Correction: Biochar affects compressive strength of Portland cement composites: a meta-analysis

Correction: Biochar (2024) 6:21 https://doi.org/10.1007/s42773-024-00309-2

Following publication of the original article (Zhao et al. 2024), it was brought to our attention that the positions of Fig. 1 and Fig. 2 and those of Fig. S1 and Fig. S2 have been incorrectly reversed.

The original Fig. 1 was:

The original Fig. 2 was:

The original Supplementary figure S1 was:

The original Supplementary figure S2 was:

The correct Fig. 1 should read:

Fig. 1

The effect sizes of biochar addition on the 7-day compressive strength of Portland cement composites, as affected by the feedstock used for biochar production, pyrolysis temperature, pyrolysis residence time, pyrolysis heating rate, biochar modification and pre-treatment. Each point represents effect sizes, and the size of the point represents the relative number of records compared to the total records. Grey bars represent 95CI. The vertical dash line represents the value of 0. The numbers of records are indicated in the brackets

The correct Fig. 2 should read:

Fig. 2

The effect sizes of biochar addition on the 28-day compressive strength of Portland cement composites, as affected by the feedstock used for biochar production, pyrolysis temperature, pyrolysis residence time, pyrolysis heating rate, and biochar modification and pre-treatment. Each point represents effect sizes, and the size of the point represents the relative number of records compared to the total records. Grey bars represent 95CI. The vertical dash line represents the value of 0. The numbers of records are indicated in the brackets

The correct Supplementary figure S1 should read:

The correct Supplementary figure S2 should read:

The original article (Zhao et al. 2024) has been updated.