ISHS Acta Horticulturae 187: I International Symposium on Mechanization of Vegetable Production
NEW APPEARANCES OF SEEDS AND DIRECT DRILLING TECHNICS FOR ONIONS |
| Author: | E.C.N. Meijer |
| Abstract:
Onions are an important crop for the Dutch arable farmer. Drilling of onions has never caused any problems in the past. Eversince sugar-beets are drilled with single seed drills, onion growers showed interest for this kind of drilling technic. Research results carried out in the mid sixties showed the advantages of direct space drilling. Grading seeds and matching seeds and metering mechanisms was a necessity however. There was no organization like the sugar industry to dictate the dimensions of the seed. That was the reason that precision drilling of onions never led to exceptional results. Both graded and ungraded seeds were drilled with precision drills. It was even so that in a certain year 60% of the total area was drilled with precision drills and only 15% of the seeds were graded. This was the main reason that a Dutch pelleting firm decided to produce onion pellets not only to come to a higher level of precision in seed distribution but also to offer possibilities of incorporating insecticides. The latter gives a more accurate application of the chemicals and prevents over and under dosing. Inevitable was however a higher price for the seeds. Inevitable also was the provocated competition between seed firms on the one hand and machine and machine manufacturers on the other hand. We as Research Institute offered for both parties the possibilities of sticky belt research. We have a fully automatic sticky belt at our disposal. Seeds falling from the drill unit, mounted over a running belt, get stuck in an oil layer. After 25 meter belt has been sown the belt stops automatically. The seed distribution can than been inspected. Seed damages, doubles, etc. can hardly be inspected better than with the human eye. During rewinding the belt the seeds pass an optical transducer and are detected by it. A second transducer generates a pulse through a slotted disc when 5 mm of the belt has passed. This signal is also used for the calculation of the driving speed of the "drill". The seed spacings are classified in 64 classes. After a complete belt is measured the data are worked out with a micro-computer. The precision drill most commonly used for onions was of the metering wheel type and thus grading of the seeds was a necessity. Once manufacturers of machines have chosen for a certain dimension of the wholes in the cellwheels seedfirms can match the seedgrading to the size of the wholes in the cellwheels. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
