Preparation and application method of rice husk carbon modified matrix suitable for multi-mode rice seedling raising

Abstract

The invention provides a preparation and application method of a rice husk carbon modified matrix suitable for multi-mode rice seedling raising, and belongs to the technical field of rice seedling raising. The preparation method comprises the following steps: soaking rice husk charcoal in clear water, soaking in a mixed solution of citric acid and ammonium sulfate, drying the rice husk charcoal in the shade to obtain modified rice husk charcoal, and finally mixing the modified rice husk charcoal with different fertilizers to obtain the rice husk charcoal modified substrate for rice seedling raising in different modes. The rice husk carbon modified substrate prepared by the invention not only can be used for pot tray seedling raising, but also has a good seedling rolling effect in blanket tray seedling raising.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rice seedling raising, and particularly relates to a preparation and application method of rice hull charcoal modified substrate suitable for multi-mode rice seedling raising. BACKGROUND

[0002] Rice is one of the main food crops in China and is of great significance to the national food security. Full mechanization of rice planting can improve production efficiency, and machine transplanting, including blanket disc machine transplanting and pot disc machine transplanting, is an important link of full mechanization. High-quality standardized seedling raising directly affects the effect of machine transplanting, and good seedling raising substrate directly determines the quality of seedlings. Traditional seedling raising substrate is usually made of field soil after crushing, disinfection and pH adjustment. However, weeds are easy to breed, soil-borne diseases are easy to occur, and long-term digging will damage the soil tillage environment. With the continuous popularization of rice machine transplanting technology, the problem of seedling raising soil taking is increasingly prominent. In view of this, people are constantly seeking alternative materials to configure the substrate. At present, the existing substrate materials include inorganic substrates such as vermiculite, perlite, slag and rock wool, and organic substrates such as straw, sawdust, peat, coconut husk, earthworm manure, compost and traditional Chinese medicine fermentation. In addition, there is biochar. In production, these organic substrates, inorganic substrates and biochar are usually mixed with yellow mud, various fertilizers and microbial agents according to a certain proportion and then used for rice seedling raising. However, the configuration of some formula processes has complex raw materials, and the limited resources bring certain obstacles to agricultural production application.

[0003] Biochar is prepared by thermal cracking under anaerobic conditions using agricultural waste biomass as raw material. Preparing rice seedling raising substrate from biochar can help alleviate the problem of seedling raising soil taking, recycle agricultural waste biomass, and achieve the effect of carbon sequestration and emission reduction.

[0004] According to different water management, seedling raising can be divided into humid seedling raising and dry seedling raising modes. In order to adapt to machine transplanting, currently, two kinds of seedling trays, i.e. blanket disc and pot disc, are mainly used. Blanket disc can only be used for machine transplanting, while pot disc can be used for both machine transplanting and machine throwing. In addition, blanket disc requires good rolling effect, while pot disc does not require rolling. Biochar has light texture, small bulk density, rich porosity, large specific surface area, good adsorption performance and air permeability, but weak water retention capacity, few nutrient components and alkaline property. Therefore, based on the advantages and disadvantages of biochar, different seedling raising modes have different characteristics, and different seedling raising trays have different requirements. It is necessary to develop biochar substrate and application method suitable for blanket disc and pot disc according to different seedling raising modes. SUMMARY

[0005] Therefore, the present application provides a preparation method of rice hull charcoal modified substrate suitable for multi-mode rice seedling raising.

[0006] (1) rice husk carbon is soaked in clean water for 1-2 days, and then washed with clean water for 1-3 times;

[0007] (2) the washed rice husk carbon is soaked with a mixed solution of citric acid and ammonium sulfate for 1-2 days, and the soaking is repeated for 2-3 times, and the rice husk carbon is dried to obtain modified rice husk carbon;

[0008] (3) the modified rice husk carbon is mixed with and / or a substrate to obtain the rice husk carbon modified substrate suitable for multi-mode rice seedling raising.

[0009] Preferably, in the mixed solution of citric acid and ammonium sulfate in step (2), the mass concentration of citric acid is 0.1%, and the mass concentration of ammonium sulfate is 0.1%.

[0010] Preferably, in step (3), the fertilizer is at least one of organic fertilizer and inorganic fertilizer; and the substrate is at least one of grass carbon soil and paddy field soil.

