Work

Optimal straw return strategies for enhancing SOC, crop yield, and mitigating CO2 emissions in Chinese wheat and maize systems

Year: 2025

Type: article

Study designs: Systematic Review, Meta-Analysis

Abstract: Boosting soil organic carbon (SOC) content and crop yield while cutting CO2 emissions is key to balancing soil health, food security, and climate governance. Straw return as a green management measure can increase SOC content and crop yield but may stimulate CO2 emissions, particularly in wheat and maize systems (i.e., wheat/maize monoculture and wheat-maize rotation). However, research on how straw return affects SOC content, CO2 emissions, and crop yield in wheat and maize systems remains limited, especially lacking in considering key drivers of carbon sequestration, yield increases, and CO2 reductions under integrated climate, soil, and management conditions. A meta-analysis of 494 paired observations from wheat and maize field experiments across China explored change patterns and drivers of SOC content, CO2 emissions, and yield under straw return. The results showed that straw return increased SOC content and yield more substantially than CO2 emissions, with SOC increments decreasing with soil depth. Climate (mean annual temperature: MAT; mean annual precipitation: MAP), straw return, and nitrogen management were the main drivers regulating SOC content, CO2 emissions, and yield in response to straw return, acting via direct effects or indirect influences on cropping systems, soil texture, tillage, and irrigation practices. Medium-term (5–10 years) straw return with medium nitrogen input (200–400 kg N ha-1) enhanced SOC sequestration and suppressed CO2 emissions, and didn't affect yield in wheat monoculture. Medium-term no-till mulching (5–10 years) synergistically enhanced SOC sequestration and yield while suppressing CO2 emissions in maize monoculture. Wheat-maize rotation with low nitrogen input (100–200 kg N ha-1) optimally enhanced SOC sequestration and crop yield while suppressing CO2 emissions in regions with MAT 10–20°C, MAP 500–1000 mm, and medium soil texture. These findings guide optimal straw return strategies to enhance SOC, crop yield, and reduce emissions in Chinese wheat and maize systems.

Source: Agricultural Water Management

DOI: 10.1016/j.agwat.2025.109982