Changes in Soil Organic Matter Associated with Land Use of Arenosols from Southern Botswana
Abstract
:1. Introduction
2. Materials and Methods
2.1. Sampling
2.2. General Analyses
2.3. Soil Respiratory Activity
2.4. Soil Humus Fractions
2.5. Humic Acid Characteristics
2.6. Statistical Data Treatments
3. Results
3.1. General Characteristics
3.2. Soil Respiratory Activity
3.3. Soil Organic Matter Fractions
3.4. Humic Acid Characteristics
4. Discussion
4.1. General Characteristics
4.2. Soil Respiratory Activity
4.3. Soil Organic Matter Fractions
4.4. Humic Acid Characteristics
4.5. Multivariate Data Treatments
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sampling Sites a | VTUL | DTUL | VMAS | DMAS | VLET | DLET | LSD | |
---|---|---|---|---|---|---|---|---|
Sand (2–0.02 mm) | /g kg−1 | 795 a | 790 a | 910 b | 860 c | 880 d | 883 d | 18 |
Silt (0.02–0.002 mm) | 90 a | 100 a | 38 b | 85 c | 63 d | 65 d | 13 | |
Clay (<0.002 mm) | 115 a | 110 a | 53 b | 55 b | 58 b | 53 b | 14 | |
pH (H2O) | 6.8 a | 7.4 a | 6.2 b | 6.9 a | 7.0 a | 7.2 a | 1.1 | |
pH (KCl) | 5.2 a | 5.9 a | 4.6 a | 5.4 a | 5.5 a | 5.6 a | 1.3 | |
Soil C | /g kg−1 | 4.25 a | 3.8 a | 2.0 b | 1.25 b | 1.75 b | 2.55 b | 1.5 |
Soil N | 0.31 a | 0.42 b | 0.25 a | 0.36 ab | 0.33 ab | 0.31 a | 0.1 | |
C/N ratio | 13.7 a | 9.0 b | 8.1 b | 4.7 c | 5.3 c | 8.2 b | 3.3 | |
P | /mg kg−1 | 4.9 a | 8.7 b | 5.7 c | 3.8 d | 10.9 e | 6.9 f | 0.4 |
K | 176.2 a | 182.5 a | 85 b | 98.7 b | 110 b | 132.5 ab | 59.0 | |
Ca | 715.0 a | 613.3 a | 278.7 b | 395.0 bc | 353.3 bc | 573.7 bc | 236.0 | |
Na | 7.5 a | 5.0 b | 5.0 b | 6.2 ab | 5.0 b | 5.0 b | 1.9 | |
Mg | 79.0 a | 78.2 a | 15.3 b | 31.3 b | 49.2 ab | 71.2 ab | 29.8 | |
Fe | 11.4 a | 14.5 a | 3.8 b | 4.3 b | 6.9 b | 9.1 ab | 3.7 | |
Mn | 29.5 a | 6.4 b | 16.7 ba | 14.0 ba | 15.5 ba | 39.5 a | 18.7 | |
Zn | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 | |
Cu | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 | <0.4 |
Sampling Sites a | Free Organic Matter b | Total Humic Extract b | Humic Acid b | Fulvic Acid b | Humic Acid/Fulvic Acid Ratio | Insolubilized Extractable Humin b | Non-Extractable Humin b |
---|---|---|---|---|---|---|---|
VTUL | 0.12 | 2.27 | 2.00 | 0.26 | 7.25 | 0.23 | 1.63 |
DTUL | 0. 04 | 1.70 | 1.17 | 0.52 | 2.21 | 0.20 | 1.87 |
VMAS | 0.03 | 1.04 | 0.50 | 0.55 | 0.93 | 0.09 | 0.84 |
DMAS | 0.03 | 0.72 | 0.44 | 0.28 | 1.79 | 0.04 | 0.46 |
VLET | 0.02 | 1.08 | 0.64 | 0.44 | 1.47 | 0.08 | 0.57 |
DLET | 0.04 | 1.27 | 0.69 | 0.58 | 1.19 | 0.17 | 1.07 |
LSD (p < 0.05) | 0.02 | 0.82 | 0.74 | 0.13 | 1.55 | 0.04 | 0.72 |
Optical Density a Values in the Visible Range (Wavelength nm) | Optical Density Values b of the Main Bands (Wavelength cm−1) in the Infrared Spectra | ||||
---|---|---|---|---|---|
Sample | E4 | E4/E6 | 3400 O–H Stretching | 2920 C–H Stretching | 1720 Carboxyl Acids |
VTUL | 2.16 | 3.3 | 0.93 | 0.98 | 0.93 |
DTUL | 2.16 | 3.4 | 0.94 | 1.00 | 0.84 |
VMAS | 2.23 | 3.6 | 1.11 | 1.89 | 0.80 |
DMAS | 1.58 | 3.5 | 1.17 | 1.27 | 0.89 |
VLET | 1.65 | 3.8 | 1.11 | 1.79 | 0.96 |
DLET | 1.47 | 3.5 | 1.02 | 1.09 | 0.83 |
LSD (p < 0.05) | 1.49 | 0.08 |
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Kgathi, D.; Sekhwela, M.; Almendros, G. Changes in Soil Organic Matter Associated with Land Use of Arenosols from Southern Botswana. Agronomy 2024, 14, 1869. https://doi.org/10.3390/agronomy14081869
Kgathi D, Sekhwela M, Almendros G. Changes in Soil Organic Matter Associated with Land Use of Arenosols from Southern Botswana. Agronomy. 2024; 14(8):1869. https://doi.org/10.3390/agronomy14081869
Chicago/Turabian StyleKgathi, Donald, Mogodisheng Sekhwela, and Gonzalo Almendros. 2024. "Changes in Soil Organic Matter Associated with Land Use of Arenosols from Southern Botswana" Agronomy 14, no. 8: 1869. https://doi.org/10.3390/agronomy14081869