Pre-germination
Pre-germination (also priming and germination stimulation ) describes the activation of the germination process before sowing. Pre-germination is a common procedure, especially for new potatoes and vegetable seeds. Above all, it serves for a faster and more even emergence after sowing .
Effects inside the potato tuber
Under the influence of light, the potato tubers form glyco-alkaloids such as solanine , which reduce diseases on the seedlings.
In tests by the Chamber of Agriculture in North Rhine-Westphalia , the emergence of tubers that had not germinated in years with poor seedlings was significantly reduced, in one year even up to 60%. Pre-germinated tubers always opened up almost completely. The pre-germination favors the entire plant development. Pre-germinated tubers emerge up to 14 days earlier than non-germinated ones. This lead in growth leads to faster tuber formation. If the stocks especially in organic farming by the Krautfäuleinfektion collapse, the pre-germinated varieties have already made a safe return.
But even if there are no yield advantages in years with lower late blight infections, a healthier plant tuber and a faster maturity remain. After pre-germination, the tubers are harder to peel and can be harvested earlier. This has advantages for problems with Rhizoctonia , dry-core and wireworm damage . The longer the tubers remain in the ground, the greater the losses.
Procedure on potatoes
The optimal illuminance was determined at the Institute for Organic Agriculture (IOL) in Bonn. It was shown that warm-tone lamps produced the most stable and shortest germs at an illuminance of 200 lux. Pre-germination should begin about 4 to 8 weeks before planting. In the case of germinating varieties, a heat surge of approx. 20 degrees Celsius over 2 to 3 days is advantageous. With careful treatment of the germs that have arisen, yield advantages of around 10% on average can be achieved, in individual cases up to 40%.
The potatoes should be pre-germinated in white pre-germination boxes . These are usually made of plastic grids and hold around 10 kg of potatoes in 2 layers. The raised corners leave an air space between the boxes, which also improves the lighting. Heating up large boxes and big bags is not suitable for stimulating germs. The temperature difference in the pile of tubers causes condensation to form, which means that putrefactive diseases such as Erwina and diseases such as silver scab can spread quickly. Dark germs can form in the middle of the lot. The result is a poor and inconsistent field emergence. As an alternative to the pre-germination boxes, pre-germination bags are available. 10 pieces of these flat sacks hang on a frame and each hold around 100 kg. The racks are transported with a forklift and can be filled by machine. They can be opened in a few simple steps and thus filled into the potato planter.
The tuber base is determined with the pre-germination temperature:
- Low pre-germination temperatures of around 6 degrees Celsius promote the secondary shoots and thus a high number of tubers. The result is less cropped crops. Mainly used in the production of seed potatoes or for large varieties with a low tendency to build-up (such as Agria ). The pre-germination time is then more than 8 weeks.
- The apical dominance is promoted by higher temperatures of around 12 degrees Celsius , i.e. H. the main instinct suppresses the formation of secondary instincts. This results in a smaller set of tubers and thus a greater sorting of higher-growing potato varieties such as Krone , Granola , Melina and Nicola .
With the appropriate humidity, ring bacteriosis is limited and the temperature effect is increased. A relative humidity of 80 to 85% is optimal.
The machines with tipping bunkers that are common today are less suitable as potato planters due to the risk of damage. Belt planting machines or roller bunkers are a suitable alternative.
Germinate
If the germs appeared too early or got too long, they can be removed. This will encourage a second multiple germination. Germination should only be used as an emergency solution. In general, it is well tolerated by varieties with long hibernation and long incubation periods. Requirements for germination are:
- Early germination and apical dominance.
- Observe a waiting period of 2 to 3 weeks between germination and planting
- Do not germinate below 8 - 10 ° C.
- Avoid damage.
- Then continue to pre-germinate at 15 to 18 ° C, little light and high humidity.
This promotes multiple germination.
Thermal shock
As an alternative, the potatoes are briefly heated to temperatures around 15 degrees Celsius. However, since the potatoes cannot adapt so quickly, the tuber formation occurs later than with normal pre-germination.
costs
For potatoes, the costs are between 200 and 600 euros per hectare, depending on the technical effort and the equipment available.
Web links
- Photo of pre-germ bags
- Agriculture Mecklenburg-Western Pomerania: Test results (PDF; 56 kB)
- Potato producers.ch
Individual evidence
- ↑ rijkzwaan.nl on Priming of Vegetable Seeds (PRPM) ( Memento of the original of October 26, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Nivaa.nl ( Memento of the original from October 14, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ oekolandbau.nrw.de ( Memento of the original from January 24, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ naturland.de ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 270 kB)
- ↑ Agrigate.ch ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 313 kB)
- ↑ Oekolandbau.nrw.de Efficiency and economy of pre-germination ( memento of the original from December 28, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
