Content uploaded by Roberto Tomasone
Author content
All content in this area was uploaded by Roberto Tomasone on Feb 07, 2017
Content may be subject to copyright.
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 1
XVIIth World Congress of the International Commission
of Agricultural and Biosystems Engineering (CIGR)
Hosted by the Canadian Society for Bioengineering (CSBE/SCGAB)
Québec City, Canada June 13-17, 2010
MECHANICALLY-AIDED HARVESTING OF ARTICHOKE WITH AN
ELECTRICALLY PROPELLED PROTOTYPE
R. TOMASONE1, M. PAGANO1, C. CEDROLA1, P.F. RECCHI1, G. COLORIO1
1 R. TOMASONE, CRA – ING Council for Research in Agriculture, Agricultural Engineering Research
Unit, Via della Pascolare 16, 00016 Monterotondo (Rome), Italy, roberto.tomasone@entecra.it
1 M. PAGANO, mauro.pagano@entecra.it
1 C. CEDROLA, carla.cedrola@entecra.it
1 P.F. RECCHI, norio87@hotmail.it
1 G. COLORIO, giuliano.colorio@entecra.it
CSBE101362 – Presented at Section III: Equipment Engineering for Plant
Production Conference
ABSTRACT Harvesting operations account for as much as 40% of the total production
costs in Globe Artichoke. The edible heads are harvested exclusively by hand, machine
harvesting being hindered by an extended harvest maturity. Many passes through the
fields are required over the season to complete the job. The pickers move through the
rows cutting the mature heads and placing them in sacks carried along the field. Work
efficiency can be increased employing machinery to move the produce in the rows and
out of the field. A variety of over the row high ground clearance equipment can be
employed to aid artichoke harvest (tractor, self-propelled machinery, conveyor belt). To
improve labour efficiency an electrically propelled over-the-row harvesting prototype
was developed at the CRA-ING “Agricultural Engineering Research Unit”. The machine
is operated by the use of foot controls, so that the operator can pick artichokes while
driving over the row and accumulates produce on a wide loading platform. In field tests,
hand and machine-aided harvesting were compared. After adequate training the driver
learns to pick at the same rate of ground harvesters, thus improving the ratio of pickers on
total field workers and consequently reducing work time (h/ha) up to 40%. Time loss due
to field stops and to walking non-working distance for unloading the sacks is avoided.
The hourly productivity (n° heads/h) of the crew in mechanically aided harvest is 73%
higher than in hand harvesting. On the whole, harvesting yield is improved by a 65%.
Keywords: Harvest, Machine-aided, Cynara cardunculus.
INTRODUCTION On a global scale, artichoke (Cynara cardunculus L. subsp. scolymus
Hayek) is ranked third among horticultural crops, following tomato and potato. Italy is
the world’s largest producer of globe artichoke, accounting for almost 40% of the total
world production, with a cultivated surface of about 50 thousand hectares and total
produce of about 520 thousand tons (Istat, 2008). Puglia, Sicily and Sardinia are the three
main Italian regions, summing together 90% of surface and 60% of production. In recent
years, the surface area under artichoke cultivation has had a negative trend in Italy,
production having remained stagnant since the end of last century.
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 2
The cultivation of artichoke requires a considerable amount of manual labour for carrying
out the numerous cultural practices necessary throughout the growing season. Among
these, harvesting is the most labor-intensive activity, representing 40 to 60 percent of the
growing costs (Dellacecca et al., 1979). The harvesting period for this crop will go on for
many weeks due to the extended time over which all the flower buds in the field will
reach harvest maturity, besides the edible heads must obtain the preferred market size
before being picked. The differences among plant growth rates in the field and the
differences among artichoke varieties adopted by farmers may furthermore accentuate the
extension of the maturation period. Artichoke harvest involves high labour need,
furthermore, for the reason that the same field must be harvested frequently, especially
during the peak season going on from March through May, for a total of more than 15
passes before the harvest is completed.
