JPH09110572A - Sustained release fertilizer for culturing sea alga - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sustained release fertilizer safe to the environment, containing, as active ingredient, ammonium polyphosphate having specific granular size. SOLUTION: This fertilizer contains, as active ingredient, ammonium polyphosphate >=70wt.% of which is >=100-mesh in granular size, <=20mm in the maximum granular diameter and pref. 5×10<4> -1×10<6> in molecular weight. This ammonium polyphosphate fertilizer sealed in nonwoven fabric bags is allowed to dissolve in seawater directly and then adhere to the surface of sea algae, and is gradually hydrolyzed to effect feeding the sea algae with both nitrogen and phosphorus elements in the fertilizer as nutrients.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sustained-release fertilizer for seaweed culture. Particularly, it relates to a sustained release fertilizer for seaweed cultivation.

[0002]

2. Description of the Related Art Conventionally, a prop method that is performed in relatively shallow water has been generally used as a method for cultivating seaweed, but due to problems such as an increase in coastal construction and pollution of seawater in recent years, a floating method that enables aquaculture even offshore. Has also started to take place. In seaweed aquaculture, it is already known that some nutrients in seawater have a great influence on the growth and yield of seaweed, but recently the phosphorus content has been reduced due to the decrease of phosphorus in domestic wastewater. It is drastically decreasing.

From such a background, the content of phosphorus is particularly emphasized. The nitrogen content and phosphorus content contained in seawater differ depending on the region, but near the coast, which is generally suitable for the pillar system, the nitrogen content is 0.4 to 0.8 ppm and the phosphorus content is 0.03 to 0.
08ppm, N / P = 6 to 10, whereas in the offshore where the floating method is used, the nitrogen content is 0.2 to 0.4 pp.
m, phosphorus content 0.03 ppm or less, N / P = 10 or more, and it is pointed out that the phosphorus content is insufficient. Various aquaculture fertilizers have been introduced to supplement these nutrients, and a mixed solution of phytic acid and phosphoric acid is often used because of its good adsorbability to seaweed (JP-A-56-155).
No. 085). In addition, ammonium phosphate, ammonium nitrate, ammonium sulfate and the like are used.

[0004]

Since all of these fertilizers for seaweed cultivation are soluble in water, they are instantly dissolved in seawater, and even if fertilizer is applied by the ocean current, most of the active ingredients are lost. Had. For this reason, phytic acid-based fertilizers having relatively high adsorptivity and high fertilizer efficiency are used, but there is a demand for more sustainable fertilizers for seaweed culture that have higher fertilizer efficiency.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies as to increase the yield of seaweed in a farm having a low phosphorus concentration in seawater. As a result, ammonium polyphosphate, particularly By specifying, it gradually elutes without being hydrolyzed in seawater and is easily adsorbed on the surface of living organisms such as seaweed. By gradually hydrolyzing and supplying nitrogen and phosphorus, seawater with low phosphorus concentration Among them, they found that they grow extremely well over a long period of time.

[0006] That is, the present invention is a sustained-release fertilizer for seaweed cultivation containing ammonium polyphosphate as an active ingredient, wherein the ammonium polyphosphate having a particle size of 100 mesh or more is 70% by weight.
The present invention relates to a sustained-release fertilizer for seaweed aquaculture, which has the maximum particle size of 20 mm or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of ammonium polyphosphate used in the present invention is carried out by the following method, but the production method is not particularly limited. As a manufacturing method, a method in which a mixture of ammonium phosphate and urea is placed in a heatable mixer and heated to about 200 ° C. to 300 ° C., a method of similarly treating a mixture of ammonium phosphate and phosphorus pentoxide is known. There is.

