JP3355623B2 - Agricultural multi seat - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural multi-sheet used for improving the quality and yield of crops or flowers, and more particularly to an agricultural multi-sheet excellent in controlling the degradability of microorganisms in soil. Regarding multi-sheet.

[0002]

2. Description of the Related Art Agricultural multi-sheets are materials for covering the ground around agricultural crops or flowers, and are used to improve the quality and yield of agricultural crops or flowers by controlling the soil temperature and suppressing the occurrence of weeds. Have been. Conventionally,
For this agricultural multi-sheet, a plastic film such as polyethylene or polyvinyl chloride has been used. However, since these are hardly decomposable by microorganisms in soil, they need to be collected and incinerated after use. This collection and incineration process requires special equipment, a great deal of labor and time, and is also problematic in terms of environmental pollution.

In order to solve the problem of such a plastic film multi-sheet, the form is maintained during the laying period, and after use, after being plowed into the soil, it is completely decomposed by microorganisms. An unnecessary agricultural multi-sheet is being considered. For example, agricultural multi-sheets using caprolactone which is a biodegradable resin (Japanese Unexamined Patent Publication No.
No. 3876) has been proposed, but is not practical because it is more expensive than conventional plastic film multi-sheets.

On the other hand, agricultural paper multi-sheets using paper or pulp as a base material have been studied as agricultural multi-sheets that do not need to be collected because cellulose, which is a main component thereof, is easily decomposed by microorganisms. Paper multi-sheets are more breathable than plastic film multi-sheets, so they are superior in terms of the effect of suppressing ground temperature rise,
On the other hand, it is inferior in promoting the temperature rise. For this reason, agricultural multi-sheets are often used in summer to prevent the occurrence of weeds, soft rot and wilt. in this way,
When the agricultural paper multi-sheet is used for crops harvested in the summer, it is necessary to maintain its form without being decomposed for about 90 days from spring to summer. Further, it is desirable that the agricultural paper multi-sheet be decomposed by microorganisms in the soil after harvesting the crop and before cultivating the next crop (about 30 days). However, since the soil temperature is high in summer, untreated agricultural paper multi-sheets quickly decompose in soil and have not been put to practical use. It decomposes quickly especially on the ground and is scattered by the wind. In order to control microbial degradation, synthetic resins such as ethylene-vinyl acetate copolymer and polyvinyl alcohol, which are hardly biodegradable,
A method of forming synthetic fibers on paper (Japanese Patent Laid-Open No. 48-36406,
Japanese Patent Application Laid-Open No. 55-92625) is proposed, but there is a problem that synthetic resin or synthetic fiber is accumulated in soil without being decomposed. Also, a method has been proposed in which an antibacterial agent comprising a salt of oxyquinoline and a derivative thereof is added to paper (Japanese Patent Application Laid-Open No. 58-70800). Is also suppressed.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an agricultural multi-sheet capable of controlling the decomposition of microorganisms in soil without affecting the activity of microorganisms in soil. did. More specifically, if it is laid in a field in the summer, it will not be disassembled for about 90 days, but it will maintain its form and provide a multi-sheet for agriculture that will be disassembled in about 30 days after being plowed into the soil The task was to do.

[0006]

Means for Solving the Problems The present inventors have made wood pulp as a main component and used mechanical pulp as a pulp component for 20 minutes.
Agricultural multi-sheet containing up to 80% by weight is not decomposed for about 90 days when laid in the field, maintaining its form,
After being plowed into the fertilizer, it was found that it was decomposed in about 30 days.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The mechanical pulp used in the present invention is groundwood pulp (GP), refiner ground pulp (RGP), thermomechanical pulp (TMP), and chemithermomechanical pulp (CTMP). Also, deinked pulp (D) manufactured from waste paper made of these pulp
IP). Also, as chemical pulp,
Unbleached kraft pulp (UKP) or bleached kraft pulp (BKP), unbleached sulphite pulp (USP), or bleached sulphite pulp (BSP) is used.

Wood pulp is roughly classified into chemical pulp, such as KP and SP, from which cellulose fibers are obtained by chemical treatment, and mechanical pulp, such as GP and TMP, from which wood fibers are obtained by physical treatment. The morphology, chemical composition, and properties of pulp vary greatly from pulp to pulp. KP dissolves the lignin adhering to the wood fiber by a chemical treatment and isolates the fiber, so that the fiber is exposed to cellulose. On the other hand, mechanical pulp breaks the lignin bond between wood fibers at the interface by physical treatment to isolate the fibers, so that the fibers are coated with cellulose by lignin.

