WASHINGTON — The preliminary national average price received by farmers for all wheat in August was $4.72 per bu, down 41c from $5.13 in July and down $2.89 from the August 2008 average of $7.61, the U.S. Department of Agriculture said in its latest Agricultural Prices report.

The average price paid for winter wheat in August was $4.44 a bu, down 54c from $4.98 in July and down $2.86 from $7.30 in August 2008.

The average price paid for durum was $5.47 a bu, down $2.10 from $7.57 in July 2009 and down $7.13 from $12.60 in August 2008. Spring wheat other than durum averaged $5.23 a bu in August, down 73c from July and down $2.95 from August 2008.

The average price received for rough rice was $13.60 per cwt, down 70c from $14.30 in July and down $4.50 from $18.10 in August 2008.

The August index of prices received for food grains was 163 compared with the 1990-92 base of 100, down 6.9% from the revised July index of 175 and down 37% from the August 2008 index of 257.

The August index for feed grains was 147, down 5.8% from a revised 156 the previous month and down 35% from 227 in August 2008. The average price received for corn in August was $3.31 a bu, down 29c from $3.60 in July and down $1.95 from $5.26 in August 2008. Farmers received an average of $5.37 a cwt for grain sorghum in August, up 18c from $5.19 in July but down $3.03 from $8.40 in August 2008. The average price paid for oats in August was $1.85 a bu, down 18c from $2.03 in July and down $1.31 from $3.16 in August 2008.

The U.S.D.A. index of August prices received for oil-bearing crops was 190, down 1% from a revised 192 in July and down 17% from 228 in August 2008. The national average price paid to farmers for soybeans was $10.70, down 10c from July and down $2.10 from $12.80 in August 2008.

The August index for dairy products was 90, up 3.4% from 87 the previous month but down 36% from 141 in August 2008. The average price paid for manufacturing grade milk in August was $10.60, up 40c from $10.20 in July but down $6.60 from $17.20 in August 2008.

The egg and poultry index was 132, down 9% from 145 in July and down 13% from 151 in August 2008. The average price paid to farmers for all eggs was 76c, up 5c from July but down 20c from August 2008.