Water-soluble fertilizer stable release agent as well as preparation method and application thereof

Abstract

The invention discloses a water-soluble fertilizer stable release agent as well as a preparation method and application thereof, and relates to the technical field of water-soluble fertilizer.By adding stable release agent components into corresponding water-soluble fertilizers, nutrient release is controlled, nutrient absorption of crops is promoted, multiple biological enzymes are activated, and the water-soluble fertilizer stable release agent has the advantages that the water-soluble fertilizer stable release agent has a stable release effect; therefore, the effects of directional effect taking, slow release, high efficiency and scientific absorption are achieved. The water-soluble fertilizer has the characteristics of slow and scientific release, high crop absorption rate and no secondary harm after long-term use, and has a relatively good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field related to water-soluble fertilizers, and particularly relates to a water-soluble fertilizer sustained-release agent, a preparation method thereof, and an application thereof. Background Art

[0002] Soil secondary salinization is a kind of damage to the soil that occurs along with the utilization of the soil by humans, and it mainly occurs in the large-scale use of chemical fertilizers. After water-soluble fertilizers were discovered for their characteristics of water-saving and rapid effectiveness, their applications have developed rapidly in recent years. However, with the improvement of water solubility, the problems of salinization and soil compaction caused by water-soluble fertilizers have become increasingly serious.

[0003] Water-soluble fertilizers are efficient but can cause secondary salinization of the soil. The reasons can be attributed to the following three points: ① The contradiction between the concentrated release of nutrients and the inability of crops to absorb them quickly results in the loss of nutrients with soil moisture; ② Water follows air, and salts are left when air goes, combined with climatic conditions, resulting in low utilization efficiency of water-soluble fertilizers in the dry season; ③ The cumulative effect caused by multiple plantings in a single year enhances soil secondary salinization.

[0004] The methods to solve secondary salinization generally include two types: one is to apply organic fertilizers for soil improvement, maintain a certain nutrient balance, and reduce the harm of salinization to crops. However, this method has a slow effect, and with the process of water-fertilizer integration, soil secondary salinization will continue to deteriorate; the other is soil rotation and planting green manure to rest the land, but this method is not advisable and does not give practitioners enough time for soil restoration. To sum up, agricultural scientific and technical personnel urgently need to develop a fertilizer with high utilization rate, but this fertilizer will not cause serious secondary salinization problems due to excessive use, so as to achieve the effect of soil restoration during the planting process. Summary of the Invention

[0005] In view of the above situation, to overcome the defects of the prior art, the present invention provides a water-soluble fertilizer sustained-release agent, a preparation method thereof, and an application thereof. The water-soluble fertilizer sustained-release agent involved is added to the water-soluble fertilizer in a certain proportion to control the release of nutrients in the water-soluble fertilizer, promote the absorption of nutrients in the water-soluble fertilizer by crops, improve the utilization rate of nutrients in the water-soluble fertilizer by crops, activate and enhance the microbial activity and the content of organic matter in the soil, and further prevent or improve soil secondary salinization caused by the application of water-soluble fertilizers.

[0006] Specifically, the present invention is achieved through the following solutions: In the first aspect, the present invention provides a water-soluble fertilizer sustained-release agent, which includes an ion exchanger, a grid-like organic dispersion substance, and a single-lattice ion sustained-release agent, and the mass ratio of the ion exchanger, the grid-like organic dispersion substance, and the single-lattice ion sustained-release agent is 1:2.4:(1.6 - 2.4).

[0007] Preferably, the ion exchanger is the magnesium salt of aspartic acid - maleic acid copolymer, the grid - like organic dispersant is polyaspartic acid amine, and the single - lattice ion sustained - release agent is a complex of biochemical fulvic acid and oligopeptide.

