speed

sensor (9) and has also been presumed to be constant. The length of the measuring distance is determined by the sowing time and working speed (sowing rate) specified in the test plan.

Measurement procedure 2 (weighing of the individual compartments of the collection tray) involves cyclic opening of the individual box chambers, weight measurement and discharge into the

seed box, and the recording of the measured values of the seed weight in the program memory to create a report. CALCULATION OF SEED SOWING QUALITY COEFFICIENT VALUES (CV AND Δ) There were

three repetitions of the experiment for all combinations of variable parameters according to the algorithm shown in Fig. 7. For the purposes of this study, the following parameters were

adopted: * (a) Constant: * sowing rate of 250 kg/ha; * sowing speed 8 km/h; * sowing time 10 min. * (b) Variables: * air velocity in three ranges: 12.22 m/s, 14.44 m/s, 16.66 m/s; *

distribution head tilt: 0°, 5°, 10°; * deflector tilt: 0°, 5°, 10°. * (c) Actual parameters: * coefficient of variation _CV_ (%); * coefficient of lateral seed sowing unevenness _δ_ (%). The

quality of sowing (seed distribution evenness) is evaluated based on the values of transverse and lateral unevenness of seed sowing. The indicator of transverse seed sowing _δ_36 is

frequently determined as variability coefficient (_CV_)37, defined as a ratio of square deviation of average distance between seeds sown in particular rows to the average distance determined

for the whole seed drill. This indicator can be also determined as a ratio of square deviation of the seed average weight falling on a measurement distance in individual rows to an average

weight for the whole seed drill. In turn, an indicator of lateral unevenness of seed sowing is defined as a ratio of square average deviation in a row to average deviation in a row38. The

indicator of lateral seed sowing unevenness is commonly defined for point seed drills38. To determine the effect of using a deflector in the distributor head on the uniformity of seed-air

distribution into individual coulters, coefficient of variation (CV) and coefficient of lateral seed sowing unevenness _δ_ were applied. Coefficient of variation (CV) was calculated from

relation (1), according to ISO-7256/237: $$ CV = \frac{S}{X} \cdot 100 \left( \% \right); $$ (1) where _S_—standard deviation of the average seed weight from three repetitions for a single

coulter, _X_—average weight of seed collected from all coulters. The coefficient value of lateral seed sowing unevenness _δ_ (%) was determined from Eq. (2), according to PN-84/R-5505036: $$

\delta = \frac{{\frac{{\sqrt {\sum \left( {\Delta q_{i} } \right)^{2} } }}{i}}}{{q_{sr} }} \cdot 100 \left( \% \right); $$ (2) where _δ_—coefficient of lateral seed sowing unevenness (%).

_q__sr_—average weight of oat seed sown in the ith container (kg), _∆q__sr_—the average deviation in weight of seed sown into seed containers (kg). The air velocity was set in 3 ranges:

12.22 m/s, 14.44 m/s, 16.66 m/s due to the oats seed critical velocity of 8.03 m/s39. STATISTICAL CALCULATIONS Measurement results were statistically analyzed. A correlation analysis was

conducted to determine the strength and nature of the relationship between the independent variables and the dependent ones. The following null hypothesis was verified H0: the correlation

coefficients between the variables are equal to zero. When the values of the correlation coefficients showed a strong relationship between the independent variables and the dependent ones,

rectilinear regression equations were determined at a further stage to describe the nature of the relationship. Fifth-degree curvilinear, multiple, multivariate polynomial, second-degree

polynomial and power equations were tested as well, followed by regression analysis with a posteriori elimination and stepwise selection procedures to determine the form of the regression

equation describing the most accurate fit of the empirical data to the model. Regression function fit assessment was determined, and description quality analyses were performed by removing

irrelevant variables from the equations. The calculated value of the F-Snedecor statistic and the probability of exceeding it, the multiple correlation coefficient, the value of the

determination coefficient, the standard deviation of the residuals and the coefficient of random variation were used as criteria for assessing the model fit to the empirical data. The rule

that functional relationships should occur in simple mathematical forms was also considered for determining the final form of the function. A statistical analysis was performed using the

