WO2009037514A1

WO2009037514A1 - A method of treating turf or plants

Info

Publication number: WO2009037514A1
Application number: PCT/GB2008/050849
Authority: WO
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: 2009-03-26
Anticipated expiration: 2010-03-20
Also published as: GB2465722B; GB0718321D0; GB201004335D0; GB2465722A; CA2715990A1; CA2715990C

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. 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 40ppm. 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 refilling 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 Il 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 50ppm, 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 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. 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 CO₂ 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 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 oneway 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. 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;

Figure 2 is a schematic diagram of apparatus for storing turf in a CO₂ depleted atmosphere;

Figure 3 is a schematic side view of a turf treatment apparatus;

Figure 4 is a schematic side perspective view of the turf treatment apparatus; and

Figure 5 is a schematic side view of a CO₂ removing section of the apparatus.

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 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^SC. In other tests a reduction of pressure to 50mbar 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^SC. The temperature was then maintained at about 18^s 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 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.

Figure 3 to 5 show a scaled-up version of the test apparatus.

Figure 3 shows a conveyor 30 on which pallets of turf 32 are placed. The pallets are conveyed to an evacuation chamber 34. Doors 35 are then closed to seal the chamber, which is then evacuated via duct 36. The chamber is then refilled via the duct 36 (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 35 are then opened and the pallets 32 of turf are then conveyed out of the chamber 34 in the direction of the arrow AA.

The CO₂ removal is performed with the system shown in Figure 5. Ambient air is introduced into duct 40 at arrow BB. The air is directed into first unit 41 , which is hollow and includes CO₂ removal media 42 (as described above) held between section of mesh 44. The air is directed through the media 42 and out of the base of the first unit 41 into a duct 46 and into a base of a second unit 48 that has the same arrangement of media 42 and mesh 44 as the first unit 41 . The air is then directed out of the top of the second unit 48 and into a top of a third unit 50, 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 52 where it is stored under pressure of for example 10 bar before being fed into the evacuation chamber 34 via the duct 36. 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 34 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 34, 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 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 are incorporated herein by reference.

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 or other plants, comprises treating the harvested turf or other plant in an atmosphere having reduced carbon dioxide, CO₂.

2. The method of claim 1 , in which the reduced CO₂ atmosphere is an atmosphere having a lower CO₂ level than ambient conditions.

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

4. The method of any preceding claim including placing the harvested turf in a chamber, said chamber being sealable to make an airtight chamber.

5. The method of any preceding claim, in which the chamber is evacuated after the turf is placed therein.

6. The method of claim 5, in which the chamber is evacuated to a pressure of less than approximately 10O mbar.

7. The method of claim 5 or claim 6, in which the chamber is re-filled with air having a reduced CO₂ content compared to ambient CO₂ content.

8. The method of claim 5 or claim 6, in which the chamber is re-filled with gases having a reduced CO₂ content compared to ambient air.

9. The method of claim 7, in which the chamber is re-filled with air having had a CO₂ content thereof reduced by filtering.

10. The method of any preceding claim, in which the CO₂ reduced atmosphere has a CO₂ content less than 100ppm.

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

12. The method of any preceding claim, in which the harvested turf is packaged before being treated in the reduced CO₂ atmosphere.

13. The method of any preceding claim, in which the harvested turf is packaged after being treated in the reduced CO₂ atmosphere.

14. A method of packaging turf comprises packaging the turf to provide an atmosphere at least initially having a reduced CO₂ level inside the packaging.

15. The method of claim 14, which includes exposing the harvested turf to a reduced CO₂ atmosphere prior to packaging the turf.

16. The method of claim 14, wherein the turf is packaged in an atmosphere having a reduced CO₂ content.

17. The method of claim 14, in which the turf is packaged and then the level of CO₂ inside the packaging is reduced.

18. A turf package wherein the turf therein has been treated in an atmosphere with a reduced CO₂ level.

19. A turf package produced with the turf therein exposed to an atmosphere having a reduced CO₂ content.

20. The turf package of claim 18 or claim 19, in which the package contains a plurality of sections of turf.

21 . A turf assemblage formed of sections of turf that have been treated in an atmosphere with a reduced CO₂ level.

22. A section of turf that has been treated in an atmosphere with a reduced CO₂ level.

23. A section of turf as claimed in claim 22, in which the treatment in an atmosphere of reduced CO₂ is 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.

24. A section of turf as claimed in claim 22 or claim 23, in which replacement air is cooled compared to ambient.

25. 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.

26. The apparatus of claim 25, in which the refilling means include CO₂ filter means operable to filter CO₂ from air being introduced into the receiving means.

27. The apparatus of claim 25 or claim 26, in which he refilling means include a pressurised storage vessel, adapted to receive CO₂ filtered air and store that air under pressure for later use.

28. The apparatus of any one of claims 25 to 27, in which the refilling means includes one or more containers adapted to provide artificial air having a reduced or negligible CO₂ content.

29. The apparatus of any one of claims 25 to 28, in which the receiving means are a package adapted to receive the turf and suitable for use in transportation of the turf.

30. The apparatus of any one of claims 25 to 29, in which the CO₂ filter means is a vessel containing a CO₂ removal agent.

31 . The apparatus of any one of claims 25 to 30, in which the CO₂ filter means include a plurality of sections that may be arranged in series.

32. The apparatus of any one of claims 25 to 31 , in which the receiving means are adapted to be located in a cold store.

33. The apparatus as claimed in any one of claims 25 to 32 which is a turf treating apparatus.

34. 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 re-enter the chamber.

35. The method of claim 34 in which the re-entering air has a reduced CO₂ content compared to ambient.

36. A section of turf that has been treated by placing the turf in a chamber, evacuating, or substantially reducing the air pressure in the chamber, and allowing air to re-enter the chamber.