Required physical properties of ammonium polyphosphate include particle size and molecular weight. This particle size odor is characterized in that 100 mesh or more is 70% by weight or more and the maximum particle size is 20 mm or less. When the particle size of ammonium polyphosphate is less than 100 mesh, not only the dissolution rate becomes faster, but it also swells in seawater and becomes a highly viscous paste, which elutes when used in a container such as a seawater-resistant non-woven fabric bag. It causes inconveniences such as difficulty. Further, if the maximum particle size exceeds 20 mm, not only the dissolution rate will decrease significantly, but also the nonwoven fabric bag may be damaged.

In the present invention, the molecular weight is 5 × 10 ⁴ to 1
It is preferable to use ammonium polyphosphate which is 0 ⁶ . When the molecular weight is less than 5 × 10 ⁴ , the dissolution rate is high, and the effect intended by the present invention cannot be exhibited. Further, if the molecular weight exceeds 10 ⁶ , the dissolution rate is remarkably reduced, and the effect as a fertilizer cannot be obtained, which is not preferable.

The effect of ammonium polyphosphate is that it dissolves in sodium chloride solution (seawater) with the molecular weight as it is without being hydrolyzed, so that it is easily adsorbed on the surface of living seaweed and the like, and then gradually. It is speculated that hydrolysis starts and supplies nitrogen and phosphorus, which are nutrient sources.

The sustained-release fertilizer for seaweed culture of the present invention is prepared by storing ammonium polyphosphate in a container such as a seawater-resistant nonwoven fabric bag and using it as a sustained-release fertilizer for seaweed culture. Ammonium polyphosphate is eluted by immersing it in, and the effect as a fertilizer is exhibited. In this way, it is used very efficiently, and the pH is 6
Since it is neutral with ~ 8, it can be used as a safe controlled-release fertilizer for seaweed cultivation without polluting the sea area.

The elution time of the controlled release fertilizer for seaweed culture of the present invention was measured as follows. 10g ammonium polyphosphate was put in a non-woven bag, and the seawater temperature was controlled at 20 ° C.
It was hung in a beaker containing L and the elution amount was measured while stirring. Once fertilized, the fertilizer effect lasts for a long time of 10 to 20 days, although it varies depending on the temperature of the seawater, the ocean current, etc. Therefore, the workability is extremely high and it is extremely suitable as a fertilizer for seaweed cultivation.

The molecular weight of ammonium polyphosphate shown in the present invention was measured by gel filtration (GPC) under the following elution conditions. Eluent: 0.1 M NaCl aqueous solution, column: SHODEX B-804 + SHODEX B-
806, column temperature; 25 ° C., detector; differential refractometer flow rate; 1.0 m / min, PEG, P as standard molecular weight
A calibration curve was prepared and measured using EG.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited thereto. In the following, all parts and% are parts by weight and% by weight. Example 1 The particle size of 100 mesh or more is 84% and the maximum particle size is 13
50 g of ammonium polyphosphate having a size of 85,000 and a molecular weight of 85,000 was placed in a non-woven bag, placed in a 5 L beaker containing seawater, and incubated with nori seaweed.
The growth rate was examined by measuring the size on 2, 5 and 10 days. The culture medium was continuously replaced with water at a flow rate of 5000 ml / day, and the culture environment temperature and the culture seawater temperature were 20 ° C.
As the light source, five 20 W fluorescent lamps were used. Nori seaweed has a length of 1
Five specimens having a width of 0 mm and a width of 2 mm were used, and their average value was obtained. The seawater used for the culture solution is natural seawater with a low phosphorus concentration, 0.1 ppm of NH ₃ nitrogen and 0.001 p of phosphorus.
pm. The test results were as follows. Day 2; Length 20 mm Width 4 mm Phosphorus in liquid 210 ppm 5th Day; Length 81 mm Width 15 mm Phosphorus in liquid 215 ppm Day 10; Length 220 mm Width 19 mm Phosphorus in liquid 200 ppm Incidentally, ammonium polyphosphate is 16 days The whole amount was eluted at.

