JP2011083194A - Material for inhibiting rice from absorbing cadmium, and method for cultivating rice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive material for inhibiting rice from absorbing cadmium which hardly causes alkaline damage, inhibits unpolished rice from absorbing cadmium and does not require either time or labor, and to provide a method for cultivating rice. <P>SOLUTION: The material for inhibiting rice from absorbing cadmium is used when cultivating rice, and mainly consists of molasses. The method for cultivating rice includes applying molasses to a farm field in the time of ear emergence of rice to cultivate the rice. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rice cadmium absorption inhibitory material and a rice cultivation method.

  Today, cadmium, a heavy metal, is toxic and distributed (emissions from industrial activities such as mine drainage and metal smelter flue gas), and is also widely distributed in natural soil through air and water. Is well known).

  Moreover, since cadmium can cause not only toxicity but also health problems due to accumulation, it is severely restricted especially in the use of plants used for food. In Japan, for example, cadmium derived from rice According to the Food Sanitation Law, the amount of cadmium in brown rice is defined as 1 ppm or less, and the notification by the Food Agency is 0.4 ppm or less, and the distribution of brown rice exceeding this standard value is prohibited (Non-Patent Document 1).

  In recent years, the FAO / WHO Joint Food Standards Committee (Codex Committee) of international organizations has determined that the amount of cadmium in foods is 0.4 ppm or less, which is stricter than the conventional domestic standard. Is required.

  In response to such a request, cadmium countermeasures for domestic agricultural land are taken depending on the degree of pollution, in paddy fields with a large degree of pollution (cadmium amount of 1 ppm or more), measures are taken by soil excavation soil and chemical cleaning, In paddy fields (0.4 to 1 ppm) where the degree of contamination is medium, cadmium absorption control measures for paddy rice by soil improvement and water management have been taken (Non-patent Document 1). In addition, research on phytoremediation (plant restoration) technology, in which a cadmium-contaminated site is restored by absorbing cadmium in a plant body, has been conducted (Patent Document 5).

  By the way, when the degree of contamination by cadmium is medium, currently proposed countermeasure technologies include soil improvement methods using alkaline materials, flooded water management methods, combined use of flooded water management and alkaline materials, etc. Has been.

  Specifically, the soil improvement method using alkaline materials and the like includes a method using lightweight aerated concrete powder fertilizer (Patent Document 1), a method using a lime-based material and a gypsum-based material in combination (Patent Document 2), It is a method using an alkaline material such as calcium silicate (Non-Patent Document 2), and there is a technique in which soil pH is increased and cadmium is combined with phosphorus in the soil so that it is hardly soluble in water and hardly absorbed from plant roots. The flooded water management method adjusts the depth of water in the paddy field before and after heading, and combines the cadmium with sulfur in the soil by reducing the soil to produce cadmium sulfide that is hardly soluble in water. This is a technique for measuring absorption from plant roots (Non-patent Document 2). In the case of paddy rice, it is disclosed that when soil improvement by spraying alkaline materials and flooded water management are used in combination, the paddy rice is effective in suppressing cadmium absorption (Patent Document 3, Patent Document 4, Non-Patent Document 2). .

Japanese Patent No. 3271533 JP 2006-000043 A Japanese Patent No. 3688272 Japanese Patent No. 3688252 JP 2007-209894 A

Ministry of Agriculture, Forestry and Fisheries, Consumer Affairs and Safety Bureau, “Information on Cadmium in Foods” (http://www.maff.go.jp/j/syouan/nouan/kome/k_cd/index.html) Ministry of Agriculture, Forestry and Fisheries, National Institute for Agro-Environmental Technology, “Technical Manual for Countermeasures for Suppression of Cadmium Absorption in Rice” H17.3 (http: //www.maff.go.jp/j/syouan/nouan/kome/ k_cd / taisaku / pdf / d_3.pdf)

  However, this method using alkaline materials has a problem that the cadmium absorption suppression effect of brown rice is unstable despite the high material cost and the spraying effort, and in detail, the soil pH is reduced by applying this alkaline material. Cadmium absorption suppression is easily performed by holding it at about 7 or more, but there is a problem that in places where the amount of alkaline material is too large, alkali damage is likely to occur, and actual fertilization work is very delicate and difficult. Moreover, there is a problem that flooded water management is easily affected by the weather.

