WO2017175549A1 - Slow-release fertilizer composition and soil - Google Patents

Abstract

Provided are a slow-release fertilizer composition which is less likely to disintegrate when absorbing water to form aggregates, can retain water and a water-soluble fertilizer active component for a long period of time, and can gradually release the water-soluble fertilizer active component; and a soil which can retain water and a water-soluble fertilizer active component for a long period of time, and can gradually release the water-soluble fertilizer active component. The slow-release fertilizer composition contains a water-retaining material consisting of an acrylic amide homopolymer having an average particle size within the range of 1 μm to 2 mm, and a water-soluble fertilizer active component which can be retained in the water-retaining material. The soil contains, in an amount within the range of 0.1-10 mass% with respect to the soil, a water-retaining material consisting of an acrylic amide homopolymer having an average particle size within the range of 1 μm to 2 mm.

Description

Slow release fertilizer composition and soil

The present invention relates to a slow release fertilizer composition and soil.

Conventionally, acrylate-acrylamide copolymer cross-linked products, acrylic acid homopolymers and the like are known as water-absorbing polymers used for disposable diapers, sanitary napkins, and the like (see, for example, Patent Document 1).

In addition to uses such as disposable diapers and sanitary napkins, the water-absorbing polymer has been studied for use as a water retention material for soil that retains moisture and water-soluble fertilizers by its water retention, and allows plants to grow appropriately. .

JP-A-7-228790

The conventional water-absorbing polymer becomes a lump by absorbing water, and retains moisture and water-soluble fertilizers in the lump. However, the conventional water-absorbing polymer has a disadvantage in that it is difficult to retain moisture and water-soluble fertilizers for a long time because the lump is easily collapsed when subjected to a load.

The present invention eliminates such inconvenience, is less likely to collapse when it becomes a lump by water absorption, can retain moisture and water-soluble fertilizer components over a long period of time, and gradually remove the water-soluble fertilizer components An object is to provide a slow-release fertilizer composition that can be released.

Also, an object of the present invention is to provide a soil that can retain moisture and water-soluble fertilizer components over a long period of time and can gradually release the water-soluble fertilizer components.

The present inventor examined the retention performance of water and water-soluble fertilizers of various water-absorbing polymers. As a result, according to the water retaining material consisting only of an acrylamide (acrylamide) homopolymer having a particle diameter in a specific range, it is difficult to collapse when it becomes a lump by water absorption, and water and water-soluble fertilizer components are retained for a long time. It has been found that it can be used as a slow-acting fertilizer composition because the water-soluble fertilizing component can be gradually released, and the present invention has been reached.

Therefore, in order to achieve the above object, the slow-release fertilizer composition of the present invention can be retained by a water retention material composed of only an acrylamide homopolymer having an average particle diameter in the range of 1 μm to 2 mm, and the water retention material. A water-soluble fertilizing component is included.

The acrylamide homopolymer having an average particle diameter in the above range used for the water retaining material is the same size as sand, and by having the average particle diameter in the above range, a lump formed by water absorption receives a load. However, it is hard to collapse and can maintain its shape. Therefore, the water retaining material can retain the absorbed moisture and water-soluble fertilizer for a long period of time. Moreover, the water retaining material can gradually release the absorbed moisture and water-soluble fertilizer.

Therefore, according to the slow-acting fertilizer composition of the present invention containing the water-retaining material and the water-soluble fertilizing component, plants can be suitably grown.

In the slow-acting fertilizer composition of the present invention, when the average particle diameter of the acrylamide homopolymer forming the water-retaining material is less than 1 μm, the single particles cannot hold water and water-soluble fertilizer components. There is an inconvenience, and when it exceeds 2 mm, there is an inconvenience that the time required for water absorption becomes excessively long.

In the slow-acting fertilizer composition of the present invention, as the water-soluble fertilizer component, at least one component selected from the group consisting of ammoniacal nitrogen, phosphoric acid, potassium, and magnesium can be used. Ammonia nitrogen is preferable because excellent retention performance and sustained release performance can be obtained.

