Abstract

A simple extraction of soils using a dilute salt solution was found to be a better indicator of trace metal availability to crops than traditional soil tests.

Issue

Currently, the most frequently used soil tests for trace elements are poor predictors of the bioavailability or mobility of these elements in soils because their chemically aggressive nature changes soil pH and elemental extractability. As a consequence, these soil tests have limited value to agronomists and regulators for evaluating potential for trace element or toxic metal uptake into crops or leaching to groundwater when a wide range of soil types is being evaluated.

Response

A simple and non-aggressive soil extraction method, using 0.01 M CaCl2 solution at 90 degrees Celsius, was shown in our laboratory as well as through greenhouse research to be superior to the most frequenetly used soil extraction method. This conclusion was based on the strength of correlation between the amount of trace element extracted from a number of soils and the concentration of the trace element in a test crop grown in these same soils.

Impact

The Cornell Nutrient Analysis Laboratory is now offering this soil test as an alternative to traditional methods, and several research groups at Cornell and Penn State are adopting the soil test for elements of concern, including cadmium, copper, molybdenum and phosphorus. It has now been demonstrated on one of these studies that this test not only estimates plant-available elements, but also predicts the fraction of cadmium in soils that is accumulated by earthworms.

Funding Sources

• Other USDA (e.g., Water Quality, Special Grants, NRI)
• Federal Formula Funds - Research (e.g., Hatch, McIntire-Stennis, Animal Health)

Collaborators

• Penn State University
• University of Guelph

Key Personnel

• N/A