JP2013144271A - Soil improving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil improving method which is capable of removing various heavy metals included in soil.SOLUTION: The soil improving method comprises steps of (S103) introducing earthworms that eat heavy metals as bait into the soil contaminated with harmful substances containing heavy metals, (S105) inducing the earthworms to a particular area in the soil using a tasteful pheromone after a predetermined period has elapsed and (S106) recovering the earthworms from the soil of the particular area. After that, the method includes a step of (S108) confirming that all the earthworms introduced into the soil are recovered or not.

Description

  The present invention relates to a soil improvement method for improving soil contaminated with heavy metals.

  In recent years, soil contamination by heavy metals has become a problem, and various methods for removing or removing heavy metals contained in soil and improving or purifying the soil have been proposed. For example, in Patent Document 1, pokeweed is planted in soil contaminated with heavy metals, the heavy potato burdock is ingested with heavy metals contained in the soil, and the ground part of the pokeweed is removed after growth. Thus, a method for improving soil is disclosed.

JP 2004-113858 A

  However, since plants can only absorb components contained in the soil through water, this method cannot remove heavy metals that are not water-soluble. Moreover, in the case of a plant, since it cannot move, there also exists a problem that it is difficult to improve the soil of a wide range.

  This invention is made | formed in view of such a situation, The main objective is to provide the soil improvement method which can solve the said subject.

  The present inventor considered that an animal that ingests heavy metals can be used to efficiently improve soil contaminated with heavy metals, and has focused on earthworms as such animals. For example, “James Owen,“ Heavy Metal-Eating “Superworms” Unearthed in UK ”, [online], October 7, 2008, National Geographic, [retrieved November 22, 2011], Internet ( URL: http://news.nationalgeographic.com/news/2008/10/081007-super-worms.html) ”, in recent years, earthworms that take in heavy metals contained in soil as food The earthworm can feed on heavy metals in the soil and accumulate in the body, and the earthworm is contaminated at such a high concentration that normal organisms cannot survive. It is also possible to inhabit in soil that has been removed.

  Then, this inventor earnestly examined about the method of soil improvement using this earthworm. While introducing earthworms into contaminated soil can be expected to promote the purification of the soil, in the case of earthworms, ingested heavy metals accumulate in the body, so that accumulated heavy metals in the body When earthworms die in the soil, the accumulated heavy metals are released into the soil, which may cause problems such as soil being contaminated again. The present inventor has made the following invention as a method for improving soil efficiently while avoiding such problems.

  That is, the soil improvement method of one aspect of the present invention introduces earthworms that feed heavy metals into soil contaminated with harmful substances including heavy metals, and has an attraction area for attracting the earthworms in the soil. The earthworm is attracted to the attracting area after a predetermined period of time has elapsed from introduction into the soil, and the earthworm attracted to the attracting area is collected.

  In the aspect, the attracting region may be formed by injecting a palatable physiologically active substance that attracts earthworms into the soil.

  In the aspect, a hollow tube may be inserted into the soil, and the palatable physiologically active substance may be injected into the soil through the hollow tube.

  Moreover, in the said aspect, you may make it form the detention area which detains the earthworm introduce | transduced in the said soil in the said soil.

  Moreover, in the said aspect, you may make it form the said detention area | region by inject | pouring into the said soil the repellent physiologically active substance which an earthworm dislikes so that the specific area | region in the said soil may be enclosed.

  In the above aspect, a hollow tube may be inserted into the soil, and the repellent physiologically active substance may be injected into the soil through the hollow tube.

  In the above aspect, the repellent physiologically active substance is injected into the soil via the hollow tube so that the repellent physiologically active substance is distributed in the vertical direction from the vicinity of the surface of the soil at a plurality of locations. Thus, the horizontal length of the specific area may be defined.

  Further, in the above aspect, the repellent physiologically active substance is injected into the soil through the hollow tube so that the repellent physiologically active substance is distributed in a horizontal direction at a predetermined depth in the soil. Accordingly, the vertical length of the specific area may be defined.

  In the above aspect, the detention region may be formed by arranging a plurality of plate members on the soil so as to surround the specific range.

  In the aspect, the attraction area may be formed in the detention area.

