References

Adams MH (1959) Bacteriophages, Wiley-Interscience Pub. Inc., New York

Radwan MA (2000) Influence of Rhizobiophage on Competition Between Root-Nodule Bacteria,

Ph.D Thesis, Fac. Agric. Zagazig University, Egypt Vincent JM (1970) A Manual for the Practical Study of Root-Nodule Bacteria, IBP Handbook No. 15, Blackwell Scientific Publications, Oxford, UK

TAGTEAM : THE DEVELOPMENT OF A COMMERCIAL DUAL INOCULANT TO ENHANCE N-FIXATION AND INCREASE AVAILABILITY OF SOIL PHOSPHATE

Philom Bios Inc., 318-111 Research Drive, Saskatoon, SK, S7N 3R2 Canada

Phosphorus plays an important role in symbiotic Nj fixation, and legumes generally require more P for optimal growth and development than non-legumes. The benefit of inoculating seed with both a nitrogen-fixing and a phosphate-solublizing inoculant was first demonstrated in Philom Bios small plot field trials in 1989 (Gleddie 1992). In 1994, Wendell Rice and Perry Olsen successfully co-cultured the phosphate solubilizing fungus Pénicillium bilaii with Rhizobium meliloti in a sterile peat carrier (Rice et al. 1994). This work instigated the development of TagTeam for pea/lentil, the world's first commercial dual inoculant.

The product development process began with a pre-project analysis of the potential of the concept. This led to the definition of the key steps and major milestones which would become the project plan. The initial research involved the development of a solid state fermentation protocol for the co-culture of Rhizobium leguminosarum and P. bilaii using sterile peat as the substrate. The challenge was to identify the optimal growth conditions that would result in the appropriate titers and proportion of both organisms in a 28 g bag. The specific requirements for nutrition, pH, available oxygen, incubation temperature, moisture level, inoculum type and carrier type were identified. The stability of the resulting product was then determined under a number of different storage conditions and the packaging was designed for optimal shelf life. Collaboration with the manufacturing sector of the company resulted in the scale up of the product to 2200 g units (bags) and the development of a standard operating procedure to supply introductory market volumes. Philom Bios internal product specifications were defined and a Quality Assurance program was developed to confirm these, as well as the specifications set by the Canadian Food Inspection Agency (CFIA). The product prototypes were tested for efficacy in small plot field research. Inoculation with both organisms significantly increased grain yield as compared to inoculation with R. leguminosarum or P. bilaii alone. TagTeam was registered with the CFIA in 1995.

Further characterization of the product led to the development of a set of use guidelines which included inoculant compatibility with seed applied pesticides. Ongoing optimization of the product continues in terms of testing for compatibility with new chemicals and new strains and improving manufacturing efficiencies to lower the cost of production and increase volumes. Additionally, the platform technology is being used to develop dual inoculants for new crops and using new formulations.

The development of a high quality peat based dual inoculant was made possible only by the effective collaboration among all key areas in the product development process.

References

Gleddie SG (1992) M.Sc. Thesis in the Department of Soil Science, University of Saskatchewan,

Saskatoon, SK, Canada Rice WA et al. (1994) Soil Biol, and Biochem. 27, 703-705

THIRTEEN YEARS OF HEAD-TO-HEAD COMPARISONS OF SOYBEAN INOCULANTS

Department of Plant Agriculture, University of Guelph, Guelph, ON, NIG 2W1, Canada

1. Introduction

Since 1988, our research group has been conducting "Head-to-Head" comparisons of commercial and pre-commercial soybean inoculants in Ontario. The first trials had six inoculants from four manufacturers. In 2000, the trials had 19 inoculant/application method combinations from five manufacturers. This poster presents some of what we have learned from 13 years of trials.

2. Materials and Methods

The Head-to-Head trials have been conducted on land which had not previously grown soybeans and so did not have existing populations of Bradyrhizobium japonicum. Bicentennial was the soybean cultivar used from 1988 to 1989 while Maple Glen was used from 1990 to 1995. The current variety, Bayfield, was first used in the trials in 1996.

In recent years, conventional tillage trials have been planted using Planet Junior units on a toolbar. The plots contained 7 rows and were 2.5 meters wide and 6 meters long. Compressed CO2 was used to apply in-furrow inoculant treatments. Since 1997, the trials have also been planted using no-till techniques with plots containing 8 rows that were 3 meters wide and 12 meters long. Nodules were sampled from 5 adjacent plants in row #2 at the start of flowering and at the start of the pod-filling period. Nodules were counted and then dried for determination of mass. Color differences were often evident in the uninoculated plots by the second nodule sampling. Plots were machine harvested and seed samples were analyzed for oil and protein content.

3. Results

Average yield responses range from over 30% to about 15% for the various inoculants. Until about 1995, sterile-carrier, powdered-peat inoculants were the top performers. Since then, performance has been in the order: liquid in-furrow sprays > seed-applied liquids > sterile-carrier powdered peats > granular inoculants > non-sterile powdered peats.

In general, high quality inoculants performed well under both conventional and no-till conditions. There are however, differences in yield levels and yield responses among locations. Seed protein concentrations are a good indicator of inoculant performance. Using a number of indicators such as nodule numbers, nodule mass, seed yield, and seed protein is necessary to comprehensively interpret the effectiveness of the different inoculants.

The magnitude of the yield responses was related to the environmental conditions as well as nodule numbers and mass. Plotting nodule numbers vs. yield response generates curves with maximums at different positions. In 1998, there was a severe drought which limited yields and yield responses to inoculants. The season in 1999 was closer to average but the responses at the no-till location were greater than at the conventional tillage location. In 2000, a wet spring resulted in late planting and early frost damaged the plants before full maturity. This again resulted in lower yields and smaller yield responses. There is no single measure of inoculant quality and performance that can predict or explain a crop's response. Multi-year and multi-location field testing will continue to be an important tool in assessing inoculant performance.

4. Acknowledgements:

Funding from the Ontario Ministry of Agriculture, Food, and Rural Affairs is gratefully acknowledged.

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