[0011] Preferably, in step (3), the organic matter content of the organic fertilizer is greater than or equal to 30%, and the effective nutrient N-P2O5-K2O is greater than or equal to 4%; and the inorganic fertilizer is at least one of diammonium phosphate, potassium dihydrogen phosphate and zinc sulfate.

[0012] The application also provides an application of the rice husk carbon modified substrate suitable for multi-mode rice seedling raising, and the rice husk carbon modified substrate is used for pot seedling raising or blanket seedling raising in a wet seedling raising mode and a dry seedling raising mode.

[0013] Preferably, the substrate used in the pot seedling raising in the wet seedling raising mode comprises modified rice husk carbon and organic fertilizer, and the mass ratio of the modified rice husk carbon to the organic fertilizer is 80-90:10-20.

[0014] Preferably, the substrate used in the blanket seedling raising in the wet seedling raising mode comprises modified rice husk carbon, grass carbon soil and organic fertilizer, and the mass ratio of the modified rice husk carbon to the grass carbon soil to the organic fertilizer is 1-2:1-2:1-2.

[0015] Preferably, the substrate used in the blanket seedling raising in the dry seedling raising mode comprises modified rice husk carbon, grass carbon soil and organic fertilizer, and the mass ratio of the modified rice husk carbon to the grass carbon soil to the organic fertilizer is 1-2:1-2:1-2.

[0016] Preferably, the substrate used in the pot seedling raising in the dry seedling raising mode comprises modified rice husk carbon and organic fertilizer, and the mass ratio of the modified rice husk carbon to the organic fertilizer is 1-2:1-2.

[0017] Preferably, during the seedling raising process, a mixed solution of ferrous sulfate and ammonium sulfate is sprayed to improve the yellowing problem of leaves; the mass concentration of ferrous sulfate in the mixed solution is 0.1-0.15%, and the mass concentration of ammonium sulfate is 0.1-0.15%.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a preparation and application method of a rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation. The present invention first soaks the rice husk charcoal in clean water, then soaks it in a mixed solution of citric acid and ammonium sulfate, and finally, shade-dries the rice husk charcoal to obtain modified rice husk charcoal. The modification method of the present invention is simple, and the modified rice husk charcoal obtained is non-sticky, non-agglomerated, and has uniform color. At this time, the alkaloids, organic acids, benzene compounds, organic heterocyclic compounds, lipids and lipid analogs in the rice husk charcoal are significantly reduced, and can be used to configure a rice seedling cultivation matrix. By mixing the above-mentioned modified rice husk charcoal with different fertilizers, a rice husk charcoal modified matrix that can be used for rice seedling cultivation under different modes can be obtained. The rice husk charcoal modified matrix prepared by the present invention can not only be used for pot tray rice seedling cultivation, but also has a good seedling curling effect in blanket tray rice seedling cultivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The results of raising seedlings in pots and trays using the substrates of formula 9 and formula 10 in the moist seedling raising mode are shown;

[0021] Figure 2 The results of formula 1 in the pot tray seedling raising mode are shown below:

[0022] Figure 3 The results of formula 2 in the pot tray seedling raising mode are shown below:

[0023] Figure 4 The results of formula 3 in the pot tray seedling raising mode are shown below:

[0024] Figure 5 The results are as follows: the machine-transplanted and hand-transplanted seedlings in the moist seedling raising mode using formula 2 and formula 3;

[0025] Figure 6 The results of blanket tray seedling raising in moist seedling raising mode for formula 3 and formula 4 are shown;

[0026] Figure 7 The curling and root packing effect of the blanket tray of formula 4;

[0027] Figure 8 The curling and rooting effects of the blanket tray of formula 3;

[0028] Figure 9 To investigate the effects of different substrates on raising seedlings in blanket trays at the one-leaf stage under dry seedling raising mode;

[0029] Figure 10 Effect of the tray seedling mode under dry seedling with different substrates on 2-leaf stage;

[0030] Figure 11 Effect of the tray seedling mode under dry seedling with different substrates on 2-leaf stage;

[0031] Figure 12 Effect of the tray seedling mode under dry seedling with different substrates on 3-leaf stage;

[0032] Figure 13 Effect of the mixed spraying of 0.1% ferrous sulfate and 0.1% ammonium sulfate on the recovery of green color of leaves;

[0033] Figure 14 Effect of the pot seedling mode under dry seedling with formula 4 and formula 7. DETAILED DESCRIPTION

[0034] The application provides a preparation method of a rice hull charcoal modified substrate suitable for multi-mode rice seedling.

