Advances in seeders boost corn cultivation

By Luan Solér Francischinelli and Paulo Roberto Arbex Silva, from Unesp

02.01.2025 | 16:54 (UTC -3)

The corn (Zeamays L.), with its origins in Central America, is one of the most important plants in the world and the most domesticated by humans throughout history. Well adapted to Brazil, corn crops play a prominent role in the national economy, given that 30% of the arable land in our country was planted in the 2017/2018 harvest, according to Conab (2018). In addition, the latest survey shows that the productivity in the first and second harvests was 5.556 and 5.564 kilos per hectare, respectively. Several new technologies have been contributing to the production of the second crop, and in this regard, the area of ​​mechanization has been one of the areas that has evolved the most in recent years.

When it comes to sowing, more and more farmers and companies in the sector are becoming aware that carrying out this process correctly is extremely important for corn to achieve high productivity. Plantability is a new term that can be classified as a qualitative characteristic and, in practice, means carrying out a good installation of the crop, always seeking to be as satisfactory as possible. This involves several aspects related to the adjustment of the seeder, such as cutting the straw well, applying the right fertilizer, closing the furrow well, among others. However, the most important point is the distribution of the seeds, at the correct spacing and depth.

Irregularity in the longitudinal distribution of seeds in the row can compromise the efficient use of water, light and nutrients, increasing the number of plants with delayed phenological development, fragile stalks, producing small ears and appearing dominated in the crop (Sangoi et al, 2012).

There are two types of seed metering devices for precision seeders on the market: horizontal alveolar disc seeders (popularly known as mechanical seeders) and pneumatically assisted seed metering devices (commonly known as pneumatic seeders), according to Dias (2009). Recently, some companies in the market have invested in technologies that favor the advancement of mechanical seeders, which are still the most widely used in Brazil.

A technology that emerged to contribute to the quality of horizontal discs was called Rampflow, which is characterized by having grooved ramps in the holes, which facilitates scraping and the removal of possible double seeds.

The Direct Planting Group (GPD) belonging to Unesp in Botucatu carried out a study evaluating the longitudinal distribution of corn seeds using two discs on a bench simulator treadmill working at a speed of 4 km/h. At the time, an 11 mm sieve was used for both and the spacing between seeds was measured with the aid of a tape measure. The values ​​obtained were subjected to descriptive statistics analysis and classified as acceptable, faulty and double according to the methodology of Kurachi (1989), which treats as acceptable the seeds spaced between 50% below and above the ideal. Values ​​smaller than the 50% margin are classified as double spacing, and larger ones as faulty spacing.

Table 1 shows that the average spacing closest to the ideal (23,9 cm) was verified in the Rampflow disc, similar results were found by Correia et al (2015). The largest standard deviation (SD) was verified in the Conventional, with an increase of 59,39% in relation to the Rampflow. The largest coefficient of variation (CV) was obtained by the conventional disc.

Table 1 - mean values ​​for seed spacing (cm); standard deviation (SD), coefficient of variation (CV); minimum significant difference (MSD) for corn seeds deposited by conventional horizontal disc and Rampflow
Table 1 - mean values ​​for seed spacing (cm); standard deviation (SD), coefficient of variation (CV); minimum significant difference (MSD) for corn seeds deposited by conventional horizontal disc and Rampflow

Table 2 shows better performance for the Rampflow disk, which achieved the highest acceptable spacing index. For double spacing, there was a large difference compared to the conventional disk, which also achieved the highest failure rate.

The aim of this work is to show that rural producers can significantly improve seeding on their properties by investing little money, given that planting discs do not usually cost much. Of course, this does not replace good adjustment of the seeder combined with low tractor travel speeds.

In addition to all this, it is important to carry out inspections on seeders during the off-season with the machine in the shed. Based on this, the Periodic Inspection of Seeders (IPS) program was created, carried out by the Direct Planting Group, which has been running throughout Brazil and consists of visiting rural properties to carry out a checklist of the machine's condition and deliver a final report to the producer, so that he can make decisions, which sometimes only involve adjustments, or even replacing parts that have been found to be worn.

Especially for corn crops, the crop's production potential is defined at the time of sowing, since this crop does not have a scion habit that compensates for some errors made in the field. Following this reasoning, each seed that is not deposited in the furrow will mean one less plant for the producer, failing to produce an ear. Sometimes, an error of, for example, 5%, which may seem small, translates into three thousand fewer plants per hectare, if the desired population were 60 thousand plants. And this same number of errors will be the number of fewer ears that will be harvested at the end of the harvest. Therefore, the losses are very large, and full attention to the sowing stage is necessary. Investments made to improve this scenario can bring good financial returns, since they are directly related to the increase in final grain productivity.

*Per Luan Solér Francischinelli e Paulo Roberto Arbex Silva, from Unesp

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