[0008] In the second aspect, the present invention provides a method for preparing the water - soluble fertilizer sustained - release agent described in the first aspect above. The magnesium salt of aspartic acid - maleic acid copolymer is formed by copolymerizing the monomers of aspartic acid - maleic acid copolymer formed by the amidation reaction of magnesium aspartate and magnesium maleate; the polyaspartic acid amine is prepared by urea / ethanolamine modification of polyaspartic acid; in the single - lattice ion sustained - release agent, the mass ratio of biochemical fulvic acid to oligopeptide is 4:1, where the oligopeptide is prepared by enzymatic hydrolysis of corn as raw material and has a molecular weight of 1 - 2 KD; the water - soluble fertilizer sustained - release agent is prepared by mixing the ion exchanger, the grid - like organic dispersant and the single - lattice ion sustained - release agent according to a predetermined mass ratio.

[0009] Among them, the magnesium salt of aspartic acid - maleic acid copolymer as the ion exchanger is formed by an ionic reaction of magnesium aspartate and magnesium maleate in an equimolar amount in a high - temperature solution. The carboxyl group of maleic acid and the amino group of aspartic acid ionized at high temperature undergo an amidation reaction to form the copolymer monomer of aspartic acid - maleic acid copolymer; the monomer continues to react under high - temperature conditions to form the magnesium salt of aspartic acid - maleic acid copolymer; the ratio of aspartic acid to maleic acid (M / M) is 1:1; the amidation temperature is 70 - 80 °C for 1 - 3 h; the copolymerization temperature is 190 - 210 °C for 2 h. The grid - like organic dispersant polyaspartic acid amine is a urea or ethanolamine modified product of polyaspartic acid; its preparation principle is as follows: the intermediate poly(succinimide) undergoes partial ring - opening in an alkaline organic amine and ammonia water system to form a polyaspartic acid system with a non - completely hydrolyzed state and a cyclic structure; the molar ratio of the organic amine to ammonia water is 1:1; the reaction conditions are: the material addition temperature is 60 - 65 °C; the heat - preservation conditions are: temperature 90 - 95 °C, 1 h. The preparation scheme of the single - lattice ion sustained - release agent is as follows: 200 g of biochemical fulvic acid and 50 g of corn oligopeptide are mixed evenly and then pulverized at 3000 - 5000 r / min for 5 min to obtain it.

[0010] In the third aspect, the present invention proposes a water - soluble fertilizer for preventing / ameliorating soil secondary salinization, which includes the water - soluble fertilizer sustained - release agent proposed in the first aspect above. The water - soluble fertilizer sustained - release agent is added to the water - soluble fertilizer production process at a ratio of 2.9 - 5.0 kg / T, and then the water - soluble fertilizer for preventing secondary salinization is obtained.

[0011] In the fourth aspect, the present invention proposes the application of the water - soluble fertilizer sustained - release agent proposed in the first aspect above or the water - soluble fertilizer for preventing / ameliorating soil secondary salinization proposed in the third aspect above in preventing and / or ameliorating soil secondary salinization.

[0012] In the water-soluble fertilizer slow-release agent, the magnesium salt of aspartic acid-maleic acid copolymer is used as an ion exchange agent. By repeatedly forming double salts with the water-soluble cation and anion nutrients in the water-soluble fertilizer and soil, the nutrient loss is slowed down and the utilization rate is enhanced; polyaspartic acid amide reduces the loss by repeatedly forming chelated substances with the water-soluble cation and small molecule organic matter nutrients in the water-soluble fertilizer and soil; the complex of biochemical fulvic acid and oligopeptide stimulates root growth, improves the crop's demand for nutrients, and enhances the crop's hunger, thereby increasing the utilization rate of nutrients, and provides small molecule organic matter as a substance directly absorbed by plants. On the basis of ensuring the crop nutrients, the crop can make full use of the nutrients in the water-soluble fertilizer and soil.

[0013] On the premise of the above action mechanism, the water-soluble fertilizer slow-release agent proposed in the fourth aspect or the water-soluble fertilizer added with the water-soluble fertilizer slow-release agent, when applied to the soil, can improve the microbial activity in the soil and increase the organic matter in the soil.

[0014] In the fifth aspect, the present invention proposes a method for improving / preventing soil secondary salinization formed by applying water-soluble fertilizer, and the method includes adding a predetermined proportion of water-soluble fertilizer slow-release agent to the applied water-soluble fertilizer or applying a water-soluble fertilizer for preventing soil secondary salinization.

