ROME, ITALY — The Food and Agriculture Organization of the United Nations (FAO) Food Price Index fell in January, slipping 1.9% below its level in the last month of 2015, as prices of all the commodities it tracks fell.

The Food Price Index averaged 150.4 points in January, down 16% from a year earlier and registering its lowest level since April 2009.

The FAO Food Price Index is a trade-weighted index tracking international market prices for five key commodity groups: major cereals, vegetable oils, dairy, meat and sugar.

The main factors underlying the lingering decline in basic food commodity prices are the generally ample agricultural supply conditions, a slowing global economy, and the strengthening of the U.S. dollar.

This month, FAO also raised its forecast for worldwide cereal stocks in 2016, as a result of lowering its projected consumption and raising 2015 production prospects.

The FAO Cereal Price Index declined 1.7% (to 149.1 points) amid ample global supplies and increased competition for export markets, especially for wheat and maize, as well as a strong U.S. dollar.

The Vegetable Oil Price Index dropped 1.7%, mainly because of a decline in soy oil prices reflecting expectations of ample global soybean supplies.

Weather patterns associated with El Niño are sending mixed signals about the early prospects for cereal crops in 2016, especially in the Southern Hemisphere, according to FAO's Cereal Supply and Demand Brief.

2016 crop prospects have been "severely weakened" in Southern Africa, and a 25% cut in wheat production in South Africa now appears likely. Conditions for the crop are generally favorable in the Russia and the E.U., but winter plantings declined in the U.S. and Ukraine. The area under wheat is also expected to be cut in India, following a poor monsoon and below average rains since October.

The 2016 outlook for rice along and south of the equator is "dim" due, at times, to insufficient water and, at others, to excessive rains.

As for the 2015 season, FAO modestly raised its forecast for world cereal production to 2.53 billion tonnes, up slightly from that released in December.

Wheat output in Canada and Russia and maize output in China, Canada and Paraguay drove the upward revision. FAO also slightly raised its expectation regarding 2015 world rice production, mostly on account of higher forecasts for China, Vietnam and the U.S.

At the same time, FAO lowered its forecast for world cereal utilization in the 2015-16 season to 2.52 billion tonnes, which remains 0.8% above that of the previous year. This reflects a 2% increase for wheat, largely on account of higher livestock feed use in developed countries and a 0.3% increase in maize. World rice utilization is projected to expand by 1.1%, keeping world per-capita consumption stable.

As a result of the upgraded production and downgraded consumption forecasts, world cereal stocks are set to end the 2016 seasons at 642 million tonnes, higher than they began. That level implies a steady and comfortable global cereal stock-to-use ratio of around 25%.

However, the inventory build-up varies geographically and depending on the crop. Notable increases in wheat inventories are forecast for the U.S., E.U. and China whereas some reductions are likely in Canada, India and the Islamic Republic of Iran. On the other hand, world rice stocks would need to be drawn down to bridge the expected gap between world production and consumption, with much of the release likely to concern India and Thailand, the two leading rice exporters.