The following content was provided by meteorologist Gail Martell of MartellCropProjections.com:
Renewed Heat and Moisture Stress in Argentina Crops, Brazil Outlook Better
Extreme heat and dryness resumed last week in Argentina, stressing corn and soybeans. Temperatures peaked Saturday with 100 F (38 C) or higher in the grain belt. A strong cool front moved through Saturday night, kicking off strong thunderstorms, but coverage was scattered. Rainfall was not enough to relieve drought, especially in Buenos Aires.
Hot dry weather threatened crops also in December. Only 50-75% of normal rain occurred in the month. Drought coincided with the period of rapid growth and development in corn and soybeans. The drought was topped off by a Christmas week heat wave, when temperatures exceeded 104 F (40 C). (For more information read on MartellCropProjections.com: "Argentina Heat Wave, Strong Drying.")
A sharp cool front will trigger strong showers and heavy rainfall to the grain belt. Scattered showers began developing Saturday night. The expectation is for very heavy rainfall with recurring storms, 2-3 inches.
Crop damage has already been incurred. The USDA has reduced its estimate for Argentina corn production to 25 million metric tons, down 6% from last season. The soybean estimate was held steady at 54.5 MMT. Soybeans are known to tolerate heat and dryness better than corn. Very late planted crops, sown in December, were most damaged. These crops developed a shallow root system increasing vulnerability to moisture stress.
La Nina Signal Emerging
We have a hunch the recurring weather stress in Argentina is related to the ENSO signal. Recently, sea surface temperatures in the equatorial Pacific Sea have sharply cooled, indicating a strengthening La Nina effect . This may explain recurring bouts of heat and moisture stress in Argentina, as this is a country where the ENSO signal is very strong. Argentina weather becomes dry with La Nina, but wet with El Nino. Note, the strong cooling recently in the Nino 3.4 region does not indicate a full-fledged La Nina, rather a La Nina signal.
South Brazil crops have maintained a favorable yield potential thanks to very generous January rainfall. Crops were threatened by heat and dryness in December, but conditions have turned around with well above-normal rainfall. January rains have been abundant in Rio Grande do Sul and Parana, the 2 key southern farm states. ("Read on MartellCropProjections.com: "Brazil Crops Benefit from Heavy Rain More than Argentina, a report published earlier this month.")
The main crop damage has been done in Argentina. This was reflected in USDA's January World Agricultural Supply- Demand Estimates. The USDA increased Brazil soybean production to 89 million metric tons, up one million tons from December representing a new record. Brazil corn production was left at 70 million metric tons, a 14% reduction from last season.
Argentina corn production was reduced to 25 million metric tons a 6% dip below last year. My bias is lower. Soybean production was held at 54.5 million metric tons, which if achieved would establish a new record. Soybeans are known to tolerate heat and moisture stress better than corn. Pod filling in soybeans would occur mainly in February-March for late planted beans, the most yield-sensitive period.