JP2009082022A - Method for improving germination of soil seed, vegetation substrate, and greening method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for improving germination of soil seeds enabling improvement in a germination ratio of soil seeds falling in topsoil: to provide a vegetation substrate: and to provide a greening method. <P>SOLUTION: The method for improving a germination ratio of soil seeds (a) falling in topsoil, and comprises a process of improving soil physicality for segmentalizing the topsoil containing the soil seeds, and a stress-giving process of giving at least two of vibration stress, air stress, photostress and damage stress to the soil seeds falling in the topsoil. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for improving germination of buried seeds, a vegetation base, and a greening method for improving the germination rate of buried seeds contained in topsoil.

In recent years, when planting slopes and bare land, we have collected surface soil (soil containing humic material) including fallen leaves of the Yamano surface layer adjacent to the construction site (construction target site) of the revegetation work, and this includes the local vegetation A greening method utilizing falling seeds (buried seeds) is being adopted (see Patent Document 1 below). In other words, surface soil containing fallen seeds of local vegetation is collected and used as vegetation soil, and this is mixed with soil improvement material to make a greening material. It is packed in a bag and used as a vegetation sandbag, so that it can be used to plant trees without disrupting the flora of the surrounding area.
And when carrying out slope planting using such a buried seed as a planting material, it is common to use the collected topsoil as it is mixed with other materials.
Japanese Patent No. 3454352

On the other hand, the quality of the collected topsoil is likely to be affected by various conditions such as the state of the collection site and the collection method.
In addition, when the buried seed contained in the topsoil is in a dormant state, it may not germinate or grow even if the buried seed is abundant. Furthermore, since multiple types of buried seeds contained in the topsoil are mixed and germination mechanisms are different, germination and growth may be uneven depending on factors such as season and field conditions.
Therefore, from the viewpoint that processing technology to improve germination and growth of buried seed groups while maintaining a certain level of quality is an indispensable technology for slope planting using future forest topsoil. The present inventors have conducted various tests, and as a result, have found that the germination promoting effect of the buried seed can be obtained by applying a plurality of treatments to the topsoil containing the buried seed.

  The present invention has been made in consideration of the above-mentioned matters, and its object is to provide a germination improvement method, a vegetation base, and a greening method for buried seeds that can improve the germination rate of the buried seeds contained in the topsoil. Is to provide.

In order to achieve the above object, the present invention is a method for improving the germination rate of buried seeds contained in topsoil, including a soil physical property improving step for subdividing topsoil containing buried seeds, and topsoil A method for improving germination of buried seeds, comprising: a stress applying step of applying at least two types of vibration stress, air stress, light stress, and damage stress to the buried seeds to be buried (claim) Item 1).
That is, the invention according to claim 1 of the present application subdivides the topsoil containing buried seeds to improve soil physical properties, and vibration stress, air stress, light stress, damage to buried seeds contained in the topsoil. It is characterized by applying at least two types of stress among stresses.

This invention includes a soil physical property improving step.
That is, in this invention, the soil particles are reduced by subdividing the topsoil containing the buried seeds, and the elements such as bulk weight, aggregate, structure, pore volume are made suitable for the germination and growth of the plant. Can do.
As a subdivision method, for example,
(1) A method of subdividing topsoil using a shredder,
(2) A method of subdividing topsoil using a blower such as an air classifier,
(3) A method of subdividing the topsoil by shaking on a filter while lightly crushing the soil mass can be mentioned.
In addition, as a measure for subdividing the topsoil, it is preferable that “soil particles (aggregates / single grains)” having a particle size of 5 mm or less as the soil structure is 30% or more. Here, “soil particles” are used to mean both single particles in which the soil particles are present alone and aggregates in which the soil particles are aggregated.
Then, the inventors adjust the collected topsoil to a particle size of 5 mm or less by means of fragmenting means such as the shredder or the filter, and mix the sampled topsoil adjusted to a particle size of 5 mm or less into the unadjusted topsoil. Then, the number of germination was investigated according to the mixing ratio.

Table 1 below shows the relationship between the mixing ratio (%) of soil particles having a particle size of 5 mm or less and the seeding test result (number of germination establishment), and FIG. 1 shows a corresponding graph.
As a result, up to 25%, the value was almost the same as that of unadjusted topsoil, but the number of germinated seeds increased from 30%. From this, it has been found that it is preferable to adjust so that the soil particles having a particle size of 5 mm or less are 30% or more as a standard for subdividing.

