Drouth during soybeans' reproductive stage reduces yield but increases protein content, Brazilian research indicates.

In a study at that country's National Soybean Research Center in Londrina, PR, soybeans were subjected to water deficit at the vegetative or reproductive stage. Yield losses due to dryness at the two stages were 55% and 75%, respectively.

The highest oil content was in beans harvested from plots with no water restriction. In all varieties tested, the lowest oil content was in beans from plots subjected to drouth during the vegetative stage.

The highest protein content was in beans stressed by dryness during the reproductive stage.

Even though soybeans grown under low water availability during the reproductive period yielded less, the grains have higher protein content and can be directed to specific markets, the research concludes.

(J.R.B. Farias, N. Neumaier, A.L. Nepomuceno and J.R. Bordingnon, National Soybean Research Laboratory, Londrina, PR, Brazil)