[0015] The present invention has the following beneficial effects compared with the prior art: In the above water-soluble fertilizer slow-release agent, the action sites of the ion exchange agent are water-soluble cation and anion nutrients. By repeatedly forming double salts, their loss is slowed down, and the utilization time of crops is extended, thereby enhancing the nutrient utilization rate in the water-soluble fertilizer; the grid-like organic dispersion substance, whose action sites are water-soluble cation nutrients and small molecule organic matter nutrients, reduces their loss by repeatedly forming chelated substances (nutrient aggregates), promotes the slow release of nutrients, and reduces nutrient loss; the single crystal lattice ion slow-release agent continuously attacks the nutrient aggregates in the soil, so that the nutrients bound to it are released through ion exchange to provide different ions for crop use, stimulates root growth, improves the crop's demand for nutrients, and enhances the crop's hunger, thereby promoting the improvement of nutrient utilization rate, and provides small molecule organic matter as a substance directly absorbed by crops; through relevant experiments, it is proved that the above three substances work together to reduce the secondary salinization caused by nutrient loss. When added to the water-soluble fertilizer according to a predetermined amount, the nutrients in the water-soluble fertilizer can be fully utilized. Adding the water-soluble fertilizer slow-release agent and cooperating with organic fertilizer to supply the nutrients absorbed by plants in the soil can effectively reduce secondary salinization, improve the soil, and realize the sustainability of the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0017] Figure 1 This is a comparison chart before and after the determination of catalase activity in soils of different groups in Application Example 1 of the present invention; the upper figure is before treatment, and the lower figure is after treatment; Figure 2 This is a comparison chart before and after the determination of alkaline phosphatase activity in soils of different groups in Application Example 1 of the present invention; the upper figure is before treatment, and the lower figure is after treatment; Figure 3 This is a comparison chart before and after the determination of urease activity in soils of different groups in Application Example 1 of the present invention; the upper figure is before treatment, and the lower figure is after treatment. Detailed implementation manners

[0018] The present invention discloses a water-soluble fertilizer slow-release agent, its preparation method and application. Those skilled in the art can draw on the content of this article and appropriately improve the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all regarded as included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. Relevant personnel can obviously make changes or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Example 1

[0019] A preparation method of a water-soluble fertilizer slow-release agent and a water-soluble fertilizer for preventing secondary salinization of soil proposed in this embodiment includes the following steps: Step 1, preparation of an ion exchanger; Step 1, preparation of magnesium salt of aspartic acid-fumaric acid copolymer as an ion exchanger The preparation scheme is as follows: Dissolve 30 g of magnesium aspartate and 26.70 g of magnesium fumarate in 160 g of water; after complete dissolution, keep the temperature at 75 °C for 2 h to carry out an amidation reaction to form a copolymer monomer; evaporate the free water of the above solution to near dryness at 150 °C, raise the temperature to 200 °C and polymerize for 2 h, then grind and reserve to obtain the magnesium salt A of aspartic acid-fumaric acid copolymer as the ion exchanger.

[0020] Step 2, preparation of grid-like organic dispersant polyaspartic acid amine (modified with ethanolamine); The preparation scheme is as follows: 49 g of polysuccinimide and 150 g of water form a highly dispersed suspension system through high-speed shearing; slowly drop 21.25 g of 20% mass concentration ammonia water into the suspension system; after completion, add 30.5 g of 50% ethanolamine solution at one time, and control the temperature at 65 °C; after completion, raise the temperature to 90 °C and keep it warm for 1 h, pay attention to sealing; after completion, evaporate the water to dryness, pulverize and reserve; to obtain the above grid-like organic dispersant polyaspartic acid amine A.

[0021] Step 3: Preparation of single lattice ion sustained release agent; The preparation scheme is as follows: 200 g of biochemical fulvic acid and 50 g of corn oligopeptide are mixed evenly and then pulverized at 3000 - 5000 r / min for 5 min to obtain.

