Spatial variability of soil fertility parameters in Kaski District, Nepal: A geostatistical approach
4 affiliations
- 1Soil and Fertilizer Testing Section, Province Agriculture Laboratory, Ministry of Agriculture, Land Management and Cooperatives, Pokhara, Kaski, Gandaki Province, Nepal
- 2Department of Soil Science, Agriculture and Forestry University, Rampur, Chitwan, Bagmati Province, Nepal
- 3Department of Agrigenomics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- 4Institute of Forestry (IOF), Pokhara Campus, Tribhuwan University, Pokhara, Nepal
Abstract
Mapping of soils and depicting spatial variability across agro-ecological regions remains underexplored, especially in Nepal’s hilly areas. The current study aimed to assess spatial variability and map key soil properties such as pH, soil organic matter, total nitrogen, available phosphorus, and available potassium across the Kaski district, Nepal. A total of 263 composite, geo-referenced samples from 0–20 cm depth were collected using a proportional random sampling design across different land- use types. Fertility maps were generated using Inverse Distance Weighting (IDW) interpolation in ArcGIS 10.8. Descriptive statistics revealed significant spatial variability among soil parameters, with a coefficient of variation from 15.2% (low) for pH to 137.93% (high) for available phosphorus. Most soils were moderately to strongly acidic with a mean of 5.48 ± 0.004. Soil organic matter, total nitrogen, and available phosphorus showed medium fertility levels (SNI = 1.91, 2.19 & 1.95), whereas available potassium reflected a low soil nutrient index (SNI = 1.61), indicating potassium deficiency. Spatial autocorrelation analysis confirmed significant positive clustering for SOM and potassium, while nitrogen exhibited a random distribution pattern (I = 0.25, z = 1.46, p = 0.14). Trend analysis revealed directional gradients with saddle-shaped curves in pH, SOM, and total nitrogen, influenced by topography, elevation, and fertilizer management practices. This study provides a comprehensive characterization of soil fertility, highlighting fertility constraints and offering insights for precision agriculture and land-use planning aimed at sustainable soil management in the Kaski district of Nepal.
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BibTeX
@article{bhusal2026spatial,
title = {{Spatial variability of soil fertility parameters in Kaski District, Nepal: A geostatistical approach}},
author = {Karishma Bhusal and Yojana Adhikari and Nirajan Acharya and Sadikshya Pokharel and Sunil Pandey and Rabindra Adhikari},
journal = {PLOS One},
year = {2026},
month = nov,
doi = {10.1371/journal.pone.0360670},
url = {https://doi.org/10.1371/journal.pone.0360670},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Spatial variability of soil fertility parameters in Kaski District, Nepal: A geostatistical approach
AU - Karishma Bhusal
AU - Yojana Adhikari
AU - Nirajan Acharya
AU - Sadikshya Pokharel
AU - Sunil Pandey
AU - Rabindra Adhikari
PY - 2026
DA - 2026/11/05
JO - PLOS One
DO - 10.1371/journal.pone.0360670
UR - https://doi.org/10.1371/journal.pone.0360670
AB - Mapping of soils and depicting spatial variability across agro-ecological regions remains underexplored, especially in Nepal’s hilly areas. The current study aimed to assess spatial variability and map key soil properties such as pH, soil organic matter, total nitrogen, available phosphorus, and available potassium across the Kaski district, Nepal. A total of 263 composite, geo-referenced samples from 0–20 cm depth were collected using a proportional random sampling design across different land- use types. Fertility maps were generated using Inverse Distance Weighting (IDW) interpolation in ArcGIS 10.8. Descriptive statistics revealed significant spatial variability among soil parameters, with a coefficient of variation from 15.2% (low) for pH to 137.93% (high) for available phosphorus. Most soils were moderately to strongly acidic with a mean of 5.48 ± 0.004. Soil organic matter, total nitrogen, and available phosphorus showed medium fertility levels (SNI = 1.91, 2.19 & 1.95), whereas available potassium reflected a low soil nutrient index (SNI = 1.61), indicating potassium deficiency. Spatial autocorrelation analysis confirmed significant positive clustering for SOM and potassium, while nitrogen exhibited a random distribution pattern (I = 0.25, z = 1.46, p = 0.14). Trend analysis revealed directional gradients with saddle-shaped curves in pH, SOM, and total nitrogen, influenced by topography, elevation, and fertilizer management practices. This study provides a comprehensive characterization of soil fertility, highlighting fertility constraints and offering insights for precision agriculture and land-use planning aimed at sustainable soil management in the Kaski district of Nepal.
SN - 1932-6203
ER -