Brazil may soon have rainfall concerns

Brazil weather improved in the last half of February with less rain falling in portions of center west, center south and northeastern parts of the nation. The change was imperative to get early soybeans harvested and Safrinha corn planted.

Field progress advanced by leaps and bounds, but further research suggests the pattern change may be a persistent one and may perpetuate less rain for some of the nation’s crops during March.

A delayed start to seasonal rainfall in late September and October 2024 kicked off a chain reaction of issues for Brazil’s summer crop production, but prior to mid-February that was not a serious problem. Some market analysts and meteorologists blamed moderate to heavy rain in January and February on the early soybean crop harvest delay.

The reality is that it would not have been harvested on time if the weather was perfect because the crop was not fully mature. The lack of maturity was linked to the three-week delay in early planting, not the abundance of rain in January and February. Certainly, drier-biased weather might have sped the crop to maturity but at the expense of lower yields.

Instead, the favorable rainfall distribution from November through early February was nearly perfect for inducing some very good yields in soybeans and first-season corn. The pressure was on, though, for getting the early soybean crop harvested so that Safrinha corn planting could be completed by the end of February. A break in the rainy pattern occured in mid-February, leading to some swift fieldwork that got much of the Safrinha crops planted. But some of the crops were planted late and will be emerging and establishing late.

Late-season corn in Brazil is a shorter season crop and can be very successful if the annual monsoon season remains in place through mid-April in a normal year. Late planting this year demands timely rain through the entire month of April and a little rain in May would be ideal, but that may not occur. World Weather, Inc. anticipates a relatively normal end to the monsoon season. A larger worry over a normal finish to the monsoon season is the potential for late-season rainfall to be lighter than usual.

While monsoon precipitation is expected to prevail through March and into April, the intensity and distribution of that rain will be less than usual. Such conditions could lead to soil moisture shortages at times and a little crop stress. It will be imperative for rain to fall in a timely manner over the next several weeks. That part of the forecast may verify for many areas, but the amount of rain will be lighter than usual and that raises a potential issue for the reproductive season.

In a normal year, when soybeans are planted on time and the harvest occurs normally, Safrinha crops yield best when the rainy season ends in mid-April and the ground is completely saturated with moisture at that point. The saturated soil then carries normal plant development through reproduction and filling and supports good yields. Poor soil moisture at the end of the rainy season can be a serious threat to reproducing and filling crops, especially if temperatures are warmer than usual.

High-pressure system impact

The weather change that occurred in mid-February brought drier weather to Brazil’s soybean and Safrinha corn production areas due to an upper air region of high pressure that expanded inland from the Atlantic Ocean into southeastern Brazil. The high-pressure system was welcome, and it did exactly what farmers needed to get soybeans harvested and Safrinha corn planted, although some late-season fieldwork will linger into March.

Unfortunately for some Brazilian producers, the high-pressure ridge aloft is projected to remain in place through much of March. No wavering was expected in the first half of the month and some computer weather forecast models have suggested the feature may come and go in the second half of March as well.

Producers will be hoping for timely breaks in the ridge of high pressure to bring enough rain to support normal crop development. However, concern is rising that long-term soil moisture will be less than usual when the monsoon season ends, raising the potential for moisture and heat stress during reproduction and filling. This potential seems to be rising.

The high-pressure system in southeastern Brazil already has dried out coffee, minor sugar cane, corn, soybean and cotton production areas from Minas Gerais through Bahia into southeastern Piaui and southeastern Tocantins. Some drying has occurred in the heart of center south Brazil while rain has prevailed in center west production areas.

The drying in Parana, São Paulo and eastern Mato Grosso do Sul has not been of much concern because subsoil moisture is favorable, and timely rain is projected for those areas. Minas Gerais and Bahia, however, will continue to be dry, and rainfall in Goias and Tocantins also may be lighter than usual as the month of March advances.

Mato Grosso is the most important Safrinha corn and cotton producing state in Brazil with Mato Grosso do Sul, Goias and Parana also important. The forecast for March suggests that Mato Grosso will stay outside of the driest conditions, but a very close monitoring of weather for the month is warranted since a drier-than-usual month could set the stage for poor yielding summer crops once the monsoon comes to an end.

There is time for change in the outlook, but for now a large part of Brazil’s grain, oilseed, cotton, sugar cane, coffee and citrus production areas are facing a lighter-than-usual rainfall bias over the next few weeks with warmer-than-usual temperatures. That does not dictate a failing in late-season corn yields, but it does warrant timely rain not only through April, but possibly into May as well.

Tags: corn, Brazil, soybean, crop condition