ST. LOUIS, Mo. — Monsanto Co. has announced it will be stepping up job cuts as it expands a cost-cutting plan to deal with declining sales.

The world leader in seed sales by revenue, Monsanto said a weak farm economy coupled with currency swings is forcing it to slash 1,000 more jobs in addition to the 2,600 cuts announced in October. This would be approximately 16 percent of the global workforce for the company.

The cuts are part of a broader plan to target $500 million in annual savings by the end of fiscal year 2018. Monsanto anticipates recording $1.1 billion-$1.2 billion in restructuring charges, up from the $850 million-$900 million previously forecast.

Monsanto reported that corn seed and traits sales, its largest source of income, dropped nearly 20 percent to $745 million in the first quarter ended Nov. 30 from a year previous.

Sales in the agricultural productivity segment, which includes the brand Roundup, fell 34 percent from $1.25 billion to $820 million.

Monsanto’s net loss was $253 million, or 56 cents per share, in the first quarter, compared with a gain of $243 million, or 50 cents a share, a year previous. Excluding restructuring charges and other items, the per-share loss was 11 cents. Total net sales fell 22.7 percent, to $2.22 billion.

This loss was smaller than anticipated, however, originally forecast at an adjusted loss of 23-33 cents a share, thanks to rising soybean sales in Brazil and growing demand in the company’s new soybean seeds and product lines. For the quarter, soybean sales were the highlight of Monsanto’s earnings report, growing 10 percent to $438 million, the company said.

For fiscal year 2016, the company expects to come in at the low end of its adjusted earnings of $5.10-$5.60 a share due to currency issues in Argentina. “Currency has become a much stronger headwind with the recent events in Argentina,” said Hugh Grant, Monsanto’s chief executive, referring to the country’s move in December to devalue its currency.

Argentina is one of the largest South American markets for Monsanto. Though the move will boost Monsanto’s agricultural sector in the long run, Grant said it will push the seed giant’s current profits to the lower end of their projected range.

Monsanto is attempting to streamline its business as seed, pesticide and equipment makers struggle with a three-year slide in crop prices that have forced farmers to scale back their spending.

The USDA projected in November that U.S. farm income would drop 38 percent in 2015 to the lowest levels in more than 10 years.

The cuts from Monsanto come on the heels of a failed buyout attempt last year of rival Syngenta AG, in which Monsanto finally concluded negotiations after being rejected for $46.5 billion in the last acquisition proposal in August for the Swiss-based company.

In December, however, Syngenta executives indicated it is open to mergers with companies, including Monsanto, after share price plummeted by 18 percent following the rejection.

Grant, acknowledging the recent merger between DuPont and Dow Chemical, told analysts the combination wouldn’t likely change DuPont’s and Dow’s status as major licensees of Monsanto’s crop gene technology.

Monsanto has been the world leader in the bioengineered seed business for more than a decade, controlling an estimated 18 percent of the $44 billion global seed market.