CA2715990C

CA2715990C - A method of treating turf or plants

Info

Publication number: CA2715990C
Application number: CA2715990A
Authority: CA
Inventors: Paul Dawson; Michael Burrell
Original assignee: ROLAWN Ltd
Current assignee: ROLAWN Ltd
Priority date: 2007-09-20
Filing date: 2008-09-22
Publication date: 2016-10-25
Anticipated expiration: 2028-09-22
Also published as: GB0718321D0; GB201004335D0; GB2465722A; CA2715990A1; GB2465722B; WO2009037514A1

Abstract

It has been found that when turf is stored in rolls or in layers placed one on top of the other that a lack of ventilation prevents heat produced from being dispersed and a build up of CO2 is evident.
Removal of CO2 from harvested turf is described.

Description

A method of treating turf or plants This invention relates to a method of storing harvested turf and to apparatus for extending a shelf life of turf.
Turf is grown on a commercial basis to be harvested, transported and sold for laying. As soon as turf is cut and stored its viability for laying reduces. The reason for the reduced viability is that the turf when harvested is rolled or placed on pallets for transportation and distribution.
The compact storage of turf in this way reduces the amount of light and the amount of air reaching the turf. These constraints are thought to be involved in the early perishing of the turf if it is not removed from the storage configuration in a timely manner.
Typically, turf may only be viable in the stored configuration for one or two days, or sometimes up to five days. This leads to a short shelf life of the product, which limits the potential distance of transportation of the turf from the point of harvesting and also the period of time during which the turf may be kept for sale, for example to a landscaper or a retailer. In view of the short shelf life it is difficult to maintain quality.
It is an object of the present invention to address the above mentioned disadvantages and to attempt to extend the shelf life, or period of time between harvest and laying of the turf and to improve quality.
According to an aspect of the present invention there is provided a method of treating harvested turf or other plants, the method comprising treating the harvested turf or other plant in an atmosphere having reduced carbon dioxide, CO2.
The treatment of the harvested turf or plant advantageously extends a shelf-life of the harvested turf or other plant, where the shelf-life is a period of time for which the harvested turf or plant can be kept before it should be laid to produce visibly attractive viable turf or used or consumed, as appropriate. References in the following to harvested turf can be replaced with a reference to horticultural products, or other plants, which may be other live plants or may be cut flowers, salads, including celery and lettuce, fruit, vegetables, or the like.
The reduced CO2 atmosphere is preferably an atmosphere having a lower CO2 level than ambient conditions. The reduced CO2 atmosphere is preferably a result of artificial reduction of the CO2 level, preferably using CO2 level reduction means.
The method preferably includes placing the harvested turf in a chamber, said chamber being sealable to make an airtight chamber.

2 The chamber may be evacuated after the turf is placed therein. Other methods of reducing the CO2 level of the atmosphere of the harvested turf may be used. The air around the harvested turf is preferably replaced with CO2 depleted air or gas mixture.
The chamber may be evacuated to a pressure of less than approximately 100 mbar, preferably to a pressure of less than approximately 50 mbar, preferably to a pressure of less than approximately 40 mbar, preferably to a pressure of less than approximately 30 mbar, preferably to a pressure of less than approximately 20 mbar, preferably to a pressure of approximately 10 mbar.
The chamber may be re-filled with air having a reduced CO2 content compared to ambient CO2 content.
The chamber may be re-filled with gases having a reduced CO2 content compared to ambient air. Stored gases, for example from pressurised containers, may be used. The gases preferably have a CO2 content of less than approximately 4Oppm. Artificial air having a reduced CO2 content may be prepared for use in the treatment of the harvested turf.
The chamber may be filled with air having had a CO2 content thereof reduced by filtering.
The re-filling may include passing air through a filter before it reaches the chamber. The re-filling may include drawing air through a CO2 filter section.
The air is preferably filtered prior to reaching the chamber.
The air may be filtered by being passed through soda lime, or a mixture of calcium hydroxide with sodium hydroxide or potassium hydroxide, or another known chemical or mixture thereof for removing CO2 from air. Preferably the CO2 removal is performed with a CO2 removal agent.
A CO2 removal agent is any physical or chemical agent operable to remove or chemically alter CO2 from a gaseous stream. An example of a CO2 removal agent is soda lime, which may be a mixture of Group I and ll metal hydroxides. Several methods of removing CO2 content from mixtures of gases are known and any could be used.
The CO2 reduced atmosphere may have a CO2 content less than 100ppm, preferably less than 5Oppm, more preferably about 25ppm.
Ambient air typically comprises approximately 400ppm CO2. Consequently, the CO2 reduced atmosphere typically has a CO2 level of less than 50% of ambient level, more preferably less than 45% of ambient level, more preferably less than 40% of ambient level, more preferably

