Table 5.
The analysis results on physicochemical parameters and macro- and micronutrient content of palm oil waste compost.
| Parameter | N | k | SMD | p | I 2(p) | Egger′s (p) |
|---|---|---|---|---|---|---|
| Physicochemical | ||||||
| Moisture | 75 | 8 | −0.946 [−1.440; −0.452] | <0.001 | 93.40% (<0.001) | 0.039 |
| pH | 95 | 8 | 0.968 [0,520; 1.415] | <0.001 | 48.54% (0.015) | 0.001 |
| C-organic | 135 | 8 | 0.926 [0.572; 1.280] | <0.001 | 92.90% (0.003) | 0.001 |
| N-total | 135 | 8 | 2.19 [1.762; 2.616] | <0.001 | 93.35% (<0.001) | <0.001 |
| C/N ratio | 120 | 8 | 0.407 [0.029; 0.785] | 0.035 | 82.28% (<0.001) | 0.001 |
| Macro- and microcomponents | ||||||
| P | 125 | 8 | 0.698 [0.321; 1.076] | <0.001 | 60.51% (0.118) | <0.001 |
| K | 125 | 8 | 0.847 [0.464; 1.230] | <0.001 | 35.41% (0.242) | <0.001 |
| Ca | 70 | 8 | −57.6 [−67.191; −48.072] | <0.001 | 0% (0.557) | ns |
| Mg | 95 | 8 | −0.212 [−0.641; 0.217] | ns | 34.46% (0.267) | ns |
| S | 18 | 8 | −0.33 [−1.34; 0.68] | ns | 10.18% (0.355) | 0.155 |
| Fe | 24 | 8 | 0.99 [−1.32; 3.30] | ns | 83.66% (0.033) | 0.005 |
| Zn | 18 | 8 | 5.64 [2.36; 8.91] | <0,001 | 52.94% (0.047) | 0.013 |
| Mn | 18 | 8 | 1.33 [−2.20; 4.85] | ns | 88.75% (0.007) | 0.008 |
| Cu | 24 | 8 | 3.38 [0.64; 6.12] | 0.016 | 76.45% (0.003) | <0.001 |
Description: N = number of samples used in the study; k = number of studies used in the analysis; SMD = standardized mean difference is a summary of each study with the effect size; p = p value; I2 = inconsistency (heterogeneity test); Egger's = publication bias test; ns = not significant.