  An object of the present invention is to provide a cadmium absorption suppression material for rice and a cultivation method for rice that are less likely to cause alkali damage, can stably suppress cadmium absorption of brown rice, are laborious and inexpensive.

  The gist of the present invention will be described with reference to the accompanying drawings.

  The present invention relates to a cadmium absorption suppressing material used for rice cultivation, which is composed of molasses as a main component, and relates to a cadmium absorption suppressing material for rice.

  Further, the present invention relates to a rice cultivation method, wherein molasses is applied to a field where rice is cultivated at the heading stage of the rice.

  The rice cultivation method according to claim 2, wherein the molasses is applied together with water.

  The rice cultivation method according to any one of claims 2 and 3, wherein the molasses is diluted molasses.

  The rice cultivation method according to any one of claims 2 to 4, wherein the rice is paddy rice.

  6. The method for cultivating rice according to claim 5, wherein the molasses is applied from 1 week before heading of the paddy rice to 1 week after heading.

  The rice cultivation method according to any one of claims 5 and 6, wherein the molasses is diluted so as to have a concentration of 5 to 30% (weight) in the field. It relates to the cultivation method.

  The rice cultivation method according to any one of claims 5 to 7, wherein the amount of molasses applied is 70 to 450 kg per 10 ares of the field. .

  Since the present invention is configured as described above, it is difficult to cause alkali damage, can stably suppress cadmium absorption of brown rice, and has low material costs and spraying labor, and is an inexpensive rice cadmium absorption suppression material and method for cultivating rice. Become.

It is a figure which shows the change of the oxidation-reduction potential of the paddy field soil by the cultivation method of the paddy rice concerning a present Example.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  Molasses used in the present invention is a sticky brownish, almost neutral liquid with a large specific gravity and a large by-product generated when sugar is produced from sugarcane, sugar beet, etc., and its composition is generally about 75% solids. The sugar content is about 40-60%.

  In the cadmium absorption suppression material for rice according to the present invention, the molasses of the main component is a liquid, so when applied in the field, it easily spreads evenly by diffusion, and since it is a neutral material, it is an alkali disorder like an alkaline material. Therefore, the cadmium absorption can be suppressed stably and easily.

  In addition, in the rice cultivation method according to the present invention, when molasses is applied to the field at the heading stage of rice, microorganisms grow in the nutrients of the molasses, thereby promoting the anaerobic state of the field soil. The soil is reduced.

As a result, when the soil is in a reduced state, cadmium dissolved in the soil (cadmium sulfate CdSO ₄ ) becomes insoluble cadmium sulfide (CdS), so that cadmium is hardly absorbed by rice.

  That is, when molasses is applied during the heading season when rice is growing well, the rice can suppress cadmium absorption from the soil and reduce the amount of cadmium in the brown rice.

  Therefore, according to the rice cadmium-suppressing material and the method for cultivating rice of the present invention, molasses is not an alkali material, so that alkali damage is not caused, and cadmium absorption of brown rice can be stably suppressed. Since it is a raw material, the material cost is low, and since it is a liquid, it is possible to reduce the labor of spraying labor.

  A first embodiment of the present invention will be described with reference to the drawings.

  This example employs paddy rice as the rice, cultivates the paddy rice in the field (farmland), uses molasses as a cadmium absorption inhibitory material applied in the cultivation of the paddy rice, and dilutes the molasses at the heading time of the paddy rice. It is applied to the field and reduces the amount of cadmium absorbed by the rice to be grown.

  The paddy rice begins to emerge around 15 days after the start of stasis and the meiosis begins, and the head of the rice is in a state where the foliage has emerged from the leaf sheath. The heading time refers to a state in which about half of the total number of stems are headed, and 40 to 50% of the whole field is headed (the day when all the ears appear is called the heading time). After the heading, the leaves of the rice become darker and flower and fertilize one after another, and the head begins to drip in about 10 days. On the 20th day after heading, the brown rice in the rice paddy has been enlarged, and after 40 to 50 days it will climb. Ripe and ready for harvest.

