Wageningen, The Netherlands
April 24, 2008
Asparagus plants that retain
sufficient sugars in their roots after harvesting survive the
harvest better and are more productive in the next season. By
contrast, when asparagus plants are cut too long, the sugar
level is depleted and the quality declines. In the middle of the
Dutch asparagus region, the
Wageningen UR station in
Vredepeel is working on a computer programme to advise Dutch
asparagus growers on the best possible moment to stop
harvesting.
Starting asparagus harvesting as early as possible is one thing,
but it is quite another to reliably stop harvesting at the most
opportune moment.
Asparagus are basically stems that are still under the soil,
without any leaves above. This is why growing asparagus stems
costs the plant such an enormous amount of energy. Plants have
to store that energy in their roots during the previous year,
which is why growers cannot just continue harvesting the stems.
Cutting too long means that there will be insufficient energy
left in the roots to obtain enough stems above the ground. These
stems grow needles (the leaves) that the asparagus plant uses to
create sugars, which are then stored in the roots to be used
during the next season.
The traditional saying that asparagus should not be cut after 24
June, Saint John's Day, no longer applies. Growers are able to
start harvesting much earlier in the year than was previously
the case. This is made possible, for example, by using the
residual heat of an energy unit to heat the soil. What has not
changed, however, is the need to stop cutting at the right time.
Farmers aim to stop at the optimal
moment: not too late and not too soon.
The sugar level of the roots is therefore a key factor in the
vitality of these plants. Unfortunately, the sugar level as an
absolute value is an insufficient indicator of when to stop
cutting. The main indicator is the reduction in sugar levels,
which is why Wageningen UR is partnering with the Geisenheim
Research Station in Germany to develop a computer programme that
will assist Dutch asparagus growers in determining the precise
moment to stop cutting. The growers regularly measure the sugar
level of the roots with a simple device, which does not take
much time.
Based on the results, the computer programme gives advice on
when to stop cutting asparagus.
The computer programme is called Aspire and will be tested on
ten Dutch asparagus farms during the 2008 season. The
researchers expect that this pilot will offer a sufficient basis
for widespread use in the 2009 season.
The Plant Sciences Group of Wageningen UR is a collaboration
of:
- Plant Research International B.V.
- Applied Plant Research (Praktijkonderzoek Plant & Omgeving
B.V.)
- Wageningen University |
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