3 less than 35%, more preferably less than 30% of ambient level, more preferably less than 25%
of ambient level, more preferably less than 20% of ambient level, more preferably less than 15% of ambient level, more preferably less than 10% of ambient level, more preferably less than 5% of ambient level, more preferably less than 3% of ambient level, more preferably less than 1% of ambient level.
The method may include cooling the turf, said cooling being in addition to that caused by evaporative cooling when evacuating air from the chamber. The cooling may be provided by refilling the chamber with cooled gases.
The harvested turf may be packaged before being treated in the reduced CO2 atmosphere.
The harvested turf may be packaged after being treated in the reduced CO2 atmosphere. The harvested turf may be packaged whilst in the reduced CO2 atmosphere. The packaging may be a substantially air tight packaging.
According to another aspect of the present invention there is provided a method of packaging turf, the method comprising packaging the turf to provide an atmosphere at least initially having reduced CO2 inside the packaging.
The method may include exposing the harvested turf to a reduced CO2 atmosphere prior to packaging the turf.
The reduced CO2 advantageously prolongs a shelf-life of the turf.
The turf may be packaged in an atmosphere having a reduced CO2 content. This therefore allows any air trapped inside the packaging to have the reduced CO2 level of the atmosphere in which it is packaged.
The turf may be packaged and then the level of CO2 inside the packaging may be reduced.
The packaging may be a substantially sealed packaging.
The turf may be arranged in a roll or rolls or may be arranged in sections one on top of the other.
The method may be performed in a cooled environment, such as a cold store.

4 PCT/GB2008/050849 According to another aspect of the invention there is provided a method of treating harvested turf or other plants, the method comprising placing the turf in a chamber, evacuating, or substantially reducing the air pressure in the chamber, and allowing air to reenter the chamber.
It has been advantageously found that removing air from the chamber also removes air from the body of the turf and the surrounding soil and causes evaporative cooling due to lower air pressure, which reduces the temperature of the turf when replaced with air. It is thought that the cooling lowers respiration activity and so prolongs shelf-life.
According to another aspect of the present invention there is provided a turf package, wherein the turf therein has been treated in an atmosphere with reduced CO2.
According to another aspect of the present invention there is provided a turf package produced with the turf therein exposed to an atmosphere having a reduced CO2 content.
The package may have been produced after exposure of the turf to the reduced atmosphere.
The package may have been produced after a cover element has been placed on the turf, followed by exposure to a reduced CO2 atmosphere.
Preferably the package contains a plurality of sections of turf.
The turf may be arranged in a roll or rolls or may be arranged in flat sections one on top of the other.
According to another aspect of the present invention there is provided a turf assemblage formed of sections of turf that has been treated in an atmosphere with reduced CO2.
According to another aspect of the present invention there is provided a section of turf that has been treated in an atmosphere with reduced CO2.
The treatment in an atmosphere of reduced CO2 is preferably a treatment involving evacuation or partial evacuation of a chamber in which the turf is located, followed by replacement of the air evacuated from the chamber with air having a reduced CO2 content compared to ambient.
The replacement air may be cooled compared to ambient. Said cooling may be to below 10 degrees C, preferably below 5 degrees C, Most preferably below 4 degrees C.

