NO123575B - - Google Patents

Description

Micro fertilizer containing one or more inorganic iron salts.

The invention relates to microfertilizers containing one or more inorganic iron salts which are added to the soil to remedy iron deficiency damage in plants and for preventive treatment of such damage. As is known, iron is an absolutely necessary element for growth and metabolism in plants. It is known that iron is an essential component of the respiratory enzymes that control the oxygen transfer in the plant organism. Iron deficiency can lead to considerable disturbances of the metabolism and to damage which manifests itself in poor growth, small yields and yellowing of the leaves, the so-called chlorosis. Meadows and pastures, lawns, fruit trees, vines, cereals and many ornamental plants are easily affected by iron deficiency damage. The causes of the deficiencies can lie in a too low iron content in the soil, too high a pH value, and less often in a lack of other main or trace nutrients.

Since the problem of supplying iron to our cultivated plants is of considerable economic importance, attempts have long been made to avoid iron deficiency by fertilizing with iron salts, e.g. ferrous sulfate, ferric sulfate, ferrous ammonium sulfate or potassium ferrocyanide. It has then been shown that most plant types are only able to take up inorganically bound iron from the soil to a very small extent or not at all. This applies particularly in alkaline calcareous soil. Furthermore, the use of inorganic iron salts in the minimum quantities required for this purpose is always associated with the risk of plant damage.

In recent times, better results have been achieved with iron complexes of organic acids, e.g. ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid and similar complexing agents. Although these compounds also offer certain disadvantages, since they simultaneously require the use of large quantities of water, and as the compounds are broken down relatively quickly by microbes in the soil, these preparations must still be described as progress. Unfortunately, such iron complexes are so expensive that they are only used when large losses of valuable crops are at stake.

It was now found that cheap, inorganic iron salts, e.g. iron-II-sulphate or iron-III-sulphate is easily and quickly taken up by the plants, contrary to all assumptions of those skilled in the art, when the compounds are added to formaldehyde-urea condensates in effective amounts. As is known, the condensates mentioned essentially consist of methylene diurea, dimethyl triurea, trimethylene tetraurea and tetramethylene pentaurea,

which breaks down in the soil at different rates and is used in fertilizers as a slowly releasing nitrogen source. If one prepares intimate mixtures of such urea-formaldehyde condensates and inorganic iron compounds, e.g. by granulating powdered ingredients, one finds such a high utilization of the iron by the plants when spread on iron-poor soil, which was previously only known when using iron complexes.

It is currently not clear what this specific effect of the combination is due to. However, based on the effect, it can be assumed that complexes are formed of iron sulfate with lower

in

condensed, easily water-soluble components in the urea-formaldehyde condensate, which in this form can be taken up particularly easily by plan-

tenes rats. This is supported by the fact that careful mixtures of urea-formaldehyde condensates and iron salts, especially those produced by granulation of finely powdered components, show the aforementioned iron fertilization effect particularly clearly. However, the same effect is not achieved with products where iron salts are incondensed by the condensation process between formaldehyde and urea. It should not be said whether the higher temperature and higher pH in the condensation conditions causes a different binding form for the iron sulphate, or whether this binding under these conditions is preferably formed with highly condensed and very slowly soluble components in the condensate.

Both possibilities explain why products whose iron content is added during condensation often need weeks to show an iron fertilization effect, while intimate mixtures of the type described above show this effect mostly after a few days. A simple and quick detection of the iron uptake by the plants can be achieved on lawns. Most grass species show a light green color on iron-poor soil, which changes to yellow-green or yellow in poor growing conditions. Mineral fertilizer does indeed favor the plants' growth, but does not change the unhealthy colour. Fertilization with iron sulphate, which, for comparison, is used in agriculture in amounts of 200 - 450 kg per year. hectares FE SO^ . 7 H20, rarely leads to improvement and often to damage to the plants. Fertilizing with regular urea-formaldehyde condensate can improve the general condition and growth of the lawns, but does not change the lack of color due to the iron deficiency or the resulting deficiency damage and diseases of the grass. By combined spreading of urea-formaldehyde condensate (with e.g. 35 - 38 fo nitrogen content) and iron sulphate (iron-vitriol) in the ratio 10 : 1 to ©arr 1 : 10 in quantities of 5 - 10 kg per hectare of iron, depending on the weather and growing conditions, over the course of a few days, the grass becomes noticeably greener, down to a deep green colour.

