GB2206340A

GB2206340A - Composition for soil improvement

Info

Publication number: GB2206340A
Application number: GB08815077A
Authority: GB
Inventors: Herbert Hans Wagner
Original assignee: PERLITE GmbH; Deutsche Perlite GmbH
Current assignee: PERLITE GmbH; Deutsche Perlite GmbH
Priority date: 1987-06-25
Filing date: 1988-06-24
Publication date: 1989-01-05
Anticipated expiration: 2008-06-24
Also published as: GB2206340B; FR2617158A1; ATA148888A; NL8801459A; GB8815077D0; CH675717A5; BE1000982A5; FR2617158B1

Description

2206340 Composition for soil improvement

Specification

The invention relates to a composition for soil improvement, particularly for improving the soil of agricultural land, in greenhouses and/or for pot plants.

Many systems are available for improving the structure of soils, including fertiliser peat, a fertiliser used in a variety of forms. At one time, brownishcoloured "white" peat was particularly common although this has largely disappeared from central Europe and is being replaced increasingly by black peat. Peat consists of 40 to 50% by weight of organic matter and water and 1 to 2% by weight of minerals (ash). On the one hand, intensive cultivation and exploitation of soil and the consequent deterioration in structure have led to an increasing demand particularly for humus peat substrates, whilst on the other hand, further long term working of natural peat supplies is no longer acceptable.

Styropor granules are als,-, used to the structure of soil, more particularly to open it up. However, styropor granules can only open up the soil and will not simultaneously add nutrients.

Consequently, it is an object of the invention to provide a soil improving agent which does away with the need for peat and by means of which the physical and chemical properties of soil and the growth of the plants rooted in the soil can be improved.

The invention results from the discovery that there are a number of natural porous substances with a high open porosity which can be provided with suitable additives and thus serve as carrier substances 5 for introducing essential nutrients into the soil.

According to one feature of the invention there is provided a composition, .for soil improvement comprising a granular carrier substance with a high open porosity, and humic acid and/or a salt thereof, the granular carrier substance preferably being coated with the humic acid and/or its salts.

By incorporating the humic acid or salt thereof in a porous carrier substance which is spread over the soil or worked into it, it is possible to achieve a uniform distribution of the humic acid in the sIbil. As a result of the extremely high open porosity of the carrier, which may for example be expanded volcanic rock, preferably perlite, the humic acid is bound in the carrier substance for a certain length of time, so that it can be slowly and continuously released into the surrounding soil.

Preferably, the porous, granular carrier substance is soaked in aqueous, flowable humic acid or a salt thereof until the desired degree of is achieved, after which it is dried. The particle size of the carrier substance may for example be between 2 and 10 mm, preferably between 2 and 5 mm. Numic acid is generally obtained from lignite and is a relatively cheap basic material which is commercially obtainable. The composition of the invention is particularly useful in soils of poor structure.

Humic acid and the salts thereof, such as the potassium or sodium salts, serve as growth promoters and soil improvers for soils of poor structure or low ion 51 1 exchange capacity. Humic acid promotes the activities of the living organisms in the soil, including earth worms, it is free from artificial additives, it improves the soil structure directly by opening up heavy soils and indirectly by promoting the production of bacterial adhesives, by means of which fine particles are cemented to form a crumbly texture. This, in particular, also results in loosening of the soil. Furthermore, humic acid increases the water capacity of the soil. This is achieved on the one hand by binding water to the organic substance and on the other hand by improving the structure of the soil. Moreover, humus substances (humic acids) imrove the ventilation of the soil, since a good crumbly structure will result in larger pores, ensuring a better supply of oxygen to the roots and easy escape of carbon dioxide from-the root space. Moreover, humic acid and the salts thereof are capable of storing nutrients on their surface in exchangeable form, which is particularly important for soils with a low clay content. Humic acid and the salts thereof also ensure, by their water capacity, that the soils can survl'v'-e periods of - drought without damage.

