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March 9, 2015

Soybean Yields in Mato Grosso have Stagnated over the last 15 Years

Farmers in Mato Grosso are frustrated by the fact that their soybean yields have basically stagnated for the last 15 years while soybean yields in other regions of Brazil have continued to increase. Even though the soybean production in the state will set a new record this year, the statewide soybean yield in Mato Grosso is essentially the same as it was 15 years ago.

During the last 15 years, the soybean yields in Mato Grosso are up only about 3%, while the yields in Rio Grande do Sul increased 46%, they were up 15% in Parana, and nationwide the soybean yields have improved 17%. Fifteen years ago, the yields in Mato Grosso were 19 sacks per hectare (16.5 bu/ac) higher than in Rio Grande do Sul (50 sacks per hectare in Mato Grosso or 43.5 bu/ac compared to 31 sacks per hectare in Rio Grande do Sul or 27 bu/ac), but during the last three years, that yield advantage in Mato Grosso has been reduced to just 6 sacks per hectare (5 bu/ac).

One of the reasons why scientists feel the soybean yields have stagnated in Mato Grosso is due to the tremendous increase in safrinha corn production. The safrinha corn acreage in Mato Grosso and in Brazil has increased 12 times during the last 15 years. In order to plant a second crop of corn, Brazilian farmers shifted to very early maturing soybeans.

Early maturing soybeans (90-100 maturity) generally have a lower yield potential compared to later maturing soybeans (120 day maturity). Additionally, farmers are planting their soybeans as early as possible in order to allow for as much time as possible for the second crop of corn. Planting the soybeans early can lead to reduced plant populations and problems with early growth and development due to the irregular nature of the rains at the start of the summer growing season.

These early maturing soybeans must also be harvested during January or early February, which could be the peak of the rainy season in Brazil. As a result, many farmers apply a defoliant to the crop to speed up the maturity process, which could potentially have a negative impact the yields as well. The harvesting of these early maturing soybeans during the rainy season is in itself problematic. Often times, the harvest of the soybeans is delayed by wet weather resulting in poor seed quality and potentially lower yields.

An additional factor as to why soybean yield improvements in Mato Grosso have lagged those of Parana is due to the different soil types in the two states. The soils in Parana are some of the best in Brazil and they hold water, nutrients, and organic matter much better than in Mato Grosso. The cerrado soils of Mato Grosso have a much lower level of native fertility and they leach nutrients much more rapidly than the soils in Parana. This requires higher levels of fertilizer applications on a yearly basis just to maintain the soybean yields in the cerrado areas.

At the turn of the century, many soybean farmers in Mato Grosso had anticipated that they would grow two or maybe even three crops of soybeans during a single year. The first crop would be planted in September and harvested in January. They would then quickly plant the second crop of soybeans that would in turn be harvested before the rains ended in early May. If they had irrigation capabilities, they could then grow a third crop of soybeans during the dry season.

The arrival of soybean rust in Brazil during the 2000/01 growing season scuttled any attempt to produce continuous soybeans year-round in Brazil. And now, even a second crop of safrinha soybeans is prohibited in Mato Grosso in order to help control the spread of soybean rust.

Even though soybean farmers in Mato Grosso may complain about the lack of improvement in soybean yields, in the big picture, they are better off now than 15 years ago. Farmers in the state now have the capacity to produce two crops per year on many of their acres and the benefits of that second crop of corn (or another grain crop such as sorghum or sunflowers) outweigh the yield penalty imposed by planting early maturing soybeans.