Polysaccharide yeast chelating synergist suitable for fertilizer and application thereof

Abstract

The invention belongs to the technical field of fertilizer synergists, and particularly relates to a polysaccharide yeast chelating synergist suitable for fertilizers and application of the polysaccharide yeast chelating synergist. The polysaccharide yeast chelating synergist suitable for the fertilizer is prepared from the following raw materials in parts by weight: 10 to 25 parts of polyglutamic acid, 1 to 5 parts of zymosan, 8 to 15 parts of modified polyacrylamide, 8 to 12 parts of sodium humate, 1 to 5 parts of trace elements, 5 to 10 parts of filler and 6 to 10 parts of organic acid. By adding the modified polyacrylamide, the zymosan, the filler and other components into the polyglutamic acid, the fertilizer retention capacity and slow release performance of the fertilizer are effectively improved, and the yield and quality of crops are further improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fertilizer synergist, and particularly relates to a polysaccharide yeast chelation synergist suitable for fertilizer and application thereof. BACKGROUND

[0002] The average utilization rate of chemical fertilizer in China is only about 33%, which is far lower than the world average level, and has brought about serious problems such as resource waste, environmental pollution and decline of agricultural product quality. The main reasons for the low utilization rate of chemical fertilizer include two aspects: one is that the nutrients are fixed or transformed into a form difficult to be absorbed by soil. For example, the cation nutrients (such as Ca 2+ , Mg 2+ , etc.) in the fertilizer are easy to generate insoluble precipitates with acid ions in the soil; at the same time, the phosphorus element is also easy to be adsorbed or fixed by soil colloids to form invalid nutrients, so that crops cannot absorb and utilize them. The other is that the nutrients are decomposed too fast in the soil and are lost in various ways. For example, nitrogen fertilizer (such as urea) is decomposed relatively fast in the soil, and NH4 + is easy to be lost by volatilization, and NO3 - is easy to be leached into groundwater or lost in the form of gas by denitrification, thereby causing the utilization efficiency of nitrogen fertilizer to decrease significantly.

[0003] The application of suitable fertilizer synergist can effectively improve the utilization rate of fertilizer, which is one of the important ways to realize fertilizer reduction and efficiency increase. Polyglutamic acid not only has good chelating capacity and water holding capacity, but also has the effect of regulating plant growth, and is therefore widely used in fertilizer synergist. However, polyglutamic acid has defects such as limited fertilizer retention capacity and insufficient slow-release performance, and it is difficult to effectively prolong the release period of fertilizer nutrients, so that the utilization rate of fertilizer is still not ideal. On the other hand, in order to improve the utilization rate of nitrogen, the existing technology relies on the addition of urease inhibitors and nitrification inhibitors, but such components generally have the limitations of short effective time, easy volatilization and difficulty in stable existence in solid fertilizer. Therefore, it is of great significance to improve polyglutamic acid synergist for improving the utilization efficiency of chemical fertilizer and reducing the cost of chemical fertilizer application in agricultural production in view of the above problems. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the primary purpose of the present application is to provide a polysaccharide yeast chelation synergist suitable for fertilizer.

[0005] Another purpose of the present application is to provide an application of the above-mentioned polysaccharide yeast chelation synergist suitable for fertilizer. The polysaccharide yeast chelation synergist is applied in combination with fertilizer, which can effectively improve the fertilizer retention capacity and slow-release performance of the fertilizer, and further improve the yield and quality of crops.

[0006] The purpose of the present application is realized by the following technical solutions: The polysaccharide yeast chelation synergist for fertilizer comprises the following raw materials in parts by weight: polyglutamic acid 10-25 parts, yeast polysaccharide 1-5 parts, modified polyacrylamide 8-15 parts, humic acid sodium 8-12 parts, trace elements 1-5 parts, filler 5-10 parts and organic acid 6-10 parts; The modified polyacrylamide is prepared by the following preparation process: (1) 4-propenylthiosemicarbazide, 4-(trichloromethyl) benzoyl chloride and N,N-diisopropyl ethylamine are added into tetrahydrofuran for reaction at room temperature; after the reaction is completed, the functional monomer is obtained through purification; The structural formula of the functional monomer is: (2) In an inert gas atmosphere, acrylamide and the functional monomer are added into dimethyl sulfoxide, and then an initiator is added for reaction under heating; after the reaction is completed, the modified polyacrylamide is obtained through purification.

