Table 1 Rank correlation tests and fail-safe numbers for publication bias
Response parameters (Abbreviation) | Study numbers (S) | Effect size (95% CI) | Spearman’s rank order correlation | Fail-safe numbers | |
|---|---|---|---|---|---|
R | P | ||||
Total biomass | 589 | 0.29 (0.24 to 0.33) | − 0.041 | 0.319 | 2 073 226 |
Shoot biomass | 499 | 0.39 (0.34 to 0.43) | − 0.133 | 0.003 | 2 284 188 |
Root biomass | 423 | 0.41 (0.35 to 0.47) | − 0.12 | 0.013 | 2 380 881 |
Proline (Pro) | 263 | − 0.08 (− 0.14 to − 0.02) | − 0.009 | 0.881 | 97 751 |
Soluble sugar (SS) | 143 | 0.18 (0.14 to 0.21) | − 0.195 | 0.02 | 143 753 |
Soluble protein (SP) | 104 | 0.2 (0.17 to 0.24) | 0.129 | 0.192 | 130 459 |
Nitrogen (N) | 287 | 0.23 (0.20 to 0.27) | 0.006 | 0.914 | 483 301 |
Phosphorus (P) | 395 | 0.38 (0.34 to 0.42) | 0.138 | 0.006 | 1 637 564 |
Potassium ion (K+) | 351 | 0.24 (0.20 to 0.28) | 0.146 | 0.006 | 826 281 |
Calcium ion (Ca2+) | 166 | 0.12 (0.06 to 0.18) | − 0.21 | 0.006 | 7 106 |
Magnesium ion (Mg2+) | 163 | 0.1 (0.04 to 0.16) | 0.191 | 0.015 | 20 747 |
Sodium ion (Na+) | 307 | − 0.17 (− 0.23 to − 0.12) | − 0.098 | 0.085 | 363 110 |
Superoxide dismutase (SOD) | 200 | 0.19 (0.14 to 0.23) | − 0.048 | 0.502 | 555 663 |
Catalase (CAT) | 162 | 0.16 (0.11 to 0.21) | 0.099 | 0.212 | 56 886 |
Malondialdehyde (MDA) | 170 | − 0.24 (− 0.27 to − 0.21) | − 0.028 | 0.719 | 708 409 |
Chlorophyll a (Chla) | 102 | 0.4 (0.32 to 0.49) | − 0.132 | 0.186 | 228 892 |
Chlorophyll b (Chlb) | 103 | 0.33 (0.27 to 0.39) | − 0.033 | 0.74 | 152 797 |
Carotenoid (Car) | 59 | 0.27 (0.18 to 0.37) | 0.242 | 0.064 | 125 869 |
Net photosynthetic rate (Pn) | 105 | 0.46 (0.39 to 0.56) | − 0.008 | 0.938 | 397 027 |
Stomatal conductance (Gs) | 116 | 0.47 (0.40 to 0.54) | − 0.02 | 0.830 | 486 569 |
Transpiration rate (Tr) | 95 | 0.48 (0.40 to 0.56) | 0.057 | 0.585 | 521 965 |