Yield response of yam (Dioscorea rotundata Poir.) to inoculation with Azotobacter and nitrogen chemical fertilization in the Caribbean region of Colombia.

• Cadena, Jorge ^[1]
  1. [1] Corporación Colombiana de Investigación Agropecuaria-Agrosavia, Centro de Investigaciones Turipaná, Cereté, Cordoba, Colombia
• Localización: Revista de Investigaciones Agropecuarias, ISSN 0325-8718, ISSN-e 1669-2314, Vol. 47, Nº. 1, 2021
• Idioma: inglés
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• Resumen

  • In previous studies, we collected roots and soils associated with yam crops (Dioscorea rotundata Poir) were along the Caribbean region of Colombia from which several strains of  Azotobacter chroococcum and Azotobacter vinelandii were identified, which in laboratory and nursery studies showed growth promotion activity in yam. In this research, we obtained from Agrosavia two of these strains (A. chroococcum DBC12, A. vinelandii DBC9) and evaluated in the field their effect, in combination with four nitrogen levels (0, 50, 75 and 100%), on yam yields and tuber quality.  In a first instance, in vitro tests confirmed the N fixation capacity and the NH3 production of both bacterial strains, while under field conditions, the highest yields were obtained by treatments that combined the individual inoculation with strains A. chroococcum DBC12 or A. vinelandii DBC9, with 50% of the recommended N fertilization. On the other hand, yam tubers were classified according to the market, and the same treatments induced the production of higher quantities of first category or export-type tubers, suggesting that these two bacterial strains were also able to increase tuber quality.  From this study it was concluded that A. chroococcum DBC12, A. vinelandii DBC9 strains have the potential for replacing up to 50% of the recommended N fertilization dose and could be included in fertilization models with small farmers, thus contributing to a more competitive and sustainable agriculture.