Method for promoting content of effective silicon in soil and rice

Abstract

The invention provides a method for promoting the content of effective silicon in soil and rice, protozoa or biological fertilizer containing protozoa is put into a rice field, and the protozoa is at least one of tetrahymena, ochracea and paramecium separated from rhizosphere soil of rice. By the adoption of the technical scheme, protozoa such as tetrahymena, ochra and paramecium or biological fertilizer containing the protozoa is put into the rice field, silicon in soil can be promoted to be converted into soluble monosilicic acid, then the content of effective silicon in the soil and the content of effective silicon in plants are increased, growth of rice is better facilitated, and the yield is increased.

Description

Technical Field

[0001] The invention relates to the technical field of agriculture, and in particular to a method for increasing the effective silicon content in soil and rice. Background Art

[0002] Increasing the silicon content in soil and plants has many benefits for plant growth. First, silicon in plants can make plant cell walls thicker and harder, improve the mechanical strength of plants, and effectively reduce the occurrence of lodging. Especially for gramineous crops such as rice and wheat, the anti-lodging effect is significant. Secondly, silicon forms silicified cells in plant epidermal cells, making it difficult for pathogens and pests to invade, reducing the incidence of diseases and pests. For example, it can reduce the occurrence of diseases such as rice blast, sheath blight, and wheat powdery mildew. In addition, silicon can regulate the opening and closing of plant leaf stomata, reduce water transpiration, improve plant water retention capacity, and enhance plant survival in arid environments. Finally, silicon helps to increase the chlorophyll content in plant leaves, allowing plants to photosynthesize more effectively and synthesize more organic matter, thereby promoting plant growth and development. In addition to being good for plants, effective silicon can also promote the formation of aggregates in the soil, making the soil more loose and breathable, which is conducive to the growth of roots and the circulation of water and air, and improves the soil structure; silicon interacts with other nutrients in the soil to increase the effectiveness of nutrients in the soil, thereby indirectly improving soil fertility. For example, silicon can promote the activation of phosphorus and improve the utilization rate of phosphorus fertilizer.

[0003] At present, in order to increase the effective silicon content in soil and rice, the more common practice is to apply phosphorus fertilizer and silicon fertilizer to the soil, hoping to increase the effective silicon content and active silicon content in the soil, and finally increase the effective silicon content in rice. However, this method of artificially adding chemical drugs from the outside world has brought many adverse effects to the environment and has become a heavy environmental burden. For example, ordinary silicon fertilizers are prone to residue after use, and there are certain safety hazards, which pose a threat to the ecological environment and the safety of surrounding organisms. From an economic point of view, this type of fertilizer itself is quite expensive, and in actual application, the amount required is relatively large, which undoubtedly greatly increases the cost of use. In addition, a large amount of fertilizer is not only extremely inconvenient to carry, but also increases the difficulty of storage and other aspects. In the specific operation of fertilization, there are also many challenges. On the one hand, fertilizer ratio is a thorny issue. The application of professional fertilizers often requires precise ratios, and usually multiple fertilizers are mixed. Once the ratio is wrong, it is easy to cause soil pollution, which in turn leads to a reduction in crop yields, so the user's professional knowledge and operating skills are very high. Even when using ordinary fertilizers, when applying multiple fertilizers together, it is necessary to fully consider the impact of the interaction between the chemical substances they contain. The application of some fertilizers must be mixed, and specific tools and professional techniques are required to complete the whole process. On the other hand, weather factors cannot be ignored. For example, if it rains when fertilizing, the rain will change the original ratio of the fertilizer, making it impossible to carry out the fertilization work normally, which seriously limits the effective application of fertilizers. What is particularly critical is that although this existing fertilization method can increase the silicon content in the soil to a certain extent, it does not effectively increase the effective silicon that plants can actually absorb and utilize directly, which greatly reduces the effectiveness of this method in practical applications. Summary of the invention

[0004] In view of the above technical problems, the present invention discloses a method for promoting the effective silicon content in soil and rice. By adding protozoa, the content of effective silicon in soil and rice can be effectively promoted, and there is no need to consider the ratio problem. No matter how much is applied, it will not pollute the soil environment or affect crops.

