Importance of correct seeding adjustment

A study shows that the moment of sowing is one of the most important stages in the implementation of the crop, where poor adjustment of the seeder, even with errors that seem small, can be the key between profit and loss at the end of the harvest.

National grain production in the 2015/2016 harvest was 186.609,5 thousand tons. And in 2016/2017 it was 232.391,5 thousand tons (an increase of 24,53%), according to Conab (2018). The planted area in 2015/2016 was 58.331,6 thousand hectares, and in 2016/2017 it increased to 58.449,9 thousand hectares (0,2%), according to Conab (2018). This means that Brazil's total production will grow much more than the new areas for planting, which represents a great challenge that must be combined with planning and innovations.

The moment of sowing is one of the most important stages in establishing a crop. Almeida et al., (2010) state that a good sowing process is characterized by the correct longitudinal deposition of seeds in the soil along with the correct depth. The quality of sowing is combined with several factors such as seed quality, contact with water and soil through good coverage, depth and uniformity of deposition in the planting line, as well as adequate furrow preparation and spacing. between ranks (Márquez, 2004).

To achieve adequate productivity, Portella (1999) states that it is necessary for the seeds to be deposited in the furrow as regularly as possible.

The travel speed of the tractor-seeder set is directly related to sowing uniformity and productivity, being able to change the depth of seed deposition, the plant stand, the quality of furrow opening and closing, in addition to fertilizer deposition, among others. things. There is a difference in the maximum acceptable speed when using a mechanical and pneumatic seeder, with the speed of the former not exceeding 6 km/h and the latter not exceeding 8 km/h. It should also be considered that very low seeding speeds affect operational performance and that good soil management helps with quality, as it is more advantageous if it is level and does not have clods, in addition to having the ideal water content. It is not enough for rural producers to invest in state-of-the-art, high-cost machinery if they do not use the ideal planting speed and do not carry out the necessary maintenance and conservation measures.

Based on the hypothesis that the error of a seed along the sowing furrow is missed, the idea arose of counting how much this error represents in the total losses in the field. As an example, a calculation was made of the failure of a single seed when sowing corn every 2,5 meters of row. For this, a population per hectare of 60 thousand seeds was considered as a hypothesis, sown 0,45 m between rows, resulting in a quantity of 2,7 seeds per meter. In the case of a producer who plants 150 hectares of crops, and obtains production per ear of 0,200 kg and sells each bag of corn for R$35,00, he would have huge losses, as shown below:

If the seeding machine is well adjusted, it is possible to create the possibility of better seeding than previously presented, for example, assuming a failure every 4 meters.

Comparing the two situations, with one failure every 4 meters and one failure every 2,5 meters, differences can be observed that make these discrepancies lead producers to pay attention to good sowing practices.

The population reached per hectare could increase from 51.111,11 to 54.444,44 plants, just by reducing the failure rate, providing a gain of 3.333,33 corn plants, thus reducing the error from 14,81% to 9,26% therefore losing 11,11 bags less per hectare, and as a result the producer would no longer lose R$388,89 per hectare. Analyzing this reduction in failures in the supposed total area, the total loss would change from R$ 155.555,56 to R$ 97.222,22, causing a decrease of R$ 58.333,34.

Therefore, it is worth noting that care when adjusting before the seeder goes into the field is paramount and could be the key between profit and loss for the producer.

At Unesp in Botucatu, members of the Direct Planting Group (GPD) have been presenting good agricultural practices with the Periodic Inspection of Seeders (IPS) project. The objective of the project is to take knowledge from university studies to rural producers, in order to show the importance of good seeder adjustment in the general aspect of a crop's harvest.

There are real cases in which the number of just one failure every 2,5 meters is extrapolated. Of all the seeders evaluated by the GPD to date in the state of São Paulo, none showed uniformity between all lines in the deposition of fertilizer and seeds. This shows that the financial losses that were simulated here really happen in the daily lives of Brazilian producers.

It can be concluded that the success of a harvest depends on planning and this is directly linked to the sowing operation. We need to be aware that sometimes it is not the seed or the purchased machinery that is bad, but that in fact, special care must be taken with the adjustment of the machine so that a uniform sowing is obtained, which aims to ensure the least possible occurrence of faults and doubles, that the seeds are all at the same depth and that the water/soil/seed contact is ideal and allows good germination, resulting in greater productivity.

Luan Solér Francischinelli, Luiz Henrique Menck Rusconi, Adriano Fabbro Gandini, Paulo Roberto Arbex Silva, FCA Unesp de Botucatu

Article published in issue 183 of Cultivar Máquinas, April 2018.