Artichokes are harvested entirely by hand, cutting the edible heads from the plant with a
knife, also paying a special attention for safeguarding the new buds coming out of side
sprouts. The head can be harvested leaving either a short or a long stem, meaning with
less or more leaves. With the long stem product, measuring up to 25 cm, harvesting
operations and product transportation are more complicated because of the bigger
volumes of vegetation and the higher working time involved (Panaro, 1982).
Crop management and cultivation techniques show a great variability between different
Italian growing locations. Artichoke farms differ for total surface extension, field
dimension, row length and plant spacing. Other important differences are related to the
characteristics of road network of farms, the distance from field to the processing
facilities. All of these aspects are important for choosing how to handle the produce and
the type of farm mechanization needed, in particular for machine-aided harvest.
MATERIALS AND METHODS Since the 1980’s, agricultural mechanization research
has worked to achieve prototypes for integral harvesting of artichoke, but no applicable
solution has been produced yet (Arrivo et al., 1979; Arrivo et al., 1979). The analysis of
the harvesting techniques used mostly in the main Italian artichoke growing areas,
showed a lot of technical and economic aspects that could be improved adopting new
technologies (Colorio et al., 2007). Working on these topics, researchers at the CRA-ING
(Italian Council for Research in Agriculture - Agricultural Engineering Research Unit)
have designed, constructed and conducted experiments with an electric traction prototype
that can optimize the employment of manpower for harvesting artichokes.
Small farms largely harvest by hand, without using any machinery inside the planted
field. Vehicles are used along the headland for transferring the produce towards the
processing facilities. Field crew workers carry out two distinct duties: some of them will
pick the buds and others will move the product out of the field employing shoulder
carried packs (Fig. 1). Alternatively each worker is independent, having his own sack for
carrying along the buds. When the sack is full, the worker will walk to the end of the row
for unloading. Product may be stored either in bins, previously located at each end of the
planted field, or it could be accumulated on the loading platform of a vehicle, for further
transportation.
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 3
Figure 1. Traditional hand harvesting.
The agricultural machinery mostly used by artichoke growers in Italy are particular “over
the row” tractors, designed with a very high ground clearance for carrying the produce in
line (Fig. 2).
Figure 2. “Over the row” tractor with rear and front frames to hold bins.
By any means artichokes are harvested by hand while the workers walk along the rows,
picking out the mature buds and cutting them off the plant. Workers then accumulate the
gathered artichokes on the containers carried by the tractor. Different kinds of containers
can be used for transporting the crop. Working time can be optimized using more than
one tractor at a time, that can alternate in the field, so that an empty one will immediately
replace the fully loaded tractor leaving the field. With this kind of organization, inactive
periods for field workers, due to tractor transfer for unloading, will be avoided.
This harvesting method employs tractor drivers and field workers. Driver obviously don’t
pick artichokes. If the total productivity of the field crew (intended as the personnel that
actually picks the product) is divided by the total number of workers involved, the
resulting per capita yield is progressively reduced as the number of non picking workers
increases. To improve the ratio between harvesting personnel and total crew members,
with the aim of reaching a value closest to 1, researchers at CRA-ING developed the
electric traction prototype so that the driving and picking tasks could be performed
contemporarily.
The new prototype has a functioning principle that is derived from a commercial electric
traction vehicle used for harvesting asparagus, the same concept was also used by the
manufacturer for harvesting zucchini (Fig. 3).
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 4
The first tests for harvesting artichoke with a mechanical aid were carried out using the
commercial zucchini harvester. The commercial model was purposely modified for the
tests, a tipping container was added in the back end of the machine, made with a steel
frame and fabric walls, for accumulating the produce. The self moving frame had two
seats placed on both sides and aligned with the wheels. The vehicle had two rear drive
wheels powered by electric motors and two front steering wheels, moved by foot
controls. As the machine moved through the rows, the two workers picked the buds from
the row in the middle and from the two side rows (Fig. 4).
