GB1564846A - Peat - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO PEAT (71) We, TORFSTREUVERBAND GESELLSCHAFT MIT BESCHRANKTER HAFTUNG, a Company of the Federal Republic of Germany, of Bloherfelder Str. 39, D-2900 Oldenburg, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a method of processing peat so as to influence its wettability by using tensides.

To reduce transport costs, peat is normally supplied in bales, usually having a water content of approximately 50%. It then feels completely dry and absorbs water with great difficulty. This is a disadvantage, particularly for peat culture substrates used by gardeners, since it has to be almost completely saturated with water when used, and this requires considerable labour. In order to improve the soil, however, peat must be completely moist. Consequently, the importance of improving the wettability of dry peat extends far beyond the domain of peat culture substrates. In the case of such substrates, however, it is particularly important to improve the wettability, since most other kinds of industrial earth are easier to moisten and this restricts the usefulness of peat culture substrates.

Attempts have, therefore, been made to reduce the resistance of peat to absorbing water by adding tensides (wetting agents). Peat treated in this manner can usually be satisfactorily moistened if it is used immediately after adding the tenside. In the case, however, of peat, peat culture substrates and other peat products delivered in bales, several months, often a year, elapse between manufacture and delivery to the consumer, whereas the improvement in wettability produced by adding tensides is lost in a few weeks. A progressive improvement is obtained by increasing the amount of tenside, but the effect tends to decrease until it is completely useless, as shown in Figure 1 of the accompanying drawings.

Anionic tensides are more suitable than non-ionic tensides, but anionic tensides cause much more damage to plants.

In order to make a start in solving this difficult problem, 28 variously-charged tensides were tested for their effect on improving the wettability of peat. It was found that only 4 tensides, all anionic, were capable, when mixed with peat, of keeping it sufficiently wettable for practical purposes after prolonged storage. In the case of the remaining 24 tensides, the wetting times after only one month of storage, using I g of tenside per litre of peat, were between 800 and 10,000 seconds for non-ionic tensides and between 300 and 7,000 seconds for anion-active tensides.

Sudh substances, therefore, cannot be used alone for improving the wettability of peat.

The wetting effect was tested by placing 20 ml of each peat/tenside mixture on a water surface and measuring the time until it sank below the surface. All the wetting times given hereafter were determined by this method. The wettability is of practical use for the gardener if the peat/tenside mixture sinks below the surface within 100 seconds even after prolonged storage (1 or 2 years). The wettability is not likely to decrease after 6 months. Peat of this kind readily absorbs water supplied from a watering-can or hose and sprinkler. In such cases, the gardener does not need to waste time in wetting the peat or peat culture substrates.

As already mentioned, we found 4 tensides which 1. Produced sufficiently rapid wetting of the peat, and 2. Did not show any substantial decrease in the effect after prolonged storage.

These tensides were added in the proportions by weight of 0.001 g to 10 g (in powers of 10) per litre of peat and the change in wettability after prolonged storage was determined by continuous measurements. These 4 tensides did not show any decrease in effectiveness. After 3 months of storage, the wetting times (in seconds) in the following Table I were obtained. Concentrations below 0.1 g tenside per litre peat are not given, since they are quite unimportant in view of the length of the wetting time.

TABLE I

Wetting times in Wetting times in seconds g tenside/ Substance litre peat 0.1 1.0 10.0 Na-diisooctyl sulphosuccinate > 700 23 2 Secondary Na-n-alkane sulphate > 7000 34 22 Dodecyl benzene sulphonic acid > 2000 110 5 Highly-branched perfluoro group + > 7000 34 2 containing compound * ICI Trade name: Montflor 31 Wetting times below 100 seconds, when 1.0 g or more of tenside is added per litre of peat, ensure excellent wettability even after a long period.The time curves of the wetting coefficients indicate that there is no decrease in effect, even after prolonged storage, down to the proportion of 1.0 g. If the amount of tenside is less, the wetting times even for these substances rapidly increase to very large amounts, as shown by the values for 0.1 g of tenside per litre of peat. Table II shows the fresh weight of 8 lettuces (from a test performed 4 times), the lettuces being grown in the peat/tenside mixtures.

