South America Calling

The growing season in South America is a long one and we are coming upon planting season as we get into September. Being very close to the equator, cold temperatures are only observed for a limited length of time, allowing for Argentina to have a wide-open planting window and for central Brazil to double-crop soybeans and corn in the same season.

Because of this, the weather situation could be hard to diagnose sometimes, as rain could be favorable to growing crops, but damaging to maturing crops in the same region. Below is a general outline for how farming is practiced in the primary countries of Argentina, Paraguay, and Brazil; but it should be noted there is a lot of variability due to the weather conditions. Some areas that can double-crop choose not to and those that do could stick with a quick-maturing crop or opt for a longer-maturing variety. Practices are being altered as producers gain more knowledge about how to effectively utilize their climate conditions, including the implementation of a third crop in parts of Brazil.

ARGENTINA

Argentina's growing areas -- effectively between 27- and 39-degrees south latitude -- is equivalent to farming from central Florida to central Kansas in the U.S. In some ways, the weather patterns are similar as well. Much of the country is dependent upon weather systems and fronts moving south to north (north to south in the U.S.), bringing moisture over the Andes (Rockies) from the Pacific; or bringing it in off the warm Atlantic or Gulf of Mexico (Gulf of America) in the U.S. Double-cropping is common in the north, generally a wheat-soybean rotation, but cooler conditions limit southern areas to more of a long-season variety of corn and soybeans.

If producers opt for winter crops, they harvest them in November or December, planting a soybean or even short-season corn variety afterward. Otherwise, producers are essentially free to plant a single, long-season crop in September or later. Anything planted in September is usually reserved for corn and sunflowers as there is still a risk of frost. The first phase of planting is open through October before producers gradually take a break in November. This is to take advantage of the storm track, which has a tendency to move northward into southern Brazil and Paraguay in January, leaving Argentina drier. If producers were to plant corn in November, it would be pollinating in January, and a potential dry stretch during this time would be unfavorable. This would be a major weather factor to watch for Argentina. If they indeed have a dry January, that could hurt those who decided to plant early. Instead, producers usually switch to planting soybeans in November and December as soybeans would not be setting pods until February, when the storm track starts to turn south again. Producers then plant the second phase of corn in December and January, either spreading out their risk of a dry spell with the first crop, or planting after harvest of a winter crop. Later plantings have become more popular in recent years as dry stretches during the summer have become more common.

Argentinians then have a long harvest period for corn that starts in March and can last through the end of July. The harvest period is shorter for soybeans, between late March and June.

With the weather situation very reliant on storm systems tracking through the country, Argentina is more susceptible to hot and dry or even wet and cool conditions throughout the growing season. That can cause major implications for production in the country. La Nina that is currently building in the central Pacific this year also tends to leave the country hotter and drier on average throughout the growing season, as storms become less frequent.

SOUTHERN BRAZIL AND PARAGUAY

Brazil really needs to be separated into two parts and treated like two different zones. The far southern state of Rio Grande do Sul along with portions of Santa Catarina, Parana, and neighboring country Paraguay have different weather patterns than all areas farther north. These southern areas are much more tropical than Argentina and precipitation peaks during the summer as the storm track gets farther north. This region has the most consistent rainfall patterns on the continent and can lead to a wide range of options that producers choose to undertake.

They are set up nearly perfectly to double-crop and many producers here do that. Farther south, that is more of a wheat-corn rotation, while farther north that is more of a soybean-corn rotation. Others choose to do a single, long-maturity corn crop as their sandier soils, especially in Rio Grande do Sul, can lead to significant stress if they undergo a dry spell.

With such a wide range of conditions and options, the season can be very long. Often underway at the beginning of September, planting season runs through the month of December. Depending on the crop, harvest is done at various periods as well. Winter wheat is harvested in late September through November, quickly followed by a double crop of usually soybeans, but sometimes corn, that can take advantage of rains before the storm track moves farther south in April. Harvest of those crops may not happen until May or June but can be spread out at the producer's discretion.

Weather is important for this region all the time throughout the season, but for various reasons. Sometimes rain in December is a good thing for developing corn and soybeans, but cause delays in the remaining planting, as well as cause quality issues for winter wheat that may still be out in the field. Temperatures can swing depending on systems moving through, but prolonged stretches of hot or cool weather are possible. Frosts can occur late in the season, especially starting in June, but most of the season is over and only northern areas that double crop with corn are affected.

Like Argentina, southern Brazil and Paraguay are usually the victims of excessive heat and dryness during La Nina, which can severely affect crop development depending on when these conditions are felt the most. Sometimes, the hot and dry conditions overlap multiple sensitive crop development periods and cause significant loss of production.

CENTRAL BRAZIL

The climate in central Brazil offers no such flexibility in farming technique but does give producers here the opportunity to double-crop soybeans with corn or cotton. Winter does not exist in central Brazil as it is firmly in a tropical climate zone. Instead, the region has a distinct dry season -- where rain rarely falls for several consecutive months -- and wet season -- where it rains nearly every day for several consecutive months. From Parana northward through Minas Gerais, Tocantins, and Mato Grosso -- Brazil's largest state for corn and soybean production -- the region relies on a timely start and end to their wet season to produce a good crop. Temperatures are always hot year-round, but precipitation follows a very monsoon-like pattern. Near complete dryness from May through most of September means soils are very dry when it comes to planting time. Producers here wait for the rains not only to start, but to be consistent so early germination isn't followed by a quick dry period that would cause the crop to suffer. Soybeans are the preferred starter crop as the wet season peaks in December through February, a time when soybeans should be filling pods. Regardless of planting date, soybean yields are usually fantastic, comparable to or even better than the U.S. Corn Belt.

With harvest from mid-January through the end of February, producers quickly harvest soybeans to plant a second-season (safrinha) crop of corn or cotton. Corn has become the more popular choice overall and producers rely on wet season rainfall to extend through the end of April to get corn through pollination with good moisture. Rain usually shuts down fairly abruptly, forcing corn to fill with the soil moisture that has built up during the wet season.

Any delays or disruption in the wet season timing can drastically affect corn and cotton production in central Brazil. A late start to the wet season means a delay in planting and then harvesting soybeans, and then a delay in planting corn, which threatens to expose the corn crop to the dry season too early. Even if it starts on time and producers are vigilant in planting their safrinha corn, an early end of the wet season could threaten pollinating and then filling corn.

La Nina has a tendency to shorten the wet season rainfall, both by delaying the start and quickening the end. The correlation is not 100%, however, and sometimes the wet season has been longer than average during La Ninas, but the risk here is mainly to corn. If delays to planting do occur, corn can also be exposed to frosts, which are also a common occurrence during La Nina in June and July. Should corn still be filling during that period, significant production cuts would be likely.

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

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