JP2536034B2 - Soil conditioner using myxobacteria - Google Patents

Description

TECHNICAL FIELD The present invention relates to a soil improving agent having an action of promoting soil aggregate formation and an effect of suppressing plant diseases such as Fusarium disease.

[Prior art]

Since ancient times, compost for the purpose of increasing the yield of vegetables and grains,
Organic matter such as green manure has been put into soil as a soil conditioner. This is because when organic matter is decomposed by soil microorganisms, the microorganisms secrete mucilage, which promotes the formation of soil aggregates and improves water retention and aeration of soil. In addition, the pore condition of the soil is improved, the roots of crops are deepened, the contact area between root hairs and soil particles is deepened, and the absorption efficiency of nutrients is enhanced. But,
These organic fertilizers have drawbacks that they require a long time for ripening and a considerable amount of labor for fertilization.

In addition, polyacrylic acid type, polyvinyl alcohol type,
Humic acid-based chemicals are also commercially available as soil conditioners that produce stable aggregates that are harmless to crops. However,
These synthetic soil conditioners are relatively expensive and are less susceptible to biodegradation, and have problems such as soil persistence.

As described above, in addition to the physical characteristics of soil, a factor that greatly affects the yield of crops is the prevention of plant diseases caused by plant pathogens such as Fusarium. Various pesticides are used for the purpose of suppressing the onset of these diseases,
There are problems such as toxicity to humans and livestock, crops, and soil persistence, and a plant disease control agent that does not rely on these pesticides is desired.

[Problems to be Solved by the Invention]

An object of the present invention is to provide a soil improving agent that promotes the formation of soil aggregates and also has an effect of preventing plant diseases caused by plant pathogens such as Fusarium.

[Means for solving the problem]

The present inventor, as a result of diligent research to solve the drawbacks of conventional soil improvers, by using viable cells of myxobacteria (myxobacteria), excellent formation of soil aggregates, and fusarium disease etc. A soil conditioner having a plant disease suppressing effect was found.

That is, the present invention is a soil improving agent characterized by containing myxobacteria. The myxobacteria contains at least one of the genus Myxococcus, alkanedium, cystobacter, and polandium having microbial lytic properties. Further, the present invention relates to a soil conditioner having a mycobacterium content of 0.1 to 100%.

The myxobacteria of the present invention are bacteria that are isolated from soil, decaying plants, bark or seawater, river water, etc. that are universally present in nature, and as their name suggests, a large amount of slime (slime) is present outside the cells. It is known to secrete. It is considered that this mucilage contributes to the formation of aggregate structure in the natural soil. Therefore, by adding this myxobacteria to the soil to increase the number of bacteria, it is possible to further enhance the formation of an aggregate structure, which promotes the growth of crops and helps increase the yield. In addition, myxobacteria are classified into a microbial lytic group and a cellulolytic group from the viewpoint of their nutritional requirements. Most of them belong to the former, and secrete proteases, degrading enzymes such as β-1,3 glucanase, etc. and antibiotics to the outside of the microbial cells, thereby lysing the surrounding microorganisms and growing them as food. Furthermore, some myxobacteria include the antifungal antibiotics myxin, ambrrucin (ambru).
ticin), myxothiazol, myxalamide, stigmatell
in) and the like are known, and these are also considered to be related to lysis. It is considered that such a slime bacterium naturally forms an ecosystem for treating waste cells.

On the other hand, various kinds of microorganisms that cause disease on plants are known, and one example thereof is a mold belonging to the genus Fusarium, which causes the wilt disease of cucumbers. This mold is often found in the soil, invades the plant body from the roots in the soil, extends upward through conduits, forms lesions on the stalks or at the nodes, and finally Kills plants. Other plant pathogens include Pythium, which causes seedling blight of various crops, Rhizoctonia, which causes roots such as potato and pea to rot, and anthracnose fungus, Colletotrichum. ),
Sclerotiu, a white scab of tobacco and other bacteria
m), fungi such as Gaeumannomyces, which is a bacterial wilt of Komigi, and xanthhomonas, which is a black rot of cabbage.
s) Genus and vegetable soft-rot fungus Erwinia spp. Pseudomonas (Solanaceae wilt fungus Pseudomonas)
There are bacteria such as genera, and all are soil pathogens.

