North America's stocks of the crop nutrient potash shrank about 8 percent in June, but remained at unusually high levels, as miners slowed production and overcame dips in export and domestic sales.

Stockpiles of potassium chloride, more commonly known as potash, fell 230,514 tonnes in the month to 2.698 million tonnes, according to data posted on Monday on Potash Corporation of Saskatchewan's website.

Inventories of the crop nutrient at the mine level still stood 14 percent above the previous five-year average.

Potash supplies started piling up last year as key global consumers China and India delayed signing new supply contracts with Canpotex, the offshore marketing company owned by Potash Corp and fellow producers Agrium Inc and Mosaic Co .

Potash production dropped 28 percent from the previous month to 1.404 million tonnes - 11 percent below the output of a year earlier. Potash Corp began idling mines for summer maintenance at the end of June.

Potash exports by North American producers dipped 6 percent in June from the previous month to 1.001 million tonnes.

Domestic sales, mainly to the United States, plunged 62 percent from May to 400,000 tonnes, as most crop planting and the spring fertilizer season wrapped up. Those sales were 20 percent less than a year earlier.