What are the best plant populations and planting times for cotton?

Mato Grosso today appears as the largest producer of cotton fiber in Brazil with 600 thousand hectares of planted area, of these 600 thousand 33% is planted in the Parecis region, around 200 thousand hectares of which 100% is safrinha planting where the harvest is harvested. soybeans between the end of December and the beginning of January and then plants cotton.

This production system gained strength due to the good rainfall conditions in the region, which has an average of 1600 mm accumulated in the year, perfectly meeting the water requirements of the cotton plant, which is 800 to 1200 mm, however it is necessary to make adjustments to population and planting time. taking into account the cycle of the cultivar used.

The choice of planting time must take into account mainly the cycle of the variety to be planted and climatic factors, while the choice of the appropriate planting population must take into account climatic factors, soil fertility, behavior of the variety to be planted and management. to be used.

 With the introduction of new varieties, some more compact and with a shorter cycle, there is a need for new studies to define the best plant populations, aiming to improve not only the quantity, but also the technological qualities of the fibers, seeking to better adapt them to the needs. of the industry.

Material and methods

The experiment was carried out in the 15-16 harvest on the Planorte farm, which belongs to the company SLC – Agricola located in the municipality of Sapezal-MT coordinates: Lat.: S 13°.57’42.7”; Long.: W 58°53’32.7”; Height: 627 m.

The experimental design used was DBC with four replications. Three FiberMax cultivars were used, being FM 983GLT, FM 954GLT and FM 906GLT of Late, Medium and Early cycle respectively, four populations being 55, 85, 100 and 130 thousand plants per Hectares and three planting times being 06/01/2016; 16/01/2016 and 26/01/2016. The experimental plot consisted of 4 rows of 5 meters and the 2 central rows were considered useful area, planting spacing used was 0,76 meters. Planting was carried out manually and population adjustment was made 20 days after emergence with thinning. Harvesting for productivity estimation was carried out manually in the two central rows. For technological evaluation of fiber, boll weight and fiber yield, 3 whole plants were harvested.

Results and discussion

Variety FM 983GLT

Below are the tables with the means of the variables studied for the FM 983GLT variety, the variables Plant Height, Boll Weight, Plume Productivity, SFI, had no statistical difference and are therefore variables that are not interfered by population and planting time for this variety. The Reliability Index (SCI), which is an estimate of reliability calculated from the variables, Microner, Length, Resistance, Uniformity and Gloss of the fiber, despite all being within the standards acceptable by the market, the planting in the population of 130.000 plants per hectare in The first planting season outperformed the others, this is due to the interference of the planting season and population in the factors that have the greatest importance in calculating the index, namely Length and Resistance.

Variety FM 954GLT

Below are the tables with the means of the variables studied for the FM 954GLT variety. The variables Plant Height, Plume Productivity, SFI and SCI had no statistical difference and are therefore variables that are not affected by population and planting time for this variety. . Boll weight had a significant gain in the population of 100.000 plants per hectare in the second planting season, however, as we can see in the productivity table, this did not translate into better productivity, which leads us to conclude that boll weight alone is not the A determining factor in final productivity, the number of apples harvested may be more important than the weight of the boll.

Variety FM 906GLT

Below are the tables with the means of the variables studied for the FM 906GLT variety. The variables Plant Height, SFI and SCI had no statistical difference and are therefore variables that are not affected by population and planting time for this variety. The boll weight had a significant gain in the population of 55.000 plants per hectare in the first planting season, as the variety is precocious, probably the highest percentage of these bolls is from the pointer where we have heavier bolls, with the lower boll being lost due to rot. Due to the high humidity at the time of opening the first bolls, with a greater amount of rot, there was a smaller number of bolls, which explains that despite having a good boll weight, we did not have the best productivity as we can see in the average productivity table. For productivity, we highlight the population of 100.000 plants per hectare in the second planting season and second highest boll weight.

Conclusion

For the FM 983GLT variety, there was no interference from population and planting time on agronomic factors such as boll height and weight, but there was significant influence on fiber quality.

For the FM 954GLT variety, population and planting time influenced the boll weight, but it did not affect the final productivity or technological quality of the fiber.

For the FM 906GLT variety, population and planting time influenced the boll weight and final productivity, but it did not affect the technological quality of the fiber.  

Sinésio Morais, Rogerio Ferreira, Filipe Sanches, Thiago Matias, Jose Ari, Vitor Freitas, Adalbert Neto, FiberMax/BASF cotton Agronomic Development Team