JPH0640767B2 - Coated seed for direct sowing of rice in flooded soil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to coated seed paddy that can be directly sown in a flooded soil and cultivated as it is.

[Conventional technology and problems]

In Japan, it is customary to transplant seedlings grown in the rice seedlings to rice fields, and over 99% of the rice cultivation area is transplanted and cultivated, but in the world rice cultivation, about 70% of the rice cultivation area is used. Direct seeding cultivation is carried out.

Of the direct seeding cultivation, the methods currently used in Japan are roughly classified as follows.

(a) Direct sowing cultivation in dry fields (b) Direct sowing cultivation in submerged soil (c) Direct sowing cultivation in submerged soil Although they have the same advantages, each has a number of problems.

The direct seeding cultivation in dry field (a) is limited to warm climate areas, is easily affected by weather conditions and animals, and requires abundant water supply.

In the direct flooding cultivation of (b), depending on the planting position of the seed pad, decay due to oxygen deficiency and rolling seedlings often occur, and the seedling establishment rate decreases.

In addition, it is easy to fall over during the harvest season.

Proposed as an improved cultivation method of (a) and (b) (c)
The direct sowing cultivation in submerged soil is a method in which seed paddy is coated with a mixture of calcium peroxide and calcined gypsum, and this coated seed is sown in a submerged soil at a depth of about 10 mm.

Oxygen is supplied to seed rice by long-term chemical change of calcium peroxide, but there are the following problems.

(i) Calcium peroxide reacts with water to generate oxygen, but calcium hydroxide accumulates in the soil and pollutes the soil.

(ii) A large amount of external force is applied to the seeds to cause damage to the seeds, although a large amount of treatment is possible because the seeds are coated in the rotating drum.

In addition, conventional direct seeding in submerged soil was pretreated by selection, disinfection, soaking, etc. before being coated, and then covered with a coating material such as calcium peroxide. It took a lot of time and effort to make direct sowing seeds.

The present invention provides a coated seed for direct seeding cultivation in submerged soil, which can solve such problems.

[Means for solving problems]

According to the present invention, seed paddy is coated with bubbles in a hollow sphere-shaped gel coating layer having substantially the same volume, and the component and concentration of the gel agent forming the gel coating layer are adjusted so that the apparent specific gravity of the entire gel coating layer is 1 or less. Bigger than that.

[Work]

The seed paddy is protected by a coating material containing a nutritional substance, a bactericide and the like, and since it is coated with air bubbles, there is no risk of oxygen deficiency and the germination rate can be increased.

Further, since the gel coating layer has a spherical shape having substantially the same volume, the mechanization of seeding becomes easy.

Since the apparent specific gravity of the whole is greater than 1, it does not float up from the soil after sowing and germinates in the soil.

〔Example〕

 Examples of the present invention will be described below.

Conventionally, it was very troublesome to make seeds for direct seeding in submerged soil because it was covered with a coating material such as calcium peroxide after performing pretreatment such as disinfection and soaking before coating, Focusing on the fact that disinfectants and pre-treatments such as soaking can add bactericides and germination promoters to the coating agent, the present invention provides coating seeds that perform pre-treatment and coating at the same time. A gel was used to allow the addition of drug.

Suitable gels are water-soluble CMC-Na, polyacrylic acid Na, sodium alginate, etc., but since all are water-soluble, the surface is immersed in water-soluble water containing Ca ²⁺ to replace Ca and Na. Harden.

Also, it is necessary to supply oxygen when the seeds germinate,
Since the method of generating oxidization by using a chemical is very dangerous, a method of enclosing air bubbles together with seed pad in the gel coating layer and physically supplying oxygen to the seed pad was adopted.

FIG. 2 shows a method of enclosing air bubbles together with seeds in the gel coating layer.

In the figure, the nozzle body 1 has a plunger insertion hole 2 penetrating in the vertical direction, and a cylindrical cutting plunger 3 is fitted into the plunger insertion hole 2.

The plunger insertion hole 2 has a taper-shaped valve seat 4 having a smaller diameter toward the lower end at the lower end, and a gel channel 5 on the left and right.

The cutting plunger 3 is a pressing member such as a spring (not shown).
The valve 3a at the lower end closes the valve seat 4, but the valve is closed when the gel filled in the gel channel 5 and the plunger insertion hole 2 is pressurized. The pressure receiving portion 3b provided on the plunger 3 is pressurized and moves up, and the valve 3a opens the valve seat 4.

Cylinders (not shown) are arranged at the right end and the left end of the nozzle body 1, and the pistons 6 and 7 of the cylinders are inserted into the gel flow path 5 so as to be able to move forward and backward (see FIG. 2A).

