Increased yields of alfalfa (Medicago sativa)inoculated with N2‐fixing bacteria and cultivated in a calcareous soil of Northwestern Egypt

Abstract

The northwestern coast of Egypt is, for the most part, high in calcium carbonate and poor in nitrogen. Seven bacterial inoculants prepared with Azospirillum brasilense, Azotobacter chroococcum, Klebsiella pnuemoniae, with or without Rhizobium meliloti, improved alfalfa (Medicago sativa L. cultivar CUF 101) growth as measured by seven cuts per year over a 2‐year experiment period. In the first year, Azotobacter increased fresh and dry weights and protein yields of plants over the control by 25%, 27%, and 40%, respectively. Inoculation with Azospirillum increased the above measurements by 19%, 19%, and 39%, while the combination of Rhizobium and Azospirillum gave the highest increase: 50%, 49%, and 89%, respectively. No significant increase over the control was detected in the second year.