  Further, in the above aspect, the detention area is divided into a plurality of areas and the attraction area, the earthworm is introduced into any of the plurality of areas, and the earthworm is transferred to another area every time a certain period elapses. The earthworms may be sequentially moved, and after the earthworms have moved to all of the plurality of areas, the earthworms may be attracted to the attraction area.

  Furthermore, in the said aspect, you may make it divide | segment the said detention area | region into a some area and the said induction area | region by arrange | positioning a several board | plate material in the said detention area.

  According to the soil improvement method according to the present invention, various heavy metals contained in soil can be removed.

The flowchart which shows the procedure of the soil improvement method which concerns on Embodiment 1. FIG. The perspective view which shows the soil which inserted the pheromone injection pipe which concerns on Embodiment 1. FIG. The schematic diagram which shows the inside of soil when injecting the repellent pheromone which concerns on Embodiment 1. FIG. The schematic diagram which shows the inside of soil when injecting the palatability pheromone which concerns on Embodiment 1. FIG. The flowchart which shows the procedure of the soil improvement method which concerns on Embodiment 2. FIG. The perspective view which shows the soil which inserted the enclosure plate and partition plate which concern on Embodiment 2. FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, each embodiment shown below illustrates the method and apparatus for actualizing the technical idea of this invention, Comprising: The technical idea of this invention is not necessarily limited to the following. Absent. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

(Embodiment 1)
The soil improvement method according to Embodiment 1 is a soil improvement method that uses earthworms that feed on heavy metals, which contain earthworms in soil contaminated with heavy metals by using pheromones and are contained in the soil. It is a soil improvement method that removes heavy metals in the soil by ingesting the heavy metals to be collected and then recovers the earthworms by using pheromones.

The detailed procedure of the soil improvement method according to the present embodiment will be described with reference to a flowchart and the like.
FIG. 1 is a flowchart showing the procedure of the soil improvement method in the present embodiment. First, before introducing earthworms into the soil, twelve first pheromone injection tubes and four second pheromone injection tubes for injecting pheromones into the soil are inserted into the soil (S101).

  FIG. 2 is a perspective view showing the soil in which the first pheromone injection tube and the second pheromone injection tube are inserted. Each of the first pheromone injection tubes 11, 11,... Is formed of a hollow tube, and a plurality of through holes (not shown) are provided on the side surface of the tube. These through holes are provided along the length direction of the tube from the middle to the tip of the tube. The pheromone that has flowed through the first pheromone injection tubes 11, 11,... Is discharged from these through holes. Thereby, pheromones are emitted from the side surfaces of the first pheromone injection tubes 11, 11,. Further, the second pheromone injection tubes 12, 12,... Are also formed of a hollow tube, and a through hole (not shown) is provided at the distal end portion of the tube. The pheromone flowing through the second pheromone injection pipes 12, 12,... Is discharged outside the pipe through the through holes. As a result, pheromone is released from the tip of the second pheromone injection tube.

  As shown in FIG. 2, the first pheromone injection tubes 11, 11,... Are inserted in the soil E1 in the vertical direction along the periphery of the soil E1 so as to surround the soil E1 to be improved. Here, the first pheromone injection pipes 11, 11,... Are embedded in the soil E 1 from the tip to the middle of the pipe provided with the through hole, and the other parts protrude from the soil E 1. Inserted. In the following, the range surrounded by the first pheromone injection tubes 11, 11,... Is expressed as an improvement target section C1. The second pheromone injection tubes 12, 12,... Are inserted in the vertical direction inside the improvement target section C1. Further, the second pheromone injection pipes 12, 12,... Are soiled so that the tip portions thereof are deeper than the positions of the through holes provided in the side surfaces of the first pheromone injection pipes 11, 11,. Inserted inside. As described in detail below, the pheromones released from the through holes of the first pheromone injection tubes 11, 11,... And the second pheromone injection tubes 12, 12,. A detention region G1 for detaining earthworms is formed.

  After the first pheromone injection pipes 11, 11,... And the second pheromone injection pipes 12, 12,... Are inserted into the soil E1, as described above, the first pheromone injection pipes 11, 11,. The injection of the repellent pheromone that the earthworm hates from the soil E1 is started from each of 12, 12, ... (S102). Here, the repellent pheromone is injected into the soil E1 for about 30 minutes. The repellent pheromone is repeatedly injected at predetermined time intervals (for example, every 3 days) until the improvement of the soil E1 is completed.