[0035] (1) The rice hull charcoal is soaked in clean water for 1 day, and then washed once with clean water;

[0036] (2) The cleaned rice hull charcoal is soaked in a mixed solution of citric acid and ammonium sulfate (the mass concentration of the citric acid is 0.1%, and the mass concentration of the ammonium sulfate is 0.1%) for 1 day, and then replaced with a new mixed solution of citric acid and ammonium sulfate every other day for 1 day, and then the rice hull charcoal is air-dried to obtain modified rice hull charcoal;

[0037] (3) The modified rice hull charcoal is mixed with a fertilizer to obtain the rice hull charcoal modified substrate suitable for multi-mode rice seedling.

[0038] In the specific embodiments of the application, the rice hull charcoal is produced by Tianjin Yadier Biomass Technology Co., Ltd.

[0039] In step (2), the fertilizer is at least one of grass charcoal soil, organic fertilizer and inorganic fertilizer.

[0040] The organic matter content of the organic fertilizer is greater than or equal to 30%, and the effective nutrient N-P2O5-K2O is greater than or equal to 4%. In the specific embodiments of the application, the organic fertilizer is produced by Guizhou Tiandi Fu Fertilizer Industry Co., Ltd., and the product registration number is Qian Nong Fertilizer (2024) Zhun Zi 1466.

[0041] The inorganic fertilizer is at least one of diammonium phosphate, potassium dihydrogen phosphate and zinc sulfate.

[0042] The rice hull charcoal modified substrate prepared by the application is suitable for multi-mode rice seedling raising, and can be used for pot seedling raising or blanket seedling raising in wet seedling raising mode and dry seedling raising mode.

[0043] Specifically, the substrate used in the pot seedling raising in the wet seedling raising mode comprises modified rice hull charcoal and organic fertilizer, and the mass ratio of the modified rice hull charcoal and the organic fertilizer is 80-90:10-20; the substrate used in the blanket seedling raising in the wet seedling raising mode comprises modified rice hull charcoal, grass charcoal soil and organic fertilizer, and the mass ratio of the modified rice hull charcoal, the grass charcoal soil and the organic fertilizer is 1-2:1-2:1-2; the substrate used in the blanket seedling raising in the dry seedling raising mode comprises modified rice hull charcoal, grass charcoal soil and organic fertilizer, and the mass ratio of the modified rice hull charcoal, the grass charcoal soil and the organic fertilizer is 1-2:1-2:1-2; and the substrate used in the pot seedling raising in the dry seedling raising mode comprises modified rice hull charcoal and organic fertilizer, and the mass ratio of the modified rice hull charcoal and the organic fertilizer is 1-2:1-2.

[0044] The application will be further described below in combination with examples.

[0045] Example 1

[0046] A preparation method of modified rice hull charcoal, steps are as follows:

[0047] (1) rice hull charcoal is soaked in clean water for 1 day, and then washed once with clean water;

[0048] (2) the washed rice hull charcoal is soaked in a mixed solution of citric acid and ammonium sulfate (the mass concentration of citric acid is 0.1%, and the mass concentration of ammonium sulfate is 0.1%) for 1 day, and then the rice hull charcoal is dried in the sun to obtain modified rice hull charcoal.

[0049] The classification proportion of rice hull charcoal metabolites is shown in Table 1.

[0050] Table 1

[0051] Class Number Percentage Alkaloids and derivatives 63 2.87% Benzene compounds 255 11.63% Hydrocarbons 5 0.23% Lignans, neolignans and related compounds 19 0.87% Lipids and lipid analogues 574 26.17% Nucleosides, nucleotides and analogues 33 1.50% Organic acids and derivatives 350 15.96% Nitrogen-containing organic compounds 23 1.05% Oxygen-containing organic compounds 167 7.62% Halogenated organic compounds 12 0.55% Organic heterocyclic compounds 430 19.61% Sulfur-containing organic compounds 21 0.96% Phenylpropanoids and polyketides 227 10.35% Other 14 0.64%

[0052] The types of compounds contained in the modified rice hull charcoal and the unmodified rice hull charcoal are shown in Table 2.

