Snow removal and cover crops influence soil nitrogen transfer to the subsequent corn crop

• Published in: Plant and soil 2024-03, Vol.496 (1-2), p.473-483
• Main Authors: Heuchan, Spencer M., Wagner-Riddle, Claudia, Henry, Hugh A. L.
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agricultural practices; Agriculture; Biomedical and Life Sciences; Cereal crops; Corn; Cover crops; Crops; Ecology; Food preservation; Freezing; Grain; Grain crops; Life Sciences; Nitrogen; Nitrogen isotopes; Plant Physiology; Plant Sciences; Recovery; Research Article; Retention; Snow; Snow removal; Soil Science & Conservation; Soils; Vegetables; Winter
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-023-06376-x

Background and aims Cover crops can increase nitrogen (N) retention in agroecosystems by taking up soil soluble N when the grain crop is absent. We examined how the combination of cover crops and variability in winter conditions can affect soil N retention and N transfer to the subsequent crop. Methods We used 15 N tracer to quantify how the presence of cover crops (both winter-hardy and winter-killed) modifies the recovery by a corn crop of soil soluble N added the previous fall, and we used snow removal to assess how increased freezing would alter 15 N recovery. We predicted snow removal would decrease 15 N recovery in corn, and this decrease would be highest for plots with winter-hardy cover crops, given they remain vulnerable to increased frost over winter. Results Cover crops approximately doubled corn grain 15 N recovery (up to 8% of the added 15 N) relative to the treatment that lacked cover crops (4% of the added 15 N). Snow removal reduced 15 N recovery in corn grain, but this effect did not differ among cover crop treatments. 15 N recovery in soil at the time of corn harvest was increased by cover crops, with retention as high as 40% of the added 15 N tracer, compared to only 20% for soil in the control plots. Soil 15 N recovery was not significantly reduced by snow removal. Conclusion Although increased soil freezing reduced grain N recovery, cover crops increased soil N retention, which indicates decreased N losses to the surrounding environment, and the potential for increased contributions to grain N in future years.