[0007] Further, in step (1), the molar ratio of 4-propenylthiosemicarbazide, 4-(trichloromethyl) benzoyl chloride and N,N-diisopropyl ethylamine is 1:(1.1-1.2):(1.1-1.5); the reaction time at room temperature is 5-8 h.

[0008] Further, in step (2), the molar ratio of acrylamide and the functional monomer is (8-9):(1-2), and the amount of the initiator is 1-3 wt% of the total mass of acrylamide and the functional monomer; the initiator is azobisisobutyronitrile; the heating temperature is 50-60℃, and the reaction time is 6-10 h.

[0009] Further, the filler is prepared by the following preparation process: (a) Montmorillonite is ultrasonically dispersed in an ethanol aqueous solution, and then γ-aminopropyl triethoxysilane and triethylamine are added for reaction under heating, followed by filtration, washing, drying to obtain aminated montmorillonite; (b) The aminated montmorillonite is ultrasonically dispersed in water, and then P1,P2-di(1-imidazolyl) pyrophosphate disodium salt is added, and the solution pH is adjusted to 8.0-8.5 for reaction under heating, followed by filtration, washing, drying to obtain the filler.

[0010] Further, in step (a), the mass ratio of montmorillonite, γ-aminopropyl triethoxysilane and triethylamine is 1:(0.4-0.5):(0.0005-0.015); the volume fraction of the ethanol aqueous solution is 50-60%; the heating temperature is 50-60℃, and the reaction time is 6-9 h.

[0011] Further, the mass ratio of the amino montmorillonite and the P1, P2-dimethyl-1-imidazole pyrophosphate disodium in step (b) is 1: (0.6-0.8); the heating temperature is 45-50 DEG C, and the reaction time is 5-8 h.

[0012] Further, the yeast polysaccharide is prepared by the following preparation process: ① After drying and crushing corn particles, 1-1.5 times of distilled water is added to mix evenly, and after sterilization, yeast bacterial liquid is inoculated, and static culture is carried out at 30-35 DEG C for 2.5-3 d to obtain a yeast exopolysaccharide fermentation broth; ② The yeast exopolysaccharide fermentation broth is centrifuged, and the supernatant is taken, 3-5% trichloroacetic acid is added to stir for 30-45 min, and then centrifuged, and the supernatant is taken, and 3-4 times of ethanol is added to stand for 24 h, and then centrifuged and collected, and then distilled water is dialyzed, and freeze-dried to obtain the yeast polysaccharide.

[0013] Further, the yeast bacterial liquid in step ① has a concentration of 1.0*10 8 CFU / mL of saccharomyces cerevisiae bacterial liquid, and the inoculation amount is 10-12%.

[0014] Further, the molecular weight of the polyglutamic acid is 800-1500 kDa; the trace element is at least one of magnesium sulfate, zinc sulfate, borax and ferric sulfate; and the organic acid is at least one of oxalic acid, citric acid and malic acid.

[0015] The application of the above-mentioned polysaccharide yeast chelation synergist suitable for fertilizers is used for application with fertilizers, and the addition amount of the synergist is 0.5-2% of the dry matter mass of the fertilizer.

[0016] The present application has the following effects relative to the prior art: 1. The present application provides a polysaccharide yeast chelation synergist suitable for fertilizers, which effectively improves the fertilizer retention capacity and slow-release performance of the fertilizer by adding modified polyacrylamide and yeast polysaccharide to polyglutamic acid. Modified polyacrylamide and yeast polysaccharide have good film-forming properties, can be wrapped on the surface of fertilizer particles to form a protective film, reduce the volatilization of nitrogen fertilizer and the leaching and runoff loss of nitrogen fertilizer, and achieve the slow-release effect of the fertilizer; in addition, yeast polysaccharide can regulate the soil microbial community structure, promote the proliferation of beneficial bacteria such as bacillus, inhibit the activity of nitrifying bacteria, and reduce the loss of nitrogen transformation; at the same time, it can also compete with the degradation enzyme to prolong the residence time of polyglutamic acid in the soil, and further improve the fertilizer retention capacity and slow-release performance of the fertilizer.