Example 2 The same as Example 1 except that the molecular weight of ammonium polyphosphate was 885,000. The test results were as follows. Day 2; Length 19mm Width 4mm Liquid phosphorus content 160ppm 5th day; Length 74mm Width 13mm Liquid phosphorus content 155ppm 10th day; Length 210mm Width 17mm Liquid phosphorus content 140ppm In addition, ammonium polyphosphate is 22 days The whole amount was eluted at.

Example 3 The particle size of 100 mesh or more is 95% and the maximum particle size is 18
The same procedure as in Example 1 was performed except that the thickness was set to mm. The test results are
It was as follows. Day 2; Length 19 mm Width 4 mm Phosphorus in liquid 225 ppm Day 5; Length 75 mm Width 15 mm Phosphorus in liquid 223 ppm Day 10; Length 215 mm Width 19 mm Phosphorus in liquid 218 ppm 18 days for ammonium polyphosphate The whole amount was eluted at.

Comparative Example 1 The particle size of 100 mesh or more is 5% and the maximum particle size is 0.5.
The same procedure as in Example 1 was performed except that mm was used. The test results were as follows. Day 2; Length 19 mm Width 4 mm Liquid phosphorus content 85 ppm 5th day; Length 55 mm Width 8 mm Liquid phosphorus content 96 ppm 10th day; Length 215 mm Width 11 mm Liquid phosphorus content 74 ppm Incidentally, ammonium polyphosphate is 21 days However, only about 50% was eluted and the content was paste-like.

Comparative Example 2 The particle size of 100 mesh or more is 20% and the maximum particle size is 5 m.
The same procedure as in Example 1 was carried out except that m was used. The test results are
It was as follows. Day 2; Length 19 mm Width 4 mm Liquid phosphorus content ppm 5th day; Length 55 mm Width 8 mm Liquid phosphorus content ppm Day 10; Length 215 mm Width 11 mm Liquid phosphorus ppm ppm In addition, ammonium polyphosphate is 18 days The content was a paste, with only about 65% being eluted.

Comparative Example 3 The same procedure as in Example 1 was carried out using 10 parts of ammonium monobasic phosphate. The test results were as follows. Day 2; Length 19 mm Width 4 mm Phosphorus in liquid 530 ppm Day 5; Length 48 mm Width 7 mm Phosphorus in liquid 0.01 pm Day 10; Length 158 mm Width 9 mm Phosphorus in liquid 0.01 pm The entire amount of ammonium phosphate was eluted at the same time when the test was started.

Comparative Example 4 20 parts of 50% phytic acid (manufactured by Mitsui Toatsu Chemicals, Inc.), urea 2
Was performed in the same manner as in Example 1. The test results were as follows. Day 2; Length 19 mm Width 4 mm Phosphorus in liquid 525 ppm Day 5; Length 52 mm Width 9 mm Phosphorus in liquid 0.01 pm Day 10; Length 187 mm Width 12 mm Phosphorus in liquid 0.01 pm

[0021]

EFFECTS OF THE INVENTION The present invention has solved the problem, which was not achieved in the prior art, that most of the active ingredient is lost even after fertilization because it dissolves instantly in seawater after fertilization. That is, the sustained-release fertilizer for seaweed culture of the present invention,
Ammonium polyphosphate, especially by having a specific particle size, after fertilizing, without instantaneously dissolving in seawater,
It is intended to provide a sustained-release fertilizer for seaweed cultivation that can be used for a long period of time, has excellent adsorbability to seaweed, and has high workability. Further, the sustained-release fertilizer for seaweed culture of the present invention is safe for the environment.

Claims (2)

[Claims] 1. A sustained-release fertilizer for seaweed cultivation, which contains ammonium polyphosphate as an active ingredient, wherein the ammonium polyphosphate has a particle size of 100 mesh or more of 70% by weight or more and a maximum particle size of 20 mm or less. A sustained-release fertilizer for seaweed cultivation characterized by the following: 2. The molecular weight of ammonium polyphosphate is 5
× 10⁴~ 1 × 10 ⁶The seaweed aquaculture according to claim 1.
Sustained release fertilizer.