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Agronomic Services

Crop Fertilization Based on North Carolina Soil Tests

The Agronomic Division of the North Carolina Department of Agriculture and Consumer Services (NCDA&CS) works to increase crop productivity, promote responsible land management and protect the environment. To achieve those ends, the Division provides diagnostic and advisory services for all North Carolina residents. It also works closely with educational institutions and agribusinesses.

The Soil Testing section analyzes soil samples to calculate fertilizer and lime requirements for crops grown throughout the state. By clarifying a soil's relative nutrient-supplying capability, soil tests help maximize amendment efficiency. Growers can then avoid nutrient deficiencies without applying economically wasteful and environmentally unsound excesses.

This laboratory provides predictive soil tests for all state residents. These tests clarify fertility status with regard to pH, acidity and nutrient levels. Site-specific recommendations are then based on crop requirements, soil type, and current pH and fertility levels.

It also provides a diagnostic service for solving problems during the growing season, thus allowing users to adjust amendments to site- and season-specific demands.

In response to public concern about the environment, soil tests now analyze for heavy metals in soil samples from sites where municipal, animal or industrial wastes have been applied. This monitoring can prevent the indiscriminate use of such wastes and thus protect land productivity, surface-water and groundwater quality, food safety and human health.

This document outlines (i) the philosophical framework employed by the Agronomic Division's Soil Testing section, (ii) the methodologies and equations it uses to calculate fertilizer and lime recommendations, (iii) the crop-specific details growers must consider when applying these recommendations, (iv) conversion factors and equivalencies useful in calculating fertilizer requirements, and (v) specifics on fertilizer properties, sources and application.

Parts I and II answer the what, why and how questions concerning our soil testing service. Intended for readers interested in the scientific foundations of our work, the text describes what testing procedures we employ, why we employ them, and how we move from soil test data to site- and crop-specific fertilizer and lime recommendations. Detailed equations and tables enable readers to recalculate recommendations should they wish to grow a crop other than the one listed on the soil sample report.

Part III contains a series of notes that address the fertilization requirements of specific crops or groups of crops grown in North Carolina. Relevant notes are typically appended as a supplement to the soil test report. Readers who are not interested in the technical procedures used to derive recommendations may prefer to turn directly to Part III.

Part IV provides tables of information that may be useful when calculating fertilizer requirements or when deciding which fertilizer to apply. Conversion factors, equivalencies, properties, sources and application methods are addressed.

In addition to the soil testing services discussed in this document, the Agronomic Division also provides nematode assay, plant tissue analysis, waste analysis, solution analysis, soilless media analysis and field advisory services.

Contact Information

Agronomic Division Website
Physical Location — 4300 Reedy Creek Rd, Raleigh NC 27607-6465
Mailing Address (U.S. Postal Service) — 1040 MSC, Raleigh NC 27699-1040
Phone (919) 733-2655
Fax(919) 733-2837
E-mail Dr. David H. Hardy, Soil Testing Section Chief :

Regional agronomists also provide assistance statewide (see Figure F.1 below). They can make on-site farm visits to address a wide range of crop nutrient-related concerns.

map of field services regions.

Figure F.1 Jursidictions of the regional agronomists; for region assignments and contact information, visit

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 31, 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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