[0022] Step 4: The ion exchanger A, the grid-like organic dispersant A, and the single lattice ion sustained release agent prepared in Step 1, Step 2, and Step 3 are mixed according to a mass ratio of 1:2.4:2.0 to obtain the sustained release agent A.

[0023] Step 5: The sustained release agent A is added to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 4.0 kg / T, and the water-soluble fertilizer I for preventing soil secondary salinization is obtained. Example 2

[0024] A preparation method of a water-soluble fertilizer sustained release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: Step 1: Preparation of magnesium salt of aspartic acid - maleic acid copolymer as ion exchanger; The preparation scheme is as follows: 30 g of magnesium aspartate and 26.70 g of magnesium maleate are dissolved in 160 g of water; after dissolution, it is kept at 70 °C for 3 h to undergo amidation reaction to form copolymer monomers; the above solution is evaporated to near dryness of free water at 150 °C, the temperature is raised to 195 °C and polymerized for 2 h, and then ground for standby, and the magnesium salt B of aspartic acid - maleic acid copolymer as the ion exchanger is obtained.

[0025] Step 2: Preparation of grid-like organic dispersant polyaspartic acid amine (urea modified); The preparation scheme is as follows: 49 g of polysuccinimide and 150 g of water are sheared at high speed to form a highly dispersed suspension system; 21.25 g of 20% mass concentration ammonia water is slowly added dropwise to the suspension system, and after completion, 30 g of 50% urea solution is added at one time, the temperature is controlled at 60 °C, and after completion, the temperature is raised to 95 °C and kept warm for 1 h, pay attention to sealing; after completion, the water is evaporated to dryness and pulverized for standby; the above grid-like organic dispersant polyaspartic acid amine B is obtained.

[0026] Step 3: Preparation of single lattice ion sustained release agent; The preparation scheme is the same as that in Example 1.

[0027] Step 4: The ion exchanger, the grid-like organic dispersant, and the single lattice ion sustained release agent prepared in Step 1, Step 2, and Step 3 are mixed according to a mass ratio of 1:2.4:2.4 to obtain the sustained release agent B.

[0028] Step 5: Add the sustained-release agent B to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 5.0 kg / T to obtain the water-soluble fertilizer II for preventing soil secondary salinization. Example 3

[0029] A preparation method of a water-soluble fertilizer sustained-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: The preparation schemes of Steps 1-3 are the same as those in Example 1.

[0030] Step 4: Mix the ion exchanger A, the grid-like organic dispersion substance A, and the single-lattice ion sustained-release agent prepared in Steps 1, 2, and 3 in a mass ratio of 1:2.4:1.6 to obtain the sustained-release agent C.

[0031] Step 5: Add the sustained-release agent C to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 2.9 kg / T to obtain the water-soluble fertilizer III for preventing soil secondary salinization. Example 4

[0032] A preparation method of a water-soluble fertilizer sustained-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: The ion preparation schemes of Steps 1-3 are the same as those in Example 2.

[0033] Step 4: Mix the ion exchanger B, the grid-like organic dispersion substance B, and the single-lattice ion sustained-release agent prepared in Steps 1, 2, and 3 in a mass ratio of 1:2.4:1.6 to obtain the sustained-release agent D.

[0034] Step 5: Add the sustained-release agent D to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 2.9 kg / T to obtain the water-soluble fertilizer IV for preventing soil secondary salinization.

[0035] Comparative Example 1 A preparation method of a water-soluble fertilizer sustained-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: Steps 1-2: The ion exchanger A and the grid-like organic dispersion substance A are the same as those in Example 1, and there is no preparation and application of the single-lattice ion sustained-release agent.

[0036] Step 3: Mix the ion exchanger A and the grid-like organic dispersion substance A prepared in Steps 1 and 2 in a mass ratio of 1:2.4 to obtain the sustained-release agent A1.

[0037] Step 4: Add the sustained-release agent A1 to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 4.0 kg / T to obtain the water-soluble fertilizer V for preventing soil secondary salinization.

[0038] Comparative Example 2 A method for preparing a water-soluble fertilizer slow-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: Steps 1-2: The ion exchanger A and the single-crystal lattice ion slow-release agent are the same as those in Example 1. The preparation and application of the gridless organic dispersant polyaspartic acid amine (modified with ethanolamine) are carried out.

