Sample Information

This section contains sample information provided by the client, including sample identifier, crop, growth stage, plant part, and plant appearance.

Plant Nutrient Concentrations

The leaf tissue concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) are reported in percent (%).  The leaf tissue concentrations of the micronutrients iron (Fe), manganese (Mn),  zinc (Zn), copper (Cu), and boron (B) are reported in parts per million (ppm) which is equivalent to mg/kg. 

• Molybdenum (Mo)  is a micronutrient that is important in certain crops with high Mol requirements.  Molybdenum is automatically included in the standard analysis for Brassicas, poinsettia, alfalfa, and spinach. It may be included in the analysis of other crops if requested on the submission form. Results are reported in ppm (mg/kg). 
• Nitrate-nitrogen (NO₃-N) is a required test for strawberry and cotton petiole samples and is widely used to monitor and optimize nitrogen levels throughout the growing season.  It also measured in post-harvest corn stalks in order to evaluate the efficiency of the grower's nitrogen management program. Results are reported in ppm (mg/kg). Growers may request this test for other crops but target recommendations are not provided for crops other than strawberry and cotton.

Interpretation Indexes

Each nutrient concentration is compared to the established sufficiency range for that nutrient in the specified crop, translated into a numerical index between 0 and 124, and assigned an alphabetic descriptor that categorizes the nutrient concentrations as either deficient (D), low (L), sufficient (S), high (H), or excessive (E).  Concentrations with an index value from 0-24 are considered deficient; from 25-49 are low; from 50-74 are sufficient, from 75-99 are high and above 100 are excessive.

Other Results

Sodium (Na)  is included in the standard analysis and reported in percent (%). it is rarely an element of concern in plant tissue concentrations but may have large impacts on root and soil health, as determined by corresponding soil tests. 

Chloride (Cl) is analyzed only by request on the submission form and reported in percent (%).  It is of primary concern in coastal areas where salt water intrusion may impact field irrigation or fertigation source water quality or where greenhouse operations have high Cl in source water, nutrient solutions, or soilless (potting) media.

Carbon (C) is analyzed only for research samples and is reported as %.

Dry weight (DW) is the weight of the plant material after complete drying and is reported in grams (g).  It is primarily used to calculate nitrogen application rates for spring wheat.  It may also be used to determine nutrient inputs from cover crops if a wet weight and area are recorded by the client in the field.

Aluminum (Al) is not a plant nutrient and is reported in ppm (mg/kg).  It is rarely an element of concern in plant tissue concentrations but may have large impacts on root and soil health, as determined by corresponding soil tests.  It is also used in horticulture to evaluate coloration of hydrangeas.

Nutrient Ratios

Nitrogen to sulfur ratio (N:S) is of primary nutritional concern in corn and small grains (e.g. wheat, barley, rye, oats, etc.). Excessively high ratios (> 18:1) may induce sulfur deficiency  even where soil sulfur is adequate.

Nitrogen to potassium ratio (N:K) is rarely a concern except where N concentrations are extremely high.

Iron to manganese ratio (Fe:Mn) is rarely a concern in field crops and occasionally a problem in greenhouse operations where excessive iron may induce manganese deficiency.

Agronomist's Comments

If the client provides information on the submission form regarding the growing and crop conditions associated with the sample, an NCDA&CS agronomist will review the results, point out any nutrient deficiencies and offer suggestions for corrective action.