[0017] 2. The polyacrylamide is modified by copolymerization of functional monomers, and trichloromethyl and thioureyl groups are introduced. The active substances (such as CHCl3) produced by the degradation of trichloromethyl in the soil can inhibit nitrification and delay the conversion of ammonium nitrogen to nitrate nitrogen, thereby reducing the decomposition and loss of nitrogen fertilizer; and the thioureyl group is an excellent ligand, and the sulfur atom and nitrogen atom thereof have strong lone pair electrons, which can chelate with potassium ions, ammonium ions and trace elements (such as Ca 2+ , Mg 2+ , etc.), fix and retain the cations in the fertilizer, and prevent them from being fixed by the soil or leaching loss. The synergistic effect of the two further improves the fertilizer retention capacity of the synergist.

[0018] 3. The modified montmorillonite is also added as a filler in the polysaccharide yeast chelation synergist of the present application, and phosphoric acid groups and imidazole groups are introduced by modification. The phosphoric acid groups not only can chelate with cationic nutrients (such as K + , NH4 + , Ca 2+ , etc.) in the fertilizer to reduce the loss, but also can gradually release phosphorus elements as a slow-release phosphorus source, thereby improving the utilization efficiency of phosphorus fertilizer; and the imidazole group has certain bactericidal property, which can reduce soil-borne bacterial / fungal diseases, help to improve the growth and health status of crops, and further improve the yield and quality of crops. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The FT-IR graph of the filler in Example 1 of the present application. DETAILED DESCRIPTION

[0020] The technical solutions of the present application are further described below in combination with specific embodiments. However, those skilled in the art should understand that the following examples are only used to illustrate the present application, and should not be regarded as limiting the present application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, such as those not specifically mentioned, are conventional products obtained through market channels.

[0021] The preservation number of the Saccharomyces cerevisiae in the examples and comparative examples of the present application is CGMCC No. 2.1539, and the molecular weight of the polyglutamic acid is 800-1500 kDa.

[0022] Example 1 Example 1 provides a polysaccharide yeast chelation synergist suitable for fertilizer, which comprises the following raw materials in parts by weight: polyglutamic acid 18 parts, yeast polysaccharide 3 parts, modified polyacrylamide 10 parts, sodium humate 10 parts, magnesium sulfate 2 parts, zinc sulfate 2 parts, filler 8 parts and oxalic acid 8 parts.

[0023] The above modified polyacrylamide is prepared by the following preparation process: (1) 4-propenylthiosemicarbazide (5 mmol), 4-(trichloromethyl)benzoyl chloride (5.8 mmol) and N,N-diisopropylethylamine (5.8 mmol) were added into tetrahydrofuran (25 mL), after reaction at room temperature for 6 h, the reaction was quenched by adding water, extracted with ethyl acetate, the obtained organic phase was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation to obtain the functional monomer (yield 93%).

[0024] The reaction process is as follows: The above functional monomer is 1 H NMR(C 12 H 12 N3OSCl3, 400 MHz, d6-DMSO) δ 10.4(s, 1H),8.35 (s, 1H), 8.02-7.99 (m, 2H), 7.84-7.81(m, 3H), 5.86-5.81 (m, 1H), 5.21-5.17 (dd, 1H), 5.07-5.01 (dd, 1H), 4.15-4.12 (d, 2H); HRMS (ESI + ): [M+H] + Calculated 351.98, found 351.98.

[0025] (2) Acrylamide (8.5 mmol) and the above functional monomer (1.5 mmol) were dissolved in dimethyl sulfoxide (20 mL) under nitrogen protection, an initiator azobisisobutyronitrile (0.03 g) was added, and the reaction was carried out at 55°C for 8 h; the reaction solution was cooled to room temperature, and then dialyzed against deionized water and freeze-dried to obtain the modified polyacrylamide.

