China restricts fertiliser exports, further crimping war-tightened supply China is clamping down on fertiliser exports to protect its domestic market, a number of industry sources said, putting an additional strain on global markets that were already grappling with shortages caused by the US-Israeli war on Iran. China is among the largest fertiliser exporters - shipping more than $13 billion worth of it last year - and it has a history of controlling exports to keep prices low for farmers. Fertilisers are essential for plant growth and crop yields.  Shipments through the war-blocked Strait of Hormuz account for roughly one-third of the sea-borne supply. In mid-March, Beijing banned exports of nitrogen-potassium fertiliser blends and certain phosphate varieties, sources told Reuters. The ban, which has not been formally unveiled, was reported earlier this week by Bloomberg News. Added to existing bans and export quotas for urea, only a handful of fertilisers - notably ammonium sulphate - can be exported, five sources said. "This pattern is consistent: China restricts supplies rather than coming to the rescue during global tightness," said Matthew Biggin, a senior commodities analyst at BMI. Reporting by Reuters