  FIG. 3 is a schematic diagram showing a cross section of the soil E1 when the repellent pheromone is injected into the soil E1 from the first pheromone injection tubes 11, 11,... And the second pheromone injection tubes 12, 12,. Here, A1 and A1 indicate the distribution in the soil E1 of the repellent pheromone injected into the soil E1 from the first pheromone injection tubes 11 and 11. In the first pheromone injection pipes 11 and 11, a plurality of through holes are arranged in parallel from the middle to the tip of the pipes, and the first pheromone injection pipes 11 and 11 are buried in the soil E1. 11 is inserted in the soil E1 in the vertical direction. Therefore, as shown in FIG. 3, the distributions A <b> 1 and A <b> 1 spread in the vertical direction from the vicinity of the surface of the soil E <b> 1 to the vicinity of the tip of the first pheromone injection tube 11. By generating such distributions A1, A1 for each of the first pheromone injection tubes 11, 11,..., It is possible to limit the movement range of the earthworm W in the horizontal direction.

  In FIG. 3, A2 and A2 indicate the distribution of repellent pheromones injected into the soil E1 from the second pheromone injection tubes 12 and 12. As described above, since the through holes for releasing pheromones are provided at the tip portions of the second pheromone injection tubes 12 and 12, the distributions A2 and A2 have the soil E1 with the tip portion of the second pheromone injection tube 12 as the center. It spreads inside. The distribution A2, A2 is generated for each of the second pheromone injection tubes 12, 12,..., So that the repellent pheromone is horizontally aligned at the depth of the tip portion of the second pheromone injection tube 12, 12,. Will be distributed. Thereby, it becomes possible to restrict the movement range of the earthworm W in the depth direction.

  As described above, the movement range of the earthworm W in the horizontal direction in the soil E1 is restricted by the distributions A1 and A1, and the movement range of the earthworm W in the depth direction is similarly restricted by the distributions A2 and A2. Thereby, earthworms can be detained in the detained region G1, which is a region surrounded by the distributions A1, A1 and the distributions A2, A2.

  After injecting the repellent pheromone into the soil E1 as described above, a plurality of earthworms that feed on heavy metals that have been bred in advance are introduced into the soil E1 in the detention region G1 formed thereby. (S103). In addition, when introducing earthworm into the soil E1, it is desirable to perform work such as digging back with a tractor in advance so that the earthworm exists as uniformly as possible in the soil E1. The earthworm thus introduced into the soil E1 remains in the detention region G1 due to the action of the repellent pheromone. Therefore, it is possible to prevent earthworms from escaping out of the detention region G1. The earthworm introduced into the soil E1 and detained in the detention region G1 ingests heavy metals contained in the detention region G1 as food while moving in the detention region G1, and the ingested heavy metal Accumulate species in the body. As will be described later, after a certain period of time has elapsed since the introduction of earthworms into the soil E1, the total weight of the earthworms collected from the soil E1 and the total weight of the earthworms before being introduced into the soil E1 Based on the above, it is determined whether or not all earthworms have been collected. In order to make this determination, before introducing the earthworm into the soil E1 in step S103, the total weight of the earthworm is measured and recorded.

  The earthworm is introduced into the soil E1, and after about two weeks, the third pheromone injection tube is inserted into the soil E1 in the vertical direction into the improvement target section C1 (S104). FIG. 4 is a schematic view showing a cross section of the soil E1 into which the third pheromone injection tube 13 is inserted. The third pheromone injection tube 13 is configured in the same manner as the second injection tube 12, and can release pheromone from a through hole (not shown) provided at the tip portion thereof. In step S104, the third pheromone injection tube 13 is inserted into the detention region G1 so that the tip portion thereof is shallower than the tip portions of the second pheromone injection tubes 12, 12,.

