In the bamboo forests of southern China, mulching the ground with straw during winter is a common management practice. Farmers use materials such as rice straw and bamboo branches to insulate the soil, helping to retain warmth and moisture while also promoting the early harvest of bamboo shoots, thereby increasing economic returns. However, this seemingly “routine” operation may quietly alter the carbon exchange between the soil and the atmosphere. Previous studies have predominantly focused on the short-term effects of straw mulching on soil CO₂ emissions, mainly targeting agricultural ecosystems. However, does straw mulching lead to changes in soil carbon emissions in artificial forests in humid regions?
Professor Xinzhang Song (Zhejiang A&F University) et al. conducted a study that revealed the response of soil CO₂ emissions in bamboo forests of humid regions to straw mulching and its long-term effects. The research found that straw mulching not only significantly increased soil carbon emissions in the short term but also had enduring effects that persisted for at least three years after the removal of the mulching material. The study has been published in the journal Frontiers of Agricultural Science and Engineering (DOI: 10.15302/J-FASE-2025607).
The researchers established three treatment groups in the bamboo forest in Huzhou, Zhejiang: “no mulch”, “one-year mulch”, and “continuous three-year mulch”, and continuously monitored soil CO₂ emissions and related indicators during the mulching period and the “enduring effect period” after the removal of the mulching materials. The results indicated that during the mulching period, soil CO₂ emissions in the straw-mulched areas were approximately 18 times higher than those in the unmulched areas. This was primarily because the mulching material acted like a “thermal blanket”, raising soil temperatures and creating a more favorable environment for microbial activity and the growth of bamboo rhizomes and shoots, thus accelerating the decomposition of soil organic matter and root respiration. Notably, even during the “enduring effect period” after the removal of the mulching material, carbon emissions were still 230%–270% higher than in the uncovered areas. At this stage, the impact of soil temperature on emissions weakened, while soil nutrients became the key driving factor. During the mulching period, the decomposition of straw and accompanying materials such as pig manure significantly increased the levels of organic carbon, nitrogen, and phosphorus in the soil, providing a richer “food” source for microbes and continuously stimulating their activity, thus maintaining elevated CO₂ emission levels.
This finding breaks through previous limitations that focused only on the effects during the mulching period, confirming for the first time that straw mulching has a lasting impact on soil CO₂ emissions in artificial forests in humid areas. The study also found that while mulching increases soil CO₂ emissions, the organic carbon content in the soil of the mulched areas significantly increased by 27%–72%, indicating that straw mulching not only promotes carbon release but also enhances carbon storage capacity by increasing soil carbon input, providing new insights for carbon management in artificial forests in humid regions.
Moreover, there was no significant difference in the enhancement of soil CO₂ emissions between the one-year cover and the continuous three-year cover, suggesting that short-term mulching can have lasting effects. Based on this, the authors recommend that in practical production, the thickness and quantity of mulching materials can be appropriately reduced to ensure bamboo shoot yields while lowering CO₂ emission intensity, achieving a “win-win” for economic returns and carbon sink capacity.
This study constructed a multidimensional evidence chain demonstrating the impact of mulching measures on carbon emissions by monitoring soil microbial biomass, functional genes, and environmental factors. It not only fills the research gap on carbon cycling in bamboo forests in humid regions but also provides theoretical references for the management of other forest ecosystems through its revelation of nutrient-driven enduring effect mechanisms.
DOI: 10.15302/J-FASE-2025607