JP2010063400A - Covered seed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain covered seeds having a high germinating/root-taking property by synthetically considering water retention effect, nutritious elements and soil microorganisms and selecting a covering substance in covering plant seeds. <P>SOLUTION: The seeds of a plant are covered with the covering substance containing a polysaccharide or biodegradable polymer having the water retention effect, a bio-originated substance decomposable by microorganisms, and the spores of microorganisms moderately decomposing/digesting the polysaccharide or biodegradable polymer and bio-originated substance. As the bio-originated substance, any of the dried powder of single cell algae or sea weeds, fine wood powder or dried powder of animals and plants are desirable and the dried powder of Haptophyta is the optimal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coated seed obtained by coating a plant seed with a coating substance, which is used for growing the plant in soil lacking in nutrients and moisture.

  The ecosystems of wasteland and newly cultivated farmland, where vegetation has not been bred until now, are poor, and it is not easy to cultivate them even by direct sowing of vegetation seeds.

In addition, the ecosystem of plateau grasslands exposed to harsh natural environments such as rain, dryness, and low temperatures is inherently poor. Recently, due to overgrazing of livestock, overcutting of trees, and artificial exploitation of fires, etc., the ecosystem has become increasingly poor, and the disappearance of grasslands and desertification has become a global problem. Water is an essential element for the restoration of lost grasslands, but sandy soils are difficult to retain moisture, and there are few opportunities for germination of plant seeds. From the soil surface where the grass has been lost, the nutrient surface soil and soil microorganisms are lost due to rainwater, making it more difficult to recover the grassland.
Moreover, even if the soil is not necessarily poorly nourished, if the soil microflora that should support the ecosystem is poor, nutrient recycling will be incomplete and it will not be easy to recover the grassland. In other words, vegetation, soil nutrition, and soil microorganisms are vines that support the grasslands. If water and soil microorganisms can be induced in deserted bare soil and herbaceous plants can be established, it will lead to the restoration of grasslands and eventually the regeneration of forests.

  So far, coated seeds in which the seeds of plants are coated with water-retaining materials and microorganisms have been proposed in consideration of the importance of moisture and soil microorganisms. For example, a coated seed (Patent Document 1) coated with a water retention substance (aqueous gel) and a coated seed (Patent Document 2) coated with a fertilizer component in addition to the water retention substance have been proposed. Furthermore, by decomposing the nitrogen compound in the coating material by microorganisms or having the function of fixing nitrogen in the air to promote germination growth of the seed (Patent Document 3), the gel constituting the coating material is decomposed. A coated seed to be softened and disintegrated (Patent Document 4) has been proposed.

JP 55-3796 A Japanese Patent Laid-Open No. 11-155308 JP 59-187706 JP 2006-180791 A

  The coating material to be applied to the seed must have a positive effect on the growth of the plant. The problem to be solved by the present invention is to obtain a coated seed having a high germination and fixing ability by selecting a coating substance in consideration of water retention, nutrients and soil microorganisms when coating a plant seed.

  The coated seed according to the present invention, which has been made to solve the above-mentioned problems, comprises a plant seed, a polysaccharide or biodegradable polymer having a water-retaining effect, and a biogenic substance that is decomposed by microorganisms and becomes a nutrient source. , Coated with a coating material containing the polysaccharide or biodegradable polymer and a spore of a microorganism capable of degrading the biogenic material.

More specifically, the coated seed according to the present invention is characterized in that it is coated with a coating material mainly composed of the following three types of substances selected in consideration of water retention, nutrients, and soil microorganisms. To do.
(A) A polysaccharide or biodegradable polymer that has water retention and is decomposed by microorganisms to become a target plant or plant nutrient source. Adhesives are advantageous for the production of coated seeds. Specific examples include xanthan gum, carrageenan, carboxymethyl cellulose (CMC), and konjac mannan.
(B) A biogenic substance that is decomposed by microorganisms and becomes a nutrient source for the target plant or plant. Specific examples include dry powders of unicellular algae and seaweed, fine wood powders, and dry powders of animals and plants.
(C) Microorganisms (filamentous fungi, actinomycetes, fungi, soil bacteria, etc.) that can decompose the substances (A) and (B) above and serve as nutrients for the target plant or plant, spores, mycelia, etc.

    When the adhesiveness of the coating material is insufficient, it is desirable to add an adhesive component separately in order to stably produce the coated seed.