Statistica 13 PL statistical software package. The significance level in the analysis and inference was set at _p_ = 0.05. RESULTS AND DISCUSSION THE INFLUENCE OF HEAD AND DEFLECTOR POSITION

AND AIR VELOCITY ON THE SOWING VALUE COEFFICIENT OF VARIATION During the experiment, the seed weight distribution to each coulter was determined in the distributor head and the values of

seed sowing quality coefficients were calculated, i.e. the coefficient of variation (CV) and coefficient of lateral seed sowing unevenness (_δ_) at three values of angles (0°, 5° and 10°) of

distributor head tilt from the vertical and deflector tilt from the distributor head. The experiment was conducted for three airflow velocities in a pneumatic seed drill system, i.e. 12.2 

m/s, 14.4 m/s and 16.6 m/s. Values obtained from laboratory tests of the seed sowing unevenness index, as a function of the airflow velocity, distributor head and deflector inclination

angles, were then statistically analyzed. Based on these findings, it was shown that the airflow velocity significantly influenced the unevenness of seed sowing, consistently with the

findings obtained by Kumar et al.40, Gierz and Kęska27 and Yatskul et al.1,30. Convergence can also be found between the results of the coefficient values of the seed sowing unevenness

within the velocity increase range from 12.2 to 14.4 m/s with the results reported in the following articles18,27,40. The lowest mean coefficient value of seed sowing quality coefficients,

i.e. coefficient of sowing variation (CV = 26.28%) and the coefficient of lateral seed sowing unevenness (_δ_ = 24.42%) occurred for the airflow velocity of 14.4 m/s, the distributor head

angle of 5° from the vertical and the deflector angle from the distributor head of 5°—a statistically significant difference at α = 0.05 (Tables 2, 3). The obtained results of the research

clearly indicate that the seed sowing quality deterioration (lateral uniformity of seed sowing) is effectively prevented by means of a deflector plate with an adjustable tilt angle when the

distributor head is inclined from the vertical up to 10°—calculated values coefficient of sowing variation (CV) and the coefficient of lateral seed sowing unevenness (_δ_) are close to the

calculated values of these quality coefficients when the distribution head is vertical. An analysis of results also shows that an increase in air velocity in the pneumatic seed transport

system to 16.6 m/s results in a deterioration of seed sowing quality, regardless of the applied combination of distribution head and deflector tilt angles. The authors have observed that the

angle of deflector tilt significantly affects the seed sowing evenness, which, according to the information reported in the literature41,42, can negatively affect the obtained crop yield.

It is, therefore, reasonable to use a deflector to improve the quality of sowing with a pneumatic seed drill, especially when sowing in fields with an angle of terrain greater than 5°

(Tables 2, 3). Based on the obtained results, regression equations were derived with a posteriori elimination procedure and stepwise selection of insignificant variables and polynomial

degree, describing the functional dependence of seed sowing quality, i.e. coefficient of sowing variation (CV)—Eq. 3 and the coefficient of lateral seed sowing unevenness (_δ_)—Eq. 4,

depending on air stream velocity (_v_) in the pneumatic seed transport system, distribution head tilt from the vertical (_h__β_) and the angle of the deflector in relation to the distributor

head (_d__α_). $$ CV = - 16.38 \cdot v + 0.54 \cdot v^{2} - 4.38 \cdot d_{\alpha } + 0.39 \cdot d_{\alpha }^{2} + 0.95 \cdot h_{\beta } + 0.06 \cdot v \cdot d_{\alpha } \cdot h_{\beta } +