  After inserting the third pheromone injection tube 13 into the soil E1, injection of a palatability pheromone having an action of attracting earthworms into the soil E1 is started through the through hole of the third pheromone injection tube 13 (S105). ). Here, the palatability pheromone is injected into the soil E1 for about 30 minutes every 24 hours. In FIG. 4, A3 indicates the distribution of the palatability pheromone injected into the soil E1 from the third pheromone injection tube 13. As described above, the tip portion of the third pheromone injection tube 13 is provided with a through hole for releasing pheromone, and the third pheromone injection tube 13 is soiled so that the tip portion is in the detention region G1. Since it is inserted into E1, the distribution A3 spreads in the detention region G1 with the tip portion of the third pheromone injection tube 13 as the center. The region where the palatability pheromone distribution A3 exists is an attracting region that attracts earthworms.

  In addition, in this Embodiment, after about 2 weeks have passed since earthworm was introduce | transduced into soil E1, step S104 and S105 are performed and the preference pheromone is inject | poured, but about the timing, the size of soil E1 and It is determined appropriately according to the amount of earthworms to be introduced.

  When the preference pheromone is injected in step S105, the earthworm introduced into the soil E1 gathers in the attracting area formed in the detention area G1 by the action of the preference pheromone. It should be noted that the repellent pheromone continues through the first pheromone injection tubes 11, 11,... And the second pheromone injection tubes 12, 12,. Injected. Thereby, earthworms can be reliably collected in the attracting area formed in the detention area G1.

  As described above, in this embodiment, after about 2 weeks have passed since the earthworm was introduced into the soil E1, the third pheromone injection tube 13 is inserted into the soil E1 and the preference pheromone enters the soil E1. Although the injection is performed, the period from the introduction of the earthworm into the soil E1 to the injection of the palatability pheromone into the soil E1 is not limited to this. This period is desirably determined mainly by the amount of heavy metals contained in the soil E1 and the amount of earthworm introduced into the soil E1.

  After the preference pheromone is injected into the soil E1 and about 3 days have passed, earthworms are collected from the soil E1 (S106). Specific contents of step S106 will be described below. First, the soil around the third pheromone injection tube 13 including the attracting area is collected. The collected soil is sieved and only the earthworm is taken out. After removing the earthworm, the soil collected with the earthworm is returned to its original state. In addition, after injecting a palatability pheromone in soil E1, it is determined by the quantity of the earthworm introduce | transduced in soil E1, the area of soil E1 used as improvement object, etc. after collecting earthworms. desirable.

  After collecting earthworms as described above, the injection of palatability pheromone is terminated (S107), and it is determined whether all the introduced earthworms have been collected (S108). Specific contents of step S108 will be described below. First, the collected earthworms are washed with water and the weight is measured. Then, the total weight of the earthworm measured in this way (total weight after collection) is compared with the total weight of the earthworm measured before introduction into the soil E1 as described above (total weight before introduction). . Here, when the difference between the total weight before introduction and the total weight after collection is within a predetermined numerical range, it is determined that all earthworms introduced into the soil E1 have been collected. This numerical range is determined in consideration of an increase in the total weight due to the growth of earthworms and a decrease in the total weight due to the death of earthworms. In addition, it is necessary to experiment in advance how much the weight changes when a large number of earthworms are grown for a certain period of time, and to determine the above numerical range based on the amount of change measured in the experiment. May be.

  If it is determined in step S108 that all earthworms have not been collected (NO in S108), the processes from step S105 to step S107 are repeated again. On the other hand, when it is determined that all the earthworms have been collected (YES in S108), injection of the repellent pheromone from the first pheromone injection tubes 11, 11,... And the second pheromone injection tubes 12, 12,. (S109), the first pheromone injection tubes 11, 11,..., The second pheromone injection tubes 12, 12,... And the third pheromone injection tube 13 inserted into the soil E1 are all collected (S110), and the soil E1 is collected. The improvement process is terminated.

  Thus, in this Embodiment, the earthworm which feeds heavy metals is introduce | transduced in the soil E1, and the earthworm is collect | recovered after progress for a predetermined period. The earthworm introduced into the soil E1 ingests various heavy metals contained in the soil E1 from the mouth and accumulates them in the body. Therefore, various heavy metals contained in the soil E1 can be removed by collecting the earthworm.