The combination of humic acid with the expanded volcanic rock perlite has the particular advantage that perlite is a very light, inorganic material with a relatively large surface area, thus ensuring that the humic preparation is optimally distributed in the soil.

The composition according to the invention may be prepared by mixing the granular carrier substance with the humic acid or salt thereof, for which purpose the humic acid or salt thereof is preferably in flowable aqueous form, in a mixer together with any other constituents described in more detail hereinafter. The components are mixed until the additives have wetted the free surface of the carrier substance up to a predetermined value. Alternatively the flowable, aqueous humic acid, or salt thereof, and optionally other constituents may be sprayed onto the carrier substance.

In order to ensure a slower release of the humic constituents after the preparation has been spread over or worked into the soil, the composition of the invention may be provided with a binder. This binder may consist of a waterglass (potassium and/or sodium waterglass). A potassium silicate is particu- larly advantageous since it additionally provides potassium as a nutrient ion. The humic acid or salt thereof may be mixed with the binder before application to the carrier substance.

In order to maintain the flow crualities of the composition during the production process, silica can be added after the perlite has been soaked in the solution consisting of waterglass and humic acid (or the salts thereof) when the composition is in the damp state. The silica may, for instance be sprayed onto the porous carrier. As a result of the chemical binding of the water the product dries out and does not have to be dried in a separate operation. Moreover, the waterglass or the silica has positive effects on the durability of the plants in the case of cultivated and ornamental plants. in the case of cereals, in particular, the silica strengthens the supportinq tissue, thereby increasing the stalk stability and reducing crop flattening. Moreover, silica promotes resistance to fungal diseases.

9 1 - 5 A further advantage is that the silicate native to the soil often cannot be mobilised in sufficient quantities; therefore, the composition according to the invention can provide a supply of soluble 5 and readily mobilisable silicate.

The composition may also contain an additional amount of revitalising substances, particularly dolomite, phosphates, other growth promoters, precipi10 tated silica and/or magnesium carbonate.

The use.of magnesium (for instance from added dolomite or magnesium carbonate) is usually necessary because magnesium deficiency occurs to a greater extent in plants which have been intensively fertilised with nitrogen-phosphate-potassium. This is seen particularly frequently in ornamental plants. It occurs particularly as the plant requires more as it grows and as a result of the magnesium being 20 washed out, especiallv in acid soils.

In order to prevent any deficiency of trace elements, a mixture of complexed trace elements may also be-added-t7o the recipe.' These elements are preferably bound in complexed form in EDTA (ethylenediaminetetraacetic acid) in a form which is readilyavailable to the plants. The following trace elements may be used: copper, iron, manganeset magnesium, zinc, boron, cobalb and/or molybdenum.

These trace elements are also released slowly and in metered form. Trace elements are imi Dortant because they are lost by leaching out from overacidified soils or when soils are limed with, for example, smelter limes which have a high content of calcium oxide, which renders the trace elements unavailable for the plants.

- 6 -1 A carrier particle coated with humic acid and/or a salt thereof, silica and kinetin has proved particularly advantageous, since it results in a synergistic interaction of the individual components to provide 35 optimum improvement of the soil.

in addition to the substances already mentioned, the recipe may also include growth-promoting compounds, such as kinetin (furfurylaminopurine C 10H9NS 0).

These growth promoters remedy fine metabolic disorders particularly in trees. Kinetin, which belongs to the kinin family, is one of the most important key substances in the cell biology of plants. Kinetin promotes cell division in plants and the rooting of seedlings and prevents premature ageing of plant parts. This is particularly important in ornamental plant cultivation.

Kinetin may be used in particular in conjunction with indole acetic acid, which is a growth accelerator, and, in this combination, it promotes a slow, i.e. not too rapid, growth and favours the metabolic conditions, thereby preventing loss of nutrients and premature exhaustion of plants such as trees.

Generally, the addition of for example 1 mg of kinetin to 1 litre of granules is sufficient.