[0026] The above filler was prepared by the following preparation process: (a) Montmorillonite (6 g) was ultrasonically dispersed in a 50% volume fraction of an ethanol aqueous solution (130 mL), γ-aminopropyltriethoxysilane (2.7 g) and triethylamine (0.04 g) were added, and the reaction was carried out at 55°C for 7 h, then the product was collected by filtration, washed with anhydrous ethanol and deionized water in sequence, and dried under vacuum to obtain the aminated montmorillonite.

[0027] (b) The above aminated montmorillonite (3 g) was ultrasonically dispersed in distilled water (90 mL), P1,P2-di(1-imidazolyl)pyrophosphoric acid disodium salt (2.1 g) was added and dissolved, then the pH was adjusted to 8.2 with 1M NaOH solution, and the reaction was carried out at 45°C for 6 h, then the product was collected by filtration, washed with distilled water, and dried under vacuum to obtain the filler. The reaction process is as follows: .

[0028] The FT-IR diagram of the filler is shown in Figure 1 Figure 1, 2 correspond to montmorillonite and filler respectively. Compared with montmorillonite, the filler (modified montmorillonite) appears characteristic absorption peaks of methyl and methylene on γ-aminopropyl triethoxysilane at 2940 cm -1 , 2885 cm -1 , characteristic absorption peaks of N-H and P=O at 1643 cm -1 , 1245 cm -1 , indicating that the modification of montmorillonite is successful.

[0029] The above yeast polysaccharide is prepared by the following preparation process: ① After drying and crushing corn particles, 1.2 times the amount of distilled water is added to mix evenly and sterilize, then yeast cell liquid with a concentration of 1.0 x 10 8 CFU / mL is inoculated at an inoculation amount of 10%, and the mixture is statically cultured at 32°C for 2.5 days to obtain a fermentation broth of yeast cell exopolysaccharide; ② The fermentation broth obtained in step ① is centrifuged, and the supernatant is taken. After stirring for 40 min with a final concentration of 4% trichloroacetic acid, the supernatant is taken after centrifugation. After 3 times the volume of anhydrous ethanol is added and left for 24 h, the precipitate is collected after centrifugation, and the yeast polysaccharide is obtained after dialysis with distilled water and freeze-drying.

[0030] This embodiment 1 also provides a preparation method of the above-mentioned polysaccharide yeast chelation synergist suitable for fertilizer, and the specific steps are as follows: According to the above weight fraction, the polyglutamic acid, magnesium sulfate and zinc sulfate are mixed and stirred evenly, then the modified polyacrylamide and yeast polysaccharide are added and stirred evenly, then the mixture is heated to 55°C in a water bath, the sodium humate and oxalic acid are added and stirred for 25 min, and finally the filler is added and stirred for 50 min, and then cooled to room temperature.

[0031] Example 2 Example 2 provides a polysaccharide yeast chelation synergist suitable for fertilizer, which comprises the following raw materials in weight fractions: polyglutamic acid 10 parts, yeast polysaccharide 1 part, modified polyacrylamide 8 parts, sodium humate 8 parts, magnesium sulfate 0.5 parts, iron sulfate 0.5 parts, filler 5 parts and citric acid 6 parts.

[0032] The above-mentioned modified polyacrylamide is prepared by the following preparation process: (1) 4-propenylthiosemicarbazide (5 mmol), 4-(trichloromethyl) benzoyl chloride (5.5 mmol) and N,N-diisopropyl ethylamine (5.5 mmol) were added into tetrahydrofuran (20 mL), and after reaction at room temperature for 5 h, the reaction was quenched with water, extracted with ethyl acetate, and the obtained organic phase was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation to obtain the functional monomer (yield 91%); the functional monomer was characterized by 1 H NMR and HRMS results were consistent with Example 1.

[0033] (2) Acrylamide (8 mmol) and the above functional monomer (1 mmol) were dissolved in dimethyl sulfoxide (15 mL) under nitrogen protection, and an initiator azobisisobutyronitrile (0.0092 g) was added, and the reaction was carried out at 50°C for 10 h; the reaction solution was cooled to room temperature, and after dialysis with deionized water and freeze-drying, the modified polyacrylamide was obtained.