  Moreover, in this Embodiment, the specific area | region in the soil E1 used as improvement object is surrounded by distribution of the repellent pheromone. Thereby, it is possible to prevent earthworms from escaping from the soil E1 to be improved, and to reliably recover earthworms introduced into the soil E1. Further, after a predetermined period of time, a palatability pheromone having an action of attracting earthworms is injected into the soil E1, and the earthworms are attracted into a specific region formed thereby. Thereby, the earthworm introduce | transduced in the soil E1 can be collect | recovered easily.

  In the present embodiment, an attracting pheromone is injected into the detention region G1, thereby forming an attracting region in the detention region G1. It is possible to collect the earthworm by providing this attraction area outside the detention area G1, but by providing the attraction area in the detention area G1 as in the present embodiment, the earthworm is generated in the detention area G1. Since the collection operation can be performed while maintaining the detained state, earthworms can be collected more reliably.

  In the present embodiment, earthworms are detained in a specific area using a repellent pheromone, and earthworms are attracted to a specific area using a palatability pheromone. Since the action of such a pheromone disappears after a certain period of time, it is not necessary to perform a special post-treatment such as washing or purification of the soil E1 to be improved after the soil improvement method described above. Therefore, the improved soil E1 can be used without performing a special post-treatment.

  In addition, after performing step S110, you may make it inject | pour repellent pheromone over the whole soil E1 using the 1st pheromone injection tube 11, 11, .... Thereby, even if there are earthworms that have not been collected, those earthworms can be killed, and diffusion of heavy metals can be prevented.

(Embodiment 2)
In Embodiment 1, as described above, earthworms are retained and recovered by using pheromones. In contrast, in the soil improvement method according to the second embodiment, earthworms are retained and collected by using a plate material.

The detailed procedure of the soil improvement method according to the present embodiment will be described with reference to a flowchart and the like.
FIG. 5 is a flowchart showing the procedure of the soil improvement method according to the present embodiment. First, before introducing earthworms, four rectangular enclosures arranged so as to surround a specific area, and 7 for dividing the area surrounded by the enclosures into 6 areas. A sheet of rectangular partition plates is inserted into the soil to be improved (S201).

  FIG. 6 is a perspective view showing the soil E2 in which the enclosure plates 21, 21,... And the partition plates 22, 22,. The surrounding plates 21, 21,... Are inserted in the vertical direction into the soil E2 so as to surround the four sides of the soil E2 to be improved. In the present embodiment, the region surrounded by the surrounding plates 21, 21,... Corresponds to the detention region in the first embodiment. The partition plates 22, 22,... Are divided so as to equally divide the range surrounded by the surrounding plates 21, 21,... Into six regions F 1, F 2, F 3, F 4, F 5, F 6 that are rectangular in plan view. Are inserted in the vertical direction into the soil E2 within the range surrounded by the plates 21, 21,. .. And the partition plates 22, 22,... Are inserted into the soil E 2 to form the six regions F 1, F 2, F 3, F 4, F 5, F 6 and then a plurality of regions F 1. One earthworm is introduced (S202). As in the case of Embodiment 1, the earthworm introduced into the region F1 ingests heavy metals contained in the region F1 as food and accumulates the ingested heavy metals in the body.

  Next, the earthworm is sequentially moved to other areas F2, F3, F4, F5, and F6 (S203). Specific contents of step S203 will be described below. The earthworm is introduced into the area F1, and after about 3 days, the earthworm is moved from the area F1 to the area F2. This movement is performed by removing the partition plate 22 that partitions between the region F1 and the region F2 from the soil E2. When the partition plate 22 that partitions between the region F1 and the region F2 is extracted from the soil E2, earthworms can move between the region F1 and the region F2. Here, in the region F1 where the earthworm has already been introduced, since the earthworm ingests heavy metals contained in the soil E2 as food, the amount of heavy metals contained in the soil is reduced compared to the region F2. doing. For this reason, the earthworm in the area | region F1 moves to the area | region F2 which contains more heavy metals which are prey. After the earthworm has moved to the area F2 and about 3 days have passed, next, the earthworm is moved from the area F2 to the area F3. Since this movement is the same method as the movement from the area F1 to the area F2 described above, description thereof is omitted. Similarly, the earthworms are sequentially moved to the areas F4, F5, and F6. After the earthworm moves to the area F6, in order to prevent the earthworm from escaping from the area F6, the partition plate 22 is inserted between the area F6 and the area F5, and the movement between the areas is finished. In the present embodiment, this region F6 corresponds to the attracting region in the first embodiment.

