AT18314U1 - Use of synthetic calcium carbonate for the treatment of plants - Google Patents

Abstract

Use of synthetic calcium carbonate for the treatment of plants, whereby a suspension of synthetic calcium carbonate in water is applied to the field. In order to protect the plants themselves from sunlight, the invention provides that the synthetic calcium carbonate is crystallized in the form of scalenehedra to an extent of at least 80% by weight, preferably at least 90% by weight.

Description

Description

[0001] The present invention relates to the use of synthetic calcium carbonate for the treatment of plants, whereby a suspension of synthetic calcium carbonate in water is applied to the field.

[0002] Synthetic calcium carbonate is a fine white powder which is obtained from natural limestone using a special manufacturing process (precipitation, crystallization). Wikipedia states

(https://de.wikipedia.org/wiki/Calciumcarbonate)

[0003] «Synthetic calcium carbonate is called PCC (precipitated calcium carbonate) - in contrast to GCC (ground calcium carbonate). PCC can be produced in various ways. Well-known processes are precipitation with carbon dioxide, the soda-lime process and the Solvay process, in which PCC is a by-product of ammonia production.

[0004] Precipitation with carbon dioxide is the most commonly used process, particularly in on-site plants in the paper industry. Clean limestone or quicklime is first slaked to form calcium hydroxide (milk of lime) and then fed to the reaction vessel as a thin suspension. There, carbon dioxide is introduced until the calcium hydroxide has been completely converted to calcium carbonate. The duration of the reaction can be assessed and controlled by the pH value.

CaCOs —> CaO0+CO2 CaO+H20 — Ca(OH)2 Ca(OH)2+CO2 — CaCOs+H2.O

[0005] Precipitation takes place at a solids content of about 20%. Different crystal forms (crystal morphologies) and grain distributions can be produced ("grown") by the process control (temperature, pressure, time, concentration). The rhombohedral or scalenohedral crystal form is preferred ...»

[0006] In fact, there are numerous other crystal forms of calcium carbonate. [0007] The differences to ground lime are well known.

special crystal structure in contrast to ground lime (cubic, round) higher fineness: average 1.2 um / D98: 4.3 um

higher purity: 99% CaCOs (calcium carbonate)

higher whiteness

[0008] Synthetic calcium carbonate is therefore not only purer, but also much whiter, finer and has a larger specific surface area. Ground lime has a cubic/spherical surface, whereas synthetic calcium carbonate has a pronounced crystal structure.

[0009] It is a common practice in agriculture to apply ground lime to raise the pH of the soil, i.e. to make acidic soils less acidic. In this case, ground lime is used to improve the soil pH. Another possible application of ground lime is spraying it onto plants to fertilize them with calcium. When using ground lime, there are often problems with clogged filters or nozzles on the crop protection sprayer, as ground lime is not very fine (products with ground lime have a grain size of approximately 100 µm to 40 µm).

[0010] However, it is already known from AU 691460 B3 to apply synthetic calcium carbonate in the form of a suspension to fields. According to this document, the aim is to raise the pH value of the soil. On page 7 at the bottom of this document, it is stated that an amount of 6.26 kg per hectare is necessary to raise the pH value of the soil by 0.1.

[0011] An advantage over ground lime is the easier application: Mixing into the spray mixture is easy due to the special structure/rheology, neither

Filters and spray nozzles are the same as with ground lime. This is due to the much finer particles of synthetic calcium carbonate.

[0012] This document does not provide any information on the crystal form of the synthetic calcium carbonate used. However, it states on page 15, lines 5-9: "As the fertiliser of the present invention is applied as a suspension, losses from wind drift are thereby obviated and furthermore because of the gelling agent, the fertiliser suspension adheres to the foliage and ground and is washed straight into the soil during rainfall.” Translated: "As the fertiliser of the present invention is applied as a suspension, losses from wind drift are thereby obviated and furthermore because of the gelling agent, the fertiliser suspension adheres to the foliage and ground and is washed straight into the soil during rainfall."

[0013] The synthetic calcium carbonate therefore adheres to the leaves only because of the gelling agent and, despite the gelling agent, is washed directly into the soil by rain.

[0014] According to the present invention, however, the suspension is to be given a new application: the leaves of the plants are to be protected, for which it is necessary that the synthetic calcium carbonate adheres to the leaves and is not washed away, or at least only slowly, even in the event of rain.

[0015] This object is achieved according to the invention in that the synthetic calcium carbonate is crystallized in the form of scalenohedra to at least 80% by weight, preferably at least 90% by weight.

[0016] For the desired effect, it is advantageous if the suspension is applied in an amount of 4-12 kg/ha of synthetic calcium carbonate and if the suspension used contains 2-3% by weight of synthetic calcium carbonate.

[0017] As has been found in the present invention, synthetic calcium carbonate in the form of scalenohedrons has a high leaf adhesion which remains effective even in rain. It is believed that this is due to the fact that scalenohedrons are needle-like, pointed.

