A three-year field study shows that incorporating maize straw 20 to 30 centimeters into soil can improve soil health, reshape microbial communities, and reduce disease and food safety risks.
Returning crop residues to farmland is widely used to improve soil fertility and recycle nutrients, but where those residues are placed in the soil may be just as important as whether they are returned at all. A new study has found that incorporating maize straw deeper into the soil can substantially reduce maize ear rot and harmful mycotoxin contamination while creating a healthier soil environment.
Researchers conducted a three-year field experiment in Jilin Province, China, comparing four straw incorporation depths: 0 to 5 cm, 10 to 20 cm, 20 to 30 cm, and 30 to 40 cm. They assessed soil physical and chemical properties, microbial communities in soil and maize roots, ear rot severity, and concentrations of the mycotoxins deoxynivalenol (DON) and zearalenone (ZEN).
The deeper treatments, particularly those at 20 to 40 cm, reduced maize ear rot incidence by 33.3% to 66.7% and reduced disease severity by 20% to 50% compared with shallow incorporation. DON and ZEN concentrations were also maintained within established safety thresholds.
"Our findings show that straw incorporation depth can influence much more than soil structure," said corresponding author Yanpo Yao of the Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs. "By improving the soil environment, deeper incorporation can favor beneficial microorganisms while suppressing important fungal pathogens, ultimately helping protect both crop health and grain safety."
The researchers found that deeper straw placement improved several indicators of soil health. Total pore area increased by as much as 162.5%, while soil organic carbon and available nitrogen, phosphorus, and potassium increased substantially. The overall soil quality index rose steadily with incorporation depth, with the 30 to 40 cm treatment reaching roughly four times the value observed under shallow incorporation.
Microorganisms appeared to provide an important link between these soil improvements and healthier maize. Deep incorporation enriched beneficial microbial groups, including Trichoderma and members of the Enterobacteriaceae family, by more than twofold. At the same time, it reduced the abundance of Fusarium and Aspergillus, fungi associated with maize ear rot and mycotoxin production, in both the rhizosphere and root tissues.
The deeper treatments also produced more complex and stable microbial interaction networks. Structural equation modeling indicated that changes in soil properties and microbial communities together explained how straw incorporation reduced disease and mycotoxin risks.
Although the 30 to 40 cm treatment produced the strongest overall improvements, deeper tillage also requires more energy, tractor power, and operating costs. The researchers therefore highlight 20 to 30 cm straw incorporation as a particularly practical option, because it already achieved substantial disease suppression and maintained mycotoxins within safe limits while avoiding some of the additional costs associated with ultra-deep tillage.
The study suggests that optimizing the depth of crop residue incorporation could turn a familiar agricultural practice into a more effective tool for soil health, disease management, and food safety. The findings may help guide more sustainable straw management strategies for maize production, although additional research across different soils, climates, and farming systems will be needed to refine recommendations.
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Journal Reference: Xue M, Jia J, Qu Z, Jiang T, Yang M, et al. 2026. Deep straw incorporation reduces maize ear rot and mycotoxin contamination by improving soil health and microbial community. Agricultural Ecology and Environment 2: e021 doi: 10.48130/aee-0026-0019
https://www.maxapress.com/article/doi/10.48130/aee-0026-0019
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