[0053] Table 2

[0054] Compound name Primary classification Secondary classification Tertiary classification Sophoridine Alkaloids and derivatives Lupine alkaloids Sophoridine Dihydrotanshinone I Lipids and lipid molecules Prenol lipids Diterpenoids Stearic acid amide Organic acids and derivatives Formimino acids and derivatives Formimino acids Octadecenoic acid (trans-6) / trans-oleic acid (C18:1 T) Lipids and lipid molecules Fatty acyls Fatty acids and conjugates Azelaic acid Lipids and lipid molecules Fatty acyls Fatty acids and conjugates Eicosenoic acid (cis-11) Lipids and lipid molecules Fatty acyls Fatty acids and conjugates Octadecadienoic acid (cis-9,12) / linoleic acid Lipids and lipid molecules Fatty acyls Linolenic acid and derivatives Neohydrtanshinone IIA Lipids and lipid molecules Prenol lipids Diterpenoids Cyclic (L-prolyl-L-valyl) Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues Caffeic acid Phenylpropanoids and polyketides Cinnamic acid and derivatives Hydroxycinnamic acid and derivatives 2-Heptyl-4-hydroxyquinoline 1-oxide Organic heterocyclic compounds Quinoline and derivatives 4-Hydroxy-2-alkylquinolines Suberic acid Lipids and lipid molecules Fatty acyls Fatty acids and conjugates O-Carboxybenzaldehyde Benzene compounds Benzene and substituted derivatives Benzoic acid and derivatives 4-Hydroxyproline Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues p-Hydroxybenzaldehyde Organic oxygen compounds Organic oxygen compounds Carbonyl compounds Benzothiazoles Organic heterocyclic compounds Benzothiazoles _ 1-Palmitoyl-sn-glycero-3-phosphocholine Lipids and lipid molecules Glycerophospholipids Glycerophosphocholine Cyclic (L-prolyl-L-leucyl) Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues Acetylsalicylic acid Benzene compounds Benzene and substituted derivatives Benzoic acid and derivatives Tetrahydropyrimidine Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues Syringic acid Benzene compounds Benzene and substituted derivatives Benzoic acid and derivatives N6,N6-dimethyladenosine Nucleosides, nucleotides and analogues Purine nucleosides _ L-xylonulose Organic oxygen compounds Organic oxygen compounds Carbohydrates and carbohydrate conjugates Glycosylated valine Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues Artemisinic acid Lipids and lipid molecules Prenol lipids Sesquiterpenoids 7-O-methylrosmaridiphenol Lipids and lipid molecules Prenol lipids Terpene lactones Vedereether Lipids and lipid molecules Prenol lipids Sesquiterpenoids Quinovic acid Organic oxygen compounds Organic oxygen compounds Alcohols and polyols Ginkgolide A Phenylpropanoids and polyketides Flavonoids O-methylated flavonoids 6-Gingerenol Benzene compounds Phenols Methoxyphenols Glycosylated methionine Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides and analogues Carboxylic acids and derivatives thereof Amino acids, peptides and analogs L-leucine Organic acids and derivatives thereof Carboxylic acids and derivatives thereof Amino acids, peptides and analogs Norepinephrine Organoheterocyclic compounds Benzopyrans 1-benzopyran Robustine Benzene compounds Phenols Benzenediols Methylsuccinic acid Lipids and lipid molecules Fatty acyls Fatty acids and conjugates 5,6-dimethylbenzimidazole Organoheterocyclic compounds Benzimidazoles _ L-asparagine Organic acids and derivatives thereof Carboxylic acids and derivatives thereof Amino acids, peptides and analogs Butein Phenylpropanoids and polyketides Straight-chain 1,3-diarylpropanes Chalcones and dihydrochalcones

[0055] The results of the metabolic group comparison analysis of the modified rice hull charcoal and the unmodified rice hull charcoal are shown in Table 3. The steps of the metabolic group analysis are as follows:

[0056] (1) 1g sample is taken and placed in an EP tube, and 1000ul of 80% methanol aqueous solution is added;

[0057] (2) Vortex, place on ice for 5 min, and centrifuge at 15,000 g and 4°C for 15 min;

[0058] (3) Take the supernatant and centrifuge again at 15,000 g and 4°C for 20 min;

[0059] (4) Take the supernatant and freeze-dry;

[0060] (5) Dissolve the solution in 200 μL of 10% methanol solution and analyze it by LC-MS.