[0039] Step 3: The ion exchanger A and the single-crystal lattice ion slow-release agent prepared in Steps 1 and 2 are mixed in a mass ratio of 1:2.0 to obtain the slow-release agent A2.

[0040] Step 4: The slow-release agent A2 is added to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 4.0 kg / T to obtain the water-soluble fertilizer VI for preventing soil secondary salinization.

[0041] Comparative Example 3 A method for preparing a water-soluble fertilizer slow-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: Steps 1-2: The preparation of the grid-like organic dispersant polyaspartic acid amine A (modified with ethanolamine) and the single-crystal lattice ion slow-release agent are the same as those in Example 1. The preparation and application of the magnesium salt of the ion exchanger aspartic acid-fumaric acid copolymer are not carried out.

[0042] Step 3: The grid-like organic dispersant polyaspartic acid amine A and the single-crystal lattice ion slow-release agent prepared in Steps 1 and 2 are mixed in a mass ratio of 1:2.0 to obtain the slow-release agent A3.

[0043] Step 4: The slow-release agent A3 is added to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 4.0 kg / T to obtain the water-soluble fertilizer VII for preventing soil secondary salinization.

[0044] Comparative Example 4 A method for preparing a water-soluble fertilizer slow-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this example includes the following steps: Step 1: The preparation of the magnesium salt of the ion exchanger aspartic acid-fumaric acid copolymer is the same as that in Example 1; Step 2: The commercially available 3.5% polyglutamic acid is used to replace the grid-like organic dispersant polyaspartic acid amine (modified with ethanolamine).

[0045] Step 3: The preparation of the single-crystal lattice ion slow-release agent is the same as that in Example 1; Step 4: The ion exchanger A, polyglutamic acid, and single-crystal lattice ion slow-release agent prepared in Steps 1, 2, and 3 are mixed in a mass ratio of 1:2.4:2.0 to obtain the slow-release agent A4.

[0046] Step 5: Add the sustained-release agent A to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 4.0 kg / T to obtain the water-soluble fertilizer VIII for preventing soil secondary salinization.

[0047] Comparative Example 5 A preparation method of a water-soluble fertilizer sustained-release agent and a water-soluble fertilizer for preventing soil secondary salinization proposed in this embodiment includes the following steps: Steps 1 to 4 are the same as those in Example 1.

[0048] Step 5: Add the sustained-release agent A to the production process of the 17-17-17 macronutrient water-soluble fertilizer at a ratio of 1.5 kg / T to obtain the water-soluble fertilizer IX for preventing soil secondary salinization.

[0049] The formulations of the above-mentioned various examples and comparative examples are shown in Table 1.

[0050] Table 1: Formulations of each experimental group in Application Example 1.

[0051]

[0052] Application Example 1: Field experiment of water-soluble fertilizer for preventing soil secondary salinization in improving and / or preventing soil secondary salinization.

[0053] Currently, the methods to solve secondary salinization generally involve soil improvement by applying organic fertilizers to maintain a certain nutrient balance and reduce the harm of salinization to crops. Secondly, soil rotation and planting green manure are used to fallow the land. The above methods are all carried out after soil secondary salinization occurs. After the soil is improved, if chemical fertilizers (water-soluble fertilizers) are used again, it will still cause soil secondary salinization again, and the above problems have not been fundamentally solved. In view of the defects of the water-soluble fertilizer itself, the inventor adds a sustained-release agent component to the water-soluble fertilizer, aiming to slow down the release of nutrients in the water-soluble fertilizer, increase the nutrient absorption efficiency of crops, and improve the utilization rate of the water-soluble fertilizer to prevent and improve soil secondary salinization.