Dolomite-i-s preferably 'Used with a particle size of up to 0.5 mm and should have a minimum magnesium carbonate content of 40% by weight. It serves primarily as a protective buffer for over-acidified soils and to provide a long term supply of calcium and magnesium.

The efficacy of the composition can be further increased if, for example, magnesium carbonate is incorporated as a plant growth promoter and/or if complexed trace elements are also added.

The composition may contain up to 70% by weight humic acid (or salt thereof) and other non-carrier constituents, more preferably up to 35% by weight.bumic acid or salt thereof and other non-carrier 10 constituents.

Claims

1. A composition for soil improvement comprising a granular carrier substance with a high open porosity, and humic acid and/or a salt thereof.

2. A composition as claimed in claim 1 in which the granular, porous carrier substance is coated with humic acid and/or a salt thereof.

3. A composition as claimed in claim 1 or claim 2, wherein the carrier substance consists of an expanded volcanic rock.

4. A composition as claimed in claim 3, in which the carrier substance consists of expanded perlite.

5. A composition as claimed in any of claims 1 to 4 in which the carrier substance has a particle size of between 2 and 10 mm.

6. A composition as claimed in claim 5 wherein the carrier substance has a particle size of between 2 And 5 iiri-.

7. A composition as claimed in any of claims 1 to 6, wherein the salt of humic acid is a sodiunt salt.

8. A composition as claimed in any of claims 1 to 6, wherein the salt of humic acid is a potassium salt.

9. A composition as claimed in any of claims 1 to 8, wherein the humic acid and/or salt thereof is mixed with a binder before being applied to the carrier substance.

11

10. A composition as claimed in claim 9, wherein the binder consists of waterglass.

11. A composition as claimed in claim 10 wherein 5 the waterglass is sodium or potassium waterglass.

12. A composition as claimed in any of claims 1 to 11, further comprising one or more revitalising substances, selected from dolomite, phosphates, growth promoters, precipitated silica and/or magnesium carbonate.

13. A composition as claimed in any of claims 1 to 12, further comprising complexed trace elements.

14. A composition as claimed in claim 13 wherein the trace elements include copper, iron, manganesef magnesium, zinc, cobalt, boron and/or molybdenum.

15. A composition as claimed in claim 13 or claim 14, wherein the complex forming agent for the trace elements is ethylenediaminetetraacetic acid.

16.- A cFdffiposition as claimed in claim 12, wherein 25 the growth promoters include kinetin.

17. A composition as claimed in any of claims 1 to 16, in which the carrier substance is charged with silica.

18. A composition as claimed in any of claims 1 to 17 comprising up to 70% by weight of humic acid or salt thereof and other non-carrier constituents.

19. A composition as claimed in claim 18 comprising up to 35% by weight of humic acid or salt thereof and other non-carrier constituents.

-

20. A process for preparing a composition as claimed in any preceding claim, wherein the granular carrier substance having a high open porosity is placed in a mixer together with the flowable aqueous humic acid and/or a salt thereof and optionally other constituents, and the components are mixed until the additives have wetted the free surface of the carrier substance up to a predeterminable value.

21. A process for preparing a composition as claimed in any of claims 1 to 19, wherein the aqueous, flowable humic acid and/or a salt thereof and optionally other constituents are sprayed onto the porous granular carrier substance.

22. A process as claimed in claim 20 or claim 21, characterised in that silica is subsequently applied to the porous, granular carrier substance coated with humic acid and/or a salt thereof and optionally other constituents.

23. A process as claimed in claim 22 wherein the silica is sprayed onto the porous, granular carrier substance.

Published 1988 at The Patent Office. State House. 6671 High Holborn. London WC1R 4TP Further copies Tnay be obtained from The Patent Offtce, Sales Branch, St May Cray. Orpington, Xent BR5 3RD. Printed by Mulltipiex teclxlqies l-d, St Mal-y Crj;. KCr. COn 18,7