According to another aspect of the invention there is provided an apparatus for treating turf, the apparatus comprising:
receiving means adapted to receive harvested turf;
pumping means operable to pump air from the receiving means in which the harvested

5 turf is located, and refilling means, operable to refill the receiving means with gases having a reduced CO2 content.
The refilling means may include CO2 filter means operable to filter CO2 from air being introduced into the receiving means. The refilling means may include a pressurised storage vessel, adapted to receive CO2-filtered air and store that air under pressure for later use.
The refilling means may include one or more containers adapted to provide artificial air having a reduced or negligible CO2 content.
The receiving means may be a package adapted to receive the turf and suitable for use in transportation of the turf. The receiving means may be a chamber. The receiving means may be located in a cold store. The location in a cold store advantageously reduces any warming that results when the turf is removed from the chamber. The pumping means and or the CO2 filter means may be located outside the cold store.
The pumping means may be a vacuum pump. The pumping means may be an evacuation pump. The apparatus may include cooling means, operable to cool turf located in the interior of the receiving means in addition to any cooling caused by the pumping of air from the receiving means.
The CO2 filter means may be a vessel containing a CO2 removal agent. The CO2 filter means may include an inlet to allow ambient air to enter the CO2 filter means. The inlet may be a one-way valve. The CO2 filter means may include a plurality of sections that may be arranged in series. The CO2 filter means may be adapted to direct air therethrough in a zig-zag path, i.e.
down through one section and up through another.
The apparatus may include a valve to isolate the receiving means from the CO2 filter means during removal of air from the receiving means.
The apparatus may include a valve to isolate the receiving means from the pumping means during introduction of air from the CO2 filter means.

6 The invention extends to all of the above aspects when used in relation to plant matter other than turf.
All of the features described herein may be combined with any of the above aspects in any combination.
For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:
Figure 1 is a schematic diagram of a test apparatus for storing turf in a CO2 depleted atmosphere and for comparison with turf stored in the same conditions in an ambient atmosphere; and Figure 2 is a schematic diagram of apparatus for storing turf in a CO2 depleted atmosphere.
It has been found that when turf is stored in rolls or in layers placed one on top of the other that a lack of ventilation prevents heat produced from being dispersed and a build up of CO2 is evident. The sections of turf may typically measure 0.6m by 1.6m or 0.6m by 1.2m or 0.4m by 2.5m or 0.4m by 1.2m, or may be larger rolls having an area of approximately 13m2.
Figure 1 shows a test apparatus that has been used. A vacuum pump 10 is attached a chamber 12 in which turf is stored. Airtight piping leads from the chamber 12 to a further chamber 14. All of the piping shown is airtight and incorporates taps A to D, which will be described below.
The chambers 12 and 14 have doors (not shown) which can be opened to allow turf to be placed therein. The doors are closed and are air tight. The turf is stored in the usual way, either In rolls or in stacked "sheets" typically on a wooden pallet. The turf may also be stored in a large roll having an area of up to 13m2 for example.
A CO2 removal section 16 is provided linked to the chamber 14 by a section of pipe which Incorporates tap A.
In order to test the efficacy of CO2 removal for improving shelf life of turf the apparatus was used in the following way.
Taps A and D were closed. Taps B and C are opened. The vacuum pump 10 is operated to evacuate chambers 12 and 14. As can be seen from the connection of the pipes removed from

7 chamber 14 passes through the chamber 12 and through to the vacuum pump 10, The chambers are evacuated to a pressure of 10 mbar. This cooled the turf to 4 C.
In other tests a reduction of pressure to 60mbar as also been used.
After evacuation, taps B and C are then closed so that the vacuum pump 10 can be turned off and so that there is no connection between the chambers 12 and 14.
Tap A on chamber 14 was then opened to refill chamber 14 with air that has had the CO2 content thereof reduced. The air can be cooled prior to or after the passage through the CO2 removal section 16. The CO2 removal section 16 is open to allow air to enter at an inlet 18 by means of a one-way valve. Consequently, when the tap A is opened air is drawn into the chamber 14 via the CO2 removal unit 16 which is fed with ambient air at the inlet 18. The CO2 removal unit 16 is filled with soda lime, which reacts with the CO2 in the air drawn therethrough to remove the CO2 from the air. The concentration of CO2 in the air is reduced to approximately 25 ppm. Once the chamber 14 is refilled with carbon dioxide reduced air the tap A is closed.
At the same time, ambient air is allowed to enter the chamber 12 by opening tap D which draws in ambient air. The air can be cooled to match that provided to the chamber 14 (except for having no CO2 removal).
Over the following two hours, the temperature of the turf increased to 14 C.
The temperature was then maintained at about 18 for the four days. After four days the concentration of CO2 in the chamber 14 had reached 5,200 ppm, whereas in the chamber 12 the concentration of carbon dioxide had reached a similar value.
A visual comparison for the turf showed that the turf from chamber 14 that had been maintained in a carbon dioxide reduced atmosphere was in considerably better condition (it had better growth and rooting and looked better) than the turf that has been stored in ambient air. Thus, the surprising advantage has been found that storing turf in an atmosphere initially much reduced in CO2 has particular benefits for the longevity of the turf.
As will be appreciated from the above, the test was carried out using chambers 12 and 14 to compare turf stored in the same conditions, except for the turf in chamber 14 being stored in a carbon dioxide reduced atmosphere. Thus, the chamber 12 was used as a control.
It was a realisation of the experiment that the longevity of turf could be increased to such a degree. The turf was maintained at a relatively high temperature for a period of four days, at

