Skip to main content
ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #381398
Research Project: Enhancing Production and Ecosystem Services of Horticultural and Agricultural Systems in the Southeastern United States

Location: Soil Dynamics Research

Title: Suitability of mehlich 3 as a universal soil test extractant for phosphorous loss risk assessment for diverse soil regions

Author
item BHATTA, ANJAN - Auburn University
item CHAKRABORTY, DEBOLINA - Auburn University
item PRASAD, RISHI - Auburn University
item SHAW, JOEY - Auburn University
item LAMBA, JASMEET - Auburn University
item BRANTLEY, EVE - Auburn University
item Torbert, Henry - Allen

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2021
Publication Date: 7/15/2021
Citation: Bhatta, A., Chakraborty, D., Prasad, R., Shaw, J., Lamba, J., Brantley, E., Torbert Iii, H.A. 2021. Suitability of mehlich 3 as a universal soil test extractant for phosphorous loss risk assessment for diverse soil regions. Agrosystems, Geosciences & Environment. 4(3):e20187. https://doi.org/10.1002/agg2.20187.
DOI: https://doi.org/10.1002/agg2.20187

Interpretive Summary: Individual states in the United States (U.S.) have adopted different soil test phosphorus (STP) methods for agronomic purposes as well as for environmental P loss risk assessment assessments such as the used in phosphorus index (P-index). There are two different extractants currently being used for Alabama soils, this study evaluated whether Mehlich 3 (M3) soil test extractant can be introduced as a universal extractant for environmental P loss risk assessment program for both calcareous and non-calcareous soils found in Alabama. Soil samples were collected from agricultural fields throughout the state representing five major soil regions: Appalachian Plateau, Coastal Plain, Limestone Valley, Piedmont Plateau, and Blackland Prairie. Conversion factors were found suitable to convert M3 P values for extractable P for both acidic and alkaline soils. Results indicated that M3 as a universal extractant is suitable for environmental P loss risk assessment for both calcareous and non-calcareous soils in Alabama.

Technical Abstract: Individual states in the United States (U.S.) have adopted different soil test phosphorus (STP) methods for agronomic purposes as well as for environmental P loss risk assessment assessments such as the used in phosphorus index (P-index). Alabama has wide range of calcareous and non-calcareous soils from five major soil regions. Laboratories in Alabama uses Mehlich 1 (M1) and Lancaster (La) as routine soil test for non-calcareous and calcareous soils, respectively. Mehlich 3 (M3) extractant has been identified as a more efficient and universal extractant applicable for broad range of soils. As there are two different extractants currently being used for Alabama soils, our goal was to evaluate whether Mehlich 3 (M3) soil test extractant can be introduced as a universal extractant for environmental P loss risk assessment program for both calcareous and non-calcareous soils found in Alabama. Soil samples were collected from agricultural fields throughout the state representing five major soil regions (Appalachian Plateau (AP), Coastal Plain (CP), Limestone Valley (LV), Piedmont Plateau (PP), and Blackland Prairie (BP)) and four soil depths: 0-5, 5-15, 15-30, and 30-45 cm. For non-calcareous soils, the M1 extracted 13.8%, 13.1%, 6.3%, and 6.2% of P whereas M3 extracted 29.8%, 35.4%, 10.5% and 14.8% of P from AP, CP, LV, and PP soils, respectively. The conversion factor of 1.42 (CI95% = 1.36-1.47) was found suitable to convert M1 P to M3 P values for non-calcareous soils. Additionally, we found no statistical difference between La and M3 extractable P for both acidic and alkaline soils and found a conversion factor of 0.92 (CI95% = 0.87-0.98) suitable to convert La P to M3 P values for calcareous soils. The linear relationship between WSP versus M3-P was stronger than WSP versus M1-P for non-calcareous soils as indicated by greater coefficient of determination (r2) value. Whereas no significant differences in slope and r2 was found between WSP vs M3-P and WSP vs La-P for calcareous soils. Results indicated that M3 as a universal extractant is suitable for environmental P loss risk assessment for both calcareous and non-calcareous soils in Alabama.