Meta-analysis on how manure application changes soil organic carbon storage.

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Manure application is recognized for nutrient provision and maintaining soil organic carbon (SOC) to mitigate climate change.
• Understanding the specific factors driving SOC stock dynamics after manure application remains crucial for optimizing agricultural practices.

Purpose of the Study:

• To analyze the relationship between SOC stock changes and various influencing factors, including site characteristics, soil properties, experimental conditions, and manure types.
• To quantify the average SOC increase resulting from manure application across diverse agricultural settings.

Main Methods:

• A meta-analysis was conducted, synthesizing data from 101 studies comprising 592 treatments.
• Statistical analysis was performed to identify correlations between SOC stock changes and factors such as tillage systems, climate conditions, soil depth, initial SOC content, soil texture, pH, and manure characteristics.

Main Results:

• On average, manure application increased SOC stocks by 35.4% (10.7 Mg ha⁻¹).
• Higher SOC increases were observed under conventional tillage, in non-tropical climates, and in intermediate/shallow topsoils.
• Clay soils, acidic soils, and applications of farmyard, cattle, and pig manure showed significant SOC increases, with combined manure and mineral fertilizer applications yielding greater results.

Conclusions:

• Manure application is an effective strategy for increasing soil organic carbon stocks in agricultural soils.
• Tillage practices, climate, soil properties, and manure type significantly influence the extent of SOC sequestration.
• Further research is needed, particularly in tropical regions and concerning long-term effects and potential carbon saturation.