Table 2.
Essential parameters for comprehensive soil fertility assessment.
| Parameter | Description | Impact on soil fertility | References |
|---|---|---|---|
| Available nutrients | Immediate plant-accessible N, P, K pools | ↑35–40% N, ↑25–30% P, ↑20–25% K with 10-year integrated fertilization | Lu et al. (2024) |
| Organic matter | Structural matrix for aggregates, microbial habitat, nutrient reservoir | 1% SOM increase enhances water retention by 3.7 L/m2, CEC by 4.2 cmol+/kg | Obalum et al. (2017) |
| Enzyme activity | Biological catalysts for organic matter transformation | Urease activity correlates with N mineralization rate (r = 0.82***) | Yang et al. (2019) |
| pH | Governs nutrient solubility and microbial function | pH 6.5 optimizes P availability (85–90% of maximum) | Ning et al. (2020) |
| Cation exchange capacity | Nutrient holding and exchange potential | CEC > 15 cmol+/kg reduces K leaching by 40–60% in sandy loams | He et al. (2021) |
| Buffering capacity | Resistance to pH fluctuation and ionic stress | High-buffer soils maintain ±0.3 pH stability under 100 kg N/ha/yr. inputs | Rieder et al. (2024) |