[0005] To this end, the technical solution adopted by the present invention is:

[0006] A method for increasing the effective silicon content of soil and rice, comprising: adding protozoa or biofertilizer containing protozoa into a rice field where rice is planted, wherein the protozoa is at least one of Tetrahymena, Ochracilium and Paramecium separated from the rhizosphere soil of rice.

[0007] Using this technical solution, protozoa such as Tetrahymena, Ochrafilia, and Paramecium can convert silicon in the soil into soluble monosilicic acids, that is, silicon that can be absorbed and utilized by plants, thereby increasing the effective silicon content in the soil and the effective silicon content in plants.

[0008] Secondly, these protozoa can ingest organic matter in the soil and decompose it into substances that can be absorbed by plants and other beneficial microorganisms. Moreover, during their movement and metabolic activities, protozoa can improve the aeration and permeability of the soil, which is beneficial to the growth of the root system and the absorption of oxygen by plant roots. Some protozoa will dig and turn over soil particles during their activities, reducing soil compaction and density and improving soil structure.

[0009] In addition, protozoa can effectively interact with fungi, bacteria and other microorganisms in the soil and plant roots, promoting the diversity and vitality of soil and plant root microbial populations. Some protozoa can prey on pathogenic microorganisms and pests in the soil, playing a certain role in biological control.

[0010] Therefore, by adding protozoa such as Tetrahymena, Ochraconida, and Paramecium, the effective silicon content of rice can be increased, which is more conducive to the growth of rice.

[0011] As a further improvement of the present invention, the Tetrahymena and Ochraconium are fed with rice grain extract and cultured in large quantities in a constant temperature incubator at 25°C; the Paramecium is fed with wheat extract and cultured in large quantities in a constant temperature incubator at 25°C.

[0012] As a further improvement of the present invention, Tetrahymena is added to rice when the rice seedlings are growing.

[0013] As a further improvement of the present invention, the amount of protozoa added is 4.4×10 5 -4.4×10 7 In the experiment, adding 100-10,000 Tetrahymena to every 50g of soil can achieve good results in one week, with about 2.2×10 5 g of soil, so 4.4×10 5 -4.4×10 7 Tetrahymena.

[0014] As a further improvement of the present invention, the amount of protozoa added is 2.2×10 5 -2.2×10 7 Only ochre-colored worms.

[0015] As a further improvement of the present invention, the amount of protozoa added is 2.2×10 5 -2.2×107 Only Paramecium.

[0016] The invention also discloses the use of protozoa as a biofertilizer for preparing effective silicon content of soil and rice. The protozoa is at least one of Tetrahymena, Ochracilium and Paramecium separated from rice rhizosphere soil.

[0017] As a further improvement of the present invention, the Tetrahymena and Ochraconium are fed with rice grain extract and cultured in large quantities in a constant temperature incubator at 25°C; the Paramecium is fed with wheat extract and cultured in large quantities in a constant temperature incubator at 25°C.

[0018] As a further improvement of the present invention, the biofertilizer for increasing the effective silicon content in soil and rice contains Bacillus arginii, which can be used as a food source for protozoa.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By adopting the technical solution of the present invention, protozoa such as Tetrahymena, Ochraecia, Paramecium, etc. or biofertilizers containing such protozoa are added into rice fields, which can promote the conversion of silicon in the soil into soluble monosilicic acids, thereby increasing the effective silicon content in the soil and the effective silicon content in plants, which is more conducive to the growth of rice and increases the yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an implementation diagram of a soil experiment according to an embodiment of the present invention.

[0022] Figure 2 It is a diagram of an implementation scheme for rice experiments according to an embodiment of the present invention.

[0023] Figure 3 It is a standard curve of phytolith carbon content in rice sample plants of the embodiment of the present invention.

[0024] Figure 4 It is the standard curve of the effective silicon content in the soil sample of the embodiment of the present invention.

[0025] Figure 5 It is the comparison result of the effective silicon mass fraction after adding protozoa to the soil in the embodiment of the present invention.

[0026] Figure 6 It is the comparison result of the effective silicon mass fraction after adding protozoa to the rice sample in the embodiment of the present invention.