  The molasses used in this example is the molasses, which is a residue obtained by refining sugar from sugar beet, but it may also be the molasses obtained by refining sugarcane. The composition of the molasses is generally about 75% (weight) solid content and about 50% (weight) sugar content. Specifically, the solid content is 74.75% (weight) and the sugar content is 49.57% ( Weight), total nitrogen 0.43% (weight), raffinose 2.64% (weight), reducing sugar 0.40% (weight), ash content 8.43% (weight), pH 7.66, color value ( SCV) 365 molasses (Hokkaido Sugar Co., Ltd.) is used.

  In this embodiment, the molasses is mixed and diluted with irrigation water so as to have a predetermined concentration in the field and applied (mixed) to the field. Therefore, it is sprayed uniformly and satisfactorily in the field and is absorbed uniformly and satisfactorily into the field soil.

  In addition, the cultivation of paddy rice in this example is carried out by sprouting the seed fir of Koshihikari seeds selected with salt water at a specific gravity of 1.13, and then seeding the seed fir in a seedling box laid with floor soil. The seedlings were grown for approximately 20 days, and the seedlings were transplanted to paddy fields.

  This paddy field is a test field owned by the National Institute of Agricultural Research, Niigata Prefecture, and the amount of cadmium was about 0.4 ppm.

  The rice cultivar used for cultivation is Koshihikari, but varieties other than Koshihikari can be expected to have the same effect. Moreover, although paddy rice was used in this example, upland rice may be used.

  The test was carried out in the test field by providing two sections, a control group for conventional cultivation of the Koshihikari and a test group for administering molasses, each with two repetitions (two sections under the same conditions were provided).

  Moreover, ammonium chloride containing nitrogen, phosphoric acid and potassium was applied as the basic fertilizer, and ammonium sulfate containing nitrogen was applied twice as the panicle.

  The water management was so-called saturated water management, in which water was supplied while the soil was moist when water was lost in the field until the molasses immediately before heading was applied after middle drying. In addition, water management may be performed by intermittent drowning water.

  Further, in this example, the field was made water-free in the heading period, and molasses was applied in the test plot, and conventional cultivation was performed without applying molasses in the control plot, and the cadmium in each of the test plot and the control plot was used. The effect of inhibiting absorption was tested and investigated.

  Specifically, in the test group and the control group, the soil pH, the soil oxidation-reduction potential (Eh), the brown rice / crop body Cd content, and the yield were tested and investigated as follows.

1 Test method (1) Field: Test field owned by Agricultural Research Institute in Niigata
0.1M hydrochloric acid extraction soil Cd about 0.4mg / kg
(2) Test varieties: Koshihikari (3) Composition of test area: a molasses (180kg / 10a), a control (conventional cultivation)
(4) District system and area: 14.4 m ² , 2 iterations (5) Cultivation outline:
Oh, source manure N: 2.5, P205: 2.5, K20: 2.5 (kg / 10a
・ Phosphorus chloride)
I Hohi N: 2.5 (kg / 10a, ammonium sulfate) applied twice
Water management Saturation management after mid-drying, harvest season water management
D Material application Molasses applied during heading
O Material summary: Sugar beet waste molasses (Hokkaido sugar, solid content approximately 75%, sugar content approximately 50%)
F Material application method: (a) Molasses is diluted with water to create a molasses aqueous solution with a concentration of about 12%
. (I) Molasses water solution created in the previous section (A) in a frame made of Azami sheet
Pour liquid.
(6) Survey items: (a) Soil Cd content, (b) Soil pH, c) Soil oxidation-reduction during the cultivation period
Potential (Eh) change, D Brown rice / Crop body Cd content (taken 4 strains at 2 locations from 1 ward)
Analysis), E growth status, yield, moss molasses application time survey

2 Test results The results of the investigation of soil pH and brown rice cadmium content are shown in Tables 1 and 2, respectively, and the results of comparing the molasses test group and the control group with respect to the soil redox potential (Eh) change during the cultivation period are shown in FIG. Shown in

  From the above results, the following can be concluded.

a There is no effect on soil pH by molasses application.
b By applying molasses, immediately after applying molasses, the soil redox potential quickly becomes negative and maintains the negative potential.
c Brown rice cadmium content was suppressed to about 65% of control.

  As a result of comparing the amount of cadmium absorbed by the brown rice in the test plot, which was diluted to 12% and applied to a field with no water 4 days before heading the paddy rice, the result was compared with the control plot where the conventional cultivation was conducted. It was judged that there was a possibility that the cadmium absorption amount of brown rice could be reduced by applying in the season.

