Responses of soil enzyme activities to increasing salinity: A quantitative meta-analysis

Area of Science:

• Soil Science
• Biogeochemistry
• Ecology

Background:

• Soil salinization is a major threat to global agriculture and ecosystems.
• Soil extracellular enzymes are crucial for microbial metabolism and biogeochemical cycles.
• Understanding enzyme responses to salinity across diverse regions is limited.

Purpose of the Study:

• To quantitatively assess soil enzyme activity responses to salinity using meta-analysis.
• To explore how enzyme functional groups, ecosystem types, plant growth forms, and climate moderate these responses.
• To identify drivers of variation in enzyme activity under saline conditions.

Main Methods:

• Synthesized 1379 observations from 47 publications via meta-analysis.
• Analyzed overall enzyme activity response to salinity.
• Investigated moderating effects of enzyme function, ecosystem, plant type, and climate.

Main Results:

• Overall soil enzyme activity decreased by 9.1% under salinity.
• Phosphorus- and sulfur-cycling enzymes were most sensitive (-26.2%, -26.3%).
• Forests showed enzyme stimulation (+69.3%), while grasslands (-49.3%) and wetlands (-23.3%) were inhibited. Woody plants had mixed effects, and climate intensified suppression.

Conclusions:

• Salinity effects on soil enzymes are context-dependent and vary by functional group and ecosystem.
• Methodological consistency in salinity measurement is crucial for comparative studies.
• Findings provide a basis for assessing ecological functions and managing salt-affected soils.