Influence of speed on sowing

Test to evaluate the influence of speed on soybean sowing in the southwest region of Mato Grosso shows that it is possible to work at higher speeds without losing efficiency.

Soy is currently one of the most important agricultural crops in Brazil. Mato Grosso is the state that produces the most, using the soybean rotation system with off-season corn, with two crops per year, or also adopting the technique known as crop-livestock integration, in rotation with pasture and in a system direct planting. For this reason, sowing needs to be well planned, in addition to requiring machines that, in addition to ensuring adequate seed distribution, must be sized for large areas.

To achieve uniform emergence and development of crops, it is essential to achieve efficient sowing, as agronomically recommended. In conservation tillage these requirements increase in importance, as soil conditions, such as surface coverage, are generally not as favorable for sowing as soils with conventional tillage. Direct planting system (SPD) seeders must have special characteristics to carry out efficient sowing, with regulation being one of the parameters that will contribute to achieving good equipment performance.

The most common seed dosing mechanisms for large seeds, such as soybeans, are the horizontal disc type, with a pneumatic type doser and a gripper finger type doser. There is currently a great demand for machines with pneumatic dosing systems, to work in off-season soybean-corn systems or in crop-livestock integration. Pneumatic systems are more advantageous than horizontal disc systems, being able to provide more uniform stands, allowing greater work speeds and consequently, greater productivity.

Among the various factors that affect the quality of the sowing process in a direct planting system is the speed of movement. The main issue is related to the demand for work when planting large areas where the recommended period for carrying out the activity is restricted, mainly determined by environmental conditions. The speed of the sowing operation has a direct influence on seed coverage, distribution uniformity, plant stand and consequently productivity. Travel speeds of 5km/h to 7km/h are ideal for operation.

For the characteristics of Mato Grosso, mechanized sets capable of guaranteeing satisfactory operational capacity must be used. Therefore, it is increasingly necessary to use modern machines with pneumatic seed dosing systems, increased sowing lines, electronic sowing monitoring equipment, and automatic pilot, which enable an increase in the speed of movement of the set. It is common to observe in the field on some rural properties the use of high-powered tractors working at speeds exceeding 8km/h.

FIELD TESTING

With the objective of evaluating a machine with a pneumatic dosing system for soybean cultivation in a crop-livestock integration system, two experiments were carried out on the Ressaca farm of the Nelore Grendene group, located in Cáceres (MT). This is a reference property in the southwest region of Mato Grosso that is adopting crop-livestock integration. All cultural treatments were carried out according to the needs of the culture. The soil in the region is classified as Red-Yellow Oxisols) and the area has a pasture history.

In the first experiment, the soybean sowing process was carried out on December 1, 2015, where the seeder was set to distribute 14 seeds in the soil, 12 plants/m. The Valtra BH210 tractor, 210 hp, year 2013, was used and a John Deere model 2122 CCS 22-row seeder, with VacuMeter pneumatic system, double “V” disc seed furrower with a regulated spacing of 0,5m between rows. . The experimental design was in randomized blocks, four replications, with three treatments, namely: speeds of 7 km/h; speed of 5 km/h and speed of 6 km/h. Each experimental plot was 30 meters long by 11 meters wide and 5 meters between plots. The speeds were achieved by scaling gear and acceleration measured by the tractor itself, higher speeds as desired in the experiment were not possible due to the power of the tractor.

The Emergence Speed ​​Index (IVE) was obtained by counting the plants emerged in two linear meters in the 5 central rows, from the first week after sowing until the stabilization of the stand in the fourth week after sowing. The stand representing the number of plants per linear meter was obtained by counting carried out in the fourth week after sowing.

The results were subjected to analysis of variance using the F test and comparison of means using the Tukey test, at a 5% probability level. In the results obtained for experiment 1, some problems with desiccation of existing pasture and also with uniformity of coverage were observed, as well as weeds on site. The results for Emergency Speed ​​Index (IVE) and Initial Stand (STI) are presented in Table 1.

The results for emergency speed index (IVE) and initial stand (STI) showed no significant difference and the stand was considered adequate. The JD 2122 CCS seeder with 22 rows has a working width of 11 m, achieving an efficiency of 85% at a speed of 7 km/h. With an operational capacity of 6,54ha/h, in a 10-hour day it would be possible to plant 65,4 ha/day. As it is equipped with electronic monitoring systems and automatic pilot that allow night shifts, this shift could be extended to 20 hours per day, which would increase yield to around 130 ha/day per mechanized set.

In the second experiment, the soybean sowing process was carried out with the John Deere 8370 tractor, 370 hp, year 2016, which allowed higher speeds in the sowing operation in the experiment, with the same JD 2122 CCS with 22 rows, set to 10 plants/m in an area with Brachiaria ruziziensis in which partial results are presented in Table 2.

The results showed no significant difference regarding the Emergency Speed ​​Index. As for the initial stand, it was observed that up to 10 km/h was satisfactory. This speed allows an operational capacity of 9,35 ha/h, a considerable increase in relation to the experiment at 7km/h, reaching 93,5 ha in a journey of 10 hours/day or with an additional 10 hours for 188 ha/day with a single mechanized set.

To deepen the subject and further analyzes more research is needed in specific conditions. But this possibility of increasing speed, considering the satisfactory index in relation to the initial stand, is of significant importance for the conditions of Mato Grosso with extensive areas and short sowing time.

Jane Maria Batista Vanini, Zulema Netto Figueiredo, Taniele Carvalho de Oliveira, Erick Marinho Samogim, Paulo César Lima Silva, Breno Caique Baioni do Carmo, UNEMAT

Article published in issue 172 of Cultivar Máquina