[0009] Both cellulose and lignin are the major natural polymers that make up wood and are degraded by microorganisms. Cellulose has a structure in which D-glucose is β1,4-bonded, is easily hydrolyzed by microorganisms, and is completely degraded. However, lignin does not contain a repeating unit which is susceptible to hydrolysis, and is constituted by a complex bonding mode, and is not easily decomposed by microorganisms. That is, cellulose and lignin have different rates of decomposition by microorganisms.

Accordingly, the present invention makes it possible to control the decomposition rate of microorganisms in soil by utilizing the difference in the decomposition rate of cellulose and lignin, that is, the difference in the decomposition rate of chemical pulp and mechanical pulp. is there.

In the agricultural paper multi-sheet according to the present invention,
The blending ratio of the mechanical pulp should be 20 to 80% by weight.
If the blending ratio of the mechanical pulp is less than 20% by weight, the multi-sheet will be decomposed on the ground and scattered by wind. On the other hand, if the blending ratio of the mechanical pulp exceeds 80% by weight, poor dewatering and paper cutting at the wire part occur in a normal paper machine, and the operating life and productivity are reduced.

To the multi-sheet of agricultural paper of the present invention, a colored pigment or dye may be added for the purpose of suppressing the growth of weeds and keeping the soil temperature warm.

It is preferable to add a wet paper strength enhancer in order to improve wet paper strength within a range that does not hinder decomposition by microorganisms in the soil. As a wet paper strength agent,
Melamine-formaldehyde resin, polyamide / epichlorohydrin resin, polyethyleneimine, glyoxal, dialdehyde starch and the like.

[0014] Fillers may be added to such an extent that decomposition by microorganisms in the soil is not hindered. Examples of the filler include white carbon, silica, clay, kaolin, calcium carbonate, titanium oxide, and plastic pigment.

Further, since the agricultural paper multi-sheet of the present invention is essentially composed of only wood constituents as a raw material, there is almost no adverse effect on organisms and microorganisms in the soil.

[0016]

Next, the present invention will be described with reference to examples, but the present invention is not limited by the examples.

In Examples and Comparative Examples, unbleached kraft pulp (UKP) having the properties shown in Table 1 as a pulp, G
P and TMP were used. In the pulp formulation shown in Table 2, polyamide-epichlorohydrin resin (trade name: WS-557, manufactured by Nippon PMC) was used as a wet paper strength enhancer.
0.1% by weight, carbon black (Product name: EMP BLACKFX0
103T, manufactured by Toyo Ink) and 0.1% by weight of pulp.
Further, the pH of the stock was adjusted to 4.5 by adding a sulfuric acid band, and an agricultural paper multi-sheet was manufactured using a fourdrinier paper machine. However, in Comparative Example 1 in which 100% GP was blended, the dewatering in the wire part of the paper machine was poor, so that the paper was frequently cut off, and it was not possible to produce an agricultural paper multi-sheet.

In order to evaluate the decomposition of the sample by the microorganisms in the soil, a ridge as shown in FIG. 1 was formed in a field, the sample was laid, and the decomposition at the ground was visually observed with time. The evaluation of the decomposition of the sample by the microorganism was performed on crops harvested in the summer, and the laying period was 90 days from mid-May to mid-August. Next, it was buried in the soil, left for 30 days until mid-September, and the state of decomposition after burying was visually observed. As shown in Table 2, GP or TMP as in Examples 1 to 7 was used.
The agricultural paper multisheet containing up to 80% by weight maintained its form 90 days after laying, and there was no problem in use.
In addition, it was almost completely decomposed in 30 days after being buried in the soil. On the other hand, the agricultural paper multi-sheet composed of 100% UKP in Comparative Example 2 was almost completely decomposed 60 days after laying, and there was a problem in using it as an agricultural multi-sheet.

[0019]

[Table 1]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a sectional view showing the shape of a ridge according to an embodiment of the present invention.

[Description of Signs] 1 Holding soil 2 Paper multi-sheet 3 Ground surface

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A01G 13/00 302

Claims (2)

(57) [Claims] An agricultural multi-sheet comprising wood pulp as a main component, said pulp containing 20 to 80% by weight of mechanical pulp and 20 to 80% by weight of chemical pulp. 2. The agricultural multi-sheet according to claim 1, wherein the form is maintained for about 90 days after laying in the field, and decomposed within about 30 days after being plowed into the soil.