[0018] The special scalenohedral form of synthetic calcium carbonate can only be produced by targeted precipitation/crystallization. It is characterized by a pointed/needle-like surface and is in contrast to the cube-like/spherical surface of ground lime, which is usually used for foliar application. Due to the scalenohedral form, synthetic calcium carbonate has the unique property that it adheres to the leaf on its own, without any additives, and is not washed away by rain or is only washed away slowly, while other products have to be applied together with an adhesive in order to adhere to the leaf. The uniqueness of scalenohedral calcium carbonate is that it is itself a natural adhesive on the leaf and can therefore develop its full effect (sun protection, mechanical protection - described below) over the entire growing season.

[0019] Effects of scalenohedral synthetic calcium carbonate:

1. PROTECTION AGAINST OVERHEATING OF THE LEAF - ENSURING PHOTOSYNTHESIS (= "SUNSCREEN" FOR PLANTS)

[0020] C3 plants (e.g. wheat, barley, spelt, rye, oats, triticale, sugar beet, potatoes, soy, rapeseed, etc.) have the highest photosynthesis performance at leaf temperatures of around 26-28°C. At temperatures above 27°C, the photosynthesis performance of C3 plants drops because the enzymes responsible for photosynthesis are destroyed. C4 plants (e.g. corn, millet, amaranth) have the highest photosynthesis rate at leaf temperatures of around 33-36°C. At higher temperatures, the photosynthesis performance also drops. Scalenohedral calcium carbonate forms a reflective protective layer (whiter than ground lime) on the leaf surface (=sunscreen for plants), which is particularly pronounced due to the high degree of whiteness. This can reduce overheating of the leaves or the destruction of the enzymes responsible for photosynthesis and photosynthesis remains active. Photosynthesis performance remains high even on warm days and yield increases.

[0021] Another advantage of the cooler leaf is the lower evaporation rate. The leaf does not have to evaporate as much water for cooling, the plants require less water and have a higher drought stress tolerance, which is becoming increasingly important in times of climate change.

[0022] In the following tests, scalenohedral calcium carbonate, marketed by eurominerals under the name InPCC Calprec PA, was used. This product is also known as crystal lime.

EXAMPLE 1: Measurement of leaf temperature in strawberries with and without scalenohedral InPCC Calprec PA:

[0023] Measurement from May 13, 2022 with thermal imaging camera VarioTech VT-WBK35:

[0024] Strawberry leaves with scalenohedral InPCC Calprec PA: O leaf temperature: 27.1°C; strawberry leaves without InPCC Calprec PA: Ö leaf temperature: 33.3°C

[0025] By applying InPCC Calprec PA to strawberry plants in this experiment, a reduction in leaf temperature of around 6°C was achieved, which brings significant benefits both for the photosynthesis rate in hot weather and for the water requirement and drought stress tolerance of the plant.

2. MECHANICAL PROTECTIVE FILM ON THE LEAF AGAINST PESTS, FUNGI, OTHER DISEASES

EXAMPLE 2: Field trial in wheat 2022, effectiveness against grain beetle (Oulema melanopus L.):

[0026] In April 2022, scalenohedral InPCC Calprec PA was applied to a subplot of a wheat field, while the rest of the field remained untreated. At the end of May 2022, leaves without an InPCC Calprec PA coating showed severe "window damage" by the larvae of the grain beetle, while leaves with an InPCC Calprec PA coating showed hardly any damage from the larvae. The InPCC Calprec PA coating thus offered effective protection against damage caused by this pest. Since InPCC Calprec PA was only applied once in April, the trial also showed that crystal lime is not washed away by rain, since there was precipitation almost every week in April/May and the InPCC Calprec PA coating was still very clearly visible and effective at the end of May.

[0027] It is therefore sufficient if the suspension according to the invention is applied to the crop plants one to eight times per season, whereby InPCC Calprec PA in combination with a wetting agent is continuously mixed into the spray mixture (suspension) with the agitator running and then applied to the crop using the crop protection sprayer.

[0028] Effects of ground lime:

[0029] Ground lime, on the other hand, does not exhibit the sun protection effect (lower whiteness and lower adhesion to the leaf) nor the mechanical effect against pests (different structure) exhibited by InPCC Calprec PA.

Claims (3)

Claims 1. Use of synthetic calcium carbonate for the treatment of plants, wherein a suspension of synthetic calcium carbonate in water is applied to the field, characterized in that the synthetic calcium carbonate is crystallized in the form of scalenehedra to an extent of at least 80% by weight, preferably at least 90% by weight. 2, Use according to claim 1, characterized in that the suspension is applied in an amount of 4-12 kg/ha of synthetic calcium carbonate. 3. Use according to claim 1, characterized in that the suspension used contains 2-3 wt.% synthetic calcium carbonate. No drawings for this