Evaluation of seeders in winter crop operations

Continuous flow seeders, as they work with narrow spacing, do not have all the components to carry out all functions in the soil, as occurs in precision seeders. Thus, a mismatched or offset double disc cuts the straw and opens the furrow for the deposition of fertilizer and seeds together. The grounding and compacting components are combined, even because there is not much space between them. The seed dosage can vary between ten and 200 seeds per linear meter, depending on the species and agronomic recommendation, and the fertilizer falls into the furrow practically next to the seeds (Casão Junior, 2016).

Seeds of food plant species and winter cover crops vary in shape, uniformity, roughness and size. Wheat and oats are most frequently found, but rye, triticale, barley, turnip, among others, also occur in these regions. These machines are also suitable for sowing rice crops and some typical summer cover crops such as moha and millet, and when coupled with specific distributors, they also sow brachiaria, which are expanding in the southern and northern regions of the country. Brazil, in crop/livestock integration or simply as a cover crop.

In the study conducted by Iapar volunteer researcher Ruy Casão Junior, together with other researchers from the institution, in 2018, 38 models of seeders were evaluated on agricultural properties, corresponding to models from ten different manufacturers, studying the quality variables of field sowing. .

In the field, continuous flow seeders were studied with 43 variables that can characterize their performance in planting crops, as well as their construction and property management characteristics.

Of the continuous flow seeders studied, the average number of rows was 23,9, with the largest having 65 rows and the smallest having 13. The spacing varied a lot, with an average of 17,6cm and coefficient of variation (CV% ) of 15,3%. The smallest spacing used was 15,5cm and the largest was 30cm. This is due to the fact that the producer was sowing oats on dense millet cover, which he chose to remove the intermediate rows of the machine.

Wheat was present in 27 cases, triticale in three, barley in four and black or white oats in four cases. The average time of using the direct planting system (SPD) of the producers interviewed was 21 years, with the oldest using the SPD for 31 years and the most recent for 2,5 years. Of the 38 producers, 30 only used the SPD, but mobilized the soil in maneuver areas and where there is compaction due to sprayer traffic. The remaining eight prepared the soil periodically for an average of 4,2 years, predominantly with scarifiers. Regarding vegetation management, 33 producers did not carry out this practice, that is, the harvester itself carried out this operation, three used the brush cutter on the corn and two used a knife roller.

Of the machines studied, 18 could be considered to have been used for less than ten years, 13 had an average age of between ten and 20 years and seven were old machines over 20 years old. Regarding the topography of the land on which the machines worked, it was found that 12 areas were flat, 17 were gently undulating and nine areas were undulating.

At the time of sowing, 13 machines worked on dry soil, as in April and part of May it did not rain in Paraná. Three producers sowed at the beginning of May and waited two weeks for the first rain, eight waited a week and two sowed the day before the rain. The machines that sowed from May 16th did so with the soil in a friable consistency.

Regarding seed treatment, 26 producers sowed with treated seeds and 12 with untreated seeds. Three of the four oat sowings did not treat their seeds. The average percentage of seed germination was 91,2%, considering that one case was found to have only 53% germination. In the case of seed vigor, the average was 85%, considering that the lowest case cited had 28% vigor. This sample was discarded for the purpose of analyzing seedling emergence.

ANALYSIS OF SEED AND FERTILIZER ADJUSTMENT ERRORS

During the evaluations, producers were asked what adjustments were made to their seeders regarding the dosage used for seeds and fertilizer. This parameter was checked with sampling carried out in three lines along a 25m route. It was observed that the dosage of seeds and fertilizer was not always close to what was desired.

The desired average seed dosage for the 38 machines was 77,5 wk/m linear. The determined average population of seeds (seeds/m) for 38 machines was very close to this value (76 sec/m). However, the difference between the desired population and that determined by each machine varied from 0,73% to 30,9%, with an average of 10,7% and a Coefficient of Variation (CV%) of 71,6%. It can be seen from this that of the 38 producers, 29% are making an error of 10% to 20% when regulating seeds and 15,8% are making more than 20% errors; 55,2% of producers made less than 10% mistakes when adjusting. Figure 1 shows the average errors in seed adjustment of field seeders.

It can be said that on average, producers are regulating their continuous flow seeders moderately, but there are still producers making a lot of mistakes, as 44,8% made more than 10% of the desired errors when adjusting seeds.

The same was observed for fertilizer regulation, in which the desired average fertilizer dosage for 27 machines that used this input was 255,8kg/ha. The average fertilizer dosage determined for these machines was also very close to this value (246,6kg/ha). However, the difference between the desired dosage and that determined by each machine varied from 0,31% to 52,3%, with an average of 18,2% and CV% of 75,2%. It can be seen that of the 27 producers evaluated, 33,3% are making a mistake of 10% to 20% when adjusting seeds and 37% are making a mistake by more than 20%. Only 29,7% of producers made less than 10% mistakes in the adjustment. Figure 2 shows the average errors in fertilizer adjustment of field seeders.