At the same time as the promotion of chlorophyll formation, the grass plants become stronger and more resistant and develop wider leaves. The presence of the urea-formaldehyde condensate has thus made it possible for the plants to absorb and utilize the iron salts. If you analyze the iron content of the plants, you will find for the treatment an iron content of approx. 20 - 25 dpm, which 1-2 weeks after spreading the fertilizer has increased to 2-4 times as much.

Similar clear attempts can be carried out in connection

with fruit cultivation using the same fertilizer mixture for the soil around the tree roots. It is clear that the ferrous sulfate is transferred in the presence of urea-formaldehyde condensates to a form that can be transported in the plant organism, which can hardly be achieved with ferrous sulfate alone. Mixtures of the two aforementioned components may contain other macro- or micro-nutrients, e.g. on the basis of phosphorus, potassium, magnesium, copper, boron, manganese, zinc, etc. When testing such mixtures or their components with the addition of iron compounds, it is always clear that only the interaction between urea-formaldehyde condensate and iron salts has the described iron fertilizing effect in the soil, namely approximately the same strong effect as with iron complexes.

Example 1

A homogeneous mixture of 9 parts urea-formaldehyde condensate with 37.5 1° N content, and 1 part ferrous sulphate FeSO^ . 7 H2O (approx. 20 in Fe) is processed in the usual way into a granule with an average particle diameter of 1-2 mm. 7.5 kg of this mixture 1 is spread on 100 m 2 of ornamental lawn growing on iron-poor soil. In the course of a few days the lawn, which was initially yellowish to pale green, takes on an increasingly intense green color down to dark green and becomes dense and vigorous.

Example 2

A homogeneous mixture of is granulated in a known manner

40 in urea-formaldehyde condensate (approx. 37.5% N content)

10% ferrous sulfate Fe SO^ . 7 RgO

10 in ammonium nitrate

20 in superphosphate (18 in ?2°5>>

10 in potassium sulfate (47% K20)

10 in magnesium sulfate (bitter salt MgSO^ 7 H20)

to a grain size of 1 - 3 ™n- This complete fertilizer shows in all common areas of use and above all on soil that suffers from a jerh deficiency in connection with plants that have a strong need for iron, e.g. in a mixture with flower soil, for the cultivation of ornamental plants, fruit trees, vineyards and grain, in the course of a few days a very strong germination effect and such a surprisingly high increase in chlorophyll formation that until now could not be achieved by the addition of inorganic iron salts and which can otherwise only be achieved by dispersing costly iron complexes. Instead of iron-II sulfate in the above-mentioned fertiliser-

IN

ning preparation, iron III-sulphate, ferrous ammonium sulphate, potassium ferrocyanide or other inorganic iron compounds can be added with the same effect.

Example 3-

In a known manner, a homogeneous mixture of

40$ urea-formaldehyde condensate (approx. 37>5$ N content) 10$ iron-II sulfate (7 H20)

10?5 ammonium nitrate

20$ superphosphate

10$ Potassium Sulphate

8$ bitter salt (Mg SO^ • 7 H20)

2$ amide of 2,4-dichlorophenoxyacetic acid

to a grain size of 1 - 2 mm in diameter. This fertilizer is ideally suited in quantities of approx. 7>5 kg per 100 m 2 to improve the quality of ornamental lawns and sports lawns, especially on iron-poor soil while simultaneously combating broad-leaved weeds.

Claims (2)

1. Micro-fertilizer containing one or more inorganic iron salts for counteracting iron deficiency damage in plants and for preventive treatment of such damage, characterized in that the fertilizer is mixed with effective amounts of urea-formaldehyde condensates to increase or enable the effect of the iron salts. 2. Fertilizer as specified in claim 1, characterized in that the iron salt is an iron sulfate and that the fertilizer contains at least 10% urea-formaldehyde condensate calculated from the amount of iron sulfate. 3" Fertilizer as specified in one or more of claims 1 or 2, characterized in that the urea-formaldehyde condensate has a nitrogen content of 35 - 38$- 4- Fertilizer according to one or more of claims 1-3> characterized in that the amount to be used per hectare contains 5-10 kg of iron.