In the Rosario grains market, soy prices rose, boosted by increasing prices for soybean futures on the influential Chicago Board of Trade.

Trading volume, however, was slim as most farmers sought to protect themselves from the fast-weakening local peso by hanging on to their soybean supplies.

In Rosario, the nation's largest agricultural port, soy closed at 2,225 pesos per tonne ($325.5), up from between 2,205 and 2,201 pesos on Friday.

Soybean futures on the Chicago Board of Trade closed modestly higher Friday on technical buying after a back-and-forth session, and spillover strength from a late rally in soymeal. The market was closed on Monday for the Martin Luther King Jr. holiday.

Ample rains expected in Argentina's agricultural belt over the days ahead should help soy farmers preserve yields that had been threatened by recent weeks of extreme dry and hot weather.

In Rosario, soy for delivery in May 2014, quoted in US dollars, closed at $288 per tonne, up from $287 in the previous session.

At the port of Quequen, soy traded at 1,990 pesos per tonne, while at the Bahia Blanca it traded unchanged at 2,100 pesos.