[0027] Figure 7These are the types of phytoliths of the aboveground part of the rice sample analyzed in the embodiment of the present invention, wherein ad, o: saddle-shaped phytoliths; e, f: fan-shaped phytoliths; g: thorn-stick-shaped phytoliths; h: double-peaked glume cell phytoliths; i: cap-shaped phytoliths; j: double-axe-shaped phytoliths; k: dumbbell-shaped phytoliths; l: rod-shaped phytoliths; m: double-peaked phytoliths; n: rectangular phytoliths; p: smooth rod-shaped phytoliths; q: hair-cell phytoliths; r: double-peaked glume cell phytoliths; s: flat-topped cap-shaped phytoliths; t: single-corner tower-shaped phytoliths. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described in further detail below.

[0029] The protozoa used in the following examples are Tetrahymena, Ochraconium and Paramecium isolated from the rhizosphere soil of rice.

[0030] The isolated protozoa are cultured in large quantities, specifically including: feeding with rice grain extract, culturing Tetrahymena and Ochracilium in large quantities in a constant temperature incubator at 25°C. Feeding with wheat extract, culturing Paramecium in large quantities in a constant temperature incubator at 25°C.

[0031] Determination of the organic silicon content in the experimental soil and rice, including:

[0032] Rice was grown in soil, and protozoa were placed directly into the soil to measure the effective silicon in the soil: 18 50ml beakers were taken, each filled with 25g of the same soil. The experimental beakers were divided into two groups, and different amounts of water were added, while the other treatments were the same. The water level just above the soil water line was considered to be low in water, and the water level at the 30ml mark on the beaker was considered to be high in water. Protozoa were added to both the high-water and low-water groups, with 100 / g, 1000 / g, and 10,000 / g of Tetrahymena, 50 / g, 100 / g, and 500 / g of Ochrafilaria, and 50 / g, 100 / g, and 500 / g of Paramecium added to each group. The experimental period was four weeks in total, and the effective silicon content in the soil was measured once a week. Figure 1 shown.

[0033] Rice was grown hydroponically to determine the effective silicon in rice: 3 identical root boxes were taken, each containing 40 rice seedlings, and protozoa were added: 38,000 Tetrahymena / box, 38,000 Ochratophora / box, and 38,000 Paramecium / box. The experimental period was one month, and the effective silicon content of rice was measured every half a month, with 20 rice seedlings taken each time. Figure 2 shown.

[0034] The wet ashing method was used to extract phytoliths from rice sample plants, and the method was improved based on the actual situation. The specific steps after the improvement are as follows: (1) Pre-treat the test material: cut the cleaned plants into small pieces with scissors; (2) Weigh 0.5 g of rice sample, put it into a 50 ml beaker, add an appropriate amount of concentrated nitric acid (15 mL) for oxidation, and then place it on an electric stove with an asbestos mesh and heat at level 3-4 until the reaction stops (the sample is completely dissolved); (3) After the sample is slightly cooled, pour it into a clean 50 mL centrifuge tube and re-weigh it to avoid the centrifuge tube from breaking during the centrifugation process, which may cause deviation in the sample data; (4) After the sample is cooled, add 2% nitric acid to the centrifuge tube. Distill water to 30mL, centrifuge (2500r / min, 10min) and wash 3-4 times; (5) Add H2O2 (concentration 30%), place on a hot plate for heating, and repeatedly add H2O2 (a total of 15-20mL) until the solution is clear and the sample is oxidized into a white powder (usually the solution is boiled until about 5ml is left); (6) After the sample is slightly cooled, add distilled water and centrifuge (3000r / min, 10min) to wash several times until neutral, add anhydrous ethanol and centrifuge (3000r / min, 10min) to wash once, discard the supernatant, keep the white powder at the bottom, and put the centrifuge tube in an oven at 75℃ to dry. After the dried phytoliths are cooled, weigh them, which is the mass of the phytoliths. Before measuring phytolith carbon, the Walkley-Black method must be used to ensure that the organic matter outside the phytolith is completely removed. The phytolith carbon is measured by alkaline dissolution spectrophotometry, and a standard curve is established using an organic carbon standard solution before the measurement. The standard curve measured in this embodiment is as follows Figure 3 shown.