The present invention also includes a stress applying step.
The topsoil contains multiple types of buried seeds, and the germination promotion (germination improvement) method varies depending on the type.
In the present invention, it is possible to deal with this diversity by applying a plurality of stresses to the buried seeds among the four types of vibration, air, light, and damage.
That is, the following was found by applying each stress to the buried seeds contained in the topsoil.
(1) Vibration stress: The dormancy of buried seeds could be overcome by applying vibration to the buried seeds contained in the topsoil.
(2) Air stress (air contact): The dormancy of the buried seeds could be overcome by positively contacting the buried seeds that were buried in the ground and not in contact with the air. Since germination factors in this air contact are various such as oxygen and nitrogen, they are collectively expressed as air hereinafter.
(3) Light stress (light irradiation): Until the surface soil was collected (until now), the dormancy could be overcome by exposing the buried seeds that had not been exposed to light to light.
In addition, since the kind (wavelength) of related light changes with buried seeds, it is most preferable to expose to sunlight.
(4) Damage stress: The germination of the buried seeds could be promoted by slightly damaging the epidermis of the buried seeds. As a method of damaging the buried seed, chemical damage due to chemical use (acid etc.) can be mentioned in addition to normal physical damage.
In the present invention, these stresses may be applied sequentially, but in order not to apply excessive stress and to shorten the processing time, the four types of stress should be applied simultaneously as much as possible. Is preferred.

In another aspect, the present invention is a method for improving the germination rate of buried seeds contained in topsoil, including a germination inhibitory action reducing step of removing undegraded coarse organic matter from topsoil, and a topsoil containing buried seeds. A soil physical property improving step for subdividing the soil, and a stress applying step for applying at least two types of vibration stress, air stress, light stress, and damage stress to the buried seeds included in the topsoil. A method for improving germination of buried seeds is provided (claim 2).
That is, the invention according to claim 2 of the present application includes a germination inhibitory action reducing step, wherein the germination inhibitory action is reduced by removing undegraded coarse organic substances present in the topsoil containing the buried seeds. Yes.
The “undegraded coarse organic matter” in the present invention includes plant rhizomes, bark, leaves, and fallen tree fragments. Of course, germinable seeds do not enter “undegraded coarse organic matter”.
In the present invention, undegraded coarse organic matter (for example, roots and rhizomes) is removed from the topsoil, so that allelopathic action from undegraded coarse organic matter (for example, roots and rhizomes) and the soil in the degradation Factors that adversely affect germination of buried seeds such as large consumption of nitrogen can be reduced.
As a removal method,
(1) Removal by the filter,
(2) Removal by the classifier
(3) Examples include removal by hand under visual inspection.
In the present invention, it is desirable to remove impurities such as gravel and stone that are difficult to use as a vegetation base at the same time.

Moreover, this invention provides the vegetation base | substrate characterized by mounting | wearing with the embedded seed containing surface soil which gave the method of Claim 1 or Claim 2 from another viewpoint (Claim 3). .
The vegetation substrate in the present invention refers to a plant that can grow a plant by installing the vegetation base on a greening target site (construction target site).
Specific forms are listed in the following (1) to (4).
(1) The topsoil (which may be mixed with other vegetation base materials) is filled with a “topsoil bag” shape.
The bag may be any sandbag, small bag, or cylindrical bag. Moreover, although there is no limitation in particular as a bag raw material, it is an essential requirement that it is a raw material which a plant can germinate and grow.
Specifically, examples of the “topsoil bag” include a bag having a mesh, a bag made of a corrosive material (partial corrosion is also possible), a water-soluble material bag, a water-decomposable material bag, and the like.
(2) A “vegetation pile” shape in which topsoil is filled in a hollow rod-like body can be mentioned.
(3) A “vegetation mat” shape in which topsoil solidified into an arbitrary shape using compression or a solidified material or topsoil packed in a bag is attached to a net.
(4) A “vegetation sheet” shape in which topsoil is sandwiched between upper and lower sheet-like bodies can be mentioned.
Examples of the material for the sheet-like body include various materials such as paper, nonwoven fabric, sufu, a sheet (film) made of a biodegradable resin or a water-degradable resin, and a plant fiber sheet such as palm. Moreover, it is preferable that the said sheet-like body has the thickness which can be selected from about 0.01-20 mm. Furthermore, it is also possible to form a mat shape by connecting upper and lower sheet-like bodies to form a bag and injecting topsoil into the bag.