[0034] The filler was prepared by the following preparation process: (a) Montmorillonite (6 g) was ultrasonically dispersed in a 60% volume fraction of an ethanol aqueous solution (125 mL), and γ-aminopropyl triethoxysilane (2.4 g) and triethylamine (0.003 g) were added, and the reaction was carried out at 50°C for 9 h, and the collected product was washed with anhydrous ethanol and deionized water in sequence, and vacuum dried to obtain aminated montmorillonite.

[0035] (b) The above aminated montmorillonite (3 g) was ultrasonically dispersed in distilled water (80 mL), and disodium P1, P2-di(1-imidazolyl) pyrophosphate (1.8 g) was added and dissolved, and then the pH was adjusted to 8.0 with 1M NaOH solution, and then the reaction was carried out at 45°C for 8 h, and the collected product was washed with distilled water and vacuum dried to obtain the filler.

[0036] The yeast polysaccharide was prepared by the following preparation process: ① Corn particles were dried and crushed, and then mixed with 1 times the amount of distilled water, sterilized, and then inoculated with a yeast cell liquid with a concentration of 1.0 × 10 8 CFU / mL at an inoculation amount of 10%, and then incubated at 30°C for 3 d to obtain a fermentation liquid of yeast cell exopolysaccharide; ② The fermentation liquid obtained in step 1 was centrifuged, and the supernatant was taken, and then 3% trichloroacetic acid was added and stirred for 30 min, and then centrifuged, and the supernatant was taken, and then 3 times the volume of anhydrous ethanol was added and stood for 24 h, and then centrifuged and the precipitate was collected, and then dialyzed with distilled water and freeze-dried to obtain the yeast polysaccharide.

[0037] The embodiment 2 also provides a preparation method of the polysaccharide and yeast chelating synergist suitable for the fertilizer. According to the above weight parts, the polyglutamic acid, the magnesium sulfate and the ferric sulfate are mixed and stirred uniformly, the modified polyacrylamide and the yeast polysaccharide are added and stirred uniformly, then the mixture is heated to 50°C in a water bath, the sodium humate and the citric acid are stirred for 20 min, finally the filler is added and stirred for 45 min, and the mixture is cooled to room temperature.

[0038] Embodiment 3 The embodiment 3 provides a polysaccharide and yeast chelating synergist suitable for the fertilizer, which comprises the following raw materials in parts by weight: 25 parts of polyglutamic acid, 5 parts of yeast polysaccharide, 15 parts of modified polyacrylamide, 12 parts of sodium humate, 3 parts of zinc sulfate, 2 parts of borax, 10 parts of filler, 5 parts of citric acid and 5 parts of malic acid.

[0039] The modified polyacrylamide is prepared by the following preparation process: (1) 4-propenylthiosemicarbazide (5 mmol), 4-(trichloromethyl) benzoyl chloride (6 mmol) and N, N-diisopropyl ethylamine (7.5 mmol) are added into tetrahydrofuran (25 mL), and after reaction at room temperature for 8 h, the reaction is quenched by adding water, and the obtained organic phase is washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporation, to obtain a functional monomer (yield 92%); the functional monomer has the following structure: 1 The results of H NMR and HRMS are consistent with those of the embodiment 1.

[0040] (2) Acrylamide (9 mmol) and the functional monomer (2 mmol) are dissolved in dimethyl sulfoxide (20 mL) under nitrogen protection, an initiator azobisisobutyronitrile (0.0402 g) is added, and the mixture is reacted at 60°C for 6 h; after the reaction liquid is cooled to room temperature, it is dialyzed with deionized water and freeze-dried, to obtain the modified polyacrylamide.

[0041] The filler is prepared by the following preparation process: (a) Montmorillonite (6 g) is ultrasonically dispersed in an ethanol aqueous solution (150 mL) with a volume fraction of 60%, γ-aminopropyl triethoxysilane (3 g) and triethylamine (0.09 g) are added, and the mixture is reacted at 60°C for 6 h, then filtered, and the collected product is washed with anhydrous ethanol and deionized water in sequence, and vacuum dried, to obtain aminated montmorillonite.

