Nutrient Management Recommendations – Agronomic Crops




Grain Corn
Grain Sorghum
Small Grains, Soybeans, Double-cropped
 Soybeans, Full season

Converting from Soil Test Value (ppm) to Fertility Index Value (UD-FIV)

Soil test interpretive categories used by the University of Delaware

Soil Test CategoryFertility Index Value (FIV)Phosphorus (P)Potassium (K)Magnesium (Mg)Calcium (Ca)
Soil Test Value (ppm)Soil Test Value (ppm)Soil Test Value (ppm)Soil Test Value (ppm)
Low0 - 250 - 250 - 700 - 550 - 450
Medium26 - 5026 - 5071 - 14056 - 110451 - 900
Optimum51 - 10051 - 100141 - 280111 - 220901 - 1800
Excessive> 100> 100> 280> 220> 1800

Calculating the Lime Recommendation
To determine the lime requirement for a field, follow these steps:

Select the appropriate lime table from the list below based upon the target pH of the crop as listed in the recommendation section.  Locate the value in the table where the Water pH row (shown along the left side of table) and the Buffer pH column (shown across the top of the table) intersect (see example).

Determine whether a lime credit is necessary. Lime credits are used to account for any lime that was applied in the past 18 months which has not had a chance to react. The equation for calculating the lime credit and an example can be obtained by clicking here.

Determine the the type of lime recommended (e.g., calcitic or dolimitic) by clicking here.

University of Delaware Lime Tables
These tables are designed to be used with the Adams-Evans buffer pH. If the lime requirement test was performed by laboratory using a different buffer method, contact the laboratory for the appropriate lime tables.

Target pH 5.2  -- Blueberries;  non-scab resistant potatoes

Target pH 5.6  -- Acid loving plants;  black high organic matter soils

Target pH 6.0  -- Most Delaware crops

Target pH 6.2 -- Many commercial vegetable crops

Target pH 6.5  -- High Calcium demand crops, golf course turf,

Target pH 6.8 -- Alfalfa

All Lime Tables -- This .pdf file contains copies of all six lime tables for commercial crops.

Commercial Agriculture Soil Test Notes

Soil Test Note 1: Explanation of Laboratory Tests

Soil Test Note 2: Grain and Silage Crops

Soil Test Note 3: Forage Crops

Soil Test Note 4: Secondary and Micronutrients

Soil Test Note 5: Nitrogen Fertilizers

Soil Test Note 6: Use of Manures

Soil Test Note 7: Fertilizing Vegetable Crops

Soil Test Note 8: Interpretation of Soluble Salts Test

Soil Test Note 12: Fertilizing Fruit Crops

Soil Test Note 14: Pre-Sidedress Soil Nitrate Test for Corn

Soil Test Note 18: Phosphorus Management and the Phosphorus Saturation Ratio

Commercial Production: Agronomic Crops
Forage and Hay Crops


Amy L. Shober, Richard W. Taylor (ret.), Karen L. Gartley, and J. Thomas Sims (ret.)
Department of Plant and Soil Sciences
University of Delaware Cooperative Extension

Original Publication Date: January 2017

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