South America Calling

Argentina Dryness Next Week

John Baranick
By  John Baranick , DTN Meteorologist
After some beneficial rain in Argentina Jan. 15-17, a dry week is forecast. The drier trend is also likely to cover eastern Brazil crop areas. (DTN graphic)

The past week sure has been what crops in South America have needed. After more than two months of significant dryness, widespread moderate to heavy showers during the last few days and through the coming weekend are bringing, and will continue to bring, more abundant soil moisture to the major growing regions. We do not yet have the satellite images to guide us, but soil moisture, both at the surface and through the soil profile, is likely to increase across much of the continent.

With much of the corn and soybean crop in the reproductive to filling stages, especially in Brazil, the timely showers should have a significant positive impact to yield prospects. And with growth a little further behind in Argentina, the showers will have a much more positive impact. That is, at least in the short term.

The train of widespread showers is set to come to an end over Argentina after a frontal boundary passes through this coming weekend, Jan. 16-17. What will follow will be around a week of almost complete dryness.

However, temperatures are likely to be near to below normal. This will help to stave off evapotranspiration, but temperatures will still reach into the lower to middle 30s Celsius (middle 80s to lower 90s Fahrenheit) for much of the region. For crops entering and going through reproduction, this week's rainfall will be paramount to the success of the crop.

In Brazil, this week's showers will be significant due to their widespread nature and the fact that the region is so far behind in total rainfall; around 200-300 millimeters (roughly 8-12 inches) over the past two months for the main growing regions in central Brazil. The lack of moisture thus far in the growing region has led CONAB, the supply department of Brazil's agriculture ministry, to slightly lower its forecast for the 2020-21 corn and soybean production from its December forecast.

As the front from Argentina moves into Brazil, it is likely to stall over southern growing regions such as Parana and Rio Grande do Sul. Drier air and reduced rainfall chances will follow into next week across eastern growing regions in Minas Gerais and Bahia and possibly a bit farther westward into Goias as well. But the front may not affect the rainfall over Mato Grosso and Mato Grosso do Sul. The current season corn and soybeans are looking to be in better shape than the outlook two weeks ago.

The significant rainfall deficits this season have caused soil moisture to be well-below normal. More importantly, the deficits are through the soil moisture profile. Most of Brazil has little reserve soil moisture as we start to near safrinha, or second-season, corn planting. The safrinha season is much more significant for corn production than the main season.

The Brazil crop year is already running on a two-week delay due to a slow start to the rainy season. The onset of the rainy season did not begin until into October. With this delay, a lack of stored moisture could be a significant hindrance to the development of corn. Should the wet season end sooner, as is typical in a La Nina year, corn may be in the reproductive to filling stages of growth with little available moisture, causing yield losses.

Again, we continue to monitor the rainfall amounts in the central growing regions in Brazil for insights on the safrinha crop production. At this time, the prospects continue to look unfavorable.

John Baranick can be reached at john.baranick@dtn.com

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