South America Calling

Drier-Than-Normal March Forecast a Long-Term Concern for Brazil's Safrinha Corn

John Baranick
By  John Baranick , DTN Meteorologist
The March forecast from DTN is calling for lower-than-normal rainfall for most of Brazil's safrinha corn areas. (DTN graphic)

A couple of weeks ago, I mentioned that the increasing rain that we had been seeing in Brazil was still lower than normal and not enough to build long-term soil moisture in the country. I also mentioned that here were worries that soil moisture may run short if the wet season rains do not increase. During the last two weeks, those rains have been pretty lackluster for most of the country, though they have still fallen. The rain is falling at a good enough clip to maintain soil moisture in much of the country, but not enough to build further subsoil moisture. And that is a huge concern over the month of March, the last full month of the wet season, as the forecast is for continued below-normal amounts.

The safrinha (second-season) corn in the country relies on good subsoil moisture built during the wet season to sustain the crop through the end of its life cycle. The hope is that the rains continue through the pollination period and that there is enough subsoil moisture for the crop to fill out kernels. But a look at the overall pattern for March does not offer a lot of good news for the crop.

Rain will still fall, but probably at a reduced rate and frequency. Scattered showers interspersed by periods of dryness on the order of several days instead of just one or two is the risk in central and south-central Brazil. Infrequent rain means that temperatures will also be higher during the drier stretches and crops may tap into the subsoil moisture more frequently than normal, reducing the overall soil moisture content too early.

Rain can still be heavy at times and not all areas will see unfortunate rainfall amounts. But the risk is there that the infrequency of rainfall will do more damage than the actual amounts. Systems moving through Argentina, which aid southern Brazil's rainfall amounts during the season, may be more active, helping some of the south-central areas with rainfall if they can bleed northward from Paraguay and the state of Rio Grande do Sul into Parana and southern Mato Grosso do Sul.

Otherwise, what looks like a good corn crop during March may turn quickly in April and May as the wet season rains start to run out. And the forecast for April is much like March, with drier-than-normal conditions in central Brazil and some above-normal in the far south.

Planting has gone well so far, though. The latest reports from Mato Grosso and Parana, the two largest safrinha corn production states, note that corn planting is 80% and 66% completed, respectively. Both are ahead of their long-term averages and that will be important if the weather situation turns out to be a poor one for the country. The faster that the corn can get through its reproductive stages, the higher the chance for decent yields.

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John Baranick can be reached at


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