GB2358394A

GB2358394A - Treatment of sugar lime; growing mushrooms

Info

Publication number: GB2358394A
Application number: GB0100874A
Authority: GB
Inventors: David Linsay Dodd
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-01-12
Filing date: 2001-01-12
Publication date: 2001-07-25
Anticipated expiration: 2021-01-12
Also published as: GB0100874D0; GB2358394B; WO2002054854A1

Abstract

A method for treating sugar lime for use for growing mushrooms comprises the steps of contacting the sugar lime with heat at a temperature of between 40{C - 450{C. The sugar lime may be treated in a flame heated worm or a soil steriliser.

Description

2358394 TREATMENT OF SUGAR LIME The present invention relates to lime

produced from sugar manufacturing and, in particular, but not exclusively, a 5 sugar beet lime treatment process.

Lime sludge/cake is produced as a by-product of the sugar beet/cane purification process. Typically, calcium hydroxide /oxide is reacted with carbon dioxide in the sugar juice to produce lime which contains high levels of impurities. In addition, due to the conditions in the sugar purification process, the lime sludge contains sugars and other impurities which may cause it to become anaerobic in storage. In addition, the lime has a high water content.

Such lime sludge may be utilised in some horticultural applications and most agricultural applications for correction of soil acidity, to improve soil structure and to provide low levels of soil nutrients. However, f or mushroom applications, to achieve a lime product that can be utilised in mushroom growing, the sugar lime requires several months storage and treatment. The lime is f irst allowed to stand so that the water content may be drained away and the sugar components broken down by microbes and chemical action. Afterwards, it must be turned and matured. The preparation process takes a number of months if not years. Although lime from sugar production can, in small quantities, be made suitable for mushroom growing.

The problem is the storage and handling lime on a commercial scale as even the smallest heaps of lime become anaerobic and thus unsuitable for mushroom growing.

2 It is one of the objects of the present inventior- to provide an alternative product which does not require F.Ch lengthy preparation times.

According to a first aspect of the present invention t' E is provided a method of treatment of sugar lime T storage and mushroom growing comprising the steps of:

contacting the sugar lime with heat at a temperaturc- f between 40OC-4500C.

Preferably, the heat treatment is carried out J r sufficient time to critically reduce populationsli f microbiological agents in the lime.

By critically reduce populations is meant SUffiCiE t reduction to prevent re-establishment of unwart d microbiological agents prior to use of the lime', n horticulture after normal shelf periods.

C Preferably, the heat treatment is between 500C and 45( more preferably, between 800C and 200"C, most preferaL- 1 between 1000C and 1500C.

Preferably, the heat treatment is continued for a per +d which critically reduces populations of nematodes r fungii populations in the lime. Preferably, the 'he t treatment is continued for a period which ki 1 s substantially all the nematodes and fungii in the lime..,' I Preferably, the water content of the lime to be h t treated has been reduced by mechanical means such s pressing of the lime sludge prior to heat treatment. S h 3 pressed lime sludge is available commercially as "LimeX7W' from British Sugar plc. This product has not been stored for many years but has only had water removed by mechanical pressing. An equivalent product is known as 5 Carbolime.

Preferably, the level of water in the lime prior to heat. treatment is between 5% and 70%, more preferably, between 15% and 40%, most preferably, between 20% and 35%.

Preferably, the solids content of the lime is above 55%, more preferably, above 65%, most preferably above 70%.

Preferably, the heat treatment'is flame treatment.

Preferably, the heat treatment is carried out for sufficient time to raise "the temperature to at least the minimum of that specified in any of the preferred ranges above throughout substantially all the lime product.

Advantageously, some of the effects of the heat treatment are to sterilise the lime product to remove odours and to lower water content. Surprisingly, the heat treatment causes yields to rise to those equivalent to a pressed lime which has been exposed to air for several months in a controlled mander.

It has been found that the product produced by the method of the invention is particularly useful when treating soils for mushrooms. Mushrooms are very sensitive to diseases, bacteria and other chemical or biological impurities in sugar lime. These impurities are not fully understood but are known to be at least partially removed by the traditional long term storage of sugar lime V:LCn allows breakdown of sugar and other impuritiesi b r microbiological agents and also by chemical action.

Surprisingly, it is found that the heat treatment step O' the invention removes such impurities and causes a rr C11 lower incidence of diseases in mushroom crops.