149.03 $$ (3) $$ \delta = - 17.24 \cdot v + 0.57 \cdot v^{2} - 3.35 \cdot d_{\alpha } + 0.40 \cdot d_{\alpha }^{2} + 0.64 \cdot h_{\beta } - 0.14 \cdot h_{\beta } + 153.04 $$ (4) Quadratic

equations of seed sowing quality obtained from regression analysis are characterized by a very good model match with empirical data. The values of the coefficient of determination (R2) of

the equations obtained was 0.94 and 0.91 respectively. These high values of the determination coefficient indicate a good match of the developed models with the empirical data, which allows

prediction of the sowing process quality depending on the velocity of air stream (_v_) in the pneumatic seed transport system, distribution head tilt angle from the vertical (_h__β_) and the

deflector tilt angle relative to distribution head (_d__α_). Graphical representation of quadratic equations describing the quality of seed sowing (coefficient of sowing variation (CV)—Eq. 

3 and the coefficient of lateral seed sowing unevenness (_δ_)—Eq. 4), are shown in Fig. 8. The experiment also determined the distribution of seed weight in the distribution head for

individual coulters. The average seed weight for one coulter at airflow velocity of 12.2 m/s varied from 0.99 kg ± 0.012 kg to 1.12 kg ± 0.021 kg, depending on the distribution head and

deflector angles. With an airflow velocity of 14.4 m/s, the mass of seed sown per coulter varied from 1.00 kg ± 0.018 kg to 1.19 kg ± 0.027 kg. In the third case, highest air flow velocity

in the pneumatic system of 16.6 m/s, the average weight of seed directed to individual coulters varied from 1.00 kg ± 0.021 kg to 1.12 kg ± 0.032 kg (Table 4). Figures 9, 10, 11, 12, 13 and

14 show the seed weight distribution for each of the 16 coulters as a function of deflector tilt angle (_d__α_) and tilt angle of the seed-air stream distributor head (_h__β_) along with the

calculated values of the seed quality coefficients, i.e. coefficient of sowing variation (CV) and the coefficient of lateral seed sowing unevenness (_δ_) and air stream velocity 14.4 m/s—at

which the highest seed sowing evenness (the lowest coefficient values CV and_ δ_). The highest CV and _δ_ (33.61% and 29.61% respectively), i.e. the most uneven seed sowing was observed

with a distribution head angle of 10° from the vertical and a deflector angle of 0° (this value of deflector angle represents the classic distribution head configuration—without deflector)

(Fig. 11). Deflector angle adjustment (_d__α_) from 0° to 10°, with a distribution head angle of 10° from the vertical (Fig. 14) improved the seed sowing quality—coefficient values CV and_

δ_ decreased to 25.73% and 21.51% respectively. The obtained CV and _δ_ coefficient values clearly show the effectiveness of the proposed solution related to the use of a deflector in the

distribution head. The relevance of the proposed solution is also confirmed by the CV and_ δ_ values (18.94 and 21.51 respectively) obtained at a deflector angle of 5° and a distribution

head angle of 5° from the vertical (Fig. 12). The CV and _δ_ values when a deflector were used, compared to the variant without a deflector and the same head seed-air stream divider angle

setting value of 5° (_h__β_) were 25.73% and 21.51%, respectively. CONCLUSIONS * The developed and manufactured innovative distributor head with a deflector that tilts in two planes,

designed to improve the distribution evenness of the air stream transporting seed to individual coulters in pneumatic seed drills, provided positive results in this experiment. * Changing

the deflector tilt angle significantly affects the value of the coefficient of lateral seed sowing unevenness and can compensate for the effect of the seed drill tilt and the supply conduit

spreader curvature. Change in the distributor head angle of tilt from the vertical position (0°) by 5° and 10°, accompanied with appropriate change in the deflector angle by the above given

angles, that is, 5° and 10° caused reduction in the value of the sowing lateral unevenness indicator from about 20% up to above 40%, depending on the working speed and indicator applied. *

The research result analysis shows that the air stream velocity transporting the seed has a significant influence on the uniformity of air stream distribution in the distributor head. The

lowest value of the seed sowing quality coefficient, i.e. coefficient of sowing variation (CV) and the coefficient of lateral seed sowing unevenness (_δ_) was obtained for air velocity of