  In this embodiment, the earthworm is moved to another area after about 3 days have passed since the introduction of the earthworm in each area. It is determined appropriately depending on the amount of

  After about 3 days have passed since the earthworm was moved to the area F6 as described above, the earthworm is collected from the area F6 (S204). This step S204 is performed in the same manner as step S106 of the first embodiment. That is, the soil in the region F6 is collected, the collected soil is sieved, only the earthworm is taken out, and the collected soil is returned to the original state.

  After collecting the earthworms as described above, it is confirmed whether all the introduced earthworms have been collected (S205). Note that the confirmation method here is the same as the determination method in step S108 of the first embodiment, and thus the description thereof is omitted. After confirming that all the earthworms have been collected, all of the enclosure plates 21, 21,... And the partition plates 22, 22,... Inserted into the soil E2 are collected (S206), and the soil E2 improvement process is terminated. .

  As described above, in this embodiment, the detention region is formed using the surrounding plates 21, 21,... And the partition plates 22, 22,. By only inserting these plate materials into the soil E2, the earthworm can be retained in the soil E2 to be improved.

  Moreover, in this Embodiment, since soil E2 used as improvement object is divided | segmented into a some area | region, and an earthworm is sequentially moved to each of those area | regions, it can be grasped | ascertained in which area | region an earthworm exists. Thereby, earthworms can be collected easily and reliably.

(Other embodiments)
In each of the above embodiments, earthworms are introduced into the soil to be improved, but the present invention is not limited to this, and heavy metals contained in the soil are moved while moving in the soil. Other organisms may be used as long as they can be ingested and accumulated in the body. However, since the earthworm which takes in heavy metals as a feed has already been discovered as described above, the present invention can be easily realized by using the earthworm. In the case of earthworms, since a large amount of heavy metals and the like can be accumulated in the body by ecological concentration compared to other organisms, other organisms cannot inhabit by realizing the present invention using earthworms. The soil improvement method of the present invention can also be applied to such contaminated soil.

  Moreover, in Embodiment 1, using the pheromone, the earthworm introduced into the soil E1 is detained or attracted to a specific region, but the present invention is not limited to this. Absent. For example, if an earthworm introduced into the soil E1 can be retained or attracted to a specific region, a physiologically active substance such as an enzyme, a hormone, or an organic compound may be used.

  In the first embodiment, the first pheromone injection tubes 11, 11,... Capable of releasing pheromones from the side surfaces and the second pheromone injection tubes 12, 12,. .., And the second pheromone injection pipes 12, 12,... Are injected into the soil E 1 to form the detention region G 1, but the other pheromone injection pipes 11, 11. It is also possible to realize the present invention using a hollow tube having a structure. For example, you may use the pheromone injection pipe which is comprised with a U-shaped hollow tube and can discharge | release a pheromone from the through-hole drilled along the pipe | tube. In this case, a plurality of pheromone injection tubes are embedded in the soil E1 so that only both ends thereof are exposed to the ground. At this time, each pheromone injection tube is disposed in the soil E1 so as to have a lattice shape in plan view. By injecting the repellent pheromone into the soil E1 through the plurality of pheromone injection tubes arranged in this manner, the region surrounded by these pheromone injection tubes can be set as the detention region G1.

  Moreover, in Embodiment 1, the movement to the depth direction of an earthworm is restrict | limited by injecting a repellent pheromone from the 2nd pheromone injection pipe 12,12, ... to the predetermined depth of the soil E1. However, this repellent pheromone does not have to be injected. Earthworms are mainly active within 1m from the soil surface due to the influence of oxygen concentration in the soil. For this reason, for example, by injecting repellent pheromones through the first pheromone injection tubes 11, 11,..., By restricting the horizontal movement of the earthworms at positions up to a depth of about 1 m, It becomes possible to detain in specific areas of the soil. Therefore, in order to limit the movement in the depth direction, it is not necessary to inject the repellent pheromone via the second pheromone injection tubes 12, 12,...

  In the second embodiment, a plate material or the like is not used to limit the movement of earthworms in the depth direction, but as described above, movement limitation in the depth direction is not necessarily performed. There is no particular problem. However, earthworms may be reliably prevented from escaping from the detention area by, for example, arranging the plate material horizontally at a specific depth in the soil.