As described above, many of mycobacteria and phytopathogenic fungi such as Fusarium are soil microorganisms, and due to the fact that myxobacteria have microbial-dissolving ability, myxobacteria also grow excessively in natural soil. It is thought that it is suppressing. Therefore, by adding myxobacteria to the soil, it is possible not only to promote the formation of aggregates in the soil but also to control the growth of plant pathogens such as Fusarium.

The myxobacteria are Myxococcuceae, Arcandiacea, and Cystobacter.
4 genera of bacteriumacea) and porandium (Polyangiacea) are known.
Any slime bacterium can promote the formation of aggregates in the soil and suppress the growth of pathogenic fungi, but Myxococcus spp.
It is easy to handle and advantageous in terms of growth. The myxobacteria used as the soil improver may be any one having at least one of the above four genera.

In order to obtain the mycobacterium of the present invention, carbon source, nitrogen source,
Cultivation may be carried out by a conventional method using an ordinary medium containing non-kione and the like. As the carbon source, glucose, fructose, maltose, raffinose, rhamnose, glycerose, xylose, lactose, sucrose, sugars such as starch, alcohols such as ethanol and sorbitol, and organic acids such as acetic acid can be used. As the nitrogen source, in addition to ammonium ions, amino acids, proteins, yeast extracts containing these, casein hydrolysates, and the like can be used. If necessary, inorganic ions such as potassium ion, phosphate ion, calcium ion, magnesium ion, copper ion, zinc ion, manganese ion, and iron ion are added to the medium.

In addition, fermented bacterial cells such as glutamic acid fermentation can be used as the only nutrient source.

The culturing is preferably carried out under aerobic conditions, and more preferable results can be obtained by culturing while adjusting the pH to an appropriate range of pH 4 to 9. The culture temperature is preferably in the range of 25 ° C to 38 ° C.

Any method of spraying myxobacteria on soil may be used, and the suspension may be sprayed or poured into the soil, or the bacterial cell pellet may be embedded in the soil. In addition, after soaking plant seeds and seedlings in a suspension of myxobacteria, Han seeds,
You may categorize.

The range of microorganisms whose growth is suppressed by myxobacteria is wide, and in addition to the Fusarium genus, the above-mentioned Pythium, Rhizoctonia, Choletotricum, Sclerotium, and Gaeuma.
It has an action of suppressing the growth of fungi such as genus nnomyces and bacteria such as genus Xanthomonas, genus Erwinia and genus Pseudomonas.

The composition of the soil improving agent containing myxobacteria may be myxobacteria itself, or may be any composition as long as the myxobacteria can exist in a viable state.
For example, it may be a mixture of mycobacteria with 1 to 99% of various microbial cells serving as a nutrient source of the bacterium, or a mixture of 0.01 to 90% of various antifungal substances. In addition, those containing peat moss, cow dung, compost, etc. may be used.

〔Example〕

 An embodiment will be described in detail based on the present invention described above.

