EP0595902A1 - Fertiliser - Google Patents

Abstract

An NPK-based fertilizer includes finely ground adularia as a source of potassium and as a base that does not undergo a hydraulic setting reaction.

Description

" FERTILISER "

DESCRIPTION This invention relates to the nutrition of plants and has for an objective the provision of an improved fertiliser or soil conditioner. The invention is a development of the invention forming the subject of our European Patent 0,033,795B.

According to this European Patent a method of fertilising plants comprises applying to the media in which the plants grow the water-insoluble mineral adularia, in the form of particles sufficiently fine to make the potash in the adularia available to the plants. This adularia occurs as a component of a naturally occurring shale and this shale is applied finely ground. The Patent Specification explains that the adularia although water insoluble, has the ability in the finely ground state to make potash available and this ability probably arises from the low temperature formation of adularia. We have now come to appreciate that finely ground adularia shale has an applicability and utility wider than the provision of potassium as set out in our earlier European Patent.

Specifically we have appreciated that finely ground adularia shale or equivalent material which makes potassium (K) available to plants in a similar manner as set out above, can be used as a base for other soil nutrients specifically nitrogen (N) and phosphorous (P) and thus be the base for an NPK fertiliser. NPK fertilisers containing nitrogen, phosphorous and potassium (K) are in massive demand in agriculture and there is an increasing requirement that these fertilisers should be made of natural rather than synthesised ingredients. NPK fertilisers in accordance with the present invention using finely ground adularia as a base and a potash provider can readily satisfy this environmental requirement as the nitrogen and phosphorous can be supplied from organic sources. An important characteristic of finely ground adularia shale is that it does not set by hydraulic reaction when wet. It can thus serve, as will be described hereinafter, to absorb liquid or damp substances without subsequently setting in the manner of cement.

Thus according to one aspect of the present invention there is provided an NPK fertiliser comprising finely ground adularia shale or equivalent potassium provider and added nitrogen and phosphorous material. The nitrogen material can be derived from a naturally occurring source and be for example animal or poultry excrement, manure or similar. The phosphorus source can similarly be naturally derived and be for example a meal of powdered animal or poultry bones.

It is a preferred feature of the present invention that this NPK mixture comprising finely ground adularia as a base be formed into pellets or granules. Pellets or granules appropriately formulated can provide slow release of the nutrient components with beneficial effects. Pellets are also easier to handle for the user with less dust problems. Pellets are not subject to lumping and are thus easier to store and to apply in a spreader or other applicator. Pellets moreover can be accurately formulated and dispensed.

In accordance with another feature bentonite (0 - 3% by weight of formulation) or a mixture of bentonite and lignosulphate up to 3% may be included to combine with the adularia and other ingredients to make the pellets. Lignosulphate is slightly sticky to assist in pellet formation while bentonite acts as a binder and also serves to cause the granules to disintegrate when contact is made with soil moisture. Molasses are another suitable sticky binder.

Natural zeolites such as those sold under the Registered Trade Mark CLINOPTILOLITE can also advantageously be incorporated. These substances have excellent ion exchanging properties and can be used instead of or in addition to the bentonite.

The pellets may be manufactured by a conventional pelleting unit wherein the ingredients are extruded through a die with holes of the required dimensions. A rotating dish pelletiser may also be used. The principles of the present invention can thus also be applied in the absorption of pressed wet sewage sludge. A mixture of adularia and burnt (quick) lime can be applied to sewage sludge; the sludge is absorbed with the development of heat which has a sterilising function and the adularia serves a chemically neutral but physical absorbent function. The product of the sludge absorption exercise which may be regarded as a waste disposal is, of course, a valuable fertiliser providing nitrogen and potassium. It can be worked up to a full NPK fertiliser by the addition of phosphate material, for example in the form of ground apatite (rock phosphate).

The following Examples illustrate the invention. In every example the adularia is in the form of finely ground shale as described in European Patent No. 0,033,795B.

Example 1.

A typical formulation incorporating a sewage sludge is prepared from a mix as follows:- Pressed Wet Sewage - 250 Kg (Calculated on the basis Sludge of dry solids)

Adularia - 500 Kg

Burnt Lime - 350 Kg

The phosphorous components such as blood and bone meal, blood meal or rock phosphate may be incorporated. The exact quantities and end combination depend upon the approximate incoming analysis of the individual components and the required NPK ratio.

The components are mixed and then extruded into pellets. Water addition may be required to facilitate the formation of the final product. Heat is generated, by friction in the die during extrusion depending on the amount of adularia used.

Example 2

The following formulation is suitable for forming pellets with the incorporation as desired of a conventional N and P components in a rotating disc pelletiser.

Adularia - 90%

Bentonite - 2%

Lignosulphonate - 1%

Again sufficient water for effective pellet formation may be added.

Example 3

The following formulation is suitable for extrusion.

Again water is added as necessary. The blood and bone meal lubricates the extrusion die which counters the rise in temperature mentioned in Example 1. An NPK ratio of 3 - 1.5 - 4 is provided. Example 4

A Stable combined synthetic/organic fertiliser with good lime imparting properties and particularly suitable for lawns and grasslands comprises:

N.28 (a proprietary synthesised aimonium compound available inter alia from Norsk Hydro) - 40%

Adularia - 25%

Ground Dolomite - 35%

This composition is an uncc-mpounded mixture and has a NPK + Mg ratio of 10-0-2+5% Mg.

Claims

1. A compound fertiliser and soil treatment agent comprising a base of ground adularia or equivalent non-water-soluble low temperature formed mineral and one or more additional fertilising elements.

2. A fertiliser according to Claim 1 including nitrogen.

3. A fertiliser according to Claim 1 or Claim 2 including phosphorus.

4. A fertiliser according to any preceding claims in the form of pellets and granules.

5. A fertiliser according to Claim 3 including a lignosulphate.

5. A fertiliser according to Claim 3 including molasses. 7. - A fertiliser according to any preceding claim including sewage sludge absorbed by lime.

8. A fertiliser according to Claim 3 incorporating blood and bone meal as a source of phosphate and a lubricant to ease extrusion into pellets.