Biological substances are selected as the nutrients for plant seeds, especially algae and seaweeds because they contain trace components such as minerals that plants need in proportions that plants need. is there. Although chemical fertilizers are efficient at first glance as nutrients, they do not contain minerals and are not optimal for germination and growth of plant seeds. Although it may be possible to chemically estimate the trace components necessary for the growth of plants and add them to chemical fertilizers, it is not easy, and this point is naturally satisfied by using nutrient sources of plant origin.
In addition, marine unicellular algae are easy to dry powder, can not survive in the surface or freshwater environment, so do not disturb the terrestrial ecosystem, nutrients such as N, P, K, etc. abundant in seawater into the soil It has characteristics that are difficult to obtain with industrial products such as being able to recirculate and having a good nutritional balance as a fertilizer for plants.

  There is no need to specify microorganisms as long as they can decompose the polysaccharides or biodegradable polymers and the biogenic substances and use them as nutrients. did. Specifically, it is conceivable to collect microorganisms by the method performed in the examples. It is conceivable to select a specific type of microorganism with high efficiency, but it may break the balance of natural microorganisms, and it is considered to be based on the principle of nature conservation. Furthermore, it is desirable for the seeds to be supplied with nutrients gradually over the entire period of germination and growth of the seeds, and microorganisms having high decomposition efficiency of nutrient substances cannot always be determined to be optimal.

When seeds with coated and uncoated seeds are sown at the same time under the cultivation conditions assuming low temperature rain and poor soil, the coated seeds germinate earlier than the uncoated seeds, and the germination / growth rate is high and the final number of growing individuals is large. The germination growth rate was different depending on the substance (mixing ratio) used for coating, and a correlation was observed with the water retention ability of the substance (gel mixed with water).
By coating the seed with a suitable coating material, the seed, or the plant, can be made the dominant species on the land.

  The dry weight (photosynthesis production amount) of the plant grown from the seed coated with the coating substance containing the above three types (A), (B), and (C) is calculated from the above three types (B) and (C). Compared with the case of seeds coated with a coating substance excluding either or both of the above, it is much larger. There are significant differences in the above-ground parts such as leaves, stems, and branches, as well as the roots (underground part; the number of nodules in the case of urchinaceae). The same relationship can be obtained even under conditions of normal temperature and rainfall in poor soils. In other words, a combination of the above three kinds of coating materials is a requirement for excellent coating.

  The respiration ability of the soil after harvesting the plant grown in the first cultivation was almost proportional to the dry weight of the harvested vegetation. Here, the respiration capacity of soil refers to the amount of carbon dioxide generated by a given amount of glucose solution, and can be estimated to be approximately proportional to the amount of aerobic microorganisms in the soil. It is presumed that microbial spores in the covering material germinate and grow, gradually decompose the covering composition, supply nutrients to the seeds of the germinated vegetation, and attract the soil microbial community to the surrounding soil. That is, the cultivation of the coated seed of the present invention not only helps the germination and growth of the seed, but also improves the surrounding soil environment.

When uncovered seeds of the same plant are sown and grown on the soil after harvesting the primary cultivated plant, the dry weight of the secondary cultivated plant is also almost proportional to the dry weight of the primary cultivated plant. The magnitude relationship according to the coating condition of the coated seed of the cultivated plant was shown. The respiration ability of the soil after harvesting the second cultivated plant maintained or increased the respiration ability after harvesting the first cultivated plant (before sowing the second crop).
It is presumed that the soil microorganisms attracted in the primary cultivation remained and contributed to the growth of the uncoated seeds sown second. If the coated seeds of the present invention are used, it is considered that permanent improvement of poor soil is possible, resulting in establishment of vegetation and restoration of grasslands.

  By covering vegetation seeds with a coating material composed of water-retaining substances, nutrient sources, and microorganisms as pointed out in the present invention, germination and growth can be more efficiently performed in wasteland and grassland than conventional methods, and the soil is improved. The plant can be permanently established. This can contribute to the efficiency of greening of wasteland and grasslands.

Embodiments of the present invention will be described below with reference to the drawings.
The optimum blending ratio of the coating substance varies slightly depending on the type of plant to be cultivated and the conditions of the land, so there are many options and must be examined individually and specifically. In that sense, the following examples are only given under the given conditions, and other coating substance blending ratios are not denied within the scope of the present invention.