  Moreover, in Embodiment 2, although the board | plate material is used in order to enclose the soil E2 used as improvement object and to divide | segment into a several area | region, you may make it divide | segment in another aspect. For example, as in the case of the first embodiment, the repellent pheromone may be used to surround the soil E2 to be improved, and the enclosed region may be further divided into a plurality of regions. In this case, when the injection of the repellent pheromone is stopped and a predetermined period elapses, the effect of the repellent pheromone disappears, and movement between adjacent regions becomes possible. Further, the method using the repellent pheromone and the method using the plate material may be appropriately combined to surround the soil E2 to be improved, and the enclosed region may be divided into a plurality of regions.

  Moreover, in Embodiment 2, after collecting earthworms from soil, only the amount of collected earthworms is confirmed, but in the same manner as in Embodiment 1, the earthworms introduced with the amount of earthworms collected. It may be determined whether or not the entire amount of earthworms has been collected according to the comparison result. Here, when the whole amount of earthworms has not been collected, the soil is collected from a deeper position in the region F6 to search for earthworms, or the soil in the regions F1 to F5 is collected to search for earthworms. It is desirable to repeat the process and collect all the introduced earthworms.

  In addition, the effects of the repellent pheromone and the palatability pheromone depend on the soil environment such as moisture content and soil property. Therefore, it is desirable to determine the amount and timing of injecting these pheromones into the soil according to the soil environment. Alternatively, the pheromone concentration in the soil may be detected, and the pheromone may be injected via each injection tube when the concentration falls below a predetermined value.

  The soil improvement method of the present invention is useful as a method for improving soil contaminated with heavy metals.

11 First pheromone injection tube 12 Second pheromone injection tube 13 Third pheromone injection tube 21 Fence plate 22 Partition plate A1, A2 Distribution of repellent pheromone A3 Distribution of palatability pheromone C1 Improvement target area E1, E2 Soil G1 Detention area W Earthworm

Claims (12)

Introducing earthworms that feed on heavy metals into soil contaminated with harmful substances including heavy metals,
Forming an attracting area in the soil to attract the earthworm;
Attract the earthworm to the attraction area after a predetermined period of time from introduction into the soil,
Collecting the earthworms attracted to the attraction area;
Soil improvement method. Forming the attraction area by injecting into the soil a palatable physiologically active substance that attracts earthworms,
The soil improvement method according to claim 1. A hollow tube is inserted into the soil, and the palatable physiologically active substance is injected into the soil through the hollow tube.
The soil improvement method according to claim 2. Forming a detention region in the soil for detaining earthworms introduced into the soil,
The soil improvement method according to any one of claims 1 to 3. Forming the detention region by injecting a repellent physiologically active substance that earthworms dislike into the soil so as to surround a specific region in the soil,
The soil improvement method according to claim 4. A hollow tube is inserted into the soil, and the repellent physiologically active substance is injected into the soil through the hollow tube.
The soil improvement method according to claim 5. By injecting the repellent physiologically active substance into the soil through the hollow tube so that the repellent physiologically active substance is distributed in the vertical direction from the vicinity of the surface of the soil at a plurality of locations, Specify the horizontal length of the area,
The soil improvement method according to claim 6. By injecting the repellent bioactive substance into the soil through the hollow tube so that the repellent bioactive substance is horizontally distributed at a predetermined depth in the soil, Defines the vertical length of the region,
The soil improvement method according to claim 6 or 7. Forming the detention region by arranging a plurality of plate members in the soil so as to surround the specific range;
The soil improvement method according to claim 4. Forming the attraction region within the detention region;
The soil improvement method according to any one of claims 4 to 9. Dividing the detention area into a plurality of zones and the attraction area;
Introducing the earthworm into any of the plurality of areas;
Each time a certain period of time elapses, the earthworms are moved sequentially to other areas,
After the earthworm has moved to all the plurality of areas, the earthworm is attracted to the attraction area;
The soil improvement method according to claim 10. Dividing the detention area into a plurality of sections and the attraction area by disposing a plurality of plate members in the detention area;
The soil improvement method according to claim 11.

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