[0061] The secondary mass spectra obtained from the metabolomics experiment were compared with databases (KEGG, HMDB, LIPID MAPS), and the similarity was calculated using the dot product algorithm, with a score ranging from 0 to 1.

[0062] Identification level: Level 1 is confirmatory identification, which is completely consistent with the authentic standard; Level 2 is speculative identification, with no standard; Level 3 is speculative structural category, which can only infer the compound category but cannot accurately identify the molecule; Level 4 is only known molecular formula, and the structure is unknown; Level 5 is completely unknown.

[0063] Table 3

[0064] Compound name Match score Identification level Chromatographic column Unmodified rice husk charcoal.aver Modified rice husk charcoal.aver Log2(modified rice husk charcoal / unmodified rice husk charcoal) Sophoridine 1.00 1 C18 8589583.6 1589633.4 -2.43 Dihydrotanshinone I 1.00 1 C18 1241897.9 402504.28 -1.62 Stearic acid amide 0.98 1 C18 254627445 120664870 -1.07 Octadecenoic acid (trans-6) / trans- petroselinic acid (C18:1 T) 0.97 1 C18 15458341 4399416 -1.81 Azelaic acid 0.96 1 C18 49428799249.97 12970446276.09 -1.93 Eicosanoic acid (cis-11) 0.94 1 C18 375751.82 170832.06 -1.13 Octadecadienoic acid (cis-9,12) / linoleic acid 0.93 1 C18 22930609 4924695.1 -2.21 Neotanshinone 0.93 1 C18 19904468 5440130.6 -1.87 Cyclo (L-prolyl-L-valyl) 0.93 1 C18 491036976 202887201 -1.27 Caffeic acid 0.91 1 C18 2965577594.66 202031225 -3.87 2-heptyl-4-hydroxyquinoline 1-oxide 0.91 1 C18 44185853 10722456 -2.04 Suberic acid 0.91 1 C18 6521852108.35 2696032041.14 -1.27 O-Carboxybenzaldehyde 0.88 1 C18 173260412 37954350 -2.19 4-hydroxyproline 0.88 1 C18 74019676 32076809 -1.2 p-Hydroxybenzaldehyde 0.87 1 C18 17472033256.99 2234087441.25 -2.96 Benzothiazoles 0.87 1 C18 857902055 266427628 -1.68 1-palmitoyl-sn-glycero-3-phosphocholine 0.87 1 C18 19908516 7507084.1 -1.4 Cyclo (L-prolyl-L-leucyl) 0.87 1 C18 669922812 322544530 -1.05 Acetylsalicylic acid 0.85 1 C18 2734110917.81 915097624 -1.57 Tetrahydropyrimidine 0.82 1 C18 12416487 3273260.4 -1.92 Syringic acid 0.79 1 C18 1184587432.99 65632955 -4.17 N6,N6-dimethyladenosine 0.79 1 C18 5836189.2 2343541.7 -1.31 L-xylulose 0.78 1 C18 6974345.3 1980060.2 -1.81 Glycosylated valine 0.77 1 C18 70476989 26895367 -1.38 Artemisinic acid 0.76 1 C18 2618567982.87 1266901406 -1.04 7-o-methylrosmaridiphenol 0.75 1 C18 44125843 15085096 -1.54 Artemether 0.75 1 C18 17717076219.08 7943058790.42 -1.15 Quinovic acid 0.74 1 C18 422566445 201474102 -1.06 Ginkgolide A 0.73 1 C18 330354459 46878359 -2.81 6-gingerol 0.73 1 C18 1848546618.36 407013169 -2.18 Glycosylated methionine 0.73 1 C18 18323196 7690776.4 -1.25 L-leucine 0.72 1 C18 4753232.5 1423506.3 -1.73 Norepinephrine 0.72 1 C18 58698549 24310207 -1.27 Robustine 0.71 1 C18 6317565 867503.53 -2.86 Methylsuccinic acid 0.71 1 C18 41246937 9067180.5 -2.18 5,6-dimethylbenzimidazole 0.70 1 C18 8833304.3 1303965.3 -2.76 L-asparagine 0.70 1 C18 117463101 19596029 -2.58 Butein 0.70 1 C18 15540601 4654949.7 -1.73

[0065] As shown in Tables 2 and 3, rice husk char contains a high proportion of benzene compounds, lipids and lipid analogs, organic acids and their derivatives, and organic heterocyclic compounds, which are potential inhibitors of rice growth. Modified rice husk char, on the other hand, contains significantly fewer alkaloids (sophoridine has allelopathic inhibitory effects), organic acids, benzene compounds, organic heterocyclic compounds, lipids, and lipid analogs.