  However, since the amount of molasses and the application time could not be determined in the above test, the investigation test was conducted again, and the molasses application time was changed to one week before heading, at the time of heading, and one week after heading. The concentration of cadmium in brown rice was investigated.

  The results are shown in Table 3 for the molasses application rate and application time, and Table 4 shows the growth status and yield in the mature stage.

  From the results of Tables 3 and 4, the following can be concluded.

a By applying molasses from the time of heading to one week after heading, the cadmium content in brown rice can be reduced, and can be reduced to about 60% of the control by appropriately selecting the timing of molasses application.
b Molasses is effective in suppressing cadmium absorption by applying 100 kg to 400 kg per 10a.
c There is no difference in the yield and quality of brown rice depending on whether molasses is applied. However, chlorophyll meter (
From the SPAD value, the leaf color of rice with molasses tends to be slightly darker than the control.

  In the above test, 100, 180, 200 and 400 kg were applied per 10 ares of paddy field. However, even when 70 kg or 450 kg was applied, there was no change in the tendency to suppress cadmium absorption. There was no change in quality. That is, even when the concentration was 5 to 30% (weight), it was confirmed that cadmium absorption was suppressed and the quality of the brown rice was not changed.

  In addition, from the test results according to this example, if molasses application is applied for 1 week before and after heading, even in the absence of water in the field, the same yield and quality as in the conventional cadmium absorption suppression cultivation method It can be seen that cadmium absorption by brown rice is suppressed. That is, it can be concluded that the effect of applying molasses to the field is equivalent to the flood management.

  Therefore, for example, it is not possible to maintain a flooded state due to problems with the weather or irrigation water, and even when there is no water, cadmium absorption can be suppressed by applying molasses.

In this way, the cadmium absorption of brown rice is reduced by applying molasses. In particular, the cadmium sulfide is insoluble in cadmium sulfate (cadmium sulfate CdSO ₄ ) dissolved in the soil by applying the molasses to reduce the paddy soil as described above. This is considered to be because it becomes difficult to be absorbed by paddy rice because it becomes (CdS) and the solubility is lowered.

  As described above, according to the present example, even if there is no water at the heading time when the growth of paddy rice is thriving and absorption of cadmium is the highest, it is easy to concentrate dilute molasses on the field in a short period before and after the heading date. It will be possible to suppress the cadmium absorption of brown rice with much effort. In addition, since the application period may be short, it is difficult to be affected by the weather, and even though the molasses application period is short, sufficient cadmium absorption suppression effect can be exerted, and furthermore, alkali damage is not caused in the molasses aqueous solution, It will be possible to stably produce good quality brown rice.

  Moreover, since molasses is diluted and applied from a water mouth, workability | operativity is very good and labor can be reduced.

  Further, even when upland rice is adopted as the rice, the effect of suppressing cadmium absorption can be expected by applying molasses at the heading time, just like the case of paddy rice of this example.

  Furthermore, in this example, a molasses solution obtained by diluting a molasses solution with water was applied to the field. Instead of the molasses solution, rice sewage drainage discharged in the process of producing rice crackers, rice cakes, aseptic packaged rice, and sake, Or, it can be obtained by diluting an organic substance-containing solution such as soybean broth discharged in the production process of soybean products or an organic substance-containing solution such as bioethanol fermentation residue or distillation waste liquid, and applying this organic substance-containing aqueous solution to the field. Therefore, the effect of suppressing cadmium absorption can be expected.

Claims (8)

  A cadmium absorption suppressing material used for rice cultivation, characterized by comprising molasses as a main component.   A method for cultivating rice, comprising applying molasses to a field where rice is cultivated at the heading stage of the rice.   The rice cultivation method according to claim 2, wherein the molasses is applied together with water.   4. The method for cultivating rice according to claim 2, wherein the molasses is diluted molasses.   The rice cultivation method according to any one of claims 2 to 4, wherein the rice is paddy rice.   6. The method for cultivating rice according to claim 5, wherein the molasses is applied from 1 week before heading of the paddy rice to 1 week after heading.   The method for cultivating rice according to any one of claims 5 and 6, wherein the molasses is diluted to a concentration of 5 to 30% (weight) in the field. .   The rice cultivation method according to any one of claims 5 to 7, wherein the amount of molasses applied is 70 to 450 kg per 10 ares of the field.

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