Heat treatment of sugar lime has not hitherto Ael envisaged using conventional sugar lime purificatiom processes because the water content of such sugar lirixE is too high and once suitable water levels are reached:he product has been aerated and altered by microbes and Aes not require further treatment. However, mechanicAly is processed sugar lime which has not been left to stand or an extended period is still highly anaerobic na unsuitable for many crops, particularly, mushroom ci---,D])s.

Even turning and screening of such products over a pE,--.oc.

of time only slowly renders them suitable for many c. MPE including mushrooms.

According to a second aspect of the present inveril A Dr there is provided an horticultural lime comprising a 1Ast sugar purification heat treated sugar lime.

Preferably, the product of the second aspect is produced by the method of the first aspect including, optiona-ly, any one or more of the preferred features thereof.

Preferably, the sugar lime has been mechanically treWed prior to heating, preferably, by pressing, to lower the water content thereof. Preferably, the water content -S sufficiently low to allow heat treatment, preferably, flame heat treatment.

The product may be heat treated with any suitable device.

one possibility is a flame heated worm or soil steriliser of conventional construction. In such a device, the flame is directed through the centre of the worm. The inside face of the hopper wall preferably, includes an inwardly projecting flange that spirally extends along the length of the barrel of the worm.

Further advantages of the method, include destruction of weed seeds, vaporisation of various odour carrying components and break up of the lumpy structure of the is mechanically pressed sugar lime.

Embodiments of the invention will now be described with reference to the examples:- The test results have been obtained by using a product (iii) derived from flame treatment, in a flame heated worm, of LimeX70, available from British Sugar plc. The temperature in the flame heated worm was set at 1800C and the throughput through the worm was 2-20 tonne per hour.

This product was compared with another pressed lime sample prepared using LimeX70 that has been exposed to air for several months in an open and controlled manner- In addition, products' containing treated conventional lime (LimeX45) were also compared for reference purposes.

Table 1 and 2 show the test results for 6 Control, HRI standard casing, L & P wet blackI at and sugar beet lime (SBL) X-45 supplied as 1 dy Mixed Casing by Tunnel Tech Ltd.

(ii) Standard Bumpacrop SBL (X-45) 5 (iii) S9L (X-70) (heat treated) (iv) SBL (X-70) New, untreated material (non. I atreated) The SBL was added 20% v/v in all the treatments and he same peat source in (i) was used in treatments (ii), (Ii-i, and (iv).

Cultural Procedure Water was added during a 90 sec mixing to achie-v I moisture content of 70-72% at application. Casing s a (Hauser CI) was added to the casing materials at a rat( 4kg /M3 casing. The casing materials were applied t depth of 45mm to trays (0.9 x 0.6m) containing!k' compost, spawn-run with the strain Hauser A15.

The compost temperature was maintained at 25-260C if i seven days; the air temperature was then reduced to I' ( C over three days and the relative humidity and 2 concentrations kept at 88-92% and go 0 _looj m respectively. The casings were given regular li 11 waterings until airing; watering was resumed when t e first mushrooms had reached 10mm in diameter.

Three flushes of mushrooms were picked off the tray Where possible, closed mushrooms were picked in the si e range 30-40mm, although proportions were also picked s small buttons and as opens. The dry matter content S 7 determined on samples of 20 mushrooms from the first flush. Casing materials were analysed for pH, conductivity and moisture content at application and during cropping.

Results and Conclusions Analysis of casings 10

The pH of the casings was similar although the HRI casing had a lower conductivity than the other materials (Table 1). Moisture contents at application and during cropping for the different treatments were similar (Table 1).

Mushroom yield and quality Mushroom yield was significantly higher for treatments (ii) to (iv) where SBL was added to peat on site, than in treatment (i) (ready mixed casing). The Bumpacrop X-45 treatment produced a slightly higher yield than the SBLX70 and new, unmatured SBL treatments (Table 2).

The percentage of closed mushrooms was slightly higher 25 from the ready mixed casing and the new SBL treatment. Mushroom dry matter content was highest from the SBL-X70 treatment (Table 2).