[0066] Example 2

[0067] A rice husk charcoal modified matrix for rice seedling cultivation is prepared by mixing the modified rice husk charcoal prepared in Example 1, unmodified rice husk charcoal, or paddy soil with different fertilizers. The specific formula is as follows:

[0068] Formula 1: Modified rice husk charcoal and peat soil are mixed in a mass ratio of 1:1 to obtain a mixture, and the mixture is then mixed with diammonium phosphate, potassium dihydrogen phosphate, and zinc sulfate in mass ratios of 95%, 3%, 1.5%, and 0.5% to obtain a seedling medium;

[0069] Formula 2: Modified rice husk charcoal and peat soil are mixed in a mass ratio of 3:1 to obtain a mixture, and the mixture is mixed with organic fertilizer in a mass ratio of 3:1 to obtain a seedling medium;

[0070] Formula 3: Modified rice husk charcoal and organic fertilizer are mixed in a mass ratio of 85% and 15% to obtain a seedling medium;

[0071] Formula 4: Modified rice husk charcoal, grass charcoal soil and organic fertilizer are mixed in a mass ratio of 1:1:1 to obtain a seedling substrate;

[0072] Formula 5: Modified rice husk charcoal, grass charcoal soil and organic fertilizer are mixed in a mass ratio of 1:1:1, and then the mixture is mixed with diammonium phosphate, potassium dihydrogen phosphate and zinc sulfate in a mass ratio of 95%, 3%, 1.5% and 0.5% to obtain a seedling substrate;

[0073] Formula 6: Modified rice husk charcoal, grass charcoal soil and organic fertilizer are mixed in a mass ratio of 1:1:1, and then the mixture is mixed with sterilized paddy soil (sterilized by sun exposure) in a mass ratio of 1:1 to obtain a seedling substrate;

[0074] Formula 7: Modified rice husk charcoal and organic fertilizer are mixed in a mass ratio of 1:1 to configure a seedling substrate.

[0075] Formula 8: Sterilized paddy soil (sterilized by sun exposure) and organic fertilizer are mixed in a mass ratio of 3:1 to obtain a seedling substrate;

[0076] Formula 9: Unmodified rice husk charcoal and organic fertilizer are mixed in a mass ratio of 85% and 15% to obtain a seedling substrate;

[0077] Formula 10: Unmodified rice husk charcoal, grass charcoal soil and organic fertilizer are mixed in a mass ratio of 1:1:1 to obtain a seedling substrate.

[0078] Experiment 1: The substrates of formula 9 and formula 10 and 448-hole pot plates are used, the seeds are sown by a flow line sowing machine, 2-3 seeds are sown in each hole (Xiang 19 rice seeds, the same below), the pot plate is sown in a wet seedling mode, the sowing procedure is to sow the bottom soil, sow the seeds, cover the soil and sprinkle water, the temperature is controlled to be not higher than 35°C before germination, the temperature is controlled to be 22-25°C when the seedlings are 1-2 leaves, and the temperature is controlled to be 18-22°C when the seedlings are 3 leaves. It is found that the seedlings of formula 9 grow slowly, and the root growth is inhibited; the rice seeds of formula 10 germinate uniformly, but the rice seedlings germinate unevenly, the seedling leaves are yellow, and the whole plant dies eventually, and the results are as Figure 1 It can be seen that the unmodified rice husk charcoal cannot be directly applied to configure a rice seedling substrate.

[0079] Experiment 2: Effect comparison of different formula carbon substrates in pot plate seedling under wet seedling mode

[0080] The seedling substrates of formula 1, formula 2 and formula 3 are sown in a wet seedling mode according to the method of experiment 1, and the results are as Figures 2-4 .

