On the Quantitative Analysis of Exchangeable Na⁺ by Puri Method

Abstract

The quantitative analysis of exchangeable Na⁺ by Puri method was examined. The proposed method was as follow:
Portions of air-dired fine soil weighing 4g. are mixed with 30cc of N-(NH₄)₂CO₃, and is centrifuged after 40min. The supernatant solution is gathered four times, and s evaporated to dryness. The residue, after being dissolved, is titrated with standard acid. This titration value gives the amount of exchageable Na⁺ and K⁺(n).
The soil residue in the centrifugal cylinder is mixed with 30cc of N-KCL, and is centrifuged after 1 hr. The supernatant solution is discarded two times. The residue is again mixed with 30cc of N-(NH₄)₂CO₃. The supernatant solution is gathered and evaporated as described in the foregoing. This titration value gives exchangeable capacity (N). Degree of alkalization is calculated by the following formula:
D. A.=100 n/N
This n value contains a few exchangeable K, but for the purpose of the present investigation it was not considered necessary to determine K⁺ separately.
Some salt treated soils were chosen to measure the D. A. values. The results showed a clear difference in the D. A. values between the treated soils (25-42%) and the untreated soils (3-6%).