[0035] The molybdenum blue colorimetric method was used to determine the effective silicon content in soil and rice. The steps for determining the effective silicon in soil are as follows:

[0036] (1) Weigh 2 g (accurate to 0.01 g) of the air-dried sample that has passed through a 2 mm sieve into a 50 mL plastic bottle, add 100 mL of 0.5 mol / L citric acid solution, plug the bottle, shake well, and place in a 30°C constant temperature box for 3-4 hours, then take out and filter. Perform a blank test at the same time.

[0037] (2) Pipette 1.00ml-5.00ml of the above filtrate (so that the silicon (Si) content is in the range of 10μm to 125μm) into a 50mL volumetric flask, dilute to about 20mL with water, add 5ml of 0.6mol / L sulfuric acid solution in sequence, and place at 30℃-35℃ for 15min, add 5ml of 50g / L ammonium molybdate solution, shake well and place for 5min, add 5ml of 50g / L oxalic acid solution and 5ml of 15g / L ascorbic acid solution, make up to volume with water, place for 20min, and compare the color at 700nm wavelength on a spectrophotometer using a 1cm optical path cuvette.

[0038] (3) The mass fraction of available silicon (Si) in soil is expressed in mg / kg and is calculated as follows:

[0039] Mass fraction of effective silicon = (ρ·V·D) / m

[0040] In the formula,

[0041] ρ: The concentration of silicon in the colorimetric solution obtained from the calibration curve, in milligrams per liter (mg / L);

[0042] V: volume of the color developing solution, in milliliters (mL), 50 mL for this method;

[0043] D: divide by multiples, 100 / 5=20;

[0044] m: sample mass, in grams (g)

[0045] The steps for determining the effective silicon in rice are as follows:

[0046] (1) Take 10 mL of 4 mol / L NaOH in a nickel crucible, heat it on a hot plate to evaporate it, accurately weigh 0.05-0.10 g of the ground air-dried sample of the plant to be tested and sprinkle it on the NaOH in the pot, cover it and place it on a common circuit to heat and ash it, then move it into a high-temperature electric furnace. Melt it at 700-720°C for 10 min, cool it down, wash it with redistilled water, and put it into a 100 mL volumetric flask filled with 10 mL.4 mol / L HCI, and make up to volume to obtain the silicon test solution.

[0047] (2) Accurately pipette 1-10 mL (containing 20-120 μg of silicon) of the test solution into a 50 mL volumetric flask, dilute to about 15 mL, add 1 drop of 2,6-dinitrophenol indicator, adjust to slightly yellow with 0.1 mol / L NaOH and 0.05 mol / L H2SO4, shake well, and place at room temperature for 15-20 min. Then add 5 mL of 0.3 mol / L H2SO4 and 5 mL of 5% ammonium molybdate solution, shake well, and place at room temperature for 5-20 min. Then add 5 ml of 5% oxalic acid solution and 5 ml of 5% ammonium ferrous sulfate solution or 15 g / L ascorbic acid solution in turn, make up to volume, and compare the color at 700 nm on a spectrophotometer after 20 min. At the same time, perform a blank test.

[0048] (3) Total silicon content of the plant (mg / kg) = (mass concentration obtained from the standard curve (μg / mL) × color development volume (mL) × fractionation multiple) / (sample weight (g))

[0049] Use silicon standard solution (1g / L) to draw silicon standard curve according to the above method, such as Figure 4 shown.

[0050] In this embodiment, after adding protozoa to the soil sample, the measured soil effective silicon mass fraction is compared with Figure 5 As shown in Figure 2. After adding protozoa to rice seedling samples, the measured effective silicon mass fraction of rice plants is compared with Figure 6 shown.