TABLE II

Fresh weight in g (8 lettuces,) g tenside/ Substance litre peat 0.001 0.01 0.1 1.0 10.0 Na-Diisooctyl sulphosuccinate 57 59 62 25 0 Secondary Na-n-alkane Sulphate ** 38 57 55 40 5 Dodecyl benzene sulphonic acid 46 64 48 26 0 Highly branched perfluoro gr oup 48 50 56 10 0 containing compound Average yield: 47 58 55 25 1 ** Corrected values, based on 60% concentration of active substance.

When 1.0 g of the above tensides is added per litre of peat, there is considerable inhibition of growth.

The results of the wetting tests, shown numerically hereinbefore, are graphically evaluated in Figure 2 of the accompanying drawings. Assuming that the wetting time should not exceed 100 seconds if possible, it is possible to calculate the minimum amount of tenside. This amount is 600 mg per litre peat in the case of the highly active tensides shown in Figure 2. If the amount is substantially below this, the peat/tenside mixture is not adequately wetted.

Similarly, Figure 3 of the accompanying drawings shows the measured fresh weight of lettuces. As before, it is possible to calculate a limiting value, that is 60 mg of tensides per litre of peat. If this amount is exceeded, plant growth is rapidly and seriously inhibited.

Figure 3 also shows that each tenside produces an optimum yield, the amount of tenside varying between 0.005 and 0.05 g per litre of peat. It can, therefore, be assumed that when 0.001 g tenside is added per litre of peat, it does not affect plant growth, that is the plant yield is the same as from the peat without tenside. In this experiment, a marked increase in yield was produced by adding about 0.01 g of tenside per litre of peat. Other authorities have reported similar improvements in yield by adding tensides.

According to Figures 2 and 3, there is a region between 60 mg and 600 mg of the given tensides per litre of peat, at which plants are damaged if the lower value is exceeded, and the peat-tenside mixture does not remain adequately wettable after prolonged storage if the upper value is less than that given.

It is an object of the present invention to process peat so that, when dry, it can be easily, rapidly and permanently wetted, without impairing the good effect of the peat on plant growth.

It was very difficult to find a solution of this apparently insoluble problem, that is to find a tenside which, when added in the proportion of 600 mg/litre peat, does not cause plant damage, or a tenside which, when added in the proportion of 60 mg per litre peat, ensures sufficient wettability even after prolonged storage. It must also be assumed that there are no known, more effective tensides for this purpose than the following 4 highly active anionic tensides: 1. Na-diisoocyl sulphosuccinate 2. Secondary Na-n-alkane sulphate 3. Dodecyl benzene sulphonic acid 4. Highly branched perfluoro group containing compound.

In the rest of the description, these tensides are called "HAP" (highly active peat) tensides. Even they, however, appear to be unsuitable for improving the wettability of peat, since they do not cause adequate wettability if added in the proportion of less than 600 mg/litre of peat, but damage plants when in the proportion of over 60 mg/litre of peat.

During subsequent research, we unexpectedly found the following key to the solution: 1. If the above-mentioned HAP tensides are added in combination, that is, 2, 3 or all 4 together, the wetting effect is greater than the additive effect.

2. If the above-mentioned HAP tensides are combined, that is if 2, 3 or 4 are added together, the limit at which plants are damaged is not reached until higher amounts of tensides are added. Apparently, the harmful prin,ciples in individual tensides act independently, so that the limit of 60 mg of tenside/litre of peat has to be observed only for individual HAP tensides. If 2 are added, this value increases to 120 mg, whereas if 3 are added, the value increases to 180 mg/litre peat.

3. A particularly surprising discovery was that the effects described in 1) and 2) are also shown by combinations of HAP tensides with tensides which have no useful effect on wettability. In such mixtures, however. in contrast to mixtures of HAP tensides, there is a decrease in effectiveness (in up to half a year, as usual).

The quantity must by increased to compensate this effect. There is no difficulty in increasing the amount, since the intrinsically inactive tensides are usually better tolerated by plants, and this property is completely taken over by the previouslymentioned combinations.

According to a first aspect of the present invention, there is provided a method of improving the wettability of peat, which method comprises adding at least two tensides to peat, at least one of the tensides being selected from: Na-diisooctyl sulphosuccinate: secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

According to a second aspect of the present invention, there is provided a method of processing peat so as to influence the wettability thereof, wherein at least two tensides are mixed with the peat, the tensides being selected from: Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

According to a third aspect of the present invention, there is provided a method of processing peat so as to influence the wettability thereof, wherein there are mixed with peat at least one tenside not having an effect on peat and at least one of the following tensides: Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

The improvement in the wettability of a peat/tenside combination prepared from the previously-mentioned HAP tensides and the less active tensides is shown in the following Table III.

