Spatial heterogeneity distribution of soil total nitrogen and total phosphorus in the Yaoxiang watershed in a hilly area of northern China based on geographic information system and geostatistics.

Yu Liu,Bing Wang,Peng Gao,Xiang Niu,Liyong Zhang

doi:10.1002/ece3.2410

Abstract

Soil total nitrogen (STN) and total phosphorus (STP) are important indicators of soil nutrients and the important indexes of soil fertility and soil quality evaluation. Using geographic information system (GIS) and geostatistics, the spatial heterogeneity distribution of STN and STP in the Yaoxiang watershed in a hilly area of northern China was studied. The results showed that: (1) The STN and STP contents showed a declining trend with the increase in soil depth; the variation coefficients (C v) of STN and STP in the 0‐ to 10‐cm soil layer (42.25% and 14.77%, respectively) were higher than in the 10‐ to 30‐cm soil layer (28.77% and 11.60%, respectively). Moreover, the C v of STN was higher than that of STP. (2) The maximum C 0/(C 0 + C 1) of STN and STP in the soil layers was less than 25%, this indicated that a strong spatial distribution autocorrelation existed for STN and STP; and the STP showed higher intensity and more stable variation than the STN. (3) From the correlation analysis, we concluded that the topographic indexes such as elevation and slope direction all influenced the spatial distribution of STN and STP (correlation coefficients were 0.688 and 0.518, respectively). (4) The overall distribution of STN and STP in the Yaoxiang watershed decreased from the northwest to the southeast. This variation trend was similar to the watershed DEM trend and was significantly influenced by vegetation and topographic factors. These results revealed the spatial heterogeneity distribution of STN and STP, and addressed the influences of forest vegetation coverage, elevation, and other topographic factors on the spatial distribution of STN and STP at the watershed scale.

Highlights

As the basic building blocks of all known forms of life on Earth, soil total nitrogen (STN) and total phosphorus (STP) are significant evaluation indexes of soil fertility in the terrestrial ecosystem (Gao, Yang, &Liu, 2015; Zhang, Cha, & Shen, 2011)
Researchers have conducted many studies about the spatial distribution characteristics of soil nutrients, and the results showed that the spatial distribution of Soil total nitrogen (STN) and STP exhibited random or structured spatial variation characteristic because of the significantly different soil physical, chemical, and biological processes in different directions (Wang, 1999; Wang, Zhang, Yu, & Zhang, 2006)
The spatial heterogeneity distribution of soil nutrients was researched employing geographic information system (GIS) and geostatistics, and the results indicated that different soil nutrients had obvious different spatial variation patterns and different spatial correlations (Cambardella et al, 1994)

Summary

| INTRODUCTION

As the basic building blocks of all known forms of life on Earth, soil total nitrogen (STN) and total phosphorus (STP) are significant evaluation indexes of soil fertility in the terrestrial ecosystem Using GIS and geostatistics, our goal was to achieve the following objectives: (1) to analyze the influences of slope, slope direction, and elevation on STN and STP, and establish the regression equation between elevation and the content of STN and STP; (2) to discuss the influences of forest vegetation coverage, elevation, and other topographic factors on the spatial heterogeneity distribution; and (3) to reveal the spatial heterogeneity distribution of STN and STP at the watershed scale using Kriging interpolation

| MATERIALS AND METHODS

| DISCUSSION

| CONCLUSIONS

DATA ACCESSIBILITY

Findings

FUNDING INFORMATION