Figure 3. General view of the zucchini harvester arranged for harvesting artichoke.
Figure 4. Zucchini harvester moving through the field in harvest.
The first tests showed that it was quite uncomfortable for the operators, seated in the
particular position, to pick all of the artichokes from the side rows, because the vegetation
in the row is wide (up to 1 meter) and they can't reach all the way across. These
preliminary results suggested further and substantial changes in the prototype design.
In the new project the frame was considerably modified: only one seat was placed at the
centre of the machine, the ground clearance was increased, a big volume tipping platform
was placed in the back for holding the produce. The seat's height can be adjusted by
means of an electric cylinder for vertical linear movement, for a better work position. The
steering controls are made using two pedals hinged to a secondary frame, that is directly
attached to the seat (Fig. 5). The pedals are linked to the wheels by means of steering rods
that are joined together behind the seat, thus avoiding placing obstacles in front of the
seat.
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 5
Behind the seat, a big tipping platform has been positioned, having a volume bigger than
to 2 m3. The big loading capacity was necessary for reducing stops during the harvest.
The trapezoidal shape studied for the platform, facilitates loading and unloading
operations. Other changes regarded the wheels, choosing tires with wider footprints to
improve stability and traction in wet soil conditions.
Figure 5. First tests with the new CRA-ING prototype.
In the tests, harvesting in a mechanically-aided way using this newly developed prototype
was compared to the traditional hand harvesting. In our trials hand harvest was identified
as Plot A and mechanically aided harvest was identified as Plot B (Fig. 6). In both cases a
crew of five members was used for carrying out the trials.
Figure 6. Machine aided harvest crew
In plot A, three workers hand harvested the mature buds and two workers carried baskets
on their backs for accumulating the artichokes. Each one of the three pickers walked
along and picked from one row, the resulting working width for the crew was 4.8 m, with
a distance between rows of 1.6 m.
In plot B, five workers are employed. Four workers walk along the rows, two on each
side of the electric powered prototype. The machine drives over a row and the driver
picks the mature heads. In this case the resulting working width for the crew was 8 m.
For both plots a suitable number of bins was previously distributed on both ends of the
field, so that the produce could be unloaded once out of the row. Otherwise, if the back
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 6
carried baskets would be filled before completing the row, the shortest journey could be
chosen each time for reducing walking distances (Fig. 7).
Figure 7. Unloading the artichokes into bins.
RESULTS AND DISCUSSION The two different harvesting methods, hand harvesting
for plot A and machine-aided harvesting for plot B, were compared in tests performed in
a field having typical characteristics for the central Italian regions (Table 1). The
harvesting crew in both cases counted 5 members, in plot A only three persons actually
picked the product while the other two carried the baskets. In the other case all of the
workers picked a row each, therefore the working width for plot A was 40% smaller than
in plot B.
The individual productivity of the pickers, intended as the number of mature heads
picked in a minute, is practically identical (Table 2). Pickers in plot A work side by side
with the basket carrier, therefore handling the product is faster, for this reason the
individual productivity was slightly higher.
The hourly productivity of the crew is much higher in the mechanically-aided harvest.
The reason, clearly, is almost exclusively attributed to the fact that, in the hand harvest
plot, 40% of the total employees are occupied not for picking but for moving the product
with the baskets out of the field where the bins are positioned. With the use of the
mechanical aid all the workers, included the driver, have a very elevated productivity. A
further difference in the productivity data is due to the time losses that are higher in plot
A. In fact, the pickers stop working many times, waiting for the product to be carried and
unloaded in the bins. In plot B, fewer time is needed for dumping the artichokes at the
end of the field (Fig. 7). This excessive increase of the time losses makes the adoption of
such a job organization totally irrational, while in the mechanically-aided harvest the
increase in crew productivity is 73%.
In the electric prototype the loading autonomy is rather insufficient because of the limited
dimensions of the dump body. The electric traction gives a maximum speed of 2,7 km/h,
for this reason the machine takes a lot of time for travelling non-working distances. This
specific characteristic has contributed to a slight increase in the plot B time loss.
