Right machine speed for good seeding

The sowing operation is decisive for the establishment of crops. In conservation preparations, their importance increases, since soil and vegetation cover conditions are generally not as favorable to seed deposition as those found in preparations used with high mobilization.

During mechanized sowing, several factors interfere with the establishment of the plant stand and crop productivity, one of them being the speed at which the machine operates in the field. According to researchers, this parameter can influence the slippage of wheelsets; in field capacity; in the speed of the dosing mechanism; in the distance, depth and exposure of seeds; in the deposition of seeds in pairs and in mechanical damage.

Nowadays, the time for sowing is increasingly shorter depending on the climate, soil conditions and availability of machines, mainly because producers are working in larger areas to reduce costs. Obviously, all these factors are affected by the sowing speed. .

DISUNIFORMITY IN DISTRIBUTION

The non-uniformity in the longitudinal distribution of seeds implies an inefficient use of available resources, such as light, water and nutrients. The efficiency of seeders-fertilizers is assessed by the quality and quantity of work they perform. The quantity is obtained by the work capacity per unit of time and the factors that interfere most directly are the working width and travel speed.

Achieving success in a direct seeding system and selecting appropriate speeds for seeders-fertilizers are, without a doubt, a necessary action to maintain the effectiveness of the system. A study carried out at the Center for Development and Dissemination of Technologies at Faculdade Assis Gurgacz, in Cascavel (PR), evaluated corn productivity as a function of increasing the speed of movement of the tractor-seeder set in a direct planting system.

THE EXPERIMENT

The experiment was carried out in a red Oxisol, aiming to evaluate corn productivity due to the increase in the travel speed of the tractor-seeder set (5km/h, 6km/h, 7km/h and 8km/h) in a direct planting system.

The hybrid Pioneer-30F53 was used and treated with insecticide. The distribution of seeds and fertilizer was the same for all plots, where the machine was adjusted to distribute 330kg/ha of formulation 08-20-20 (N-P2O5-K 2O), fertilization based on soil analysis and crop to be implemented.

MACHINES AND IMPLEMENTS USED

In the sowing operation, a precision seeder-fertilizer, brand Marchesan, model PST3 TRA, trailed, was used, equipped with five lines spaced 0,80 m apart, transmission system using chains and interchangeable gears, horizontal perforated disc type seed meterer. , 15” smooth disc for cutting straw, furrowing rod for fertilizer deposition, 13” and 15” double offset discs for seed deposition, compacting and depth regulating wheels, “V” wheels for covering the seeds. The set was driven by a Massey Ferguson tractor, model 5285, engine power of 62,5kW (85hp), 4 x 2 TDA (auxiliary front-wheel drive). To determine the speed of travel, a Dickey-john radar unit, model DJRVS II, was used, with an error of less than 3% for speeds from 3,2km/h to 70,8km/h, monitoring the instantaneous speed at which the The group walked through the experimental unit, delimited by two wooden markers.

TRACTOR-SEEDER SPEEDS

The results showed that increasing the speed in the sowing operation of the evaluated set to 7km/h and 8km/h provided a reduction in the deposition depth and increased the spacing between seeds. There was practically no change in the emergence speed index and the initial and final population of corn plants used with the increase in the speed of the tractor-seeder set (Table 1). Some researchers found similar results, verifying that the uniformity of seed distribution in the sowing line was not influenced by the speed of movement of the tractor-seeder set when planting corn and soybeans.

PRODUCTIVITY COMPONENTS

The results presented in Table 2 show that the increase in speed of the tractor-seeder set practically did not change the ear insertion height, the stalk diameter and the mass of one thousand grains. Which presented very similar values ​​to each other. The stem diameter and ear insertion height showed the same behavior, indicating that the plants presented uniformity in their longitudinal distribution. Due to the uniform distribution of seeds in the sowing line, there were no physiological anomalies, as competition for nutrients remained in the same proportion. Increasing speed from 5km/h to 8km/h reduced corn productivity by 8,36%, although this reduction is not considered significant according to the statistical test used. Several researchers also found that the increase in the displacement speed of the tractor-seeder set affected the longitudinal distribution of seeds and, consequently, caused a reduction in the yield of corn grains, also reporting that the speed in the sowing operation is one of the parameters that most influence the performance of seeders.

In the present study, it can be concluded that increasing the speed of the sowing operation reduced the deposition depth and increased the spacing between seeds. The percentage of seed distribution and the initial and final stand of plants were practically not affected by the increase in the speed of the tractor-seeder set evaluated, with a tendency towards a reduction in productivity with the increase in the speed of the set from 5km/h to 8km/h. H.

Methods and parameters evaluated during the experiment

The uniformity of longitudinal distribution of seeds in the sowing line was evaluated with the aid of a measuring tape to measure the spacing between seeds, in two lines, discarding the lateral lines and the central sowing line of each experimental plot, since the seeder had five rows. This procedure was carried out by carefully removing the soil in the sowing line to expose the seeds, stretching a measuring tape at the bottom of the furrow, reading the spacing from one seed to another and recording the values ​​on a field spreadsheet. The evaluations were based on the recommendations of the Brazilian Association of Technical Standards (1996), which considers all seed spacings of 0,5 and 1,5 times the expected average spacing (EM) as acceptable. Values ​​obtained outside this limit were considered as failed spacings (above 1,5 times EM) or multiples (below 0,5 times EM).

The deposition depth of corn seeds was determined in two sowing lines per experimental plot. In each row, the depth of ten seeds was determined. With a spatula, the soil over the seeds was carefully removed so as not to remove it from its place of deposition. With the seeds uncovered, the distance from the edge of the furrow to the point where the seed was located was determined.

To determine the initial population existing in the plots, the plants were counted in all plots; counting was done manually, approximately ten days after germination. The final population was determined by counting all plants, in all plots, on the same day that the final harvest of the experiment was carried out.

Productivity was achieved after harvesting the plots manually, where the ears were deposited in plastic bags duly cataloged and sent for mechanical threshing. The grain mass was corrected to 14% moisture. The data were subjected to analysis of variance, using the “F” test at 5% probability. Then, the means were compared using the Tukey test at 5% probability. For statistical analyses, the computer program Sisvar 5.0 was used.

Suedêmio de Lima Silva, Anailson de Sousa Alves, Ufersa; Paulo Roberto de Souza Silveira, UFC; Joaquim Odilon Pereira, Tayd Dayvison Custódio Peixoto, Ufersa

Article published in issue 151 of Cultivar Máquinas.