TABLE III

Wetting time in Peat culture substrate mixed with Amount in seconds after 3 following tensides mg/litre peat months of storage Na-diisoocyl sulphosuccinate 50 2100 Na-lauryl alcohol ether sulphate 100 9600 Secondary Nan-alkane sulphate 400 8640 Substances in combination: 400 18 In this Example, two anionic HAP tensides, that is Na diisooctyl sulphosuccinate and secondary Na-n-alkane sulphate, and a tenside which has practically no effect on the wettability of peat, that is anionic Na-lauryl alcohol ether sulphate, were added singly and in combination.The individual substances, when added in the given quantities, do not make any practical improvement in the wettability of the peat/tenside mixture. The three substances in combination, however, produce very good wettability even after 3 months of storage. In spite of the large doses of tensides, there was no observable decrease in yield. On the contrary, the tensides produced a considerable increase in yield, as shown in the following Table IV.

TABLE IV

Fresh weight of Peat culture substrate 8 lettuces Percentage With tens ides in the proportions given in the last table 22.9 137% Withouttensides 16.7 100% The test results clearly show a region which is important for the invention and in which adequate wettability and complete toleration by plants are ensured only if at least two HAP tensides or at least one HAP tenside is added with at least one tenside which does not act on peat. The following preferred upper and lower limiting values can be fixed for this region.In view of the fact that peat may often contain wide variations in the weight of dry substance per unit volume (due perhaps to the degree of decomposition and also in the difficulty of determining bulk weight), it is advantageous to give the figures also as percentage weights. Since, without exception, the peat in these tests contains about 50 g dry substance per litre, the percentage weights relative to dry substance can easily be calculated.

Under these conditions, we obtain the following preferred lower and upper limiting values: l. For combinations consisting for example only of' the following HAP tensides: Na-diisooctyl sulphosuccinate Secondary Na-n-alkane sulphate Dodecyl benzene sulphonic acid Highly branched perfluoro group containing compound, the following upper and lower limiting values are obtained: a) Preferred lower limiting value: 60 mg of HAP tensides per litre peat or 0.12 wt.% HAP tensides related to dry substance; the number of the individual HAP tensides in the combination are unimportant.

b) Preferred upper limit: 600 mg of HAP tensides/litre of peat or 1.2 wt. ó of HAP tensides relative to peat dry substance; as before, the number of the HAP tensides in the combination is unimportant.

2. In the case of the HAP tensides mentioned in 1) in combination with other tensides which are completely without effect on the wettability of dry stored peat, the preferred lower and upper values are: a) Preferred lower limiting value: 30 mg of HAP tensides or 0.06 wt.% of HAP tensides relative to peat dry substance: the number of the HAP tensides in the combination is unimportant.

b) Preferred upper limiting value: 1.2 g of total tensides including at least 30 mg of HAP tensides per litre peat or 2.4 wit.% relative to peat dry substance. The amount above the 30 mg HAP tensides can be made up with one or more HAP or other tensides.

The following Example further illustrates the present invention.

Example A slightly decomposed bog peat to DIN 11542 containing 50 kg/m2 dry substance and 450o water was mixed with fertiliser required for peat culture substrate and with the following amounts of tensides: 1. HAP tensides: 40 g of sodium diisooctyl sulphosuccinate, 60 g of secondary Na-n-alkane sulphate.

2. Other tensides which have no practical effect on the wettability of peat: 100 g of nonylphenol, 50 g of propylene oxide and ethylene oxide block polymers.

Total: 250 g tensides per m3 peat.

The tensides can be added in liquid form with water to the peat and fertiliser before mixing. The peat, fertiliser and tensides are mixed in conventional manner in a mixer.

