The Vina series consists of very deep, well drained soils on floodplains. These soils formed in alluvium derived from mixed sources. Slope ranges from 0 to 2 percent. The mean annual precipitation is 14 to 16 inches, and the mean annual temperature is 60 to 62 degrees F.

Taxonomic class: Coarse-loamy, mixed, superactive, thermic Pachic Haploxerolls

Vina loam, 0 to 2 percent slopes, cropland. When described on August 4, 1988, the soil was moist throughout.

Ap—0 to 8 inches; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine interstitial pores; moderately acid (pH 5.8); clear smooth boundary.

A1—8 to 14 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and common very fine roots; common very fine interstitial pores; slightly acid (pH 6.4); clear smooth boundary.

A2—14 to 21 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine interstitial and few fine tubular pores; slightly acid (pH 6.5); abrupt smooth boundary.

A3—21 to 26 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine roots; common very fine interstitial and few fine tubular pores; slightly acid (pH 6.5); abrupt smooth boundary.

AC—26 to 46 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and few coarse roots; few very fine interstitial and few fine and common very fine tubular pores; few fine distinct dark brown (7.5YR 3/4) masses of iron accumulation; slightly acid (pH 6.5); abrupt smooth boundary.

C1—46 to 48 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; few fine distinct grayish brown (2.5Y 5/2) masses of iron accumulation; neutral (pH 6.6); abrupt smooth boundary.

C2—48 to 60 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; neutral (pH 6.9).

Type location: Colusa County, California; located about 5 miles north of Colusa; 1900 feet east and 300 feet north of the southwest corner of section 31, T. 17 N., R. 1 W., MDB&M; 39 degrees, 16 minutes, 33 seconds north latitude and 122 degrees, 00 minutes, 54 seconds west longitude; Moulton Weir, California topographic quadrangle.

The mean annual soil temperature is 63 to 65 degrees F. The soil temperature is above 47 degrees F. the entire year. The soil moisture control section, 8 to 24 inches, is dry in all parts from May 15 to October 31 unless irrigated and is moist in some or all parts from November 1 to May 15. The weighted average clay content of the textural control section 10 to 40 inches ranges from 12 to 18 percent clay.

The Ap and A horizon is 10YR 5/3, 5/2. Moist color is 10YR 3/3, 3/2. Texture is loam or fine sandy loam. Reaction is moderately acid to slightly alkaline.

The AC horizon is 10YR 5/3, 5/2. Moist color is 10YR 3/3, 3/2. Texture is loam, fine sandy loam or silt loam. Reaction is slightly acid to slightly alkaline.

The C horizon is 10YR 6/3, 6/2, 5/3, 5/2. Moist color is 10YR 4/4, 4/3, 4/2, 3/4, 3/3, 3/2. Texture is sandy loam or silt loam. Reaction is neutral to slightly alkaline.