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 7
Table 1. Characteristics of test plots.
Table 2. Average values of the harvesting tests.
CONCLUSIONS The principal advantage of the mechanically-aided system is that the
operator that drives the machine can also harvest the product. The results confirm that the
harvesting ability of an experienced operator is comparable to that of the hand workers.
A rational organization of the work crew employed in the mechanically-aided system
requires the combination of a worker on board of the machine and at least two operators
that pick from the adjacent rows. In this case the three workers perform the job normally
carried out by four persons in manual harvest, with a 25% manpower reduction.
The results obtained in the harvesting tests with the prototype have highlighted the real
possibility of achieving a significant increase in labour productivity. The low travelling
speed of this prototype is a limiting factor. A good work organization consists in the use
of the electric vehicle only for the harvest phase, unload the machine at the end of the
field.
Other advantages of the electric traction system are represented by in the absence of
harmful exhaust gasses, low noise level, low energy expenditure. Besides the vehicle has
a modest purchase cost and maintenance is simple and economic.
ACKNOWLEDGEMENTS The authors are grateful to Pietro Papalini, a dear late
friend, for his precious help in carrying out the research.
REFERENCES
Arrivo, A. & Panaro, V. 1979. Aspetti tecnici ed economici della meccanizzazione
integrale del carciofo. Rivista di Ingegneria Agraria, Anno decimo Numero 3-4
Dicembre 1979, pp. 256-263.
Parameters and characteristics Plot A Plot B
Crop Spacing
m
1.6 x 0.9
1.6 x 0.9
Row length
m
170
170
Total work crew
n°
5
5
Total pickers
n°
3
5
Rows harvested each passage
n°
3
5
Test field dimension
m
816
2
1360
Parameters Plot A Plot B
Actual Working width (1 picker/row )
n° rows
3
5
Average field yield
n° buds/ha
10.100
10.450
Individual productivity
n° heads/min
16,3
15,8
Time loss
%
19
13
Crew hourly productivity
n° heads/h
2376
4110
Increase in crew productivity
%
-
73
Actual working time
h/ha
4,21
2,54
Reduction in work time
%
-
40
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 8
Arrivo, A. & Panaro, V. 1979. La raccolta agevolata del carciofo con impiego di carri
appositamente realizzati. In atti del 3° Convegno Nazionale A.I.G.R. “l’impegno e il
contributo del genio rurale allo sviluppo agricolo del mezzogiorno” Catania 16-19
Maggio 1979, 3° Volume, pp. 66-82.
Arrivo, A. & Panaro, V. 1979. La raccolta meccanizzata del carciofo: aspetti tecnici ed
organizzativi. Rivista di Ingegneria Agraria, Anno decimo Numero 3-4 Dicembre 1979,
pp. 199-214.
Arrivo, A., Monelli, C. & Panaro, V. 1979. Progetto e realizzazione di una macchina per
la raccolta dei carciofi. Rivista di Ingegneria Agraria, Anno decimo Numero 3-4
Dicembre 1979, pp. 191-198.
Colorio, G., Tomasone, R., Cedrola, C. & Pagano, M. 2007. Meccanizzazione per
agevolare la raccolta del carciofo: sistemi in uso e nuove proposte. In Atti del
Convegno “Ricerca ed innovazione per la Valorizzazione del carciofo nella Regione
lazio”. Azienda Sperimentale Dimostrativa ARSIAL Loc. Portaccia – Tarquinia 30
Novembre 2007, pp.42-51.
Istat, Stima delle superfici e produzioni delle coltivazioni agrarie, 2008.
Panaro, V. 1982. Il carciofo e la sua meccanizzazione. Macchine e motori agricoli,
numero 3 Marzo 1982, pp. 207-218.
Macua, J.I. 2007. New horizons for artichoke cultivation. Acta Hort. (ISHS) 730:39-48