In addition, the soil of the present invention has an average particle size in the range of 1 μm to 2 mm with respect to the soil (excluding soil having a total of 50 to 98% by weight of silt and clay and an organic matter content of 2% by weight or less). The water-retaining material comprising only the acrylamide homopolymer is contained in the range of 0.1 to 10% by mass.

According to the soil of the present invention, the total particle size of silt and clay is 50 to 98% by weight, and the average particle size is in the range of 1 μm to 2 mm with respect to the soil excluding the soil having an organic matter content of 2% by weight or less. By containing only the acrylamide homopolymer in the range of 0.1 to 10% by mass, the water and water-soluble fertilizer can be retained for a long time, and the absorbed water and water-soluble fertilizer are contained. Can be released gradually. Therefore, according to the soil of this invention, a plant can be grown suitably.

In the soil of the present invention, when the average particle diameter of the acrylamide homopolymer forming the water retention material is less than 1 μm, there is a disadvantage that the single particles cannot retain moisture and water-soluble fertilizers. If it exceeds 1, there is a disadvantage that the time required for water absorption becomes excessively long.

In the soil of the present invention, when the content of the water retaining material is less than 0.1% by mass, the water and the water-soluble fertilizer are retained for a long time, and the absorbed water and the water-soluble fertilizer are gradually added. It is not possible to obtain the effect of being released into the film, and even if it exceeds 10% by mass, no further effect can be obtained.

The graph which shows the change of the weight which generate | occur | produces when the acrylamide homopolymer used as a water retention material is made to absorb water and repeatedly compresses in the slow release fertilizer composition of this invention compared with another water retention material. The graph which shows the water retention of the acrylamide homopolymer used as a water retention material compared with another water retention material in the slow release fertilizer composition of this invention. The photograph which shows the growth state of the root of the plant cultivated using the soil of this invention. The photograph which shows the growth state of the root of the plant cultivated without using the soil of this invention. The photograph which shows the growth state of the mini carrot cultivated using the soil of this invention. The photograph which shows the growth state of the mini carrot cultivated without using the soil of this invention.

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

The slow-acting fertilizer composition of the present embodiment includes a water retention material consisting only of an acrylamide homopolymer having an average particle diameter in the range of 1 μm to 2 mm, and a water-soluble fertilizer component that can be retained in the water retention material. Such an acrylamide homopolymer can be obtained from SNF Corporation.

The acrylamide homopolymer used as the water-retaining material has an average particle diameter in the above range, so that it forms a lump when it absorbs water, but the lump is less likely to collapse when subjected to a load, and maintains its shape. It has the characteristic of being able to. Therefore, the said acrylamide homopolymer can hold | maintain a water | moisture content and a water-soluble fertilizer for a long time in soil. Moreover, the water retaining material can gradually release the absorbed moisture and water-soluble fertilizer.

As the water-soluble fertilizing component, at least one component selected from the group consisting of ammonia nitrogen, phosphoric acid, potassium and magnesium can be used, and ammonia nitrogen is particularly preferable.

In addition, the soil of this embodiment has a total of 50 to 98% by weight of silt and clay and 1 μm to other soils excluding soil having an organic matter content of 2% by weight or less (hereinafter referred to as silt soil). A water retention material consisting only of an acrylamide homopolymer having an average particle diameter in the range of 2 mm is added in the range of 0.1 to 10% by mass. The soil to which the water retaining material is added in the above range can retain moisture and water-soluble fertilizers for a long period of time. The soil of this embodiment is preferably added in the range of 0.3 to 10% by mass, and in the range of 0.3 to 0.6% by mass, with respect to other soils other than silt soil. More preferably.

The soil other than the silt soil is not limited to soil in which plants are generally cultivated, such as farmland, gardens, and forests, but may be any soil such as desert or rough terrain. Therefore, the soil of the present embodiment can be used for soil improvement and greening in deserts and desert areas, for example.

