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Maturing
and harvest
Since
the maturing process and the harvest method have a great influence
on the quality of the products, they deserve special notice.
Principally,
the transition to the sprouting resistance phase starts with maturity.
This is the beginning of the transition to the second, generative
year and serves for the overcoming of unfavourable weather periods.
The
negative influence of physical disturbance factors on storage life
demands that the majority of the harvest and preparation works have
been finished when the sprouting resistance begins. The onion is
then solid and dry, the neck narrowly and dryly constricted (as
a protection against diseases).
The
maturing phase is introduced by the cut off of the sap supply, especially
upwards. The onion neck becomes soft, drops over, becomes shriveled
and begins to "pull-in". The most favourable time for the harvest
is when aprox. 60% of the leafage has fallen down. To accelerate
the drying process, the leafage is cut down on a neck length of
5 - 10 cm by leave cutters and the onions are immediately collected
by disk and riddle chain diggers and arranged in the rows. Too long,
dry leafage that remains on the bulb impedes the ventilation of
the stocks, requires more laborius sorting, and not least, delays
the drying process and thus prolongs the harvesting process.
When
the weather is unfavourable and rainy, the natural drying in rows
of the so-called one-phase harvest can be replaced by an artificial
drying process, which, when handled correctly, nowadays leads to
comparable results as the "ideal" drying on the field.
The
onions remain in rows on the field or in the artifical drying installation,
until the neck and the root are completely pulled in and constricted.
Only when this process has been finished, the onions are taken to
the long-time storehouse or prepared for the marketing. The choice
of the harvest method depends on the factors soil and climate as
well as on the variety (spring or autumn sown onions, regular maturing
of the hybrids), on the existing machinery (harvest-, drying- and
storage capacity) and on the marketing method (immediate sale, storehouse,
central marketing) and must be determinded individually.
More-phase
harvest, i. e. cutting off of the leafage, collecting and arrangement
in rows, drying in the field, collecting and storing, is recommendable
in warmer regions with relatively stable climate.
Single-phase
harvest, i. e. immediate loading after collecting, artifical drying
and storing or marketing is recommendable in regions with instable
and rainy weather.
When
the onions are put in rows on the field it is absolutely necessary
that they are kept as dry as possible. This means that after rainfalls
they should be turned over one or two times by riddle chain machines.
When the weather is generally warm and dry, one or two rainfalls
do no harm to the onions on the field. They may even destroy hard
clods which otherwise would damage the bulbs during the loading
and preparation process and, thus, make it necessary that the onions
are sorted a second time.
For
the placing in rows, and the loading on the cart or in boxes nowadays
combiners, reconstructed potatoe diggers and other methods are used.
The most careful method should be applied.
Height
of fall and shocks by hard edges must be limited as far as possible
by the corresponding measures such as catching bags and clothes,
paddings etc. It goes without saying that onions that are damaged
mechanically or by diseases mustnīt be put in the storehouse or
on the market.
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Onions