(Manufacture of coated seeds and cultivation conditions)
As plant seeds, commercially available monocotyledonous Italian ryegrass (scientific name: Lolium multiflorum, hereinafter abbreviated as IRG, Kochi Maekawa Seed Seed Company) and dicotyledon genge (scientific name: Astragalus sinicus, hereinafter referred to as CMV, known as Kochi Maekawa Seed Seed Company) were used. Both are vegetation normally found in highland grasslands, and the former is a winter forage crop that dislikes mixed weeds. The germination rates in a water-saturated environment at a temperature of 25 ° C and a light period of 16 hours were 86% and 88%, respectively.

  Seeds were cultivated using poorly eutrophic soil with low water retention. Commercially available Akadama soil, Kanuma soil, and sand were mixed at a ratio of about 1: 2: 7 to obtain an oligotrophic test soil, but even if the mixing ratio changed slightly, the results were not significantly affected. As a result of the analysis, this soil was in a region called the loamy sand or sandy loam in the USDA soil particle size classification.

For the germination / growth experiments, the light period (2400 lux) was set to 16 hours and the dark period was set to 8 hours using an artificial meteorological instrument (Japan Medical Instruments LH220). Also, during measurements in natural daylight and temperature conditions in the outdoors, seeded in a pot of area 300 cm ² depth 20 cm, it was controlled irrigation placed under the roof of transparent polycarbonate wave plate.

  The seeds were coated using a rotating bowl and a spray drying cylinder, and the coated seeds were dried. A spray-drying cylinder is a self-made device that produces seeds by flying seeds with warm air from the bottom, spraying and adhering a liquid / powder containing a coating substance to the seeds, and drying them. A thing was used.

  As seaweed, we used unicellular seaweed haptophyceae Phaeocystis sp. Necolon-1 wrapped in thick polysaccharide envelope (less than 50% of dry weight of algae) and strengthened with Eppley solution Grown in artificial seawater. The cultivated seaweed was collected and dried to obtain a dry seaweed powder. The components of the dried seaweed were about 60% organic (polysaccharides, proteins, lipids, etc.) and about 37% inorganic (Ca, Na, Mg, K chloride, carbonate, phosphate, etc.).

The four types of coating substances used in the present invention, their constituent materials and composition ratios are shown in FIG. These coating materials (#a, #b, #c, #d) were used and compared with the case without coating. Among them, coating #b composed of dry seaweed powder (20%), xanthan gum (20%), CMC (40%), and carrageenan (20%) was used as a standard. In the following experiments, the coating unless otherwise specified for the coating material composition is #b. In experiments comparing the coating with and without seaweed powder, the carrageenan was increased by 20% by replacing the seaweed powder with carrageenan.
Here, it is known that there are three types of carrageenan, kappa, iota and lambda, depending on the raw materials. In this study, kappa type carrageenan (Nippon Biocon C80) was used.

The gel dehydration rate is obtained by mixing 0.5 g of the coating substance and 1 g of water to form a gel, and determining the time (t) change in the residual water weight (W) when air-dried at 40 ° C., and calculating the value as W = a exp ( The value of b when analyzed as -bt).
The average weight of one IRG seed and one CMV seed was 3.2 mg and 3.6 mg, respectively. As shown in FIG. 1, the coating increased the weight by 4-6 mg per seed.

  Microorganisms that degrade the coating substance can be left open on the paper plate made of the seaweed powder and waste cellulose at the site where the coated seed is to be sown, or it can be left covered with the soil at the site. The collected ones were grown. The microorganisms collected in this way were selected and those that formed conidia were isolated. The microorganisms used in the present application were mainly the genus Aspelgillus and the genus Streptomyces, but the present invention is not limited to these. If normal microorganisms collected in an area where the coated seed is desired to be sown in this way, the microbial ecosystem in the area is not disturbed even if the coated seed is sown. In carrying out the invention as in the present application, it is always important to not disturb the local ecosystem. It is extremely difficult to restore a once disturbed ecosystem.

  After culturing these microorganisms on PDA medium to make spores, wash the medium surface with 0.85% saline containing 0.01% Triton X-100, and centrifuge the washings to remove these spores. collected. The collected spores were suspended in 0.85% saline and stored at −20 ° C. until use. In the present invention, it is not the microorganism itself but the spores that are added to the coating material. This is because when the microorganisms themselves are included in the coating material, the coating material is decomposed by the action of slight moisture and the coated seeds are deteriorated. In this regard, spores are better preserved.