In addition, silt soil has excessive water retention and requires drainage, and it is not necessary to add a water retention material.

[Experimental Example 1]
Next, a lump formed by absorbing 200 ml of ion-exchanged water into 5.0 g of an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm is accommodated in a container having a diameter of 45 mm so as to have a thickness of 6 mm. The operation of applying a 1N load with a 40 mm compression plate was repeated 3600 cycles over 1 hour, and the maximum load generated during compression was measured. The results are shown in FIG. 1 as an example.

Next, instead of an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm, ion-exchanged water was added to 2.0 g of an acrylamide-potassium acrylate cross-linked copolymer (manufactured by SNF Corporation, trade name: AQUASORB 3005K4). Except that a lump formed by absorbing 200 ml of water was used, the maximum load generated during compression was measured in the same manner as in the above example. The results are shown in FIG.

Next, instead of the acrylamide homopolymer having an average particle size of 1 μm to 2 mm, 0.5 g of crosslinked acrylic acid polymer sodium salt (manufactured by Sanyo Chemical Industries, Ltd., trade name: Sunfresh ST250 *) was added to ion-exchanged water. Except for using a lump formed by absorbing 300 ml of water, the maximum load generated during compression was measured in exactly the same manner as in the above example. The results are shown in FIG.

From FIG. 1, the acrylamide homopolymer (Example) having an average particle diameter of 1 μm to 2 mm maintains a substantially constant maximum load, whereas the acrylamide-potassium acrylate cross-linked copolymer (Comparative Example 1), It can be seen that the maximum load of the acrylic acid polymer partial sodium salt crosslinked product (Comparative Example 2) gradually decreases as the cycle is repeated.

This is because an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm is difficult to break a polymer chain even when subjected to a load, whereas an acrylamide-potassium acrylate crosslinked copolymer or a crosslinked sodium salt of an acrylate polymer. This is probably because the polymer chain is broken by the load.

Therefore, it is considered that the acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm is less likely to collapse when a mass formed by absorbing water is subjected to a load and can maintain its shape.

[Experimental example 2]
Next, 6.0 g of an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm and 240 ml of purified water are added to a 300 ml beaker, and the mixture is allowed to stand for 24 hours. (Manufactured by Hyponex Japan Co., Ltd., product name: Hyponex liquid 6-10-6, containing 2.90% by mass of ammonia nitrogen, 10.0% by mass of phosphoric acid, and 5.0% by mass of potassium as water-soluble fertilizers) ) 60 g was added. The beaker was left in a room of 23 ± 1 ° C. and 50 ± 5% RH with the upper part opened, and the water retention was determined from the following equation by measuring the mass loss.

Water retention rate = (mass of water after elapse of a predetermined time / mass of water immediately after addition of fertilizer) × 100
The change with time of the water retention rate is shown in FIG.

Next, in place of the acrylamide homopolymer, an acrylic acid polymer partial sodium salt cross-linked product (manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name: Sunfresh ST250 *) was used. Thus, the change with time of the water retention rate was determined. The results are shown in FIG.

Next, in place of the acrylamide homopolymer, an acrylic acid polymer (manufactured by Omiya Green Service Co., Ltd., trade name: water answering machine) was used. The change with time was determined. The results are shown in FIG.

Next, in place of the acrylamide homopolymer, JIS standard sand (Kinzuna No.5 S208) was used, and the change over time in the water retention rate was determined in the same manner as in the above example. The results are shown in FIG.

From FIG. 2, according to the acrylamide homopolymer (Example) having an average particle diameter of 1 μm to 2 mm, the crosslinked acrylic acid polymer partial sodium salt (Comparative Example 2), acrylic acid polymer (Comparative Example 3), JIS standard Compared to sand (Comparative Example 4), it can be seen that the water retention rate in the state containing fertilizer is high, and the water retention performance and the sustained release performance are excellent.