It can be said that on average, the producers surveyed are not adequately regulating their continuous flow seeders, as there are still producers making a lot of mistakes in the fertilizer dosage, with 70,3% making more than 10% of the desired adjustment errors. .   

EMERGENCY OF PLANT AND PERFORMANCE OF SEEDERS

The seed dosage expected by the 26 producers analyzed was on average 155,5kg/ha, which would result in a population of 82,4 seeds/m. The average quantity of seeds determined was close to this, with 80,1 seeds/m. However, when each seeder was analyzed separately, an average error was obtained across the 26 machines of 10,7%. This fact had already been verified when analyzing all the machines. Showing that producers must improve the regulation of their machines.

The average initial stand obtained was 62,3 seedlings/m, which resulted in 77,8% emergence. It is noteworthy that 11 machines sowed with dry soil and the seeds remained in the furrow for one to two weeks awaiting rain and 15 machines sowed with friable soil, or it rained shortly afterwards. However, there is no evidence of better emergence between the two groups. Those who sowed in dry soil obtained an average of 77,7% emergence and those who sowed in friable soil obtained 76,8% emergence.

It is considered that 76,9% of the seeds were treated, the average weight of a thousand seeds was 33,6g. The average percentage of seed germination was 94,7% and vigor was 90,8%. The quality of wheat and triticale seeds can be considered good, as the worst sample obtained 87% germination and 82% vigor.

The percentage of soil coverage with straw was determined before and after the seeder. There was an average of 88% coverage before and 74,8% after. Analyzing the straw reduction percentage of each machine separately, it was observed that the overall average reduction was 15,2%. Showing good performance of Brazilian machines.

It was found that two of the seeders did not have components for grounding and compacting the soil over the seeds. They were very old models and, in a third machine, also old, a chain and wooden beam were added for grounding.

It was observed that 84,4% of the seeders had well-filled furrows. It is noteworthy that the two seeders that did not have grounding/compacting components, had only 8,3% and 30% of well-grounded furrows and the machine that added a beam behind, had 78,3% of well-grounded furrows, showing that it helped in the furrow coverage.

Of the 26 seeders studied, 53,8% had exposed seeds, but in small quantities, that is, the average was 0,55% of exposed seeds. The seeders that did not have grounders/compacters had no exposed seeds, and the one with a beam behind had 1,2% of exposed seeds. It is noteworthy that the seeder that presented the highest percentage of exposed seeds obtained a value of only 2,3%.

The average working speed of the 26 machines was 8,94km/h. The average soil temperature was 22,70C and the ambient temperature was 240C.

The average seed depth was 3,67cm with a CV% of 21,3%. As this depth was determined with eight repetitions, the CV% of this depth was calculated in each case. Thus, the average CV% of seed depths was 15,7%. This value is important as it shows how the seeds varied their depth within the sowing furrow. It is noteworthy that the highest CV% was 33,7%. Considering that the average depth of this machine was shallow, 2,44cm, and it is known that 95% of the seeds remained at a depth that varied from 1,62cm to 3,26cm. Thus, several seeds were very shallow. Even so, no exposed seeds or poorly filled furrows were found. The error, in this case, appears to have been one of adjustment by the producer.

The same was done for the depth of the groove, which presented an average of 5,06cm (CV% = 10,1%) and an average CV% of the depth of the grooves of 15,1%. It is noteworthy that the highest CV% was 48,2% (on the same machine previously mentioned). Considering that the average groove depth of this machine was shallow, 4,2cm, and it is known that 95% remained at a depth that varied from 2,34cm to 6,21cm.

It was possible to identify that as the working speed increased, there was a tendency towards a reduction in the depth of the groove (R= -0,49). This is a well-known fact in the literature and from practical experience. Figure 3 shows the dispersion of data, justified mainly by the fact that each producer regulated his seeder in a personalized way.

This data was also analyzed with the aim of finding groups of producers with a certain similarity. So, as a final conclusion, I would like to say a few things. The speed of work is high, especially among producers who are very experienced in the direct planting system (25,6 years), compromising the implementation of the crop, despite being those who best regulate the machines. Producers with less experience in the direct planting system (14,6 years) were those who made the most errors when adjusting their seeders, almost on a widespread basis. Thus, it is concluded that, despite the great progress of machines and producers in the implementation of winter crops, there is room for improvement, and if there is greater concern with care in regulation, productivity will improve.

Ruy Casão Junior,
Hevandro Colonhese Delalibera,
Alexandre Leôncio da Silva,
Audilei de Souza Ladeira and
André Luiz Johann,

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