WASHINGTON — The preliminary national average price received by farmers for all wheat in July was $8.31 per bu, up $1.61 from $6.70 in June and up $1.21 from $7.10 in July 2011, the U.S. Department of Agriculture said in its latest Agricultural Prices report.

The average price paid for winter wheat in July was $8.26 per bu, up $1.72 from $6.54 in June and up $1.49 from $6.77 in July 2011. The average price paid for durum was $8.62 in July, up 31c from $8.31 in June but down $1.58 from $10.20 in July 2011. Spring wheat other than durum averaged $8.68 a bu, up 90c from $7.78 in June and up 23c from $8.45 in July 2011.

The average price paid for all rice was $14.20 a cwt, up 10c from $14.10 in June and up $1.30 from $12.90 in July 2011.

The July index of prices received by farmers for food grains was 275 compared with the 1990-1992 base of 100, up 23% from 224 the previous month and up 17% from 236 in July 2011.

The July index of feed grains was 302, up 12% from 269 in July and up 15% from 262 in July 2011.

The average price paid to farmers for corn was $7.36 a bu, up 99c from $6.37 in June and up $1.03 from $6.33 in July 2011. Farmers received an average of $12 a cwt for grain sorghum in July, up $2.44 from $9.56 in June and up $1.60 from $10.40 in July 2011. The average price paid for oats in July was $3.81 a bu, up 4c from $3.77 in June and up 46c from $3.35 in July 2011.

The index of July prices received for oilseeds was 278, up 12% from 249 in June and up 17% from 237 in July 2011.

Farmers received an average of $15.60 a bu for soybeans in July, up $1.70 from $13.90 in June and up $2.40 from $13.20 in July 2011.

The July index for dairy products was 127, up 2% from 124 in June but down 24% from 167 in July 2011. The average price paid for all milk in July was $16.60 a cwt, up 40c from $16.20 in June but down $5.20 from $21.80 in July 2011.

The July poultry and egg index was 159, down 2% from 162 in June but up 6% from 150 in July 2011. The average price paid to farmers for all eggs in July was 97c a dozen, up 6c from 91c in June and up 9c from 88c in July 2011.