[Experimental Example 3]
Next, fertilizer (3.12% by mass of ammonia nitrogen as a water-soluble fertilizer) was added to a mass formed by absorbing 500 ml of purified water into 5.0 g of an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm. 0.125 g of phosphoric acid (11.7% by mass, potassium 3.84% by mass, magnesium 0.04% by mass) was added to prepare a slow release fertilizer composition.

Next, after standing for 24 hours, it is separated into a lump and water, the mass of each water-soluble fertilizer is found, and the difference from the initial blending amount is the amount absorbed by each water-soluble fertilizer. It was. Moreover, the absorption rate was calculated | required from following Formula (1) as a percentage of the absorption amount with respect to the initial compounding quantity.

Absorption rate (%) = (absorption amount / initial blending amount) × 100 (1)
The mass of each water-soluble fertilizer was determined by IC (ion chromatograph) for ammonia nitrogen and phosphoric acid, and by ICP-AES (inductively coupled plasma emission spectrometer) for potassium and magnesium. The results are shown in Table 1.

Next, 150 ml of purified water is added to the lump separated after standing for 24 hours. After standing for another 24 hours, the lump is separated into lump and moisture, and each of the water-soluble fertilizers contained in the moisture is separated. Mass was calculated | required and it was set as the discharge | release amount of each water-soluble fertilizer. Moreover, the release rate was calculated | required from following Formula (2) as a percentage of discharge | release amount with respect to absorption amount.

Release rate (%) = (release amount / absorption amount) × 100 (2)
The mass of each water-soluble fertilizer was determined in exactly the same way as in the case of water separated after standing for 24 hours. The results are shown in Table 1.

 

 

From Table 1, it can be seen that according to the slow-acting fertilizer composition of this experimental example, the absorption rate of ammonia nitrogen is particularly high and the release rate is low. Therefore, it is clear that the slow-acting fertilizer composition of this experimental example is excellent in ammonia nitrogen retention performance and sustained release performance.

(Experimental example 4)
Next, 0.3% by mass of a water retention material consisting only of an acrylamide homopolymer having an average particle diameter of 1 μm to 2 mm is added to the soil in the vicinity of Iwaki City, Fukushima Prefecture (hereinafter abbreviated as “Iwaki City Soil”). The soil of this experimental example was prepared. Next, FIG. 3 and FIG. 4 show a comparison between the case where the plant is cultivated using the soil of this experimental example and the case where the plant is cultivated without adding the water retention material to the Iwaki city soil. .

FIG. 3A shows the state of plant roots when cultivated using the soil of this experimental example, and FIG. 3B shows the state of plant roots when cultivated using Iwaki City soil as it is. From FIG. 3A and FIG. 3B, it is clear that when the soil of this experimental example is used, the roots grow very well compared to the case where the Iwaki city soil is used as it is.

4A shows the state of the mini carrot when cultivated using the soil of this experimental example, and FIG. 4B shows the state of the mini carrot when cultivated using the Iwaki city soil as it is. From FIG. 4A and FIG. 4B, it is clear that when the soil of this experimental example is used, the mini carrot grows very well as compared with the case where the Iwaki city soil is used as it is.

No sign.

Claims (4)

A slow-acting fertilizer composition comprising a water retention material composed only of an acrylamide homopolymer having an average particle diameter in the range of 1 μm to 2 mm, and a water-soluble fertilizer component that can be retained in the water retention material. The slow-release fertilizer composition according to claim 1, wherein the water-soluble fertilizer component is at least one component selected from the group consisting of ammoniacal nitrogen, phosphoric acid, potassium, and magnesium. Slow release fertilizer composition. 3. The slow release fertilizer composition according to claim 2, wherein the water-soluble fertilizer component is ammoniacal nitrogen. It consists only of acrylamide homopolymer having an average particle size in the range of 1 μm to 2 mm with respect to the soil (excluding soil with a total of 50 to 98% by weight of silt and clay and an organic content of 2% by weight or less). A soil comprising a water retention material in a range of 0.1 to 10% by mass.

Images