[0054] The water-soluble fertilizers prepared according to the above examples and comparative examples were used in a potato field planting experiment to measure the effects of the water-soluble fertilizers on improving and preventing soil salinization. The experiment was carried out in Zhangbei County, Zhangjiakou City, Hebei Province (114°72′ E, 41°16′ N). The total salt content of the selected plot was 0.51%, the organic matter content was 7.40 - 8.10 g / kg, the available nitrogen was 576.62 - 592.36 mg / kg, the available phosphorus was 572 - 603.50 mg / kg, and the available potassium was 2.73 - 3.14 g / kg. It was a slightly saline and low-oxygen soil; the area of each treatment was 20 hm 2, select a flat and uniform plot of land, avoiding adverse environments such as the roadside and manure piles; for fertilizer application, choose organic fertilizer with 30% organic matter content as the base fertilizer, and the application rate is 30 T / hm 2 ; Use the 17-17-17 water-soluble fertilizer produced in Example 1 and Comparative Examples 4-5 as the basal nutrient fertilizer, which are respectively recorded as Experimental Group 1 and Control Groups 1-2; at the same time, set up a 17-17-17 water-soluble fertilizer without any slow-release agent as the blank group, and the application rate is 600 kg / hm 2； , and spray the above water-soluble fertilizer as foliar fertilizer during the growth period, and the application rate is 30 kg / hm 2 / 15d, apply a total of 4 times, avoiding the full-bloom period, and the other plant protection and horticultural conditions are the same; detect relevant soil indicators 5-7 days after potato harvest. Measure the organic matter content, microbial activity, catalase activity, alkaline phosphatase activity, urease activity, etc. in the soil respectively.

[0055] Detection methods for the above indicators: Detect relevant soil indicators 5-7 days after potato harvest. The sampling method is the S method, avoiding the roadside, manure piles, etc.; each treatment in each group is divided into three plots, and 20 sampling points are selected in each plot. The sampling depth at each sampling point is 20 cm, and the sample quality is not less than 500 g; each group uses the quartering method to obtain 3 samples for detection; during the experiment, use the soil respiration intensity - CO2 determination method to detect soil microbial activity, and use the regulations in the soil agrochemical analysis method to determine the soil organic matter content, salt content and N-P2O5-K2O nutrient content. The regulations in the soil enzyme and its research method are used to determine the activities of catalase, alkaline phosphatase and urease. The comprehensive statistical analysis method is used to study the soil effect, and the SPSS12.0 data analysis system is used for one-way analysis of variance and the Dunckan method is used for significant difference test to obtain the soil data results in Table 2.

[0056] Table 2: Effects of adding different slow-release agent components on soil-related indicators.

[0057]

[0058] It can be seen from the measurement results in Table 2 that in terms of soil organic matter, after the application of Experimental Group 1, compared with the blank control group, the organic matter content in the soil increased by 3.90%; while in Control Groups 1 and 2, it increased by 0.40% and 1.21% respectively, showing an obvious gap compared with Experimental Group 1.

[0059] In terms of soil microbial activity, Experimental Group 1 improved the microbial activity significantly, and the effects of the other treatments were significantly different from that of Experimental Group 1; the reason for the analysis is that the action mechanism of the slow-release agent components in Experimental Group 1 balanced the organic matter and various nutrient elements in the soil, thus reducing the impact on the local dominant flora, and this result corresponded to other indicators; In terms of soil enzymes, the activities of catalase and alkaline phosphatase in the soil were significantly increased compared with other groups. At the same time, urease was significantly inhibited, and these trend changes were associated with microbial activity, showing a trend of increasing the holding amounts of nitrogen, phosphorus, and potassium nutrients in the soil, which also coincided with the trend changes of nitrogen, phosphorus, and potassium nutrients. In terms of soil salinity, after applying Experimental Group 1, the soil salinity of the experimental plot also began to change, and the secondary salinization of the soil (represented by the salt content) showed a decreasing trend during the experiment.

[0060] It can be concluded from the above data analysis that the improvement of the above aspects of the soil by Control Group 1 and Control Group 2 was not ideal, which was significantly weaker than that of Experimental Group 1 for the above aspects of the soil. This indicates that the three components of the slow-release agent component have a complementary and synergistic effect on the soil. The slow-release agent component containing three components in a specific proportion is added to the water-soluble fertilizer in a specific proportion, which can slow down the release of nutrients and improve the utilization rate of nutrients, thereby reducing soil secondary salinization. Therefore, applying the water-soluble fertilizer in Experimental Group 1 can effectively improve and prevent soil secondary salinization.