Furthermore, the present invention provides a greening method characterized in that the buried seed-containing topsoil subjected to the method according to claim 1 or claim 2 is applied to the construction target site (claim 4).
In this case, using a known spraying method such as a wet spraying method or a dry spraying method, the buried seed-containing topsoil to which the method according to claim 1 or 2 is applied is applied to the construction target site (greening target site). ) Is preferred. In addition, as an alternative method of customer land, it is possible to simply spread out the buried seed-containing topsoil that has been subjected to the method according to claim 1 or claim 2 to the construction target site (greening target site).

Moreover, this invention provides the tree planting method characterized by installing the vegetation base | substrate of Claim 3 in a construction object ground (Claim 5).
The invention according to claim 5 of the present application uses the vegetation base. In this case, a vegetation mat sheet, a bag body (sandbag) or a greening pile using topsoil is a construction target site (a greening target site). It is preferable to construct it.

The present invention improves the germination rate of buried seeds in the topsoil by subdividing the harvested topsoil and performing a certain treatment. By making the topsoil smaller than a certain particle size by subdividing, the elements such as bulk weight, aggregate, soil structure, pore volume are adjusted, water retention is improved, etc. it can. In addition, at least two kinds of stresses such as vibration, air contact / light / damage, more preferably all four kinds are applied to the buried seeds almost simultaneously, which leads to activation of various kinds of buried seeds. It is.
Furthermore, by removing undegraded coarse organic matter (impurities such as root hair and leaves) from the topsoil containing buried seeds, plant growth-inhibiting factors such as allelopathic action and nitrogen starvation are removed. A state suitable for germination and growth can be formed.

  Thus, by performing the treatment according to the present invention, it is possible to stabilize the quality of the vegetation material of the topsoil compared to the conventional method of using the topsoil, and more potential from the viewpoint of germination and growth of the buried seeds. The topsoil can be utilized in a high state.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited thereby.

First, the topsoil collected by an arbitrary method is used to remove impurities such as undecomposed coarse organic matter and stones / gravels contained in the topsoil with a wind classifier (reducing germination suppression action). After that, the topsoil is put into a rotary blade shredder with a transparent cover and stirred and shredded to subdivide the topsoil (improve soil physical properties), and vibration and mildness to the buried seeds Active air contact and light irradiation (stressing) are performed while causing serious damage, and the buried seed is activated, so that germination from the buried seed-containing topsoil is improved.
In addition, when a shredder is charged, it is preferable that an acid solution or an alkali solution is added to the top soil so that different kinds of damage stress can be imparted to the buried seed. Moreover, it is also possible to give another kind of damage stress by giving an electric current to the surface of the rotary blade of the shredder by an appropriate method.
The topsoil thus subjected to the germination improvement treatment may be used as it is, but filtering with a perforated filter prior to the greening construction is preferable because the germination power is further improved. In other words, the topsoil is subdivided again by filtering, vibration (vibration given to pass through the filter), air contact (contact with air when falling from the filter), light (light falls when falling from the filter) Because all four types of damage (the seed surface undergoes slight physical damage by touching the material constituting the eye of the filter) can be applied to the buried seed almost simultaneously, the germination improvement effect is ensured It can be demonstrated. It should be noted that the effect of improving germination can be sufficiently exerted only by filtering with a filter, and it is possible to use properly depending on conditions such as a site where only a small amount of topsoil is used or a site where it is difficult to carry in machinery.

  In order to clarify the germination improvement effect according to the present invention, a seeding test was conducted as follows.

Test method (1) After collecting the topsoil by human power, the sampled topsoil was stirred using a tool such as a paddle in order to make the collected topsoil uniform.
(2) Test section (treatment section): The above-mentioned topsoil is subjected to the germination improvement treatment described above (removal of coarse organic matter by an air classifier, fragmentation / stress by a shredder, re-segmentation / stress by a filter), The planter was filled (see FIG. 2). By applying this treatment, the volume of the topsoil was reduced by about 25% compared to before treatment. This is because coarse organic matter such as extra roots and pieces of wood was removed, and the topsoil constituting soil particles were subdivided.
(3) Comparative plot (untreated plot): The topsoil (the same volume as the test plot) of (1) was filled in the planter as it was (see FIG. 3).
(4) To prevent plants from entering the planter from the surrounding area, cover the planters in the test area and the comparison area with a net (transparent plastic net with a mesh of 1.25 mm), and make the same conditions in both the test area and the comparison area. To germinate and grow. The test results were as follows.

