Effect of the Application of Gluconacetobacter diazotrophicus and Its Interaction with Nitrogen and Phosphorus Fertilization on Carrot Yield in the Field

Carrot production is expensive since approximately 51% of the total costs are allocated to the nutrition of the crop. Bacterial inoculants are a promising alternative for crop fertilization. This research aimed to evaluate the effect of Gluconacetobacter diazotrophicus on the performance of carrot cultivar "Royal Chantenay" and its interaction with nitrogen and phosphorus fertilization. An experimental design of sub-subdivided plots was applied, where the largest plot consisted of the reference strain (ATCC 49037) and a native Colombian isolate of the bacterium (GIBI029); two concentrations of the bacterium were applied in the subplots (8.8 x 10(7) and 18 x 10(7) CFU/mL), and the levels of nitrogen and phosphorus were sorted within each one of them. The best positive effect was observed with the application of G. diazotrophicus ATCC49037 and GIBI029 at a concentration of 18 x 10(7) CFU/mL without the application of phosphorus or nitrogen in which yields of 37,417 and 30,606 kg/ha were obtained, respectively, exceeding the national average production in Colombia. In contrast, conventional treatment had a yield of 27,909 kg/ha. Additionally, higher quality was evidenced in the product weight with values of 126.48 g (ATCC49037) and 104.98 g (GIBI029), compared with the conventional treatment (93.19 g). G. diazotrophicus was shown to exhibit growth-promoting properties not only in crops such as sugarcane but also in economically important vegetable crops. The results obtained may contribute to the development of a novel microbial inoculant for vegetables under agroecological conditions in tropical areas.