This section is coordinated by the professors from the Federal University of Pelotas-Brazil, with the objective of answering the inquiries sent by the readers.
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Verticalization - "I have been in a conference in which the term "verticalization" was used repeatedly, regarding how it affected seed producers and farmers in general. Could you please comment on this issue?"
Any seed program involves the participation of various sectors or players, if you like. Plant breeding, foundation seed production, commercial seed growers, extension services, farmers and end consumers (supermarkets) are all linked to this chain. When some of these players come together, as when the breeder, the foundation seed and commercial seed are all part of the same company, then the process of seed production is considered to be verticalized. Under this scheme, the newly-bred variety is not licensed to third parties for seed multiplication; the most important example in the seed sector is maize, which has achieved in excess of 80% verticalization, whereas for soybean more than 80% of the commercial seed is produced by seed growers that pay royalties to the varieties breeders.
Germination and emergence - "I have the habit of conducting emergence tests in soil for all the seed lots I purchase. It is a common trend that the percentage of emerged seedlings is lower than that of germination, and at times, much lower. What is it that causes these differences?"
The germination test is carried out under optimal conditions, standardized throughout the world by the International Rules for Seed testing (edited by ISTA), to favor seed germination. The emergence test is carried out in field conditions and it is not standardized, which is why, under the best environment, the percentage value for emergence may be equal to that of germination. The most common situation is for emergence values be lower than germination, and when the seed is of low physiological quality, the difference is even larger.
Capital - "I know that seed production involves various factors, among which, the financial resources. I would like to have an idea of the amount of rotating capital necessary for seed producer."
This is no easy subject for a clear-cut answer; however, to come up with an estimate the items to consider are production costs, processing, quality control, advertising and marketing costs. It is sensible to consider a minimum turn over period of 18 months, since the seed producer normally collects his sales after the grower harvests his produce. This period between collecting the amount for the seed retailed and the initial investment can be considered that necessary for rotational capital, and must be included within the seed cost.
Spiral separators - "We are presently grading soybean into two or three sizes, after going through the spiral separator. I would like to know if seed size is a factor that can interfere on the separator's performance."
The spiral separator works based on the seeds' or grains' capacity to roll, so that the larger or rounder the material, the higher will be its speed through this device. Likewise, a large soybean seed will run easily through the separator so in some cases a device that slows the passage can be mounted onto the spiral, so that the larger seeds won't go out the separator at the first coil. This being said, it would be a sensible step to grade seeds before they enter the spiral since their size does have an effect on the separating efficiency.
Drying - "I have four operative intermittent dryers, two of which are fed from a direct heat source and the remaining two, are fed indirectly . While indirect heating demands 14 operational hours for a soybean seed load to dry from 18% to 13% moisture content, with direct heating I'm able to dry two loads per day. How could I possibly increase the capacity of the two indirect-heat dryers?"
In general, intermittent dryers are capable of drying more than one percentage point per hour, so that if this is not happening something must not be functioning properly. What may be happening in your case is that, the indirect heating oven is not being fed the appropriate volume of air, which causes that a minimum volume of cool air, be enough to substantially decrease the heating air's temperature. As you know, drying speed is a function of airflow through the seed and temperature (relative humidity), which then combine in this case to reduce the drying speed. An appropriate measure would be for you to increase the opening of the vent that allows air into the oven.