Test results Table 2 below shows the seeding test results (number of germination establishment). FIG. 4 shows the state of growth on the planter in the test area after 3 months. FIG. 5 shows the growth state in the planter of the comparative plot after 3 months. FIG. 6 is a graph showing the comparison of the number of germinations in the planter of the test plot and the number of germinations in the planter of the comparative plot.

As described above, in this test, the topsoil volume was reduced by 25% before the treatment by applying the germination improvement treatment to the topsoil. In this case, assuming that 25% of the coarse organic matter has been removed, it is considered that the amount of buried seed contained in the treated topsoil and the untreated topsoil is about 33% higher in the treated topsoil. However, in the test results, as can be seen from Table 2 and FIG. 6, the number of germinated seedlings is three times as large with the treatment than without the treatment. From this, it was confirmed that the germination improvement effect was exhibited by this invention.
The equipment used in the present invention is not particularly limited, and any equipment having basic functions such as a classification function and a subdivision function can be used. Any filter may be used as long as it can exert an effect as a physical filter, such as a net or a perforated plate, and a hard material such as metal is preferable for imparting damage stress, but the material and shape are particularly limited. is not.
However, the filter mesh is preferably 5 to 50 mm, more preferably 20 to 30 mm. This is a numerical value derived from the following test results.
The relationship between the size of the mesh and the proportion of the topsoil passing through the filter, and the state of plant growth from the topsoil after the treatment were confirmed by tests. In the seeding test, each topsoil 4L was put into a planter, and the number of germinated seeds after 28 days was measured.

  Table 3 below shows the relationship between the filter mesh (mm) and the ratio (%) of the filter passing topsoil by mesh, and FIG. 7 shows a corresponding graph.

  Table 4 below shows the filter mesh (mm) and the seeding test result (number of germinations) according to the filter mesh, and FIG. 8 shows the corresponding graph.

As a result, the following was found.
A. In the filter having a scale larger than 50 mm, only 1 to 2% of the undecomposed coarse organic matter was removed, and the results of the seeding test showed almost no difference from the untreated section.
B. In addition, when a filter having a mesh size of 2 mm was used, only 20% of the charged topsoil passed, and the results of the seeding test were much inferior to the untreated section. This is presumably because the filter has a small scale of 2 mm, and the undegraded coarse organic matter as well as the buried seeds have been removed.
C. From the above, since a germination rate improvement of 10% or more is expected compared to the untreated section, it is preferable to use a filter having a scale D (5 mm ≦ D ≦ 50 mm) of 5 mm or more and 50 mm or less. I understood.

  In addition, considering the yield of topsoil and the results of the seeding test, it is found that it is more preferable to use a filter having a mesh size of 20 to 30 mm that improves the germination rate by 1.5 times or more from the untreated section. It was.

  Next, two demonstration tests showing the superiority of the present invention will be described.

<One verification test>
(A) The collected topsoil is stirred indoors in a state where light is blocked, and it is sown in a planter as it is,
(B) A growth comparison test was carried out with a plant that had been air-dried for 1 hour outdoors on a fine day and then sown in a planter.
As a result, it was confirmed that the germination rate was improved in the case of the latter (b) condition in that the light irradiation was performed as compared with the case of the former (a) condition.

<Another demonstration test>
(C) When the collected topsoil is planted as it is,
(D) when the planted soil is subdivided using a shredder and the planter is sown;
(E) When subdividing the collected topsoil using a shredder, remove the undegraded coarse organic matter by visual inspection in advance, and then apply the same growth comparison test in three patterns when thrown into the shredder. went.
As a result, the number of formations performed under the condition (d) was larger than that performed under the condition (c), and the condition performed under the condition (e) was performed under the condition (d). It turned out to be even more than the ones. This confirms that it is preferable to subdivide after removing undecomposed coarse organic matter.

