Calcium Status of Some Nebraska Soils and Its Laboratory Evaluation

Calcium as a plant nutrient, has been shown to be deficient in the soils of eastern Nebraska. Application of lime by farmers is becoming a relatively common practice in this area. Many soil tests have been devised based on the chemical properties of the soil. However, due to the empirical nature of these methods, field experiments of this type involve long periods of time as well as much labor and expense. A cheaper and less time consuming method is desirable. Such a method, the concept of ‘A’ values, exists. This concept utilizes the composition of plants grown on a soil which has been tagged with a radioactive nutrient source as an indication of the nutrient supply of the soil. This method may be extended to suggest a method of calibration of chemical soil tests for lime requirement. Making use of this concept, a greenhouse experiment was devised whereby the calcium contents of some of the more common Nebraska soils could be studied. The results of this study show soil texture is one of the primary considerations where the lime status of soils is studied. Coarse textured soils of the Sandhills region had the lowest lime delivery power of any studied. Soils coarser textured than loam were found to have the lowest lime delivery power. The soil type name presents a relatively reliable criterion on which to base lime recommendations. Advisor: R. A. Olso