When the piston 6 enters the gel flow path 5 from such a state, the cutting plunger 3 pressurized in the pressure receiving portion 3a rises, the valve 3a opens the valve seat 4, and the gel 8 flows out (see FIG. 2).
(See (b)).

Next, when the piston 6 retracts, the gel flow path 5 becomes negative pressure, the gel is replenished from the reed valve (not shown), the cutting plunger 3 descends, and the valve 3a closes the valve seat 4. The gel 8 flowing out from the valve seat 4 forms a film whose center hangs by its own weight, but does not fall by its own weight due to the adhesive force.

At this time, seed 9 is dropped and supplied from above (Fig. 2 (C)).
reference).

Next, the piston 7 enters the gel flow path 5 and the valve 3a
Is separated from the valve seat 4 and the gel 8 flows out, and the seed 9 bubbles 10
Together with this, it is sealed in the gel 8 (see FIG. 2 (D)).

Then, when the piston 7 retracts and the valve 3a again closes the valve seat, the hanging gel 8 falls without supporting the increased weight and falls into the hardening liquid in the hardening liquid tank below. Are spheroidized by surface tension (see Fig. 2 (e)).

Thus, as shown in FIG. 1, the gel coating layer 8 of the seed 9 with the air bubbles 10 sealed is completed.

Larger seeds require more oxygen during germination, but the oxygen supply period required for germination of seed paddy is the period from seed germination to emergence of the first true leaf.

Therefore, the required amount of bubbles together with the seed pad may be enclosed in the gel, but when seeding the paddy field with the coated seeds having bubbles, there arises a problem of floating in water.

In order to immerse the coated seeds with air bubbles in the paddy soil, the problem can be solved by making the apparent specific gravity of the coated seeds larger than 1, and the solution is as follows: (1) increase the concentration of the coated gel (2) Add a specific gravity material such as fine sand at the conventional coating gel concentration.

There are two methods described above.

Next, the specific gravity increase test when the specific gravity material is added is shown below.

The specific gravity increase test in which the specific gravity material is added is shown below.

Substances that can be used as a specific gravity material are required to be harmless to plants and soil, and in principle, they are for agriculture.

Based on these conditions, the following specific gravity materials were tested.

(a) Crushed solid fertilizer (b) Crushed sand for cultivation (c) Crushed hydroball for hydroculture (d) Crushed Kanuma soil (e) Crushed red clay soil If the above specific gravity materials are water-soluble Although it cannot be used as a specific gravity material, the water solubility and specific gravity of each specific gravity material are shown below.

From the above results, both can be used with the specific gravity material, but when the solid fertilizer pulverized product is added, the salt concentration inside the coating material increases, so it is not suitable in that seeds are likely to cause salt damage .

Further, if calcium is present in the specific gravity material, the gel may be hardened, but the gelation properties of the respective specific gravity materials are as follows.

Explanation of symbols in the table A: Aggregates are formed and do not disperse evenly in the gel B: Particles are solidified in minute amounts and dispersed in the gel C: Fine particles are dispersed in the gel as they are From the results, it was confirmed that the solid fertilizer cannot be used as the material for increasing the specific gravity, but other materials can be used as the material for increasing the specific gravity, and the apparent specific gravity can be made larger than 1.

However, when a large amount of the specific gravity material is added, the binding force of the gel decreases, so the gel concentration must be increased to some extent without relying on the addition of the specific gravity material.

By the method as described above, direct seeding cultivation in submerged soil was made possible by controlling the specific gravity of the gel coating layer and using the gel coating seed in which air bubbles were enclosed.

〔effect〕

 The present invention has the following effects.

(1) The seeds can be mechanically seeded by covering the seeds with a spherical gel of approximately the same volume.

(2) The seed germination rate can be increased by gel-coating the seeds with air bubbles, and the soil is not polluted because an oxygen generating agent such as calcium peroxide is not used.

(3) Since seed rice is coated with a gel containing chemicals, pretreatment and coating can be performed simultaneously.

(4) The gel coating agent can be made to have an apparent specific gravity of more than 1 by incorporating a specific gravity material, and the coated seeds having bubbles can be reliably cultivated in the flooded soil.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of a gel-coated seed having air bubbles, and FIG. 2 is an explanatory view of gel-coating the air bubbles and the seed. 8 ... Gel, 9 ... Seed, 10 ... Air bubbles.

Claims (1)

[Claims] 1. An apparent specific gravity of the whole gel coating layer is obtained by coating seed paddy with a bubble-shaped gel coating layer having a hollow sphere shape having substantially the same volume and adjusting the components and concentrations of the gel agent forming the gel coating layer. The coated seed for direct seeding in submerged soil of rice, characterized in that