Belarusian state potash producer Belaruskali produced 12.2 percent less of the soil nutrient in 2013 after the collapse of a Russia-Belarus joint venture hit global prices, state data showed on Thursday.
Potash output at Belaruskali, which has had to develop a new strategy since the breakup of the alliance in June, fell to 7 million tonnes last year, according to Reuters calculations based on data from the country's National Statistics Committee.
The data showed output picked up significantly in the last month of the year, with production rising 32 percent in December compared with the previous month.
Any significant long-term output fall could severely impact the finances of Belarus, where potash accounts for more than 10 percent of state revenue and about 10 percent of export income.
In an attempt to support the country's key industry, Belarussian President Alexander Lukashenko scrapped the duty on the fertiliser in September.