[0061] Application Example 2: Field experiment on improving crop yield with a water-soluble fertilizer for preventing soil secondary salinization.

[0062] The water-soluble fertilizer for preventing soil secondary salinization prevents and improves soil secondary salinization by improving the nutrient absorption efficiency of crops and the utilization rate of the water-soluble fertilizer. Based on this, it is necessary to verify the effects of applying the water-soluble fertilizer of the present application on improving crop yield and so on.

[0063] When applying the water-soluble fertilizer, if the crop has a high nutrient absorption rate, the crop quality and yield should be significantly improved. Therefore, a greenhouse tomato field planting experiment was carried out using the water-soluble fertilizers produced in Examples 1-4 and Comparative Examples 1-5 to verify the effects of the water-soluble fertilizer in greenhouse tomato planting, which were respectively recorded as Experimental Groups 1-4 and Control Groups 1-5, and a treatment of 17-17-17 water-soluble fertilizer without adding a slow-release agent was set as a blank control group. Among them, for each group of fertilizers, organic fertilizers with 30% organic matter content were selected at 37.5 T / hm 2 and 750 kg / hm of 17-17-17 water-soluble fertilizer was applied in combination with each treatment. 2 。

[0064] This experiment was carried out in Gaocheng District, Shijiazhuang City, Hebei Province (114°84′ E, 38°03′ N); the experimental area was of typical cinnamon soil texture, with a soil organic matter content of 1.93%, total nitrogen of 1.23 g / kg, available phosphorus of 31.57 mg / kg, and available potassium of 117.23 mg / kg, being a plot with low organic matter and medium nitrogen, phosphorus, and potassium levels; the experiment adopted a randomized block design, and the application methods were the same, all being basal application of organic fertilizer and drip fertigation with the water-soluble fertilizer, and the area of each treatment was 1000 m 2(An entire greenhouse); The above water-soluble fertilizer was applied 5 times. From the transplanting stage to the harvesting stage, the full-bloom stage was avoided, and the other plant protection and horticultural conditions were the same; After each harvest of greenhouse tomatoes, the yield indicators were counted, and the tomato quality was analyzed (requiring the sample uniformity to be basically the same).

[0065] For the analysis results of the yield and quality of tomatoes, the following detection methods were used: After each harvest of greenhouse tomatoes, the yield indicators were counted, and the tomato quality was analyzed (requiring the sample uniformity to be basically the same); During the experiment, the rate of deformed fruits was investigated at the same time; The soluble solid content was determined by an Abbe refractometer to measure the soluble solid content in the fruits; The fruit organic acid content was determined by the sodium hydroxide titration method; The VC content was determined by the 2,6-dichlorophenol indophenol titration method; The fruit hardness was measured by a GY-2 type hardness tester to measure the hardness of strawberry fruits. The yield and quality effects were studied by the method of comprehensive statistical analysis, and the single-factor variance analysis was carried out using the SPSS12.0 data analysis system and the Dunckan method was used for the significance test of differences to obtain the data results in Table 3.

[0066] Table 3: Comparison of the analysis results of tomato yield and quality.

[0067]

[0068] In terms of yield, after applying the water-soluble fertilizers of Experimental Groups 1-4, the tomato yield was significantly higher than that of Comparative Groups 1-5 and the control group (blank); It shows that the water-soluble fertilizers of each treatment in the experimental group can significantly increase the tomato yield; In terms of quality, after applying the water-soluble fertilizers of Experimental Groups 1-4, the soluble solids, Vc content, and fruit hardness of tomatoes were all significantly increased, and at the same time, the organic acid content was also significantly decreased. It can be known that applying the water-soluble fertilizers of the experimental group can improve the tomato quality; The above results prove that applying the water-soluble fertilizers of each experimental group can make tomatoes achieve the effect of improving both yield and quality, ensuring that the nutrients of greenhouse tomatoes can be supplemented in a timely manner during the entire growth process. In addition, although there are no accurate survey data, the descriptions of vegetable farmers can also show that there are indeed significant changes in the fruit setting rate, fruit uniformity, and size of greenhouse tomatoes.

