BUENOS AIRES (Reuters) - Mauricio Macri, Argentina's main opposition challenger in the presidential race, on Wednesday threw his support behind an anti-government protest staged by farming groups, hunting for extra votes to ensure this month's ballot goes to a run-off.
Macri, who has lost ground in past weeks to the ruling party candidate Daniel Scioli, pledges to unwind controls on the economy that include hefty export taxes and quotas on grains exports imposed by the outgoing president, Cristina Fernandez.
In the run-up to the Oct. 25 vote, the centre-right Macri has also come under mounting pressure in the fight for second place from a resurgent Sergio Massa, a dissident Peronist, intensifying the battle for swing voters.
Dozens of producers of cotton, blueberries, apples and other fresh fruit and vegetables beat drums and carried banners reading "Don't kill the countryside" to demand better prices and lower taxes when a new government takes office on Dec. 10.
"In December, we're going to set clear rules. We'll work together with farmers to restore growth," Macri told the protesters.
Macri, mayor of Buenos Aires, reiterated his promise to apply "zero taxes on farm exports to regional economies, zero quotas on exports."
Agriculture is a key source of jobs and earner of hard currency in Latin America's No. 3 economy.
Relations between Fernandez and farmers turned icy early in her first term after she imposed export quotas on beef, corn and wheat to keep local prices low and levied taxes on grains and soybeans shipments that farmers say kill profits.
Argentina is the world's leading supplier of soymeal and a major exporter of wheat and corn. Farmers estimate soy, corn and wheat output could increase by up to a fifth if the next president scraps the quotas and eases taxes.
Massa vows to gradually eliminate export curbs and reduce duties on grains and soybeans. Scioli talks of reducing costs to increase competitiveness of Argentine products but has said only that he would review the taxes and quotas on agricultural goods.
"It is impossible to continue producing under these conditions," said Ruben Ferrero, president of the Argentine Rural Confederations.
To avoid a run-off, Scioli needs to win 45 percent of the vote or 40 percent with a 10-point margin over his nearest rival. Polls show him just short of 40 percent with a roughly 10 point lead over Macri. In a run-off, he would be vulnerable to a united opposition.