MOSCOW: Russia, which controls up to 40 percent of the global trade in ammonium nitrate, said on Tuesday it will stop exports of the fertilizer for one month until April 21 to ensure sufficient supply during the spring planting season. Russia, a major fertilizer exporter, lacks the capacity to boost production this year amid a global supply crunch caused by the closure of the Strait of Hormuz, through which 24 percent of global trade in ammonia, an ingredient of ammonium nitrate, passes.