How to minimize damage from delayed cotton planting

Rains in recent weeks make sowing difficult in Mato Grosso; there are alternatives to deal with the problems

01.02.2025 | 05:55 (UTC -3)
Cultivar Magazine
Photo: Fabiano Perina
Photo: Fabiano Perina

Delays in cotton sowing in Mato Grosso can cause significant losses to productivity and fiber quality and affect the planning of subsequent harvests.

According to researcher Sidnei Douglas Cavalieri, from Embrapa Cotton, the ideal sowing time is in January. When sown from February onwards, the cotton plant may face water stress, an increase in the presence of weeds and negative impacts on crop rotation.

The delay can also generate additional costs with herbicides and affect the destruction of ratoons, interfering with the sowing of soybeans in the subsequent crop.

Hydrical stress

Mato Grosso concentrates around 70% of the area cultivated with cotton, with approximately 90% of the crops cultivated in the second harvest, after the soybean harvest. Cavalieri explains that, when sown in February, cotton has less rainfall available.

In some regions of the state, rainfall stops in April, while in others, it stops in May. The shorter rainy period can compromise crop development and reduce its productive potential.

In the 2024/25 harvest, the delay in the onset of rains delayed soybean sowing, which, as a result, is harvested later. This shortens the cotton sowing window. If the producer does not reschedule his crop, maintaining medium or long-cycle cultivars, there may be a direct impact on productivity, as the plants will have less time to benefit from the rains.

Strategies to minimize impacts

To reduce the effects of the delay, Cavalieri recommends that producers use shorter-cycle cultivars. This allows the cotton plant to make better use of the available rainfall.

It is also possible to reduce the spacing between planting rows, making the arrangement of plants more equidistant. This technique can help mitigate losses caused by weed competition.

Sidnei Douglas Cavalieri
Sidnei Douglas Cavalieri

Phytosanitary challenges

The researcher warns that the lack of rain can make it difficult to close the crop canopy, favoring the infestation of weeds.

Some species, such as goosegrass, caruru, and bittergrass, have populations that are resistant to herbicides and can compromise crop development.

To get around the problem, there may be a need to invest more in herbicides, which increases production costs.

Furthermore, delayed sowing may increase the presence of pathogens and nematodes, requiring more rigorous management. If the producer needs to change the planned cultivar for another, the resistance of the new variety to certain pests may be different, requiring adjustments in phytosanitary control.

Photo: Valdinei Sofiatti
Photo: Valdinei Sofiatti

Impact on crop rotation

Delayed sowing also interferes with planning for the next harvest. Cotton is a perennial species, and its crop residues must be eliminated before soybean cultivation begins.

The ratoon control is done mechanically and chemically, with the application of the herbicide 2,4-D. This product has residuals in the soil and, if soybeans are sown immediately after its application, there may be an impact on the establishment of the crop.

If cotton is harvested later, the time for the destruction of the ratoon crop decreases, reducing the soybean planting window. This can compromise the oilseed cycle and affect its productivity, damaging the soybean-cotton production system, which is common in Mato Grosso.

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