[0051] It can be seen that the effective silicon mass fraction increased most significantly after adding Paramecium to the soil, reaching 3.9 mg / kg, an increase of 0.675 mg / kg compared to the control group of 3.225 mg / kg. After adding protozoa during the growth of rice seedlings, the addition of Tetrahymena had the most significant effect, with an effective silicon mass fraction of 95.2143 mg / kg, 0.4286 mg / kg more than the control group of 94.7857 mg / kg. It can be seen that after adding protozoa to the soil and rice (hydroponic water), the corresponding effective silicon mass fraction was measured, and the results showed that protozoa significantly increased the effective silicon content in the soil and rice seedlings.

[0052] In this example, the phytoliths in the aboveground part of the rice samples to be tested were also observed under a microscope, and 14 types of phytoliths were identified, such as Figure 7As shown. A certain number of rice-characteristic phytoliths were found, such as rice bimodal, rice fan-shaped and rice horizontal dumbbell-shaped phytoliths. At present, people mainly use rice fan-shaped and rice bimodal phytoliths to study the domestication process of rice. These phytoliths show diversity in plant tissues, providing silicon storage structures for the growth and development of rice. These diversified structures provide a reference for in-depth research on the functions and physiological significance of phytoliths, and help to more fully understand the participation of silicon in biogeochemical processes in rice.

[0053] This embodiment designed an experiment to determine the aboveground parts of mature rice from three sample plots, namely Heishizuizi, Xuanwu Lake, and Yupin 16 in Shuiliandong, Shangguandi Village, Mudanjiang, for phytolith and phytolith carbon content.

[0054] The phytolith extraction and content determination include the following steps:

[0055] Pretreatment: Cut the cleaned rice sample into 1 cm segments with scissors, weigh 0.5 g and put it into a 50 mL beaker.

[0056] Oxidation: Add 15 mL of concentrated nitric acid, place on an electric stove with an asbestos mesh, and heat at level 3-4 until the sample is completely dissolved.

[0057] Transfer and weigh: After the sample has cooled slightly, pour it into a 50 mL centrifuge tube and re-weigh.

[0058] Cleaning: After cooling, add distilled water to 30 mL and centrifuge (2500 r / min, 10 min) to clean 3-4 times.

[0059] Oxidize until clear: Add H2O2 (concentration 30%), heat on a hot plate, and repeatedly add H2O2 (a total of 15-20 mL) until the solution is clear and the sample is oxidized to a white powder (usually boiled until about 5 mL remains).

[0060] Wash and dry again: After cooling slightly, add distilled water and centrifuge (3000r / min, 10min) to wash several times until neutral, add anhydrous ethanol and centrifuge (3000r / min, 10min) to wash once, discard the supernatant, and leave the white powder at the bottom. Put the centrifuge tube in an oven at 75℃ to dry, and weigh it after cooling to obtain the mass of phytoliths.

[0061] Phytolith microscopy

[0062] Preparation: Add anhydrous ethanol to 5 mL into the centrifuge tube where fresh phytoliths have just been extracted, and shake evenly; use a disposable dropper to draw a small amount of liquid and drop 1 drop on the slide, heat and dry with an alcohol lamp or wait for the ethanol to evaporate naturally and dry (to ensure that the sample is evenly dispersed); drop 2 drops of neutral resin on the slide, cover the sample, cover with a coverslip to fix the slide, and label it.

[0063] Microscopic examination: Place the prepared fixed slide under a Zeiss microscope, adjust the magnification to 500 times, observe the morphological type of phytoliths and take photos to record.

[0064] Determination of phytolith carbon content

[0065] Phytolith examination: Use the Walkley-Black method and heat the solution of potassium dichromate in a water bath to ensure that the organic matter on the surface of the phytoliths is completely removed.

[0066] Cleaning and drying: Wash the phytoliths with deionized water and dry them.

[0067] Colorimetric determination: Alkaline dissolution spectrophotometry is used for on-machine colorimetric determination. Before determination, a standard curve (y = 0.002x + 0.0162, R 2 =0.9969), a regression equation was established, and the absorbance was substituted into the standard curve regression equation to obtain the phytolith carbon content.