[0042] (b) The above amino montmorillonite (3 g) was ultrasonically dispersed in distilled water (100 mL), and P1, P2-di(1-imidazolyl) pyrophosphate disodium salt (2.4 g) was added to dissolve completely. Then, the pH was adjusted to 8.5 with 1M NaOH solution, and the mixture was reacted at 50°C for 5 h. The product was collected by filtration, washed with distilled water, and dried under vacuum to obtain the filler.

[0043] The above yeast polysaccharide was prepared by the following process: ① The corn particles were dried and crushed, and then mixed with 1.5 times the amount of distilled water, sterilized, and inoculated with a yeast liquid with a concentration of 1.0 x 10 8 CFU / mL at an inoculation amount of 10%, and then incubated at 35°C for 2.5 d to obtain a fermentation liquid of yeast exopolysaccharide; ② The fermentation liquid obtained in step ① was centrifuged, and the supernatant was taken. Trichloroacetic acid was added to a final concentration of 5%, and the mixture was stirred for 45 min. Then, the mixture was centrifuged, and the supernatant was taken. Four times the volume of anhydrous ethanol was added, and the mixture was allowed to stand for 24 h. Then, the mixture was centrifuged, and the precipitate was collected. The precipitate was dialyzed against distilled water and freeze-dried to obtain the yeast polysaccharide.

[0044] The present embodiment 3 also provides a preparation method of the above polysaccharide yeast chelating synergist suitable for fertilizers, and the specific steps are as follows: The raw materials were taken according to the above weight fractions. The polyglutamic acid, zinc sulfate, and borax were mixed and stirred uniformly. Then, the modified polyacrylamide and yeast polysaccharide were added and stirred uniformly. Then, the mixture was heated to 60°C in a water bath. The sodium humate, citric acid, and malic acid were added and stirred for 30 min. Finally, the filler was added and stirred for 60 min. The mixture was cooled to room temperature.

[0045] Comparative Example 1 The present comparative example 1 is basically the same as embodiment 1, except that the modified polyacrylamide in embodiment 1 is replaced by acrylamide.

[0046] Comparative Example 2 The present comparative example 2 is basically the same as embodiment 1, except that the filler in embodiment 1 is replaced by montmorillonite.

[0047] Test Example 1 In order to verify the effect of the synergists obtained in embodiments 1-3 and comparative examples 1-2 on crop yield, the following test was conducted: Rice was selected for a plot test. The test design had 6 treatment groups, three repetitions, and a plot area of 24 m 2 . The 6 treatment groups were as follows: (1) control group: only compound fertilizer (N:P:K=20:15:10) 450 kg / hm 2(2) Example 1-3 and Comparative Example 1-2 group: simultaneously applying compound fertilizer and each group of synergist 450 kg / hm 2 , wherein the added amount of the synergist is 0.5 wt% of the compound fertilizer. Each plot of the test is randomly arranged, four weeks are set as protection rows, all fertilizers are applied as base fertilizer for one-time fertilization, no topdressing is performed in the later period, and only natural precipitation is relied on; after the corn matures, each index is tested, and the specific results are shown in Table 1, wherein the yield increase is the yield increase of Example 1-3 group or Comparative Example 1-2 group compared with the control group.

[0048] Table 1 Influence of each treatment group on the yield of rice As shown in Table 1, compared with the ordinary compound fertilizer of the control group, the compound fertilizer added with the polysaccharide yeast chelate synergist of Example 1-3 group of the application can significantly increase the effective ear number, thousand-grain weight and yield of rice, and the maximum yield increase is 21.0%; compared with Example 1, the yield increase effect of Comparative Example 1-2 group decreases.

[0049] Test Example 2 In order to verify the effect of the synergist obtained in Example 1-3 and Comparative Example 1-2 on improving the fertilizer utilization rate, the following test is performed: 1. Corn is taken as the test object to perform plot test, seven treatment groups are designed, three times of repetition, and the plot area is 30 m 2 , and the seven treatment groups are (1) blank group: no fertilizer is applied; (2) control group: only compound fertilizer (N: P: K = 15: 15: 15) 500 kg / hm 2 is applied; (3) Example 1-3 and Comparative Example 1-2 group: simultaneously applying compound fertilizer and each group of synergist 500 kg / hm 2 , wherein the added amount of the synergist is 2 wt% of the compound fertilizer. Each plot of the test is randomly arranged, four weeks are set as protection rows, all fertilizers are applied as base fertilizer for one-time fertilization, no topdressing is performed in the later period, and only natural precipitation is relied on, and after the corn matures, relevant index test is performed, and the specific results are shown in Table 2.

