Biofertilization with Gluconacetobacter diazotrophicus: Effects of a Native Isolate and a Reference Strain on Soil and Foliar Chemical Profiles and Economic Performance in Greenhouse Tomato Production
The intensive use of synthetic fertilizers in horticulture generates environmental and economic constraints, highlighting the need for sustainable alternatives such as plant growth-promoting bacteria. However, their effectiveness depends on strain adaptation to local conditions. This study evaluated the effect of Gluconacetobacter diazotrophicus (native isolate GIBI029 vs. reference strain ATCC 49037) under four nitrogen (0 and 100% of the recommended dose) and phosphorus (0 and 100% of the recommended dose) fertilization combinations on soil chemical properties, foliar nutrient uptake, and economic performance in greenhouse tomato production in Colombia. The native isolate was associated with higher soil nutrient levels, reaching 185.1 g/kg organic matter, 6.4 g/kg total nitrogen, 284.75 mg/kg available phosphorus, 9.32 cmol/kg calcium, and 3.93 cmol/kg magnesium. In addition, foliar nitrogen content reached 22.4 g/kg in treatments inoculated with GIBI029. These responses were associated with yields up to 106.4 t/ha, exceeding those obtained with the reference strain. Yield data were obtained from a previous study conducted under the same experimental design and environmental conditions and were incorporated here exclusively for the economic assessment. Economically, the native isolate achieved the highest benefit–cost ratio (2.65) and net income (USD 20,106/ha). A strong correlation between soil organic matter and nitrogen (r = 0.99) was observed, indicating a close association between these variables within the evaluated production system. These results suggest that strain origin may influence biofertilization efficiency and indicate that native microbial inoculants can contribute to improved agronomic and economic performance under the conditions evaluated, supporting their use in sustainable tomato production systems.