Comparative Assessment of Extractants for Available Potassium in Calcareous Soil of Punjab

ABSTRACT

The overestimation of potassium (K) levels in ammonium acetate extractant has led to a significant concern in calcareous soil (CS). Therefore, a pot experiment was conducted to investigate the response of K application on grain yield and to determine the most suitable extractant along with their critical limits. The study utilized soil collected from both calcareous and non-calcareous soils, which were subjected to ten levels of K in a completely randomized design with three replications. The findings revealed that K application had a positive effect on yield and yield parameters in calcareous soils, up to 13.5%, with a response up to 7.5 mg kg⁻¹. The study also demonstrated that grain and straw K concentrations were 2.5% and 8.9% higher, respectively, in calcareous soils when compared to non-calcareous soils (NCS). The study also tested the effectiveness of different extractants in extracting K from both soils. The available K extracted using various extractants varied, with the highest correlation coefficient (r = 0.87***) found in the barium chloride (BaCl₂) extractant. The critical limit of soil-K by Cate-Nelson method was found to be 964.3 kg ha⁻¹ for 0.1 M BaCl₂, 0.74% for grain, and 3.55% in straw in CS. In conclusion, K application had a significant effect on yield and yield parameters in calcareous soils, with barium chloride being the most effective extractant for estimating potassium levels. The findings of this study provide valuable insights into the appropriate extractants and critical limits for the accurate evaluation of K levels in calcareous soils.

KEYWORDS:

• Barium chloride
• Cate and Nelson
• critical limit
• crop response
• extractant

Acknowledgements

The authors are grateful to the Head of the Department of Soil Science for providing the facilities to conduct the research. Help received by Mrs Manpreet Kaur for statistical analysis is gratefully acknowledged. We thank all the lab staff for their consistent support and help during the research work. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

Data available on request from the authors.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.