Researchers have discovered that using cover crops as "living mulch" between rows of maize can significantly improve soil health and nutrient cycling, offering a sustainable approach to agricultural management. The research, conducted at Changtu County in northeastern China, investigated the effects of different types of cover crops—legumes, grasses, and a mixture of both—on soil properties and microbial communities.

Cover crops, planted either during or after the main crop's growth, can help prevent soil erosion, improve fertility, and increase the input of plant-derived nutrients. Soil degradation, driven by unsustainable farming methods, poses significant threats to food security and regional agricultural development. Cover crops offer an integrated “use-and-maintain” solution to restore degraded farmland. While earlier research have focused on the effects of decaying cover crop residues, this study examined the impact of living cover crops growing alongside the main crop.

The research team, from the Institute of Applied Ecology of the Chinese Academy of Sciences in Shenyang, conducted a field experiment where maize was intercropped with different cover crop treatments.

The researchers found that legume cover crops increased dissolved organic carbon and available nitrogen in the soil, altering the microbial community structure and promoting carbon cycling. This alleviated microbial carbon limitation, meaning the microbes had easier access to the carbon they needed to thrive. Grass cover crops, on the other hand, maintained soil carbon and total nitrogen levels and increased overall microbial biomass, particularly bacterial groups.

The most promising results came from the mixed cover crop treatment. This approach combined the benefits of both legumes and grasses, enhancing both carbon and nitrogen levels while maintaining overall soil nutrient balance. The mixed treatment also significantly enhanced microbial functions, as evidenced by the temporal dynamic shifts in microbial functional groups revealed in the study.

The study highlights the potential of using cover crops as a "living mulch" technique to improve soil health. The researchers suggest that a mixture of legume and grass cover crops is the most effective approach for maize intercropping systems. This method could help address soil degradation issues, such as declining fertility and erosion, which threaten food security.

The findings, published in the journal Agriculture Ecosystems & Environment, provide valuable insights for developing and implementing cover crop-maize intercropping techniques, particularly in black soil regions facing degradation.