8 the end of which the turf was still viable for relaying to a much greater degree than the control turf stored in chamber 12.
Figure 2 shows an apparatus for filling a chamber with carbon dioxide reduced air, more in the manner of a production apparatus, as opposed to the test apparatus shown in Figure 1 and described above, In Figure 2 like numerals have been used for the same parts of those that were present in Figure 1. In essence, the "control" part of the apparatus of Figure 1 has been removed. The chamber 12 has been removed as have the taps C and D. The apparatus is used in the same way, namely chamber 14 is evacuated using vacuum pump 10 with valve B
open and valve A closed. Afterwards, B is closed so that the vacuum pump can be turned off.
Tap A is then opened to allow refilling of the chamber 14 with CO2-reduced air that has been drawn through the CO2 removal unit 16, With both of the apparatus as described above, evacuation of the chambers 12/14 results in cooling of the turf. It is possible to further cool the turf by re-circulating cooled air into the chambers whilst evacuation takes place. Although, it is not necessary to specifically cool the turf.
Furthermore, a feature of the method described above is that the chamber 14 is evacuated prior to re-filling of the chamber with CO2-reduced air. The advantage of evacuation prior to re-filling is thought to be significant to the efficacy of the method described above.
The invention can be applied to the packaging of turf, perhaps by replacing the chamber with a package that can be evacuated and refilled with CO2-reduced air, or a mixture of gases to make artificial air having negligible CO2 content. The package may not be evacuated, but may be flushed with CO2 reduced air or the mixture of gases mentioned above. The turf may be sealed in the package for subsequent distribution. The package may not necessarily be airtight, but may simply be a cover.
One version of the test apparatus includes a conveyor on which pallets of turf are placed. The pallets are conveyed to an evacuation chamber. Doors are then closed to seal the chamber, which is then evacuated via a duct. The chamber is then refilled via the duct (or optionally a separate duct) with air that has had CO2 removed therefrom, or a reduced level compared to ambient, as described below. The doors are then opened and the pallets of turf are then conveyed out of the chamber.
The CO2 removal is performed in one embodiment where ambient air is introduced into a duct.
The air is directed into a first unit, which is hollow and includes CO2 removal media (as described above) held between a section of mesh. The air is directed through the media and

9 out of the base of the first unit into a duct and into a base of a second unit that has the same arrangement of media and mesh as the first unit. The air is then directed out of the top of the second unit and into a top of a third unit, constructed in the same way as the other units. The air thus zig-zags through the units.
After that the air with CO2 removed or reduced is directed into a pressurised storage vessel where it is stored under pressure of for example 10 bar before being fed into the evacuation chamber via the duct. The returning gases may optionally be cooled.
The pallets can then optionally be wrapped for distribution, or can be stored in a cold store for later distribution.
The apparatus is located in a much larger cold store, so that when turf is removed after treatment it can be stored at a cold temperature of, for example 3 degrees C
before further treatment or distribution, or both.
It has been found that the combination of evacuation, which results in evaporative cooling of the turf combined with CO2 removal/reduction has an unexpectedly beneficial effect. The turf cools because as the pressure reduces in the sealed chamber any moisture within the turf starts to 'boil ie evaporate. At very low pressures the moisture in the turf evaporates at low temperatures. It is the evaporation of the moisture which cools the turf in the same way that sweating cools a person. The low pressure means that this can happen at a low temperature, rather than the higher temperatures that would usually be needed, Evacuation in the chamber, which leads to evaporative cooling, and refilling with air with ambient levels of CO2 is also beneficial for turf shelf life, most likely because the evacuation causes local cooling of warm air within the body of the turf, which may not occur if the turf is simply placed in a cooled atmosphere. This is particularly the case when turf is stacked in flat layers, because the evacuation causes cooling in the centre of the turf stack and the cooled effect is maintained because of the compact nature of the package, which has little ventilation and so is well insulated.. This effect is contrary to usual teaching because ventilation in a stack of turf is usually thought necessary to allow heat of respiration to be allowed to escape. Thus the important benefit of cooling the centre of the turf is achieved because of the evacuation.
When the method is used with the returning gases being low in CO2 the effect on turf shelf life is unexpectedly enhanced.
The beneficial provision of a stack of turf pieces in which ventilation is not needed also allows the turf to be provided in a packaged form that has end user benefits, particularly in a retail environment, where a product that does not spread soil onto a user may be attractive.

