Correctly estimating phosphorus (P) availability in soil is important for crop production. Soil test P also plays an important role for estimating P loss in the Wisconsin Phosphorus Index. Common soil test P methods include the Bray P1, Mehlich-3, and Olsen. The validity of Bray P1 to predict plant available P levels on the Eastern Red Soil (ERS) region of Wisconsin has been questioned due to concerns that the weak acid Bray P1 extracting solution could be neutralized by reaction with carbonates in these soils. Studies have found that Bray P1 extracts less P at higher soil pH and that Bray P1 does not correlate as well with Mehlich 3 or Olsen in soils with higher carbonate contents. The research described above indicates that Bray P1 may not perform well on ERS soils and research is needed to determine if Bray P1 should be used on those soils. Soils analyzed from the ERS region ranged in pH from 5.3-7.6, with an average of 6.9; and organic matter content ranged from 2.0-4.6%, with an average of 3.0%. The samples represented a broad range of soil test P: Bray P1 values ranged from 5-278 ppm, Mehlich-3 values ranged from 4-327 ppm, and Olsen values ranged from 4-60 ppm. The correlation between Bray P1 and Mehlich-3 on these soils was high, r² = 0.99. However, lower correlations existed between Bray P1 and Olsen (r² = 0.76) and between Mehlich-3 and Olsen (r² = 0.82). Carbonate content was also determined and the results indicate that carbonate content in the soils from this region were not high enough to adversely affect the Bray P1 extraction. Soils with known high carbonate contents were included in the analyses as comparisons.