This section is coordinated by professors from the Federal University of Pelotas/Brazil, with the aim of answering enquires sent by the readers. Send your questions to

    The seeds should be prepared so that sowing can be made easely and not contaminating our fields with weed seeds. In this sense, I wondering if you could tell me, what are the main machines used for processing  seeds.

    There are several machines available for cleaning and grading seeds and its choice will depend on the undesirable materials that are together with the seeds. The basic machine of all seed processing units is the air screen cleaner, however, there are also other important ones, such as the gravity table, spiral, cylinder and the screens to grade the seeds according to width and thickness.

    I have been observing that SEEDnews has published some articles with companies that are providing in the market, soybean seed lots with germination over than 90%. In what is based the process of production and post-harvest technology that provides this confidence from these companies?

    For sure, what is good must be released and promoted. To obtain soybean seed lots with germination over than 90% involves the use of high technology, with a good program of internal quality control. Some of the high technologies used by companies is to harvest at the right time combined with adequate seed artificial drying, use of equipment to minimize seed mechanical damage and the use of cold, for storage.

    We know that it is possible to commercialize some forage seeds with a purity of 60%, according to the last SEEDnews. However, I wonder what should be done so that this pattern is at least 98%, as in major crops.

    There is technology and equipment for cleaning the seeds in such a way that the lot purity, almost from any species, be at least 98%. The situation is that whoever is buying the seed, is not giving much importance to this quality attribute. The trend, however, is that this pattern gradually rises, until it reaches the standard from the other crops. After experiencing a good product, people can better distinguish what is from an inferior quality.

    I am in the process of buying a dryer, but I am having some doubts about the capacity of the dryer, as there are several types on the market.

    There are, actually, several types of dryers, such as the stationary, in which the seed remains stopped throughout the drying process, and the intermittents, in which the seeds are in constant movement. For the stationary it should be considered around a load of dryer per day, while for the intermittents we may consider, an average of three loads of dryer a day. Thus, knowing the static capacity of the dryer, we can determine the amount of dry seeds per day.

    The mechanical damage is a serious thing in the production of soybean seeds. How can I deal with it, in order to be minimum in the harvesting process?

    All seeds have three essential parts: the embryo, which will result in a new plant, one part for the reserves and the coat. The harvest is the production stage that, usually, causes more damage to the seed. Thus, we should adjust the combine carefully, so that the damage is minimal. The combines that thresh the seeds in an axial flow tend to damage less.

    In the seed treatment process, I note that some seeds hold better the products. Could you comment on that?

    The seeds of canola and soybean, for example, have a waxy layer on the seed coat, causing the products to better add the seeds. However, fortunately, there are those polymers which have a characteristic that fixes the products of the treatment to the seeds.



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