Furthermore, when flat turf is provided it is possible to cut the turf into a greater variety of shapes, other that the usual rectangles or squares. The turf may have curved edges or may be in more useful or unusual shapes.

The method allows for the advantageous distribution of turf that can be maintained in a viable state for much longer that was possible previously.
Attention is directed to all papers and documents which are filed concurrently with or previous

10 to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s).
The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1 A method of treating harvested turf in an atmosphere having reduced carbon dioxide, CO2, compared to ambient air, comprising the steps of placing the harvested turf in a chamber, evacuating the chamber after the turf is placed therein, and .
refilling the chamber with air or gases having reduced CO2 compared to ambient air .

2 The method of claim 1, in which the reduced CO2 atmosphere is a result of artificial reduction of the CO2 level using CO2 level reduction means.

3 The method of claim 1 or 2, said chamber being sealable to make an airtight chamber.

4. The method of claim 3, in which the chamber is evacuated to a pressure of less than 100 mbar

The method of any of claims 1 to 4, in which the chamber is re-filled with air having had a CO2 content thereof reduced by filtering.

6. The method of any of claims 1 to 5, in which the CO2 reduced atmosphere has a CO2 content less than 100ppm.

7. The method of any of claims 1 to 6, which includes cooling the turf, said cooling being in addition to any cooling caused by evacuating air from the chamber.

8 The method of any of claims 1 to 7, in which the harvested turf is packaged before being treated in the reduced CO2 atmosphere

9 The method of any of claims 1 to 8, in which the harvested turf is packaged after being treated in the reduced CO2 atmosphere.

10. A method of packaging turf comprises packaging the turf in a packaging to provide an atmosphere inside the packaging at least initially having a reduced CO2 level compared to ambient air, the method including exposing the turf to a reduced CO2 atmosphere compared to ambient air prior to packaging the turf.

11 The method of claim 10, wherein the turf is packaged in an atmosphere having a reduced CO2 content compared to ambient air

12. The method of claim 10, in which the turf is packaged and then the level of CO2 inside the packaging is reduced.

13. An apparatus for treating turf, the apparatus comprising:
receiving means adapted to receive harvested turf;
pumping means operable to pump air from the receiving means in which the harvested turf is located, and refilling means, operable to refill the receiving means with gases having a reduced CO2 content compared to ambient air.

14. The apparatus of claim 13, in which the refilling means include CO2 filter means operable to filter CO2 from air being introduced into the receiving means.

15. The apparatus of claim 13 or claim 14, in which the refilling means include a pressurised storage vessel, adapted to receive CO2 filtered air and store that air under pressure for later use.

16. The apparatus of any one of claims 13 to 15, in which the refilling means includes one or more containers adapted to provide artificial air having a reduced or negligible CO2 content.

17. The apparatus of any one of claims 13 to 16, in which the receiving means are a package adapted to receive the turf and suitable for use in transportation of the turf.

18. The apparatus of any one of claims 14 to 17, in which the CO2 filter means is a vessel containing a CO2 removal agent.

19. The apparatus of any one of claims 14 to 18, in which the CO2 filter means include a plurality of sections that may be arranged in series.

20. The apparatus of any one of claims 13 to 19, in which the receiving means are adapted to be located in a cold store.

21. A method of treating harvested turf, the method comprising placing the turf in a chamber, evacuating, or reducing air pressure in the chamber, and allowing air to re-enter the chamber, in which the re-entering air has a reduced CO2 content compared to ambient.