[0068] Experimental results:

[0069] Phytolith morphology: 14 types of phytoliths were identified from mature rice samples from three plots, including saddle-shaped, fan-shaped, thorn-stick-shaped, bimodal glume cell phytoliths, cap-shaped, double-axe-shaped, dumbbell-shaped, rod-shaped, bimodal-shaped, rectangular, smooth rod-shaped, hair cell phytoliths, flat-topped hat-shaped, and unicorn-shaped phytoliths. Among them, characteristic phytoliths of rice, such as rice bimodal-shaped, rice fan-shaped, and rice horizontal dumbbell-shaped, were found.

[0070] Phytoliths and phytolith carbon content: After harvest in September, the phytolith content of rice straw is 105.333–117 g kg -1 Fluctuates, phytolith carbon content is 2.145-3.329 g·kg -1 The rice phytolith content in the 16th plot of Yupin was the highest (119 g·kg -1 ), but the carbon content of phytoliths was the lowest (2.145 g kg -1 ); the rice phytolith content in the Xuanwu Lake sample site was the lowest (111.665 g·kg -1 ), but the carbon storage capacity of phytoliths is the highest (3.329 g kg -1 ); Phytolith content in Heishizuizi plot (117 g·kg -1 ) and phytolith carbon content (2.245 g·kg -1 ) is at an intermediate level.

[0071] Prediction of phytolith carbon storage and spatial distribution: The annual rice straw phytolith carbon flux and phytolith carbon storage per hectare in the three sample plots of Heishizuizi, Xuanwu Lake, and Shuiliandong Yupin 16 were estimated. The results were Xuanwu Lake> Heishizuizi> Yupin 16. Among them, the phytolith carbon flux of Heishizuizi was 277kg CO2ha -1 yr -1 , carbon storage (CO2 storage) is 249.3kgCO2ha -1 yr -1 (67.991kg C ha -1 yr -1 ); the phytolith carbon flux of Xuanwu Lake is 454kg CO2ha -1 yr -1 , carbon storage (CO2 storage) is 408.6kg CO2ha -1 yr -1 (111.436kg C ha -1 yr -1 ); the phytolith carbon production flux of product 16 is 199kg CO2ha -1 yr -1 , carbon storage (CO2 storage) is 179.1kg CO2ha -1 yr -1 (48.845kg C ha -1 yr -1 ). According to the highest dry matter phytolith carbon content in this study (3.329 mg·g -1 ) estimated that the global rice straw phytolith carbon production rate is 8.03 Tg CO2yr -1 (49.85kg CO2ha -1 yr -1 ), the global carbon storage in rice straw phytoliths is about 7.19 Tg CO2 (44.84 kg CO2 ha -1 yr -1 ), which is equivalent to 12.88% of the soil carbon sequestration of conservation agriculture.

[0072] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for increasing the effective silicon content of soil and rice, characterized in that: Protozoa or biofertilizer containing protozoa is added into the rice field. The protozoa is at least one of Tetrahymena, Ochraconida and Paramecium separated from the rhizosphere soil of rice.

2. The method for improving the effective silicon content in soil and rice according to claim 1, characterized in that: The Tetrahymena and Ochracilium are fed with rice grain extract and cultured in large quantities in a constant temperature incubator at 25°C; the Paramecium is fed with wheat extract and cultured in large quantities in a constant temperature incubator at 25°C.

3. The method for improving the effective silicon content in soil and rice according to claim 2, characterized in that: Add Tetrahymena to rice when the rice seedlings are growing, or add Paramecium to the soil.

4. The method for improving the effective silicon content in soil and rice according to claim 1, characterized in that: The amount of protozoa added is 4.4×10 5 -4.4×10 7 Tetrahymena, 2.2×10 5 -2.2×10 7 Ochre worms, or 2.2 × 10 5 -2.2×10 7 Only Paramecium.

5. The use of protozoa as a biofertilizer for increasing the effective silicon content of soil and rice, characterized in that: The protozoa is at least one of Tetrahymena, Ochraconium and Paramecium separated from the rhizosphere soil of rice.

6. The use of the protozoa according to claim 5 as a biofertilizer for improving the effective silicon content of soil and rice, characterized in that: The Tetrahymena and Ochracilium are fed with rice grain extract and cultured in large quantities in a constant temperature incubator at 25°C; the Paramecium is fed with wheat extract and cultured in large quantities in a constant temperature incubator at 25°C.

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