  9-12, for example, soil seed-containing topsoil a treated in a soil physical property improvement step (for example, removal by the filter 20), germination suppression action reduction step and stress application step, fertilizer, water retention material, A vegetation base material c is prepared by mixing with a vegetation base material b containing peat moss, bark compost, etc., and the vegetation base material c is packed in non-woven sachets 9a, 9b, 9c, and the pocket of the net 1 with the erosion prevention sheet 8 Another embodiment of the present invention attached to the portion 6 is shown. 9 to 12, the same reference numerals as those shown in FIGS. 1 to 8 are the same or equivalent.

9 to 12, reference numeral 1 denotes a pocket net. This pocket-equipped net is continuously or vertically spaced in the longitudinal (A direction) direction between the nets 2 and 3 of the double-structured net body with the front net 2 and the back net 3 superimposed. A plurality of accommodating portions 4 are provided along the lateral direction (B direction), and further, in one to a plurality of locations in the intermediate position in the lateral direction of the accommodating portion 4, the adjacent warps for a plurality of meshes are not connected so The pocket 5 is formed by forming the opening 5 [see FIG. 12 (B)] or forming the horizontally long opening 5 ′ (see FIG. 12 (C)) by not connecting adjacent wefts for a plurality of meshes. It is.
7 is a vegetation mat, on the lower surface of the back net 3 of the net 1 with a pocket, a vegetation sheet 8 as an erosion prevention sheet weakened by rainwater or the like such as thin cotton, paper, and non-woven fabric (an example of a covering material) It is formed by sticking a vegetation sheet as an erosion prevention sheet of a soluble material (example of a covering material) such as a PVA sheet that melts after weakening.
9a, 9b, and 9c are obtained by subjecting, for example, a soil physical property improving process, a germination inhibiting action reducing process, and a stress applying process to topsoil containing buried seeds collected from surrounding areas (including within the same prefecture or the same region). It is a bag body for storing a vegetation base material c obtained by mixing the embedded seed-containing topsoil a and a vegetation base material b containing fertilizer, water retention material, peat moss, bark compost, and the like. These bag bodies 9a, 9b, 9c are accommodated in the respective accommodating portions 7.

  And the pocket part 6 is formed by the accommodating part 4 with which the right-and-left end is closed, and the vertically long opening part 5 (refer FIG. 12 (A)), and the said pocket in which the bag bodies 9a, 9b, 9c are accommodated The pocket-equipped net 1 is constituted by the part 6, the fertilizer bag housing part 11 in which the fertilizer bag 10 is housed, and both the nets 2, 3 between the both parts 6, 11.

  In addition, although the accommodating part 4 which knitted the side part was shown, you may use the accommodating part which the side part open | released and connected with the accommodation opening on either side as needed.

  Thus, the vegetation mat 7 configured as described above is laid through the vegetation sheet 8 on the soil surface of the slope N such as a mountainside, and the bags 9a, 9b, 9c accommodated in the accommodating portion 4. However, it is fixed by a retaining skewer (not shown) penetrating the accommodating portion 4 bulging upward.

  And since the accommodating part 4 bulges upwards, the accommodating part 4 will have a weir function that separates adjacent fertilizer bags 10 and 10 along the direction (A direction) perpendicular to the contour line, The movement of the flow of the long-term nutrient supply base 10a in the fertilizer bag 10 due to rainfall can be effectively prevented, and the movement of the surface soil can be prevented.

  Moreover, plant seeds and invading vegetation flying from the outside are easily settled due to the presence of the swelled accommodating portion 4. Furthermore, even after the net 1 with the pocket is stretched through the vegetation sheet 8 at the site, the vegetation base material c including the buried seed-containing topsoil a collected and processed in the field is stored from the vertically long openings 5 and 5. A plurality of bag bodies 9a, 9b, 9c can be easily inserted. Moreover, since the vertically long openings 5 and 5 are formed in the pocket-equipped net 1, it is not necessary to cut the net at the site to form the opening, and the construction is not complicated. In addition, since topsoil containing buried seeds collected locally is processed and used, there is little environmental change and it is easy to become a small animal house.

  In this embodiment, the vegetation base material c formed by mixing the treated seed-containing topsoil a and the vegetation base material b containing fertilizer, water retention material, peat moss, bark compost, and the like is made of a nonwoven fabric. Although the sachets 9a, 9b, 9c are packed in the pocket portion 6 of the net 1 with the erosion prevention sheet 8, the vegetation base material c is applied to the construction site without using the non-woven sachets 9a, 9b, 9c. For example, it may be simply landed on the (greening target site) by sowing or spraying.

