Impact of tillage practices and arbuscular mycorrhizal fungi inoculation on organic sweet corn yield and nutritional quality

Authors: ZINATI, GLADIS - Rodale Institute; Carrara, Joseph; DAS, SAURAV - Rodale Institute; CEATANI, ROMANS - Rodale Institute; KALRA, AMIYA - Purdue University; CARR, ERIC - Rodale Institute; Heller, Wade

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2025
Publication Date: 3/13/2025
Citation: Zinati, G., Carrara, J.E., Das, S., Ceatani, R., Kalra, A., Carr, E.A., Heller, W. 2025. Impact of tillage practices and arbuscular mycorrhizal fungi inoculation on organic sweet corn yield and nutritional quality. Soil and Tillage Research. 251:106545. https://doi.org/10.1016/j.still.2025.106545.
DOI: https://doi.org/10.1016/j.still.2025.106545

Interpretive Summary: The application of mycorrhizal biofertilizers in agriculture has shown potential for enhancing crop yield and nutritional quality, yet their effectiveness across different farming practices and in on-farm trials are largely underexplored. A two-year sweet corn mycorrhizal inoculation study was completed under organic management practices to assess the differential impacts of arbuscular mycorrhizal fungi (AMF) inoculation and the additional variable of tillage intensity, in which a winter-grown cover crop was terminated by moldboard plowing for full tillage plots, and roller-crimping for reduced tillage plots. Parameters measured included yield, stalk dry weight, kernel content of minerals, protein, amino acids, Vitamins B6 and C, and root mycorrhizal colonization. In both years, yields were higher in the full tillage treatments, whereas kernel potassium, calcium, magnesium, zinc, and Vitamin C content were higher under reduced tillage. AMF inoculation, especially with Rhizophagus irregularis resulted in higher kernel phosphorus, and potassium content, and increased levels of aspartic acid and taurine. These results demonstrate the effectiveness of AMF biofertilizers in boosting the nutritional quality of crops for public health benefit, even in organic reduced tillage cropping systems which are naturally conducive to high native AMF soil populations.

Technical Abstract: The application of mycorrhizal biofertilizers in agriculture has demonstrated potential for improving crop yield and nutrition. However, their effectiveness across different tillage systems and under on-farm conditions remain underexplored. This two-year study evaluated the effects of tillage practices and supplemental arbuscular mycorrhizal fungi (AMF) inoculation on the yield and nutrient composition of organically grown sweet corn (Zea mays). The experiment followed a split-plot design with two tillage practices—full tillage (FT) and reduced tillage (RT)—and four AMF treatments: mock (control), native AMF community (NAT), Rhizophagus irregularis, and Funneliformis mosseae. Results showed that FT significantly increased fresh and dry ear yields compared to RT. AMF inoculation, particularly with R. irregularis, enhanced kernel phosphorus (P) and potassium (K) concentrations. Inoculation with R. irregularis and F. mosseae also increased kernel vitamin B6 and C levels. Tillage influenced amino acid composition, with leucine and phenylalanine concentrations being higher in FT, while tryptophan was greater in RT. Additionally, R. irregularis and F. mosseae inoculation increased aspartic acid and glycine concentrations, which play a role in scavenging reactive oxygen species (ROS), suggesting a potential role for AMF in enhancing crop stress resilience and nutritional quality. Despite these benefits, natural AMF colonization across treatments may have masked the full effects of supplemental inoculation, highlighting the complexity of evaluating AMF biofertilizers in field conditions. Overall, this study suggests that while the presence of native AMF complicates the assessment of exogenous inoculation, AMF biofertilizers have positive implications for enhancing nutrient density of sweet corn across tillage practices.