Sales of small tractors are climbing for the eighth straight year, but sales of bigger new tractors are sliding again.

Equipment manufacturers said January-July sales of new two-wheel-drive tractors rated at less than 40 horsepower climbed 11 percent from a year ago, continuing the seven-year advance that started in 2010, according to data from the Association of Equipment Manufacturers.

Meanwhile, manufacturers’ January-July sales of new 40- to 100-hp tractors held virtually steady from a year ago. The number of 100-plus horsepower tractors sold dropped 15.5 percent from last year, and four-wheel-drive tractor sales fell 5.5 percent. Self-propelled combine sales lost 5.7 percent.

This year’s decline hasn’t surprised manufacturers.

Deere & Co. said in a financial statement for the six months ended April 30, “Industry sales for agricultural equipment in the U.S. and Canada are forecast to be down about 5 percent for fiscal year 2017, reflecting weakness in the livestock sector and the continuing impact of low crop prices. The decline is affecting both large and small equipment.”

The equipment industry expected steady to weaker sales in the European Union due to low commodity prices and farm incomes. However, Deere noted industry forecasts for tractor and combine sales growth of about 20 percent in South America given improving economic and political conditions.

AGCO, in a financial statement for the six months ended June 30, noted near-record harvests in the past four years “are satisfying growing global demand for grain.” Higher grain inventories weigh on commodity prices and generally lead to lower farm income. Weaker economic conditions have pushed industry demand for equipment in most of the world to “historically low levels.”

However, AGCO said, “Following severe declines in the prior three years, demand is starting to stabilize as some farmers are returning to more normal equipment replacement schedules.”

CNH Industrial reported its first-half 2017 net sales in the NAFTA region down “due to unfavorable industry volume in the small grain sector, cash crop tractors, and hay and forage product lines.”

In its financial comments, AGCO said softer North American industry demand for farm equipment and efforts to reduce dealer inventories reduced the company’s first-half equipment sales in 2017 compared to 2016.

Equipment manufacturers “are feeling better about their own inventory levels as well as that of their dealers,” according to Curt Blades, senior vice president and ag sector lead for AEM.

AEM and the Equipment Dealers Association teamed up to survey members in July.

“The short term indicates a more positive trend towards a reduction of inventories at both the dealer and the manufacturer level,” Blades said.

Surveys showed 45 percent of dealers in the past three months indicated a decrease in new equipment inventories, and 40 percent reported lower used equipment inventories. Stable inventories were reported by 34 percent of dealers for new equipment and 37 percent for used.