Geostatistical, deterministic and interpolation with barriers methods—a comparative analysis for interpolating soil NPK

Abstract

The spatial distribution of soil pH, electrical conductivity, available nitrogen, phosphorus and potassium concentrations at Anaimalai block of Coimbatore district, India was interpolated by geostatistical analysis to create digital maps of soil NPK that renders numerous information for agro based policy making. 1627 soil samples in 30,700 acres were gathered by composite soil sampling method and rendered interpolation analysis to predict the soil parameters at unsampled locations. Based on geostatistical, deterministic and interpolation with barriers methods 13 interpolation models were generated and compared to validate the precision. Interpolation reveals the deficiency of soil available nitrogen and phosphorus whereas available potassium was in sufficient range. Radial basis function, inverse distance weighting, probability kriging, empirical Bayesian kriging and local polynomial interpolations were validated by linear correlation method that reveals the precisions of models with R² values of 0.74, 0.82, 0.98, 0.89 and 0.79 (soil pH, EC, nitrogen, phosphorus and potassium respectively).

Keywords:

• Geostatistics
• soil NPK interpolation
• linear correlation
• Anaimalai
• Coimbatore

Acknowledgement

Authors express their gratitude to the management and faculties of SRM Institute of Science and Technology, Kattankulathur for the support received. We thank Mr. Vickram Muthu Rathinasabari for his valuable field assistance. We extend our thanks to editorial board of Geocarto International Journal and reviewers for theirs valuable comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Availability of data

Data available on request from the authors.