WASHINGTON — The preliminary national average price received by farmers for all wheat in January was $4.79 per bu, down 6c from $4.85 in December and down $1.41 from $6.20 in January 2009, the U.S. Department of Agriculture said in its latest Agricultural Prices report.

The average price paid for winter wheat in January was $4.54 a bu, down 14c from $4.68 in December and down $1.16 from $5.70 in January 2009.

The average price paid for durum was $4.58 a bu, down 40c from $4.98 in December and down $3.68 from $8.26 in January 2009. Spring wheat other than durum averaged $5.19 a bu, up 5c from $5.14 in December but down $1.83 from $7.02 in January 2009.

The average price paid for rough rice was $14.60 per cwt, up 20c from $14.40 in December but down $3.60 from $18.20 in January 2009.

The January index of prices received for food grains was 171 compared with the 1990-92 base of 100, equal to the revised December level but down 22% from 220 in January 2009.

The January index for feed grains was 150, down 3% from 155 the previous month and down 20% from 188 in January 2009. The average price received for corn in January was $3.45 a bu, down 14c from $3.59 in December and down 91c from $4.36 in January 2009. Farmers received an average of $5.53 a cwt for grain sorghum in January, down 18c from $5.71 in December and down 15c from $5.68 in January 2009.

The average price paid for oats in January was $2.19 a bu, down 4c from $2.23 in December and down 58c from $2.77 in January of the previous year.

The U.S.D.A. index of January prices received for oil-bearing crops was 169, down 2% from a revised 172 in December and down 6% from 179 in January 2009. The national average price paid to farmers for soybeans was $9.49 a bu, down 31c from $9.80 in December and down 48c from $9.97 in January 2009.

The January index for dairy products was 126, unchanged from a revised 126 in December but 24% higher than 102 in January 2009. The average price paid for manufacturing grade milk in January was $15.90 a cwt, down 30c from $16.20 in December but up $3.50 from $12.40 in January 2009.

The egg and poultry index was 150, up 7% from a revised 140 in December and up 1% from 149 a year earlier. The average price paid to farmers for all eggs was $1.03 a dozen, down 2c from December but unchanged from January 2009.