The spore concentration of the spore suspension prepared by mixing almost equal amounts of the above two types of microorganism spores is about 1.7x10 ⁶ spores / ml, and the germination rate of the two types of spores when thawed and cultured in PDA medium Was about 89-96%. The coated seed before sowing was passed through 1 ml of a spore suspension (denoted as x1) or a 10-fold dilution thereof (denoted as x0.1), and the coated seed coating contained spores. Coated seeds containing no microbial spores in the coating (denoted x0) were prepared by simply passing the coated seeds through pure water and used for comparison.

As a measure of the amount of soil microorganisms and their biological activity, the apparent respiration capacity of the soil was measured. In one glass jar, 5 g of soil sample and 4N KOH solution were placed in separate containers, and two sets were prepared. The two sets of jars were connected with a thin plastic tube via a micro differential pressure transducer (KYOWA PDV-10GA). The voltage output of the differential pressure transducer was connected to the recorder.
Glucose solution (700 mg / ml) was applied to the soil sample in one jar and an equal volume (5 ml) of water was applied to the soil sample in the other jar. Microorganisms in the soil sample digest the glucose solution, consume oxygen, and generate an equal volume of carbon dioxide. As the generated carbon dioxide is absorbed by the KOH solution, the pressure in the jar changes. The resulting slight differential pressure change was recorded, and the rate of decompression 2 minutes after the start of the reaction was defined as the relative respiratory activity (ml / min) of the soil. The volume was quantified by increasing or decreasing air with a syringe. Respiratory activity was measured by changing the mixing ratio between the upland soil and the soil sterilized by high pressure sterilization, and a relative calibration curve was obtained.

(Effect of coating on seed germination)
50 sets of IRG seeds and 50 sets of uncoated IRG seeds coated with coating #d (Fig. 1: Seaweed powder 20%, CMC 30%, carrageenan 20%, wheat flour 30%), one set each, and three sets each for test soil Seeded in separate 50cm ² trays. In an artificial meteorological device, the plants were grown for 45 days with a temperature and irrigation amount of 16 hours in the light period (2400 lux) and 8 hours in the dark period, and germination and growth rate were measured. Here, the germination rate was defined as the ratio (%) of the number of germinated seeds to the number of seeds sown for uncoated seeds. The growth rate was defined as the ratio (%) of the number of seeds that broke the cover and sprouted to the number of coated seeds sown for the coated seeds. In the case of coated seeds, germination is considered to be a preliminary stage of growth in terms of time, but cannot be visually observed due to a phenomenon in the coating.
The average value of three sets of experiments in which 50 seeds were measured for 45 days was determined and shown in FIG. The irrigation amount here was 40 ml / 50 cm ² of water at the time of sowing, and then additional irrigation as shown in the table. The illumination conditions were the light period (2400 lux) 16 hours and the dark period 8 hours, which were the same in all experiments.

  Under the condition of sufficient irrigation at 25 ° C (saturated irrigation: the surface of the seed was always wet), the germination / growth rate was 90% for both coated and uncoated seeds. When irrigation after sowing was limited to 5 ml once every morning (equivalent to about 1 mm of precipitation per day), the growth rate of coated seeds (buds that broke through the coating) decreased to 60%. The germination rate of coated seeds decreased to 38%. When the irrigation was 5 ml / every other day, the uncoated seeds hardly germinated, but the coated seeds grew 36%. In this experiment, germinated and grown seeds were removed from the tray after germination and growth confirmation, so it was not possible to determine whether or not germination and post-growth growth could be continued, but at least in the situation where water was the limiting factor for germination, the coating was applied to the seeds. It is thought that necessary moisture was preserved to help germination and growth.

50 seeds each coated with different coating materials (#a, #b, #c, #d) are sown in separate 50cm ² trays each covered with test soil, light period (2400lux) 16 hours 15 ° C dark period The germination / growth number was examined for 8 hours at 5 ° C., with 40 ml / 50 cm ² of irrigation at the time of sowing and the subsequent irrigation limited to 5 ml once every morning (assuming highland spring). The average value of the three sets of measured values is shown in FIG. The germination rates of uncoated seeds under this restriction condition are 38% and 24%, respectively, which is very low compared to 86% and 88% (Fig. 1) in a 25 ° C undried environment. On the other hand, the germination rate of the coated seeds reached 80% and 82% with #a coating, which was close to the value of the saturated environment even under irrigation restricted conditions.