[0081] From Figures 2-4As can be seen, the seedling raising substrates of Formula 1, Formula 2 and Formula 3 all can normally germinate, and the root systems of the seedlings grow well, the root systems are good, and there is no problem of substrate floating and large loss. From the above test results, it can be seen that in the humid seedling raising mode, only the biochar is used as the medium, and a small amount of organic fertilizer is added, and the seedlings with good quality can be raised. Considering the cost and the convenience of configuring the substrate, Formula 3 is more suitable for the pot and tray seedling raising in the humid seedling raising mode.

[0082] The Formula 2 and Formula 3 are used to carry out seedling raising demonstration in Yashui County, Qian Nan County, Guizhou Province, and the total seedling raising demonstration area is 4 mu. The seedling raising demonstration adopts the tray sowing machine for sowing, and the bottom soil and the covering soil both adopt the same formula substrate. After the covering soil, the atomizing pipe is used to wet the surface soil, then the trays are stacked for darkening treatment. Before the trays are placed, the seedling field is leveled, and no water layer is left in the field. When the trays are placed, the trays are inserted into the mud, and the non-woven fabric single mode is used for covering. As shown in Figure 5 , the seedling quality for machine transplanting is good, the root system is more and strong, and the seedling for hand transplanting also has good quality, the root system is developed, and the white roots are more.

[0083] Experiment 3: Effect comparison of different formula substrates in the tray seedling raising in the humid seedling raising mode

[0084] The seedling raising substrates of Formula 3 and Formula 4 are used, the flow line sowing machine is used for sowing, and the humid seedling raising mode of the tray seedling raising is carried out according to 0.75 kg of substrate per tray and 70 g of rice seeds. The sowing procedure is to sow the bottom soil, sow the seeds, cover the soil and sprinkle water. Before germination, the temperature is controlled to be not higher than 35℃, the temperature is controlled to be 22-25℃ when the seedlings are 1 leaf 1 core to 2 leaf 1 core, and the temperature is controlled to be 18-22℃ when the seedlings are 3 leaves. The results are as shown in Figure 6 ; the rolling seedling and the tray root effect of the Formula 4 tray are as shown in Figure 7 , and the rolling seedling and the tray root effect of the Formula 3 tray are as shown in Figure 8 .

[0085] From Figures 6-8 , it can be seen that the seedling raising substrates of Formula 3 and Formula 4 all normally raise seedlings, but the tray root and the rolling seedling effect of Formula 4 are good, and no tray scattering occurs. However, Formula 3 is prone to tray scattering, and the tray root effect is not as good as Formula 4. Therefore, in the agricultural production, in the humid seedling raising mode, Formula 4 has better seedling raising effect in the tray seedling raising.

[0086] Experiment 4: Effect comparison of different formula substrates in the tray seedling raising in the dry seedling raising mode

[0087] The formula 4, formula 5, formula 6, formula 7, formula 8, pipeline seeder is seeded, according to every blanket disc 0.75kg substrate, 70g rice seed is carried out in the dry seedling mode under the blanket disc seedling, the sowing procedure is to sow the bottom soil-seed- cover soil-spraying, the temperature is controlled to be no more than 35 DEG C before germination, 1 leaf 1 core to 2 leaf 1 core temperature control is at 22-25 DEG C, 3 leaves control is at 18-22 DEG C.The effect of different formula substrate blanket disc seedling 1 leaf period is as Figure 9 The effect of different formula substrate blanket disc seedling in 2 leaf period is as Figure 10 The disc root effect of formula 4, formula 6, formula 7 and formula 8 in 3 leaf period is as Figure 11 The roll seedling effect of formula 4 and formula 6 and formula 7 is as Figure 12 .

[0088] Figure 9 It shows that, at 1 leaf period, formula 5 fertilizer amount is too much, leading to seedling yellowing, formula 4, formula 6 and formula 7 and formula 8 seedling quality is equivalent; Figure 10 It shows that, at 2 leaf period, formula 5 seedling yellowing and plant dwarf, growth is slower, formula 4 and formula 6 seedling grows faster, plant is higher; Figure 11 It shows that, at 3 leaf period, the disc root effect of formula 4, formula 6, formula 7 and formula 8 is good; Figure 12 It shows that formula 4 and formula 6 seedling can normally roll seedling, and formula 7 is easy to scatter disc.

[0089] At the same time Figure 11 It shows that, formula 4, formula 6 and formula 7 seedling color is yellow than formula 8, by mixing and spraying 0.1% ferrous sulfate and 0.1% ammonium sulfate solution, to spray to leaf drip, can quickly restore leaf green, initial yellowing leaf will form green spots in the local leaf, then, the spot gradually expands and connects after the whole leaf restores green, the result is as Figure 13 .

