The corn crop is considered one of the most “technical” crops, that is, it is highly responsive to the management used. There are several factors that can interfere in the final performance, such as the level of fertilization, the management of pests and diseases, the quality of planting, the climate, the plant stand, among others. The plant stand, also called plant population, has been extensively studied by companies and institutions, as it is one of the factors of greatest influence on productivity. A correct plant stand is achieved through good planting quality associated with management to preserve the plants, avoiding the loss of plants and the development of irregular (dominated) plants.
Year after year, the direct relationship between the final plant stand and the yield components and the final crop yield has been observed. Recalling, the components of corn yield are the number of ears per area, the number of grains per ear and the weight of grains. According to Strachan (2004), 85% of the productivity is attributed to the number of grains and it is precisely in this that an ideal plant stand can contribute, through the largest number of ears per area.
To understand the importance of the number of ears per area, we will simulate two crops: one with 55,000 ears / ha and the other with 60,000 ears / ha. In this example, we can see that the increase of 5,000 ears / ha resulted in a difference of more than 16 sc / ha, this cannot necessarily be attributed to an increase in the plant population, but to a better plant pattern (better pattern of ear) that is obtained through a correct management of the area and mainly a good quality of planting.
The development of new hybrids with greater productive potential, modern architecture and the adoption of intensive management practices associated with planting in reduced spacing have contributed greatly to plantations with high rates of plant population. This practice has proved to be viable and profitable, reaching high levels of productivity. Currently, yields above 200 sc / ha are already a constant in summer plantings in several regions of the country, however, this can also be obtained in the safrinha plantations
DuPont Pioneer, in the United States, has conducted tests in recent years comparing the performance of old and modern materials under different plant populations, and noted that, as the plant population increased, the old materials suffered a considerable reduction in the number grain per ear, modern materials have managed to maintain an excellent ear pattern.
Each material has an ideal plant population range by area. This information is obtained based on a series of tests conducted by the company over the years that precede the commercial launch of the material and that are continued after this event. These tests are carried out in different regions, times and levels of investment and it is through these that we have the basis to inform and guide the producer on the correct sowing management in the area. It is important to highlight that the recommendations refer to the final plant stand, that is, at the time of sowing, germination of the lot and the possible losses that may occur, such as discovered seeds, climate, pest attack, and others, should be considered. Based on this, an additional percentage of seeds is calculated for the desired final population:
Sowing rate = Final Desired Stand + Losses
Author: José Carlos Cazarotto Madaloz