(Example 1) (Culture of myxococcus) To 30 jars, 20 SP2 medium having the following composition was added, and myxococcus Myxococcus (Myxococcus) was added.
xanthus) IFO 13542 and Myxococcus flavescence JCM 6245 preculture liquid (also cultured in SP2 medium at 27 ° C. for 3 days) were inoculated, and
Culturing was carried out for 48 hours under the conditions of ℃, aeration of 0.05 / min and 250 rpm. The culture broth was collected by centrifugation and washed twice with distilled water to obtain wet bacterial cells (about 80 g). SP2 medium (unit: g /) Raffinose 1 Galactose 1 Sucrose 1 Soluble starch 5 Caditon (Difco) 2.5 Magnesium sulfate 1 Dipotassium phosphate 0.5 Yeast extract (Difco) 1 pH 7.2 (Melon growth test and suppression of mildew disease) Test) Fusarium oxysporum melonis (M-1)
(Fusarium oxysporum melonis (M-1)) has a spore concentration of 10 ³ cells / (g soil), and an appropriate amount of myxobacteria suspension is irrigated, and the mixed soil is put into a vinyl pot and germinated 2-3
Transplant one cotyledon of the day into one pot. The seedlings were grown in an artificial weather device under the conditions of a temperature of 27 ° C., a humidity of 70%, and a sunshine of 40 klux for 12 hours. Around 3 to 4 true leaves (after 30 days), the growth condition and disease state of plants (atrophy of foliage,
(Aging) was observed. The results are shown in Tables 1 and 2.

The group to which the myxobacteria were added was superior to the control group (no-addition group) in growing the seedlings. No plant growth inhibitory factor was present in the addition zone. On the other hand, the disease was significantly suppressed in the addition group, and the disease suppressing effect was also enhanced depending on the amount of myxobacteria added.

(Example 2) Pseudomnas putida AJ 23 causing competitive inhibition of Fe as an antagonistic microorganism of the genus Fusarium
38, and Bacillus liqueniformis AJ 1352, which causes hyphal malformation, are known. The synergistic inhibitory effects of these antagonistic microorganisms and myxobacteria on Fusarium disease were examined. The culture of the bacterium and the disease suppression test for melon are the same as in Example 1. As shown in Table 3, the inhibitory effect was higher when Pseudomonas or Bacillus was added than when the myxobacteria were added alone.

(Example 3) Examining the effect of myxobacteria against plant pathogenic bacteria other than Fusarium genus Colletotrichum lagenarium, which causes anthracnose fungus of rain and cucumber,
Rhizoctonia solani causes stem rot of pea
octonia solani) and Xanthomonas campestris causing black rot of cabbage, as in Example 1. Myxobacteria (M. xanthus IFO 1354
The inhibitory effect of 2) was investigated. The results are shown in Table-4.

It was confirmed that myxobacteria have a similar disease suppressing effect on plant diseases other than those caused by Fusarium.

(Example 4) To 1 kg of compost or glutamic acid-fermenting bacterial cells, the culture solution 1 of myxobacteria (M.xanthus IFO 13542) was added and mixed, and then allowed to stand for 5 days at 30 ° C and 70% humidity. When the fertilizer or the glutamic acid-fermenting bacterium was fertilized at a rate of 5 to 50% with respect to the soil and a Fusarium disease inhibition test was conducted in the same manner as in Example 1, the onset of the disease was significantly suppressed.

It is understood that the myxobacteria can use, as well as the SP2 medium used in Example 1, unnecessary microbial cells produced by amino acid fermentation or the like as a nutrient source.

Example 5 Mycobacterium other than the genus Maxococcus were examined for their disease suppressive effect. That is, the Arkandium gefila (Ar
changium gephyra) ATCC 25201 and Cystobacter fuscus ATCC 25194 were subjected to a test for suppressing the Fusarium wilt of melon in the same manner as in Example 1. The results are shown in Table-5. All myxobacteria showed remarkable disease suppressive effects.

[Effects of the Invention] As described above, according to the present invention, since it is a soil improving agent having a soil aggregate formation promoting action and a plant disease suppressing effect, the growth promotion of plants such as melon and cucumber and the Fusarium wilt disease. It can be widely used for the prevention of such diseases.

Claims (2)

(57) [Claims] 1. A genus of alkanedium having microbial lytic properties,
A soil improvement material comprising at least one kind of bacterium belonging to the genus Cystobacter and the genus porandium. 2. A genus of alkanedium having microbial lytic properties,
0.1% cystobacter and porandium bacteria content
The soil conditioner according to claim 1, which is -100%.