The time course (germination / growth curve) of the germination number of seeds coated with each coating substance and uncoated seeds is shown in FIG. 4 for IRG and FIG. 5 for CMV. The slope at the midpoint of the germination / growth curve, that is, the number of germination / growth per day when the half of the maximum germination / growth number was reached was defined as the germination / growth rate, and the value is shown in FIG. Coated seeds have a larger value for germination / growth maximum arrival (germination / growth rate) and germination / growth rate than uncoated seeds, and the number of days until the first germination observation is short. This tendency is common to all of the coated seeds, but the degree varies depending on the components of the coating and correlates with the rate of dehydration from the gel shown in FIG. 1 (the reciprocal of the water retention capacity).
This result shows that seeds covered with water-retaining substances improve the germination and growth rate of seeds at relatively low temperatures and low rainfall, and as a result, the plants are dominant in the land. It suggests the possibility of becoming a seed.

(Effects of seaweed powder and spores in seed coating on germination and growth of plants)
The effect of the presence or absence of seaweed powder in coating #b and the addition or absence of microbial spores that can assimilate coating #b on seed germination / growth to the extent that irrigation conditions are not a strong limiting factor (300 ml / 300 cm ² -Every other day) and shown in FIG. This figure shows the average of three experiments with 50 grains each. The main reason for selecting #b instead of coating #a as the test sample is that xanthan gum contained in coating #b had a high viscosity advantageous for coating formation and maintenance. In this experiment, outdoor natural sunshine conditions were adopted, the cultivation period was 80 days from summer to autumn, the temperature was 9-31 ° C., the average sunshine was 6.8 hours / day, and the irrigation was 300 ml / 300 cm ² every other day.

  The dry weight shown in FIG. 6 is divided into a leaf part (aboveground part: including stem) and a root part (underground part), and FIG. 7 shows the IRG and FIG. 8 shows the CMV. Shown as the distribution of 30 seeds seeded.

  Under the given irrigation conditions, the germination / growth rate of coated IRG seeds did not differ depending on the presence or absence of seaweed or the amount of spores, but both were superior to uncoated seeds and the advantages of seed coating were obvious. It is. On the other hand, there is a clear difference in the photosynthetic production (dry weight) of IRG grown from each coated seed, and it can be concluded that the coated seed coexisting with seaweed powder and spores grew best. The results are shown in FIG. 9 in addition to FIG. In FIG. 9, + indicates that the cover contains seaweed, and − indicates that the cover does not include seaweed (the seaweed is replaced with carrageenan). Moreover, the error range of the dry weight was determined from the standard deviation of the average value of three experiments.

Germination / growth of CMV seeds showed exactly the same tendency as IRG seeds as shown in FIGS. In the case of CMV, the result of the number of nodules was also shown. From the viewpoint of the number of nodules, it can be concluded that it is very meaningful to include both seaweed powder and spores in the coating.
From the viewpoint of dry weight, it can be concluded that under the given experimental conditions, the more spore formation (x1 coating 1.7 × 10 ⁶ /ml>x0.1 coating 0.17 × 10 ⁶ / ml), the better.

  From these results, for seed germination growth, a substance that can be slowly digested and decomposed by microorganisms such as seaweed powder to supply nutrients and a nutrient source in a coating substance such as seaweed powder over the entire period from germination to growth. It can be concluded that it is effective to coexist microbial spores that can be slowly digested and decomposed with the seed coating material.

After the primary cultivation was harvested and finished, the apparent respiration capacity of the soil in each cultivation pot was measured.
The apparent respiration ability of the soil varies depending on the coating of the seeds of the plant cultivated in the soil, and the magnitude relationship is almost the magnitude relationship of the dry weight of the plant cultivated in the soil, as shown in FIG. It was proportional. In this figure, the average dry weight is a transcription from FIG. FIG. 11 shows the causal relationship whether the growth (dry weight) of the plant has grown / activated the aerobic microorganism or the growth / activated aerobic microorganism has promoted the growth of the plant. Suggests that, regardless of the type of plant, it is greatly influenced by the type of coating, especially the absence of seaweed powder and spores.

