NEW YORK – Wal-Mart Stores Inc. plans to double its sales of locally sourced produce in the United States by the end of 2015.

The move by the world’s biggest retailer is part of a new sustainable agriculture strategy that looks to steer more business to small and medium-sized farmers globally while also reducing farming’s environmental impact.

If Wal-Mart meets its goals in the United States, local produce will still make up only 9 percent of the produce it sells.

But because of the the retailer’s sheer scale, it has the potential for a sizable impact. More than half of Wal-Mart’s $405 billion in annual revenue is from food.

In other countries, the goals are bolder. Wal-Mart said it would source 30 percent of its produce in Canadian stores locally by the end of 2013, and set a goal of 100 percent when local sources are available.

Wal-Mart plans to buy more of select U.S. crops. It also plans to train 1 million farmers and farm workers in emerging markets in crop selection, sustainable farming practices and other subjects and selling $1 billion in food sourced from 1 million small and medium-sized farmers.

Wal-Mart said Thursday that it will start asking suppliers about water, energy, fertilizer and pesticide used per unit of food produced.

The retailer also wants to lower food waste at its stores, with plans for a 15 percent reduction at emerging-market stores and clubs and a 10 percent reduction at stores and clubs in other markets by 2015’s end.

“Our efforts will help increase farmer incomes, lead to more efficient use of pesticides, fertilizer and water and provide fresher produce for our customers,” president and CEO Mike Duke said in a statement.

The retailer’s other goals include expanding the practice started at Walmart Brazil of sourcing only beef that doesn’t contribute to the Amazon rainforest’s deforestation. It also wants to require sustainably sourced palm oil for all of its store brand products worldwide by the end of 2015.

Wal-Mart Stores, based in Bentonville, Ark., runs more than 8,400 locations in 15 countries.