Parameter | 2017 | 2018 | 2019 |
---|---|---|---|
Water contenta (%) | 35.70 | 28.45 | 31.50 |
pHa | – | 5.07 | 4.92 |
Electrical conductivitya (mS cm−1) | – | 0.70 | 0.59 |
Total nitrogenb (%) | 0.19 | 0.20 | 0.34 |
Total carbonb (%) | 49.50 | 52.90 | 50.20 |
Phosphorus pentoxideb (%) | 0.21 | 0.12 | 0.08 |
Potassium oxideb (%) | 0.54 | 0.41 | 0.27 |
Calcium oxideb (%) | – | 0.03 | 0.05 |
Magnesium oxideb (%) | – | 0.05 | 0.07 |
Silicic acidb (%) | – | 0.28 | 0.20 |