Next, an embodiment of the present invention by spraying will be described.
FIG. 13 shows a mixture of a buried seed-containing topsoil a and a vegetation base material c, which are collected from the mountain topsoil adjacent to the greening construction site (construction target site) and processed using a dry spraying method. Still another embodiment of the present invention will be described in which the vegetation base material c is landed on the construction target site (greening target site). In FIG. 13, the same reference numerals as those shown in FIGS. 1 to 12 are the same or equivalent.
In FIG. 13, a greening construction site (construction target site), in this case, a net 30 for runoff prevention is stretched on the slope N, and a stirring tank 31 is used by using a sprayer 31 such as an aero seeder. A necessary amount of buried seed-containing topsoil a and vegetation base material b are added to 32, and the vegetation base material c as a greening material that has been agitated is placed on the slope N from the nozzle 34 at the tip of the hose 33, for example, 1-15 cm. Spray with moderate thickness and plant the slope N with the seeds of local vegetation.
Moreover, instead of this spraying construction, a base layer is formed on the slope N in advance with soil or a mixture of soil and a vegetation base b, or with only the vegetation base b, and then the collected buried soil It is also suitable to take the form of two-layer spraying in which seed-containing topsoil a is sprayed, and a large area of greening can be performed with a small amount of buried seed-containing topsoil a.

It is a graph which shows the relationship between the mixing rate (%) of the soil particle of a particle size of 5 mm or less, and a seeding test result (the number of germination establishment). In one Embodiment of this invention, it is the photograph replaced with drawing which shows the state of the test start which processed the top soil containing a buried seed, and filled this into the planter of a test area. It is the photograph which replaces drawing which shows the state of the test start which filled the topsoil containing a buried seed into the planter of a comparison plot as it is. In one Embodiment of this invention, it is the photograph which replaces drawing which shows the growth state in the planter of the test area 3 months after the test start. It is the photograph which replaces drawing which shows the growth state in the planter of the comparison plot three months after the start of the test which filled the planter with the topsoil containing the buried seed as it is. It is a graph which compares and shows the number of germination establishment in the planter of a test plot, and the number of germination establishment in a planter of a comparison plot. It is a graph which shows the relationship between the mesh (mm) of a filter, and the ratio (%) of the filter passage topsoil according to mesh. It is a graph which shows the seeding | inoculation test result (the number of germination establishment) according to the filter mesh (mm) and the filter mesh. (A) is a perspective view which shows other embodiment of this invention. (B) is a configuration explanatory view showing the accommodation form in this other embodiment. It is a top view which shows the net with a pocket used in the said other embodiment. It is a perspective view which shows the accommodation state in the net with a pocket used in the said other embodiment. (A) is the schematic which shows having accommodated the bag body in said other embodiment from the vertically long opening part provided in the center two places of the accommodating part. (B) is a figure which shows the said vertically long opening part in said other embodiment. (C) is a figure which shows the horizontally long opening part of this invention. It is a figure which shows other embodiment of this invention.

Explanation of symbols

      a Landfilled seed-containing topsoil that has been treated

Claims (5)

A method for improving the germination rate of buried seeds contained in topsoil,
Soil physical property improvement process to subdivide the topsoil containing buried seeds,
A stress applying step for applying at least two kinds of vibration stress, air stress, light stress and damage stress to the buried seeds included in the topsoil;
A method for improving germination of buried seeds, comprising: A method for improving the germination rate of buried seeds contained in topsoil,
Germination inhibitory action reduction process to remove undecomposed coarse organic matter from topsoil,
Soil physical property improvement process to subdivide the topsoil containing buried seeds,
A stress applying step for applying at least two kinds of vibration stress, air stress, light stress and damage stress to the buried seeds included in the topsoil;
A method for improving germination of buried seeds, comprising:   A vegetation substrate comprising a buried seed-containing topsoil subjected to the method according to claim 1 or 2.   A greening method characterized in that the buried seed-containing topsoil subjected to the method according to claim 1 or 2 is applied to the construction target site. A planting method according to claim 3, wherein the vegetation substrate according to claim 3 is installed in a construction target site.