[0069] In addition to the above content, the inventor also found that the incidence of tomato basal stem rot was also different among different treatments in the experimental field. A rough investigation found that the comprehensive incidence rate decreased by about 7%. This should be related to the more balanced nutrients after the use of the water-soluble fertilizers in each experimental group, the good supplement of calcium, and the promotion of the thickening of the stems due to the nutrient balance, which comprehensively led to the reduction of tomato basal stem rot disease.

[0070] In combination with the above embodiments, when the sustained-release agent component in the water-soluble fertilizer of the present application comprises magnesium salt of aspartic acid-fumaric acid copolymer, urea or ethanolamine modified product of polyaspartic acid, and a complex of biochemical fulvic acid and oligopeptide (mass ratio 4:1), and the mass ratio is 1:2.4:(1.6 - 2.4), the water-soluble fertilizer prepared by adding it to the corresponding water-soluble fertilizer production process at a ratio of 2.9 - 5.0 kg / T can be used to prevent and improve soil secondary salinization, indicating that the present invention has good application prospects.

[0071] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A water-soluble fertilizer sustained-release agent, characterized in that, It includes an ion exchanger, a grid-like organic dispersant, and a single-crystal lattice ion sustained-release agent, and the mass ratio of the ion exchanger, the grid-like organic dispersant, and the single-crystal lattice ion sustained-release agent is 1:2.4:(1.6 - 2.4).

2. The water-soluble fertilizer sustained release agent according to claim 1, wherein, The ion exchanger is the magnesium salt of aspartic acid-fumaric acid copolymer, the grid-like organic dispersant is polyaspartic acid amine, and the single-crystal lattice ion sustained-release agent is a complex of biochemical fulvic acid and oligopeptide.

3. The water-soluble fertilizer sustained release agent according to claim 2, characterized in that The magnesium salt of aspartic acid-fumaric acid copolymer is formed by copolymerizing the monomers of aspartic acid-fumaric acid copolymer formed by the amidation reaction of magnesium aspartate and magnesium fumarate.

4. The water-soluble fertilizer sustained release agent according to claim 2, wherein The polyaspartic acid amine is prepared by modifying polyaspartic acid with urea / ethanolamine.

5. The water-soluble fertilizer sustained release agent according to claim 2, wherein, In the single-crystal lattice ion sustained-release agent, the mass ratio of biochemical fulvic acid to oligopeptide is 4:1, and the oligopeptide is prepared by enzymatic hydrolysis of corn as raw material with a molecular weight of 1 - 2 KD.

6. The water-soluble fertilizer sustained release agent according to claim 1, wherein The water-soluble fertilizer sustained-release agent is prepared by mixing the ion exchanger, the grid-like organic dispersant, and the single-crystal lattice ion sustained-release agent according to a predetermined mass ratio.

7. A water-soluble fertilizer for preventing secondary salinization of soil, characterized in that, It includes the water-soluble fertilizer sustained-release agent according to any one of claims 1 - 6, and the water-soluble fertilizer sustained-release agent is added to the water-soluble fertilizer production process at a ratio of 2.9 - 5.0 kg / T, and then the water-soluble fertilizer for preventing secondary salinization is obtained.

8. Use of the water-soluble fertilizer sustained-release agent according to any one of claims 1 - 6 or the water-soluble fertilizer for preventing soil secondary salinization according to claim 7 in preventing and / or improving soil secondary salinization.

9. The application according to claim 8, wherein The prevention and / or improvement of soil secondary salinization includes at least one of the following two aspects: (a) Enhancing soil microbial activity; (b) Enhancing the organic matter content in the soil.

10. A method for improving / preventing soil secondary salinization formed by applying water-soluble fertilizer, characterized in that, The method includes adding the water-soluble fertilizer sustained-release agent according to any one of claims 1 - 6 in a predetermined proportion to the applied water-soluble fertilizer or applying the water-soluble fertilizer for preventing soil secondary salinization according to claim 7.

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