IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
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17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Title Compatibility with rhizobia of polymer adhesives and colourants used in preinoculated<br />
legume pasture seed<br />
Authors Elizabeth Hartley, Greg Gemell & Jade Hartley<br />
Poster Board Number 18<br />
Australian Inoculants Research Group, NSW Department of Primary Industries, Ourimbah<br />
Campus, University of Newcastle<br />
In recent years there has been an increase in commercially-produced preinoculated pasture legume seed.<br />
Nowadays, preinoculation is the incorporation of ingredients beneficial to seedlings, into a sticker solution<br />
containing rhizobia. Seed is coated then dried. Preinoculated seed is often stored for weeks or months before<br />
use. Data show that survival of rhizobia on preinoculated seed varies and is generally poor after a few weeks.<br />
Sowing preinoculated seed with nil or very few rhizobia may contribute to inadequate nodulation and possible<br />
crop failure costing the farmer in lost production.<br />
Many physical and chemical factors affect the ability of rhizobia to survive in high numbers when inoculated onto<br />
seed.<br />
This presentation focuses on ingredients such as polymers, stickers, dyes, pigments and insecticides and their<br />
compatibility with rhizobial strains when used in the commercial seed coating process.<br />
Chemical and agricultural companies who manufacture and supply such materials contributed 60 ingredients for<br />
assessment.<br />
To determine the compatibility with rhizobia, and their suitability as an ingredient in the seed coating process,<br />
each was applied at recommended rates to rhizobial broth cultures of 3 commercial strains, TA1 (white clover),<br />
WSM1325 (subterranean clover) and CB1809 (soybean). Viable rhizobia were counted after 0h, 3h, 24h and 72h<br />
incubation. 29 ingredients that were compatible with rhizobia were screened to determine their effect on survival<br />
of rhizobia when incorporated into peat slurries used to inoculate polyethylene beads as seed substitutes. Viable<br />
rhizobia on beads were counted 1h, 24h and 48h after coating. Results varied. The affect of each of the<br />
ingredients to rhizobial survival depended upon the strain, and the method of exposure of the cells to the<br />
ingredients. After 24h, 6 ingredient treatments supported better survival of rhizobia on beads than the control<br />
treatment. However, after 48h, only one ingredient promoted better survival than the control.<br />
133<br />
2011