Moisture Stress Building in Argentina Corn

December 12, 2011

Growing conditions have become increasingly stressful in southern South America the past 2-3 weeks with intense drying. The crop area affected by emerging drought includes Argentina’s eastern grain belt in Buenos Aires, Entre Rios and Santa Fe. La Nina is the suspected culprit.   Uruguay and Rio Grande do Sul in Brazil also are very dry.

Argentina’s Buenos Aires province, the leading corn growing area, is very susceptible to drought with La Nina.

Last week, extreme heat dominated the key western corn area.   Maximum temperatures were persistently above 90 F even reaching 96 F Saturday.   Nights were abnormally cool with lows near 60 F.  The 35 F difference in daily temperatures indicates a very dry atmosphere with desert-like growing conditions.

High Pressure Stabilizes Atmosphere

Large stable high pressure normally residing in the Atlantic Ocean extends its influence onshore, bringing dry conditions to crop growing areas in Argentina.  Rio Grande do Sul and Uruguay also are affected by a stabilizing influence on the atmosphere that hinders rainfall.   See the December 15 forecast map showing high pressure extending onshore, affecting South America crop areas. 

Buenos Aires Subsoil Moisture Depleted

Corn is in jeopardy in Buenos Aires, the top producing area, because of reduced subsoil moisture from dry conditions August-October.  Typically corn planting begins mid September, but this year it was too dry.

Not only was corn planting seriously delayed, but also growth was stunted by persistently cool dry conditions. Drought breaking heavy rainfall finally developed early in November, replenishing dry fields and improving growth potential.   Drought seems to be resuming in December, however.

The late November vegetation was sub-par in Buenos Aires the leading corn province:

A strong cool front moved through Buenos Aires province Saturday night setting off scattered showers.  Very heavy rain is needed to boost corn after 2 weeks of hot dry weather.  Not much rainfall is in the weekly forecast,  just .10-.25 inch at the highest.

Scattered rains helped where they occurred in Buenos Aires corn growing areas:

Sharply cooler air is coming to Argentina this week.  Maximum temperatures would drop some 20-25 degrees F into the mid 70s F to low 80s F.  Chilly nights in the 50s F are also predicted.  Cooler temperatures are certainly welcome, less stressful for corn and soybean development, but without heavy rainfall not much improvement is expected in crops. 

The USDA prediction for Argentina record corn production is starting to look overly optimistic. The December estimate for corn was 29 million metric tons compared to 22.50 MMT last year.