(Post-effect on the cultivated soil)
In each pot after IRG is cultivated and harvested under various covering conditions as primary cultivation, 30 seeds of uncoated IRG seeds are seeded as secondary cultivation, cultivated with sufficient irrigation, We investigated how much the effect remained. The soil of each pot after cultivating three kinds of coated IRG seeds and uncoated seeds with different spore concentrations as primary cultures in each pot was compared with the same unused soil (for control). The germination / growth rate and dry weight of uncoated IRG seeds cultivated secondarily were determined and shown in FIG. Similar measurements were performed on CMV seeds and the results are shown in FIG.

  Comparing the five types of pots, no significant difference was found in the germination / growth rate of uncoated seeds based on differences in primary cultivation. However, there was a very large difference in the dry weight of secondary (uncoated) cultivated plants grown and harvested in each pot. The order of dry weight was the same as the result for primary (coated / uncoated) cultivated plants (FIG. 6). In addition, since there is a difference in cultivation time and period, a direct comparison of the dry weight between the primary and secondary production is inappropriate. However, it is considered possible to compare the relative values of the relative values. The results for CMV were the same as for IRG.

  These facts suggest that the effect of the seed coating substance remains in the soil after the seeds of primary cultivation germinate, grow and are harvested, depending on the amount or absence of the coating substance. Yes. Production of phytonutrients enhanced by seaweed powder and added spores / microorganisms, and / or the growth of soil microorganisms that are eventually attracted and activated by the two, or both. It is estimated to be.

The apparent respiration ability of the soil after the harvest of the second cultivated plant and the respiration ability of the soil before the second cultivation (= after the harvest of the first cultivated plant) are compared and shown in FIG.
It is considered that the respiration ability after the second cultivation is increased or maintained as compared with the respiration ability after the first cultivation, even though the second cultivation is an uncoated seed. This suggests that the aerobic soil microorganisms increased with the cultivation of the primary plant maintained the same amount / activity after the cultivation of the secondary plant. The post-cultivation effect in CMV is not as remarkable as IRG and is relatively large, probably because of the influence of nodules during the primary cultivation.

  The coated seed proposed in the present invention is extremely useful for growing plant seeds in wasteland, unfarm land, plateau, and grassland. Furthermore, the use of coated seeds can contribute to permanent improvement of poor soil. As a result, it became clear that poor soil can be expected to become grassland.

Table showing coated seeds and their composition ratio Table showing germination and growth rate of IRG seeds Table showing the effect of coating substances on germination and growth of coated seeds Germination and growth curves of coated IRG seeds Germination and growth curves of coated CMV seeds Table showing the effect of seaweed powder and microbial spores during coating on the growth of coated seeds Dry weight distribution table of growing IRG leaves and roots with and without seaweed powder and spores in the coating Table of dry weight distribution of leaves and roots of growing CMV with and without seaweed powder and spores in the coating Graph showing the effect of seaweed powder and spores during coating on the growth of coated IRG seeds Graph showing the effect of seaweed powder and spores during coating on the growth of coated CMV seeds Graph showing the relationship between apparent respiration capacity and seed coating composition of soil after first plant cultivation harvest Table showing the effect of primary cultivation conditions on germination and growth of uncoated seeds in secondary cultivation Table showing apparent respiration capacity (ml / min) of soil after secondary cultivation in soil after primary cultivation

Claims (6)

Plant seeds
A polysaccharide or biodegradable polymer having water retention,
A biogenic substance that is decomposed by microorganisms and becomes a nutrient source;
Microbial spores capable of degrading the polysaccharide or biodegradable polymer and the biogenic substance,
Coated seed coated with a coating material containing   The coated seed according to claim 1, wherein the biogenic substance is one or more biogenic substances selected from dry powders of single-celled algae or seaweed, fine wood powders, and dry powders of animals and plants.   The coated seed according to claim 1, wherein the biogenic substance is a dry powder of haptoalgae.   The coated seed according to any one of claims 1 to 3, wherein the polysaccharide having water retention is one or more polysaccharides selected from xanthan gum, carrageenan, CMC and konjac mannan.   The coated seed according to any one of claims 1 to 4, wherein the spore of the microorganism is derived from a microorganism collected in an area where the coated seed is sown.   A method for improving a soil environment by spraying the coated seed according to any one of claims 1 to 5 on soil.

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