(Bloomberg) -- Argentina’s farmers need precipitation to arrive within the next three weeks to stand any chance of emerging from a disastrous drought that has shriveled harvests and slashed agricultural exports.

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Growers in the heart of the Pampas growing region, the so-called zona nucleo, need fresh rain in the coming days to moisten fields so they can sow wheat, said Cecilia Conde, chief crop analyst at the Buenos Aires Grain Exchange. Failing that, the bourse would have to cut back its forecasts for expanded acreage and higher production, which are predicated on the La Nina climate pattern coming to an end.

Agriculture is key to Argentina’s economy since the cash-strapped central bank needs US dollars from crop exports to arrest a slide of the peso.

Farmers are struggling to recover from three consecutive years of drought. Soy fields being harvested now will produce the least in two decades of record-keeping at the grain exchange, while last season’s wretched wheat crop slashed Argentine exports by two thirds.

Argentina, a top global food producer, has two growing seasons in the year: wheat and barley, then soy and corn.

Read More: Argentina’s Epic Drought Sends Economic Crisis to New Extremes

Rains last weekend were good news for wheat growers, “but more are needed,” Conde said.

The repercussions of a another failed harvest would be felt by the world’s feedlots and by agriculture traders from Chicago to Singapore. Global grain markets have been upended by droughts — curbing production and causing transportation bottlenecks on rivers in the US and South America — and by the Russia-Ukraine war.

El Nino