[0050] 2. After the corn is harvested, the biomass of each aboveground plant is measured, and the nitrogen content of the plant is measured, the utilization rate is calculated by measuring the nitrogen absorption amount of the corn in the blank no-fertilizer treatment, the nitrogen fertilizer utilization rate = (nitrogen absorption amount of corn in fertilization area - nitrogen absorption amount of corn in no-fertilization area) / nitrogen application amount x 100%; the phosphorus fertilizer utilization rate = (phosphorus absorption amount of corn in fertilization area - phosphorus absorption amount of corn in no-fertilization area) / phosphorus application amount x 100%; the potassium fertilizer utilization rate = (potassium absorption amount of corn in fertilization area - potassium absorption amount of corn in no-fertilization area) / potassium application amount x 100%, and the results are shown in Table 3.

[0051] Table 2 Influence of each treatment group on the growth characteristics and yield of corn The results of Table 2 show that the compound fertilizers of the polysaccharide yeast chelation synergist of Examples 1-3 can promote the development of corn and have obvious promoting effect on the plant height and ear length of corn. In the comparative example 1, the modified polyacrylamide in the synergist is replaced by acrylamide, and in the comparative example 2, the filler in the synergist is replaced by unmodified montmorillonite, and the yield-increasing effect is not as good as that of Example 1.

[0052] Table 3 Fertilizer utilization rate of each treatment group As can be seen from Table 3, compared with the control group using ordinary compound fertilizer, the compound fertilizers of Examples 1-3 added with the polysaccharide yeast chelation synergist of the application can promote the absorption of nitrogen, phosphorus and potassium elements and significantly improve the utilization rate of nitrogen, phosphorus and potassium elements by crops.

[0053] Compared with Example 1, the effect of comparative examples 1-2 decreases obviously, which shows the importance of modified polyacrylamide and modified montmorillonite in the synergist. In the application, the polyacrylamide is modified by copolymerization of functional monomers, and trichloromethyl and thioureyl groups are introduced. The active substances (such as CHCl3) produced by the degradation of trichloromethyl in the soil can inhibit nitrification and delay the conversion of ammonium nitrogen to nitrate nitrogen, thereby reducing the decomposition and loss of nitrogen fertilizer. The thioureyl group is an excellent ligand, and the sulfur and nitrogen atoms have strong lone pair electrons, which can chelate with potassium ions, ammonium ions and trace elements (such as Ca 2+ , Mg 2+ , etc.), fix and keep the cations in the fertilizer, and prevent them from being fixed or leaching loss in the soil. The synergistic effect of the two further improves the fertilizer retention capacity of the synergist. In addition, the surface of the montmorillonite is modified to introduce phosphate groups and imidazole groups. The phosphate groups not only can fix the cation nutrients (such as K + , NH4 + , Ca 2+ , etc.) in the fertilizer through chelation and reduce the loss, but also can gradually release phosphorus elements as a slow-release phosphorus source, thereby improving the utilization efficiency of phosphorus fertilizer. The imidazole group has certain bactericidal property and can reduce soil-borne bacterial / fungal diseases, which helps to improve the growth and health status of crops and further improves the yield and quality of crops.

[0054] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the application, but not to limit them. The basic principles and main features of the application have been described above with specific embodiments, and some modifications or replacements can be made on the basis of the application, but these modifications or replacements do not make the corresponding technical solutions deviate from the scope of the application.