14.4 m/s. Changing the air velocity from 14.4 to 12.2 m/s or 16.6 m/s significantly worsened the seed distribution evenness in the distributor head—increase in the value of indicators of

seed sowing lateral unevenness within the range from about 5% to about 18%. * The second-degree equations of seed sowing quality determined from a multiple regression analysis, i.e.

coefficient of sowing variation (CV) and the coefficient of lateral seed sowing unevenness (_δ_), is characterized by a high percentage of explained variability (R2 0.94 and 0.91,

respectively). This definitely confirms usefulness of the equations for prediction of the seed sowing process quality as a function of the airflow stream velocity (_v_) in the pneumatic seed

transport system, the deviation of the distributor head from the vertical (_h__β_) and the deflector tilt angle relative to the distributor head (_d__α_). * The research results indicate

that it is reasonable to improve the quality of sowing with pneumatic seed drills, especially when sowing in areas with an over 5° inclination. This requires continuous measurement of the

asymmetry coefficient of the seed stream distribution in the head seed distributor and the use of a system for automatic adjustment of the deflector angle that can be performed by the

increasingly used 3D printing method43 or by incremental manufacturing44. These topics may be the subject of further research. DATA AVAILABILITY Correspondence and requests for materials

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https://doi.org/10.3390/ma11050840 (2018). Article  PubMed  Google Scholar  Download references ACKNOWLEDGEMENTS This study was supported by the National Centre for Research and Development

under the LIDER VIII programme, project No. LIDER/24/0137/L-8/16/NCBIR/2017. The authors thank the breeders for providing the Main Seed Warehouse with Top Farms Seeds, Production Plant in

Runów, located in Greater Poland Province and allowing their plant material to be used for scientific and research purposes. on the legal protection of plant varieties of January 22, 2021

(Journal of Laws of 2021, item 213) belongs to him. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Institute of Machine Design, Faculty of Mechanical Engineering, Poznań University of

Technology, Ul. Piotrowo 3, 60-965, Poznan, Poland Łukasz Gierz * Department of Heavy Duty Machines and Research Methodology, University of Warmia and Mazury, Oczapowskiego 11, 10-719,

Olsztyn, Poland Piotr Markowski & Dariusz Jan Choszcz * Department of Biosystems Engineering, Poznan University of Life Sciences, Wojska Polskiego 50, 60-627, Poznan, Poland Dawid

Wojcieszak Authors * Łukasz Gierz View author publications You can also search for this author inPubMed Google Scholar * Piotr Markowski View author publications You can also search for this

author inPubMed Google Scholar * Dariusz Jan Choszcz View author publications You can also search for this author inPubMed Google Scholar * Dawid Wojcieszak View author publications You can

also search for this author inPubMed Google Scholar CONTRIBUTIONS These authors: Conceptualization, Ł.G.; methodology, Ł.G.; software, Ł.G.; validation, Ł.G., P.M. and D.J.C..; formal

analysis, Ł.G., D.J.C. and P.M.; investigation, Ł.G. and P.M; resources, Ł.G and P.M.; data curation, Ł.G. and P.M.; writing—original draft preparation, Ł.G., P.M. and D.W.; writing—review

and editing, Ł.G., P.M. and D.J.C.; visualization, Ł.G. and D.W.; supervision, Ł.G.; project administration, Ł.G., P.M. and D.J.C.; fund acquisition, Ł.G. All authors have read and agreed to

the published version of the manuscript. CORRESPONDING AUTHOR Correspondence to Łukasz Gierz. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. ADDITIONAL

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Choszcz, D.J. _et al._ Effect of using deflector in the distributor head of a pneumatic seed drill on the oat seed sowing unevenness. _Sci Rep_ 13, 15471 (2023).

https://doi.org/10.1038/s41598-023-42476-5 Download citation * Received: 07 June 2022 * Accepted: 11 September 2023 * Published: 19 September 2023 * DOI:

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