Doug Kremer President Mike Kelly Director Turf Operations
Company Background Founded in 1998 to develop microbiological products - Integrated Fertility Management (IFM) Convert atmospheric nitrogen to plant usable forms Stimulates root growth and increases yields Released first defined microbial products in 2000 Azospirillum based Agriculture and Turf Rhizobium based - Agriculture
Biological Nitrogen Fixation
The Rhizosphere Classified as the zone of soil under the influence of plant roots Due to low available carbon, the natural state of microbes in soil is starvation. In the rhizosphere, plants give off a variety of organic substances that facilitate microbial growth In return, the microbes provide a number of services for the plant: Production of plant growth hormones Solubilization of inorganic minerals Protection from plant pathogens
The Rhizosphere
Effects of the microbial community on plant growth Beneficial Soil Stabilization Water Uptake Growth Promotion Harmful Disease Nutrient Competition Microbial Competition Nitrogen Fixation Biocontrol Nutrient Availability Adapted from Maier 2004
Where Does Nitrogen Come From?
Nitrogen Cycle
Sources of Nitrogen Type of fixation N2 fixed (10 6 metric tons per year) Non-biological Industrial (Haber Bosch Process) about 50 Combustion about 20 Lightning about 10 Total about 80 Biological Agricultural land about 90 Forest and non-agricultural land about 50 Sea about 35 Total about 175 Data from various sources, compiled by DF Bezdicek & AC Kennedy, in Microorganisms in Action (eds. JM Lynch & JE Hobbie). Blackwell Scientific Publications 1998.
Microorganisms have a central role in almost all aspects of nitrogen availability and thus for life support on earth: some bacteria can convert N 2 into ammonia by the process termed nitrogen fixation; these bacteria are either free-living or form symbiotic associations with plants or other organisms (e.g. termites, protozoa) other bacteria bring about transformations of ammonia to nitrate, and of nitrate to N 2 or other nitrogen gases many bacteria and fungi degrade organic matter, releasing fixed nitrogen for reuse by other organisms. All these processes contribute to the nitrogen cycle.
Biological Nitrogen Fixation (BNF) BNF occurs when atmospheric nitrogen is converted to ammonia by a pair of bacterial enzymes called nitrogenase. The simplified formula for BNF is: Air (78% N 2, 20% O 2 ) + Protons + electrons + Energy gives Ammonia N 2 (from air) + 8H + + 8e + 16 ATP 2NH 3 + H 2 + 16ADP + 16 P
Examples of nitrogen-fixing bacteria Free Living Azotobacter Associated Azospirillum Symbiotic Bradyrhizobium Endosymbiotic Herbaspirillum Acetobacter Burkholderi
Symbiotic interaction Nodules from bacterial and plant interaction
Associative Interaction B RH = Root Hair, RS = Root Surface, B = Unattached Azospirillum Bacteria
Azospirillum Fixes Nitrogen for use by cereal crops, grasses and tuber plants
Azospirillum Bacteria Found on many plant species Close to the roots (Rhizoplane) and attached to the roots Not a nodulater
History The first species of the genus, originally named Spirillum lipoferum, was isolated from soil in the Netherlands in 1925. Forgotten for half a century, Azospirillum was 'rediscovered' in the 1970s during a search for associative nitrogen fixers in the rhizosphere of Digitaria and Zea mays in Brazil. Since then, isolation of azospirilla from roots of numerous wild and cultivated plants and from different soil types has been reported from all over the world.
Azospirillum Colonization The first step (the adsorption step), consists of a rapid, loose, and reversible binding of Azospirillum to the root. The second step (the anchoring phase), the bacteria become irreversibly bound to the root surface.
Azospirillum and root interaction, E = Zone of elongation, RH = Root Hairs
Bacterial Attachment RS = Root Surface B = Attached Azospirillum Bacteria B B
Bacterial Attachment RH = Root Hair, RS = Root Surface, B = Attached Azospirillum Bacteria B B B
Azospirillum Case Studies TAZO University Nebraska Lincoln (Data slides to come) University Wisconsin Madison Iowa State University
Case Histories Photos and testimonials of sports field users to be inserted if permitted