11 December 2019

Hybrid maize seeds. Detasseling

Last July we were visiting the Steyr tractor factory in St. Valentin (Austria), as we have already told you in this article. On the second day, we were lucky to go to the field where we were able to test several Steyr tractors. A Vermande machine arrived to a plot nearby the event to cut the tassel of maize plants, so we took the opportunity to see it since it is an unusual job for us.

The corn plant has a male part (tassel) and a female part (ear). The male inflorescence (tassel) normally becomes visible among the last leaves of the plant, 7 to 10 days before the styles of the female inflorescence appear. Usually, 2 to 3 days before the pollen release takes place, theearsreach their maximum size and this is completely unfolded, so the plant reaches its final height. The tassel is composed of a central stem, which corresponds to an extension of the stem of the plant. In this stem is developed a spike, under which several fine branches of feathery aspect are originated that correspond to lateral spikes. When the time comes, the pollination process begins, with the pollen falling from the top of the plant (tassel) to the middle part of the plant where the female part (ear) is located. This would be a natural or open pollination process. In the fields of hybrid seed generation, this process is altered in the following way that we will show you in the next paragraphs.

The fields we saw in Austria are used to produce hybrid seeds. In this field, two varieties of maize were sown. The sowing system is by means of a 6 furrow sowing machine; having one seed variety in the 4 central furrows and the other seed variety in the two outer furrows. In this way, the field is planted with 4 furrows of one variety and two furrows of another variety. To the variety that is used in the 4 central furrows, the tassel is removed to have a much more controlled pollination. The plants in these furrows, from which the tassel has been removed, are pollinated by the plants in the furrows that have the tassel (of a different variety), so that hybrid seeds are obtained by being pollinated with different varieties.

The most common corn sowing frames for hybrid seed generation are 6:2, 6:1, 4:2, or 4:1. For example, for frame 4:2, it would be 4 female furrows, which are the rows from which the tassel is removed (male part of the plant) and 2 male furrows (rows that are used to pollinate plants that have run out of tassel).

Hybrid maize produces much higher yields than maize produced by open pollination, as well as other important features such as resistance to disease, drought, climate, etc. In the case of modern maize seed, the varieties to be hybridized are carefully selected so that the new variety shows specifictraits found in both mother plants.

Versión en español.



28 November 2019

Sowing days 2019. Disc or coulter, which do you prefer?

Direct sowing is absolutely established in many areas of Spain and it is already a fact because almost all the farmers’ who practice this sowing technique are really satisfied with the results obtained. Therefore, we do not understand why it is not fully consolidated in all areas... the key might be that all areas do not have the same characteristics of soil, climatology, etc. or it may be even be due to the farmers’ culture, as it is necessary to be open-minded and willing to change. Some farmers stay halfway and do minimal tillage, which can also be a good solution.

As we have already said in several articles dedicated to sowing, in our area nobody practices direct sowing, so we went to talk to our friends Fernando (from Medina de Rioseco - Valladolid) and Daniel (from Barchín del Hoyo - Cuenca). Our two friends are great farmers, with large farms of hundreds of hectares in extensive crops that have practiced direct sowing for several years. The conclusion they draw is that the results are very similar to those of traditional sowing and the costs are much lower, especially costs in agricultural machinery and time because the soil preparation task are eliminated and the tasks are limited to sowing, fertilizing and spraying.

One of the dilemmas for the farmer who wants to do direct sowing is the choice of the seed drill machine and, therefore, whether it is with disc or coulter... this is the key piece in this sowing technique. Fernando works with a Gil disc seed drill machine and a Solá coulter seed drill machine. In its field, the disc sower works much better because it does a perfect conservation of the surface layer of soil where the seed is left (the disc opens the soil, deposits the seed and closes; this is a similar operation to that performed by a scalpel). Fernando observes that the seed drill machine with coulter breaks the soil more and in its fields the seed takes longer to germinate.

On the other hand, Daniel tells us that for him the seed drill with coulter is ideal, as they tend to have a lot of clay soil and when sowing, if it is wet, the disc does not work well. Another problem they have is that when the straw (which is chopped by the combine harvester and incorporated as organic matter into the soil) has not decomposed well and is wet, then, the disc is often not able to stick into the soil and the seed remains too shallow. Needless to say, for terrains with a lot of stone, coulters work much better by penetrating better between the stones than the disc.

As we said, the costs are usually lower because the soil preparation tasks are completely removed. It is true that the use of herbicides to control weeds increases, so it is necessary to have a control of its use to not increase costs and pollution. Daniel does an herbicide treatment just before sowing in order to eliminate the few weeds that have been able to be born with the autumn rains. If it does not rain, the recommendation is to wait for the rains or sow as late as possible in order to do a purge of weeds before the sowing.

Versión en español.