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Agronomic Services

Crop Fertilization Based on North Carolina Soil Tests
Part IV:  Resource Information
This section contains nineteen tables that provide quick reference for
  1. making fertilizer substitutions,
  2. determining equivalent fertilizer rates and
  3. converting English units to metric equivalents.

Fertilizer Substitutions

Fertilizers recommended on NCDA&CS reports are often commercial agricultural grades, such as those given in Table 4.1. Agricultural dealers that cater to farmers are most likely to have these fertilizers in stock. These grades may not be available at local discount stores or garden centers. Therefore, growers may need to substitute equivalent fertilizers. Table 4.2 provides some substitutions for commonly recommended fertilizer materials.

North Carolina Limestone Specifications

All limestone sold, offered for sale or distributed in North Carolina must show on the label
  • a guarantee of % calcium,
  • a guarantee of % magnesium,
  • the % calcium carbonate equivalent and
  • the number of pounds of material that equal 1 ton of standard lime.
Standard lime has a calcium carbonate equivalent of 90%. Each type of lime must meet the screen requirements outlined in Table 4.3. This information must be displayed on the label. For example, with dolomitic lime, 90% must pass through a 20-mesh screen and 35% must pass through a 100-mesh screen.

Reference Tables

Table 4.1 Amounts of fertilizer that provide 1 lb of nitrogen per 1000 ft²
Table 4.2 Nitrogen fertilizer substitutions
Table 4.3 North Carolina limestone specifications
Table 4.4 Equivalent fertilizer rates
Table 4.5 Properties of fertilizer materials
Table 4.6 Fertilizer dilutions necessary to deliver parts-per-million rates
Table 4.7 Commonly available sources of nitrogen
Table 4.8 Commonly available sources of phosphorus
Table 4.9 Commonly available sources of potassium
Table 4.10 Commonly available sources of magnesium
Table 4.11 Commonly available sources of sulfur
Table 4.12 Commonly available sources of boron
Table 4.13 Commonly available sources of copper
Table 4.14 Commonly available sources of manganese
Table 4.15 Commonly available sources of zinc
Table 4.16 Commonly available sources of molybdenum
Table 4.17 Commonly available sources of iron
Table 4.18 Equivalent measurements
Table 4.19 Conversion factors for English and metric units
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

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