Agronomic Home
About the Division
Find Your Report (PALS)
Field Services
Nematode Assay
Plant Tissue Analysis
Soil Testing
Soilless Media Analysis
Solution Analysis
Waste/Compost Analysis
Agrotips
News Releases
Publications
Staff
Virtual Tour
Instructional PowerPoints
Related Sites
Agronomic Site Map

Agronomic Services

Crop Fertilization Based on North Carolina Soil Tests
Table 1.4  Multiplication factors for converting soil test index values to a quantitative equivalent*
Soil Test Index Value mg/dm³ kg/ha lb/acre meq/100 cm³ meq/dm³
P-I 1.2 2.40 2.138 N/A N/A
K-I 1.955 3.91 3.484 0.005 0.05
Ca% × CEC 200.0 400.0 356.40 1.0 10.0
Mg% × CEC 121.6 243.2 216.69 1.0 10.0
Na 230.0 460.0 409.86 1.0 10.0
Mn-I 0.16 0.32 0.285 N/A N/A
Zn-I 0.04 0.08 0.071 N/A N/A
Cu-I 0.02 0.04 0.036 N/A N/A
S-I 0.48 0.96 0.857 N/A N/A
* Soil tests in North Carolina are made on a volume of soil. Conversion to an area equivalent is based on a depth of 20 cm (7.9 inches). To convert phosphorus and potassium from the elemental forms to lb/acre, use these multipliers: 2.29 × P gives lb of P2O5 per acre; and 1.2 × K gives lb of K2O per acre.

The Volume Rationale: The area of a hectare (ha) is 10,000 or 1,000,000 dm². The volume per hectare to a depth of 20 cm or 2 dm equals 2,000,000 dm³. The following conversion factors apply: mg/dm³ = parts per million (ppm); mg/dm³ × 2 = kg/ha; kg/ha × 0.893 = lb/acre; or mg/dm³ × 1.78 = lb/acre. Refer to Part IV of this manual for other conversion factors.

return icon.Hardy DH, Tucker MR, Stokes CE. 2014. Crop fertilization based on North Carolina soil tests. Raleigh (NC): North Carolina Department of Agriculture and Consumer Services, Agronomic Division. Circular No. 1.

Last Update January 10, 2014

 

 

NCDA&CS Agronomic Services Division, Colleen M. Hudak-Wise, Ph.D., Director
Mailing Address: 1040 Mail Service Center, Raleigh NC 27699-1040
Physical Address: 4300 Reedy Creek Road, Raleigh NC 27607-6465
Phone: (919) 733-2655; FAX: (919) 733-2837