While Dave Hula is cognizant of the potential benefits of taking care of microbes in the soil and seeks to boost their populations with additional carbon, researchers say the understanding of soil microbes and the workings of their positive interactions with crop plants is a subject still largely unexplored.
In the late 1990s, soil scientists began an earnest look at the interrelationship of plants and soil fungi and bacteria. At that time, Canadian researchers George Lazarovits and Jerzy Nowak reported many microbes congregate around the root zone (rhizosphere) because of the carbon-rich compounds shed by the plant as nutrients from the leaves are translocated to the roots and various compounds are naturally cast off into the adjacent soil. In all, the scientists say the microbes affect roots and seedlings in 14 different manners – half of which are beneficial, five are neutral to plant well-being, and only two are detrimental to the plant – infections and phytotoxicity.
Citing earlier research, Lazarovits and Nowak say there is good potential for exploiting bacterial inoculants for plant performance in areas in which newly-planted seed will be challenged by soil-borne pathogens and when they will be in a stressful environment.
In their own laboratories the researchers saw significant increases in rooting activity in potato and sweet pepper plants treated with Pseudomonas bacterial strains when compared with untreated plants. Those same Psuedomonas bacterial treatments also saw beneficial results when the crops were taken to the field.
Other beneficial results of the presence of plant-growth-promoting rhizobacteria include the apparent ability of the microbes to enhance the plant’s own disease fighting mechanisms, the Canadian researchers note.
Over the past 10 years, a number of seed and crop protection companies have turned their sights below the ground surface to further explore and exploit the natural relationships between rhizobacteria, fungi and agronomically-important field crops.