Gladis Zinatia,*, Joseph E. Carrarab, Saurav Dasa, Romans Caetania, Amiya Kalrac, Eric A. Carra, Wade P. Hellerb,*
a Rodale Institute, Kutztown, PA, USA
b USDA-ARS, Eastern Regional Research Center, Sustainable Biofuels and Co-Products Research Unit, Wyndmoor, PA, USA
c Purdue University, Department of Agronomy, West Lafayette, IN, USA
* Correspondence: gladis.zinati@rodaleinstitute.org (G. Zinati), wade.heller@usda.gov (W.P. Heller)
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.
Keywords: Bio-nutrients, Mycorrhizal root colonization, Organic farming, Management practices, Sweet corn