Maize yield response to bio-inoculation and chemical fertilization reduction under field conditions
Soil microorganisms often play a strong ecological and economic role in agricultural production systems. In this study the agro-biological response to inoculation or co-inoculation of arbuscular mycorrhizal fungi (AMF), rhizobacteria (Azospirillum brasilense, Ab), and reduced dose of inorganic fertilizer (IF) on maize (Zea mays L.) crop was evaluated under f ield conditions. This study was conducted within the experimental f ield La Bandera in the municipality of Actopan, Veracruz, Mexico, property of the School of Agricultural Science, Universidad Veracruzana, Campus Xalapa (FCA-UV). The evaluated treatments were: T1: (Traditional management of the producer (control group), TM) with total inorganic fertilization (100% IF); T2: (inoculation of the AMF); T3: (inoculation of Ab); T4: (co-inoculation of AMF + Ab); T5: (inoculation of AMF + 50% IF); T6: (inoculation of Ab + 50% IF); and T7: (co-inoculation of AMF + Ab + 50% IF), analyzing plant height (cm), length and width of the flag leaf (cm), stem diameter (mm), arbuscular mycorrhizal colonization percentage, colony forming units (CFU) and total maize grain production (kg). These variables were analyzed using one-way analysis of variance (ANOVA) and the post-hoc Fisher's Least Signif icant Difference (LSD) test with a signif icance level of 5% (α = 0.05) for comparison of means. The results indicated signif icant differences between the treatments (Fisher’s LSD, P ≤ 0.05) for height, flag leaf length and width with increments of 75.59, 75.43, and 28.68% in the AMF + Ab + 50% IF treatment compared to the control group. For stem diameter (44.73%) and grain weight (74.21%), the Ab + 50% IF treatment showed increased presence of CFU·mL-1 (198). The positive interactions between AMF and Ab had a higher percentage of mycorrhizal colonization (62.7%) compared to the other treatments. The best results were observed in the majority of the variables evaluated where these microorganisms interacted in reduced fertilization dose (AMF + Ab + 50% IF).