May 11 (Reuters) - China's fertiliser exports rose 27.6% in April from a year earlier, with shipments in the first four months of the year up 17.5%, despite Beijing's latest efforts to tighten export controls amid a global fertiliser crunch linked to the Iran war.

KEY DETAILS:

• China's fertiliser exports rose to 3.24 million metric tons in April, from 3.1 million tons in March and 2.54 million tons a year earlier, the customs data showed on Sunday.

• Shipments in January-April totalled 11.4 million tons, up from 9.7 million tons in the same period last year.

• The increase came despite China further tightening restrictions on exports of most fertiliser products in mid-March to protect its farmers, Reuters previously reported, citing sources.

• Exports of a limited number of products, notably ammonium sulphate, are still allowed.

• In late April, China also tightened inspections of ammonium sulphate shipments after local officials uncovered cases of exporters falsely declaring restricted urea fertiliser as ammonium sulphate, Reuters reported, citing sources.