Table 1 Analysis of Casings Casing moisture content, % w/w Casing Treatment I PH Conductivity at I during 8 gs application cro,.:)])ing HRI Casing 7.82 328 72.5 71. 4 (Control) 45 Bumpacrop X-45 7.56 560 70.0 69A (iii) SBL X-70 7.81 525 70.0 7 0 j (iv) New SBL X-70 7.63 488 72.7 70-L-J (untreated) __1 Table 2 Mushroom yield and quality grades Least significant difference (P = 0.05) = 21 Flame treatment may be carried out in a conventional so! steriliser known in the art of soil sterilisation, such, 1 1 that described in PCT publication no. W09927779, the 10 contents of which are incorporated herein by reference In the context of the invention, the heat treated lime 11 not immediately returned to the ground but is fix.;-. collected and treated as set out below.

Casing Total % Closed Mushrook, Treatment yield, Mushrooms Dry kg/tonne matter, spawned compost HRI Casing 252 91.7 8.90 (Control) 45 (ii) Bumpacrop X-45 308 86.1 8.79 (iii) SBL X-70 282 86.7 9.56 (iv) New SBL-X70 273 91.9 8.41 Untreated 9 A suitable soil steriliser is "The Garden Terraliser 2" available from Gardner Engineering, Erith, Kent, UK. The machine consists of a revolving steel drum mounted within a steel frame. Lime fed into the machine passes through S the drum towards a vaporising burner fitted at the discharge end. The drum may be inclined and has internally projecting vanes to impart a tumbling action to the lime as it passes through the drum. The steriliser effects vaporisation of the moisture content of the lime into steam which has the effect of sterilising the lime. The throughput and temperature are accurately controlled by varying the angle of inclination of the drum and the pressure of the burner. It is found that the levels of water in the lime are not too high to hinder the is sterilising process.

The reader's 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 It td otherwise. Thus, unless expressly stated otherwise, 1 a -h c - feature disclosed is one example only of a generi se ies of equivalent or similar features.

The invention is not restricted to the details oll tlie foregoing embodiment(s). The invention extend to any V(l one, or any novel combination, of the features disc 1 sed in this specification (including any accompanying cl I ms, abstract and drawings), or to any novel one, or any vel combination, of the steps of any method or proce ss 40 disclosed.

Claims

1. A method of treatment of sugar lime for storage and mushroom growing comprising the steps of:

contacting the sugar lime with heat at a temperature of between 40OC-450'C.

2. A method of treatment of sugar lime according to claim 1, wherein the heat treatment is carried out for sufficient time to critically reduce populations of microbiological agents in the lime.

3. A method of treatment of sugar lime according to either claim 1 or claim 2, wherein the heat treatment is continued for a period which critically reduces populations of nematodes or fungii populations in the lime.

4. A method of treatment of sugar lime according to any preceding claim, wherein the heat treatment is continued for a period which kills substantially all the nematodes and fungii in the lime.

5. A method of treatment of sugar lime according to any preceding claim, wherein the water content of the lime to be heat treated has been reduced by mechanical means.

12

6. A method of treatment of sugar lime according to ny preceding claim, wherein the water content of the lime to be heat treated has been reduced by pressing of h lime sludge prior to treatment. 5

7. A method of treatment of sugar lime according to ny preceding claim, wherein the level of water in. he lime prior to heat treatment is between 5% and 70%]

8. A method of treatment of sugar lime according to 1]L preceding claim, wherein the solids content of E lime is above 55%.

9. A method of treatment of sugar lime according to i n., e preceding claim, wherein the heat treatment is f:. treatment.

10. A method of treatment of sugar lime according to E y preceding claim, wherein the heat treatment is carri d 20 out for sufficient time to raise the temperature to t least the minimum of that specified in any of it e preferred ranges above throughout substantially li the lime product.

11. An horticultural lime comprising a post s.Qic_ r purification heat treated sugar lime.

12. An horticultural lime according to claim 11, wheile n the sugar lime has been mechanically treated prior 0 heating.

13 13. A horticultural lime according to either claims 11 or 12, wherein the water content is sufficiently low to allow heat treatment.

14. A horticultural lime according to any of claims 11 to 13, wherein the sugar lime is treated with a flame heated worm or soil steriliser.

15. A horticultural lime according to claim 14, wherein the flame is directed through the centre of the worm.

16. A horticultural lime according to claim 15, wherein an inside face of the hopper wall includes an inwardly projecting flange that spirally extends along the is length of the barrel of the worm.

17. A method of treatment of sugar lime as herein described with reference to, and as illustrated by, the accompanying example.

18. An horticultural lime as herein described with reference to, and as illustrated by, the accompanying example.