Claims

1. A polysaccharide yeast chelate synergist suitable for use in fertilizers, characterized in that, Raw materials including polyglutamic acid 10-25 parts, yeast polysaccharide 1-5 parts, modified polyacrylamide 8-15 parts, humic acid sodium 8-12 parts, trace elements 1-5 parts, filler 5-10 parts and organic acid 6-10 parts by weight are included. The modified polyacrylamide is prepared by the following preparation process: (1) 4-propenylthiosemicarbazide, 4-(trichloromethyl) benzoyl chloride and N,N-diisopropyl ethylamine are added into tetrahydrofuran, and reacted at room temperature; after the reaction is completed, the functional monomer is obtained by purification; The structure of the functional monomer is: (2) Acrylamide and the functional monomer are added into dimethyl sulfoxide under an inert gas atmosphere, and then an initiator is added, and the reaction is carried out under heating; after the reaction is completed, the modified polyacrylamide is obtained by purification.

2. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 1, characterized in that, In step (1), the molar ratio of 4-propenylthiosemicarbazide, 4-(trichloromethyl) benzoyl chloride and N,N-diisopropyl ethylamine is 1:(1.1-1.2):(1.1-1.5); the reaction time at room temperature is 5-8 h.

3. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 1, characterized in that, In step (2), the molar ratio of acrylamide and the functional monomer is (8-9):(1-2), and the amount of the initiator is 1-3 wt% of the total mass of acrylamide and the functional monomer; the initiator is azobisisobutyronitrile; the heating temperature is 50-60℃, and the reaction time is 6-10 h.

4. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 1, characterized in that, The filler is prepared by the following preparation process: (a) Montmorillonite is ultrasonically dispersed in an aqueous ethanol solution, and then γ-aminopropyl triethoxysilane and triethylamine are added, and the reaction is carried out under heating, and then filtration, washing and drying are carried out to obtain aminated montmorillonite; (b) The aminated montmorillonite is ultrasonically dispersed in water, and then P1, P2-di(1-imidazolyl) pyrophosphate disodium salt is added, and the pH of the solution is adjusted to 8.0-8.5, and then the reaction is carried out under heating, and then filtration, washing and drying are carried out to obtain the filler.

5. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 4, characterized in that, In step (a), the mass ratio of montmorillonite, γ-aminopropyl triethoxysilane and triethylamine is 1:(0.4-0.5):(0.0005-0.015); the volume fraction of the aqueous ethanol solution is 50-60%; the heating temperature is 50-60℃, and the reaction time is 6-9 h.

6. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 4, characterized in that, In step (b), the mass ratio of the aminated montmorillonite and P1, P2-di(1-imidazolyl) pyrophosphate disodium salt is 1:(0.6-0.8); the heating temperature is 45-50℃, and the reaction time is 5-8 h.

7. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 1, characterized in that, The yeast polysaccharide is prepared by the following preparation process: ① After corn particles are dried and crushed, 1-1.5 times the amount of distilled water is added and mixed uniformly, and then sterilized and inoculated with yeast bacterial liquid, and then incubated at 30-35℃ for 2.5-3 d to obtain a fermentation liquor of yeast bacterial extracellular polysaccharide; ② The fermentation liquor of yeast bacterial extracellular polysaccharide is centrifuged, and then the supernatant is taken, and then 3-5% trichloroacetic acid is added and stirred for 30-45 min, and then centrifuged and the supernatant is taken, and then 3-4 times the volume of ethanol is added and left to stand for 24 h, and then centrifuged and the precipitate is collected, and then distilled water dialysis and freeze-drying are carried out to obtain the yeast polysaccharide.

8. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 7, characterized in that, The yeast liquid in step 1 has a concentration of 1.0 x 10 8 CFU / mL of Saccharomyces cerevisiae, and the inoculation amount is 10-12%.

9. The polysaccharide yeast chelate synergist suitable for use in fertilizers according to claim 1, characterized in that, The polyglutamic acid has a molecular weight of 800-1500 kDa; the trace element is at least one of magnesium sulfate, zinc sulfate, borax, and iron sulfate; and the organic acid is at least one of oxalic acid, citric acid, and malic acid.

10. Use of a polysaccharide yeast chelate synergist according to any one of claims 1 to 9 for a fertilizer, characterized in that, The synergist is added in an amount of 0.5-2% of the dry matter mass of the fertilizer for application in combination with the fertilizer.

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