Nutritional aspects and yield of corn intercropped with cover crops and inoculated with diazotrophic bacteria

Vagner Nascimento^1*Samuel Ferrari¹Ronaldo Cintra Lima¹Carolina Dos Santos Batista Bonini¹Evandro Prado¹Fernando Shintate Galindo¹Jorge João Delfim¹Orivaldo Arf²Loiane Fernanda Romão de Souza²Mauricio Andrés Molina Roco³Borja Vel Ásquez Martí⁴Shereen Korany⁵Emad Alsherif⁶Arshad Jalal⁷Marcelo Minhoto Carvalho Teixeira Filho^2*

• ¹Faculdade de Ciências Agrárias e Tecnológicas, Universidade Estadual de São Paulo, Dracena, Brazil
• ²Faculty of Engineering, São Paulo State University, Ilha Solteira, Brazil
• ³University of Los Lagos, Osorno, Los Lagos, Chile
• ⁴Universitat Politècnica de València, Valencia, Valencia, Spain
• ⁵College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
• ⁶Faculty of Science, Beni-Suef University, Beni-Suef, Cairo, Egypt
• ⁷King Abdullah University of Science and Technology, Thuwal, Saudi Arabia

Intercropping corn with cover crops and inoculating with diazotrophic bacteria are sustainable lowcost practices that enhance nutrient cycling and uptake, leading to improved crop yield. Thus, this study evaluated the effects of monocropped corn versus intercropping with cover crops alongside foliar inoculation with Azospirillum brasilense. The experiment was conducted during the autumn-winter season in Dracena, within the Nova Alta Paulista region, Brazil, using a sandy-textured dystrophic Ultisol. The experiment was designed in a randomized blocks in a 4 x 2 factorial scheme, having four replicates. The treatments consisted of the cultivation of corn alone and intercropped with cover crops (Crotalaria spectabilis, Urochloa ruziziensis and C. spectabilis + U. ruziziensis) in the presence and absence inoculation with Azospirillum brasilense via foliar spray at crop growth stage V4. The inoculant contained strains AbV5 and AbV6 of A. brasilense (2 × 10⁸ viable cells mL⁻¹) applied at 500 mL ha⁻¹. Intercropping corn with U. ruziziensis under inoculation, as well as corn with C. spectabilis + U. ruziziensis, regardless of inoculation, significantly increased grain yield in the second year. The corn intercropped with C. spectabilis irrespective of inoculation enhanced relative leaf chlorophyll content at the V4, V8, and R1 stages. In addition, intercropping corn with U. ruziziensis also enhanced leaf phosphorus (P) content while reducing sulfur (S) content. These findings suggest that farmers can optimize corn production by intercropping with Urochloa ruziziensis and Crotalaria spectabilis alongside diazotrophic bacterial inoculation to improve nutrient use efficiency and corn nutrition while reducing reliance on synthetic fertilizers and supporting low-carbon agriculture.