WASHINGTON — The preliminary national average price received by farmers for all wheat in August was $6.91 per bu, down 2c from July and down $1.13 from $8.04 in August 2012, the U.S. Department of Agriculture said in its latest Agricultural Prices report.

The average price paid for winter wheat in August was $6.78 per bu, down 7c from July and down $1.14 from $7.92 in August 2012. The average price paid for durum was $8.07 per bu, down 10c from July but up 31c from $7.76 in August 2012. Spring wheat other than durum averaged $7 per bu, down 29c from July and down $1.27 from $8.27 in August 2012.

The average price paid for all rice was $15.60 a cwt, up 30c from $15.30 in July and up $1 from $14.60 in August 2012.

The June index of prices received by farmers for food grains was 232 compared with the 1990-92 base of 100, down slightly from 233 in July and down 12% from 263 in August 2012.

The June index of feed grains was 258, down 10% from 286 in July and down 17% from 312 in August 2012. The average price paid to farmers for corn was $6.02 per bu, down 77c from $6.79 in July and down $1.61 from $7.63 in August 2012. Farmers received an average of $9.55 a cwt for grain sorghum in August, down 9c from July and down $1.75 from $11.30 in August 2012. The average price paid for oats in August was $3.69 a bu, down 20c from July and down 13c from August 2012.

The index of June prices received for oilseeds was 232, down 12% from 263 in July and down 19% from 287 in August 2012. Farmers received an average of $13.80 a bu for soybeans in August, down $1.50 from $15.30 in July and down $2.40 from $16.20 in August 2012.

The August index for dairy products was 148, up 2% from 145 in July and up 7% from 139 in August 2012. The average price paid for all milk was $19.30 a cwt, up 30c from July and up $1.10 from $18.20 in August 2012.

The August poultry and egg index was 173, down 4% from 181 in August but up 8% from 161 in August 2012. The average price paid to farmers for all eggs in August was $1.08 a dozen, up 4c from July but down 5c from August 2012.