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October 2, 2014

Lack of Uniformity in Maturing Soy Worries Brazilian Processors

Researchers in Brazil feel that changes over the years of how soybeans are produced in Brazil has led to a lack of uniformity in the way soybeans mature. This has resulted in an increasing amount of green plants and green soybeans in the fields at the time the soybeans are being harvested.

This does not cause any significant problems for the farmers, but the higher than normal amount of green soybeans is causing problems for soybean processors. The chlorophyll left in the green soybeans gives the resulting soybean oil an off color and sometimes an undesirable taste. To resolve this problem, processors must take additional costly steps to remedy the situation.

What is causing the problem is still open for debate. A soybean researchers for Embrapa, Antonio Eduardo Pipoto, feels it is a combination of factors including: early maturing soybean varieties, a switch from determinate to indeterminate varieties, insect feeding, and harvesting during a traditionally rainy time of the year.

In the 1990's Brazilian farmers realized that they could produce two crops per year by planting early maturing soybean varieties as early as possible and then following the soybeans with early maturing corn hybrids. This allowed them to produce two crops during one growing season. In order to maximize the yield potential of these early maturing soybeans, over time Brazilian researchers replaced the traditional determinate types of soybeans with indeterminate types of soybeans.

Determinate soybeans put on most of their growth first before moving into their reproductive phase. In other words, they do all their vegetative growing first and then they start to flower. These are the type of soybeans generally grown in the southern U.S. Indeterminate soybeans start to flower and set pods while the plant is still putting on vegetative growth. As a result, there can be full sized pods at the bottom of the plant while the top of the plant is still putting on new vegetative growth. These are the type of soybeans generally grown in the central and northern U.S.

These indeterminate type of soybeans apparently do not mature uniformly in the hot and humid conditions typical of central Brazil. These early maturing soybeans can be ready for harvest in mid-January, which can be the peak of the rainy season. For some yet undetermined reason, some of these early maturing soybeans don't mature under these climatic conditions. Excessive insect feeding, which is typical in Brazil, is also suspected as being a contributing factor for this lack of uniformity. The bottom line is that the cause of this phenomena remains unclear and scientists feel it is a combination of factors.

While the cause of these green soybeans is still being debated, research is being conducted on how these green soybeans may be screened out prior to processing. The cooperative Comigo has been experimenting with machinery that could potentially remove the green soybeans before they are processed into oil and meal, but they have met with limited success.