Studies on the Relationship Between Photosynthesis and Nitrogen Fixation in the Symbiotic System of Soybean and Nodule Bacteria( Rhizobium) Soybean Seedling Extracts Inhibit Supernodulation AN EFFECTIVE WAY TO IMPROVE SOIL FERTILITY IN TRADITIONAL AGROFORESTRY: PLANTING ALNUS NEPALENSIS Characteristics related to symbiotic nitrogen fixation of legumes in northwest arid zone of China A STUDY ON NATURAL RESOURCES OF NODULATING TREE LEGUMES AND STRAINS OF RHIZOBIA STUDIES ON THE CHARACTERISTICS RELATED TO SYMBIOTIC NITROGEN FIXATION OF LEGUMES IN HEXI CORRIDOR,GANSU Review of research advancements on the molecular basis and regulation of symbiotic nodulation of legumes