WHAT WE CLAIM IS:- 1. A method of improving the wettability of peat. which method comprises adding at least two tensides to peat, at least one of the tensides being selected from:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. The test results clearly show a region which is important for the invention and in which adequate wettability and complete toleration by plants are ensured only if at least two HAP tensides or at least one HAP tenside is added with at least one tenside which does not act on peat. The following preferred upper and lower limiting values can be fixed for this region. In view of the fact that peat may often contain wide variations in the weight of dry substance per unit volume (due perhaps to the degree of decomposition and also in the difficulty of determining bulk weight), it is advantageous to give the figures also as percentage weights. Since, without exception, the peat in these tests contains about 50 g dry substance per litre, the percentage weights relative to dry substance can easily be calculated. Under these conditions, we obtain the following preferred lower and upper limiting values: l. For combinations consisting for example only of' the following HAP tensides: Na-diisooctyl sulphosuccinate Secondary Na-n-alkane sulphate Dodecyl benzene sulphonic acid Highly branched perfluoro group containing compound, the following upper and lower limiting values are obtained: a) Preferred lower limiting value: 60 mg of HAP tensides per litre peat or 0.12 wt.% HAP tensides related to dry substance; the number of the individual HAP tensides in the combination are unimportant. b) Preferred upper limit: 600 mg of HAP tensides/litre of peat or 1.2 wt. ó of HAP tensides relative to peat dry substance; as before, the number of the HAP tensides in the combination is unimportant. 2. In the case of the HAP tensides mentioned in 1) in combination with other tensides which are completely without effect on the wettability of dry stored peat, the preferred lower and upper values are: a) Preferred lower limiting value: 30 mg of HAP tensides or 0.06 wt.% of HAP tensides relative to peat dry substance: the number of the HAP tensides in the combination is unimportant. b) Preferred upper limiting value: 1.2 g of total tensides including at least 30 mg of HAP tensides per litre peat or 2.4 wit.% relative to peat dry substance. The amount above the 30 mg HAP tensides can be made up with one or more HAP or other tensides. The following Example further illustrates the present invention. Example A slightly decomposed bog peat to DIN 11542 containing 50 kg/m2 dry substance and 450o water was mixed with fertiliser required for peat culture substrate and with the following amounts of tensides: 1. HAP tensides: 40 g of sodium diisooctyl sulphosuccinate, 60 g of secondary Na-n-alkane sulphate. 2. Other tensides which have no practical effect on the wettability of peat: 100 g of nonylphenol, 50 g of propylene oxide and ethylene oxide block polymers. Total: 250 g tensides per m3 peat. The tensides can be added in liquid form with water to the peat and fertiliser before mixing. The peat, fertiliser and tensides are mixed in conventional manner in a mixer. WHAT WE CLAIM IS:-

1. A method of improving the wettability of peat. which method comprises adding at least two tensides to peat, at least one of the tensides being selected from:

Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

2. A method of processing peat so as to influence the wettability thereof, wherein at least two tensides are mixed with the peat, the ten sides being selected from: Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

3. A method of processing peat so as to influence the wettability thereof, wherein there are mixed with peat at least one tenside not having an effect on peat and at least one of the following tensides: Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecyl benzene sulphonic acid; and a compound having a highly branched perfluoro group.

4. A method according to Claim 2, wherein the tensides are added within the following limits:- (a) Lower limiting value: 60 mg of tensides/litre of peat or 0.12% by weight of tensides, related to the dry substance, and (b) Upper limiting value: 600 mg of tensides/litre of peat or 1.2% by weight-Qf tensides relative to the dry substance.

5. A method according to Claim 3, wherein the Na-diisooctyl sulphosuccinate, secondary Na-n-alkane sulphate, dodecyl benzene sulphonic acid, and the compound having a highly branched perfluoro group are added within the following limits:- (a) Lower limiting value: 30 mg of tensides listed above or 0.06% by weight of tensides listed above relative to peat dry substance, and (b) Upper limiting value: 1.2 g of total tensides including at least 30 mg of tenside listed above per litre peat or 2.4% by weight relative to peat dry substance.

6. A method according to Claim 5, wherein the following amounts of tensides are added per m3 peat: 40 g of sodium diisooctyl sulphosuccinate, 60 g of secondary Na-n-alkane sulphate, 100 g of nonylphenol and 50 g of propylene oxide and ethylene oxide block polymer.

7. Peat having improved wettability which has added thereto at least two tensides, at least one of the tensides being selected from: Na-diisooctyl sulphosuccinate; secondary Na-n-alkane sulphate; dodecylbenzene sulphonic acid; and a compound having a highly branched perfluoro group.

8. A method of improving the wettability of peat, substantially as described in the foregoing example.

9. Peat whenever having wettability improved by the method of any one of Claims 1 to 6 and 8.