[0090] Experiment 5: under dry seedling mode, the effect comparison of different formula substrate in pot disc seedling

[0091] Formula 4 and formula 7 and 448 hole pot disc, pipeline seeder is seeded, every hole is seeded 2-3 grains and is carried out in the dry seedling mode under the pot disc seedling, the sowing procedure is to sow the bottom soil-seed- cover soil-spraying, the temperature is controlled to be no more than 35 DEG C before germination, 1 leaf 1 core to 2 leaf 1 core temperature control is at 22-25 DEG C, 3 leaves control is at 18-22 DEG C.The effect is as Figure 14 .

[0092] From Figure 14 It can be seen that, formula 4 and formula 7 pot disc seedling effect is good, the disc root effect of seedling in independent pot is good, comprehensive consideration formula configuration's difficulty, formula 7 is selected and is carried out in the dry seedling mode under the pot disc seedling.

[0093] The above merely preferred embodiments of the present application, it should be noted that for those of ordinary skill in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered within the scope of the present application.

Claims

1. A method for preparing a rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation, characterized in that: The following steps are involved: (1) Soak the rice husk charcoal in clean water for 1-2 days, then wash it with clean water 1-3 times; (2) soaking the washed rice husk charcoal in a mixed solution of citric acid and ammonium sulfate for 1-2 days, repeating the soaking 2-3 times, and air-drying the rice husk charcoal to obtain modified rice husk charcoal; (3) The modified rice husk charcoal is mixed with fertilizer and / or substrate to obtain the rice husk charcoal modified substrate suitable for multi-mode rice seedling cultivation.

2. The method for preparing the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 1, characterized in that: In the mixed solution of citric acid and ammonium sulfate in step (2), the mass concentration of citric acid is 0.1%, and the mass concentration of ammonium sulfate is 0.1%.

3. The method for preparing the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 1, characterized in that: In step (3), the fertilizer is at least one of organic fertilizer and inorganic fertilizer; and the matrix is ​​at least one of peat soil and paddy soil.

4. The method for preparing the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 3, characterized in that: The organic fertilizer in step (3) has an organic matter content of ≥30% and an effective nutrient content of N-P2O5-K2O of ≥4%; and the inorganic fertilizer is at least one of diammonium phosphate, potassium dihydrogen phosphate, and zinc sulfate.

5. A use of the rice husk charcoal modified substrate for multi-mode rice seedling cultivation according to any one of claims 1 to 4, characterized in that: The rice husk charcoal modified matrix is ​​used for pot tray seedling cultivation or blanket tray seedling cultivation in a moist seedling cultivation mode and a dry seedling cultivation mode.

6. The use of the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 5, characterized in that: The matrix used in the pot tray seedling raising in the wet seedling raising mode includes modified rice husk charcoal and organic fertilizer; the mass ratio of the modified rice husk charcoal to the organic fertilizer is 80-90:10-20.

7. The use of the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 5, characterized in that: The matrix used in the blanket tray seedling raising in the wet seedling raising mode includes modified rice husk charcoal, peat soil and organic fertilizer; the mass ratio of the modified rice husk charcoal, peat soil and organic fertilizer is 1-2:1-2:1-2.

8. The use of the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 5, characterized in that: The matrix used in the blanket tray seedling raising in the dry seedling raising mode includes modified rice husk charcoal, peat soil and organic fertilizer; the mass ratio of the modified rice husk charcoal, peat soil and organic fertilizer is 1-2:1-2:1-2.

9. The use of the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 5, characterized in that: The matrix used in the pot tray seedling raising in the dry seedling raising mode includes modified rice husk charcoal and organic fertilizer; the mass ratio of the modified rice husk charcoal to the organic fertilizer is 1-2:1-2.

10. The use of the rice husk charcoal modified matrix suitable for multi-mode rice seedling cultivation according to claim 5, characterized in that: During the seedling raising process, a mixed solution of ferrous sulfate and ammonium sulfate is sprayed to improve the yellowing problem of leaves; the mass concentration of ferrous sulfate in the mixed solution is 0.1-0.15%, and the mass concentration of ammonium sulfate is 0.1-0.15%.

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