The Brazilian Chamber of Deputies has approved controversial legislation that eases rules on how much land farmers must preserve as forest.
Brazil's powerful farmers' lobby argues that the changes will promote sustainable food production.
But environmentalists say the new forest code will be a disaster and lead to further destruction of the Amazon.
The bill now goes to President Dilma Rousseff, who may use her veto to remove some clauses.
Wednesday's 247-184 vote in favour of the new forest code capped a year of political wrangling.
Brazil's farmers have long pushed for changes, arguing that uncertainty over the current legislation has undermined investment in the agriculture sector, which accounts for more than 5% of GDP.
Severe environmental restrictions have also forced many smaller farmers off their land, they argue.
Rural producers would have "more stability ...