Quality assessment of meta-analyses on soil organic carbon
<p>Soil organic carbon (SOC) plays a vital role in the global carbon cycle and is a potential sink for carbon dioxide. Agricultural management practices can support carbon sequestration and, therefore, offer potential removal strategies whilst also improving overall soil quality. Meta-analysis...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-02-01
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| Series: | SOIL |
| Online Access: | https://soil.copernicus.org/articles/9/117/2023/soil-9-117-2023.pdf |
| Summary: | <p>Soil organic carbon (SOC) plays a vital role in the
global carbon cycle and is a potential sink for carbon dioxide. Agricultural
management practices can support carbon sequestration and, therefore, offer
potential removal strategies whilst also improving overall soil quality.
Meta-analysis allows one to summarize results from primary articles by
calculating an overall effect size and to reveal the source of variation
across studies. The number of meta-analyses published in the field of
agriculture is continuously rising. At the same time, more and more articles
refer to their synthesis work as a meta-analysis, despite applying less than
rigorous methodologies. As a result, poor-quality meta-analyses are
published and may lead to questionable conclusions and recommendations to
scientists, policymakers, and farmers.</p>
<p>This study aims at quantitatively analyzing 31 meta-analyses, published
between the years of 2005 and 2020, studying the effects of different management
practices on SOC. We compiled a set of quality criteria suitable for soil and
agricultural sciences by adapting existing meta-analytical guidelines from
other disciplines. The set is supported by a scoring scheme that allows for a
quantitative analysis. The retrieved meta-analyses were structured according
to 11 management categories, such as tillage, cover crops, crop residue
management, and biochar application, which allowed us to assess the
state of knowledge on these categories. Major deficiencies were found in the
use of standard metrics for effect size calculation, independence of effect
sizes, standard deviation extraction for each study, and study weighting by
the inverse of variance. Only 1 out of 31 SOC meta-analyses, which studied
the effects of no tillage/reduced tillage compared with conventional tillage, was
found to be of high quality. Therefore, improved meta-analyses on the
effects of organic agriculture, biochar, fertilization, or crop
diversification on SOC are urgently needed.</p>
<p>We conclude that, despite efforts over the last 15 years, the quality of
meta-analyses on SOC research is still low. Thus, in order for the scientific
community to provide high-quality synthesis work and to make advancements in
the sustainable management of agricultural soils, we need to adapt rigorous
methodologies of meta-analysis as quickly as possible.</p> |
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| ISSN: | 2199-3971 2199-398X |