WASHINGTON — The preliminary national average price received by farmers for all wheat in August was $5.56 per bu, up $1.06 from $4.50 in July and up 71c from $4.85 in August 2009, the U.S. Department of Agriculture said in its latest Agricultural Prices report. It was the largest month-to-month increase since $2.14 from January to February of 2008.

The average price paid for winter wheat in August was $5.60 a bu, up $1.13 from $4.47 in July and up 93c from $4.67 in August 2009. The average price paid for durum was $5.01 a bu, up 57c from $4.44 in July but down 82c from $5.83 in August 2009. Spring wheat other than durum averaged $5.54 a bu, up 81c from $4.73 in July but equal to the August 2009 level.

The average price paid for rough rice in August was $12.10 a cwt, down 20c from $12.30 in July and down $2.60 from $14.70 in August 2009.

The August index of prices received for food grains was 186 compared with the 1990-92 base of 100, up 22% from a revised 153 in July and up 10% from 169 during the same month of the previous year.

The August index for feed grains was 157, up 4% from a revised 151 in July and up 6% from 148 a year earlier. The average price received for corn in August was $3.65 a bu, up 16c from $3.49 in July and up 32c from $3.33 in August 2009. Farmers received an average of $6.28 a cwt for grain sorghum in August, up 31c from $5.97 in July and up 91c from $5.37 in August 2009. The average price paid for oats in August was $2.07 a bu, down 3c from $2.10 in July but up 21c from $1.86 in August 2009.

The index of August prices received for oilseeds was 179, up 3% from 174 in July but down 7% from 192 in August 2009. The national average price paid to farmers for soybeans was $10.10 a bu, up 31c from $9.79 in July but down 70c from $10.80 in August 2009.

The August index for dairy products was 127, up 3% from 123 in July and up 37% from 93 in August 2009. The average price paid to farmers for manufacturing grade milk in August was $15.10 a cwt, up $1 from $14.10 in July and up $3.30 from $11.80 in August 2009.

The egg and poultry index was 149, down 3% from 153 in July but up 13% from 132 in August 2009. The average price paid to farmers for all eggs was 79c a dozen, up 8c from 71c in July and up 3c from 76c in August 2009.