Influence of Sampling Point Discretization on the Regional Variability of Soil Organic Carbon in the Red Soil Region, China
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Area
2.2. Soil Sample Collection and Processing
2.3. Sample Discretization Levels Setting
2.4. Spatial Interpolation Methods
2.5. Uncertainty Evaluation of Spatial Interpolation
3. Results
3.1. Statistical Characteristics of SOC Content
3.2. Geostatistical Analysis of SOC Contents
3.3. Interpolation Contours of SOC Content at the Various Sample Discretization Levels
3.4. Uncertainty Evaluation of Spatial Interpolation at Various Discretization Levels
4. Discussion
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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Land Use | Sample Size | Minimum | Maximum | Mean † | SD | CV |
---|---|---|---|---|---|---|
g kg−1 | ||||||
Paddy fields | 80 | 2.66 | 24.15 | 15.05a | 5.02 | 33% |
Dry land | 75 | 2.23 | 21.66 | 7.95b | 5.11 | 64% |
Forestland | 11 | 3.72 | 14.95 | 8.20b | 2.85 | 35% |
Total | 166 | 2.23 | 24.15 | 11.39 | 6.06 | 53% |
Discretization | VMR † | Minimum | Maximum | Mean ‡ | SD | CV |
---|---|---|---|---|---|---|
g kg−1 | ||||||
V1 | 0.12 | 2.66 | 24.15 | 11.11a | 6.21 | 56% |
V2 | 0.80 | 2.66 | 24.15 | 11.56a | 6.37 | 55% |
V3 | 1.46 | 2.23 | 24.15 | 10.88a | 6.06 | 56% |
V4 | 2.17 | 2.23 | 22.24 | 11.46a | 6.09 | 53% |
Method | Discretization | Distribution | Model | C0 | Sill | C/Sill | Range (m) | R2 |
---|---|---|---|---|---|---|---|---|
Ordinary Kriging (OK) | v1 | Normal | Exponential | 0.28 | 1.10 | 0.74 | 3480 | 0.94 |
v2 | Normal | Spherical | 0.31 | 1.06 | 0.71 | 2190 | 0.82 | |
v3 | Normal | Exponential | 0.54 | 1.09 | 0.50 | 3870 | 0.75 | |
v4 | Normal | Exponential | 0.56 | 1.06 | 0.47 | 2430 | 0.58 | |
Kriging with land use information (LuK) | v1 | Normal | Spherical | 0.40 | 1.04 | 0.62 | 2170 | 0.96 |
v2 | Normal | Spherical | 0.51 | 1.03 | 0.50 | 2030 | 0.88 | |
v3 | Normal | Exponential | 0.52 | 1.05 | 0.50 | 2340 | 0.79 | |
v4 | Normal | Exponential | 0.54 | 1.02 | 0.47 | 1830 | 0.42 |
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Zhang, Z.; Sun, Y.; Yu, D.; Mao, P.; Xu, L. Influence of Sampling Point Discretization on the Regional Variability of Soil Organic Carbon in the Red Soil Region, China. Sustainability 2018, 10, 3603. https://doi.org/10.3390/su10103603
Zhang Z, Sun Y, Yu D, Mao P, Xu L. Influence of Sampling Point Discretization on the Regional Variability of Soil Organic Carbon in the Red Soil Region, China. Sustainability. 2018; 10(10):3603. https://doi.org/10.3390/su10103603
Chicago/Turabian StyleZhang, Zhongqi, Yiquan Sun, Dongsheng Yu, Peng Mao, and Li Xu. 2018. "Influence of Sampling Point Discretization on the Regional Variability of Soil Organic Carbon in the Red Soil Region, China" Sustainability 10, no. 10: 3603. https://doi.org/10.3390/su10103603