Soybean field

DowDuPont Inc. slumped after cutting the asset value of its DuPont Co. agriculture business by $4.6 billion less than nine months before a planned spinoff of the seed-and-pesticide unit.

The impairment charge reflects weaker markets for farm products since last year’s merger with Dow Chemical Co., DuPont said in a regulatory filing Thursday. Reduced planting areas and delays in product registrations mean that sales will grow more slowly, while an unfavorable shift to soybeans from corn in Latin America will dent profits.

The world’s largest chemical maker is contending with ripple effects through global agricultural markets as trade tensions prompt shifts in crop plantings and export markets. For example, farmers in Brazil are planting more soybeans and less corn after China levied tariffs on U.S. soybeans in response to duties imposed by President Donald Trump. Currency weakness in Brazil, a key market, is also weighing on DowDuPont’s farm business.

“Less Latin America corn planting and more cost-conscious farmers confirm that cheap crops are biting buyers,” Bloomberg Intelligence analysts Jason Miner and Richard Bourke said in a report.

DowDuPont fell 5.1 percent to $55.60 in late trading in New York. The shares dropped 18 percent this year through the Thursday close, worse than the 12 percent drop of a Standard & Poor’s index of materials companies.

The impairment charge won’t hurt third-quarter results because the fair value of the merged company’s agriculture assets exceeded the carrying value, DowDuPont said in a separate filing. The company plans to split into three publicly traded entities, with the agriculture operation to be called Corteva Agriscience.

The chemical giant also filed an initial registration statement for Corteva with securities regulators and said the separation remains scheduled for June 1. The filing provides an overview of the business as well as historical financial data.

Corteva’s slumping seed sales reduced first-half earnings 2.5 percent to $2.26 billion, according to the filing.