A water-soluble fertilizer based on nanocomposite hydrogel and preparation method thereof

Abstract

The invention discloses a water-soluble fertilizer based on a nano-composite hydrogel and a preparation method thereof. The water-soluble fertilizer is prepared from 25-35 parts of the nano-composite hydrogel, 20-35 parts of ammonium sulfate, 35-55 parts of potassium dihydrogen phosphate, 0.5-1.5 parts of gibberellins, 1-3 parts of chelated medium elements and 1-3 parts of chelated trace elements as raw materials. By introducing carboxylated mushroom residue cellulose nanofibers, the water solubility and stability of the water-soluble fertilizer can be improved, which is beneficial for crops to better absorb and utilize nutrients in the soil. The nano-composite hydrogel prepared by using the carboxylated mushroom residue cellulose nanofibers and nanoemulsion significantly improves the swelling performance and water retention performance of the water-soluble fertilizer. Applying the water-soluble fertilizer based on the nano-composite hydrogel can significantly improve the plant height, the number of pods, the 100-grain weight and the yield of the crops.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizers, and in particular to a water-soluble fertilizer based on nanocomposite hydrogel and a preparation method thereof. Background Art

[0002] Water-soluble fertilizer is a fast-acting fertilizer that can be completely dissolved in water and directly absorbed and utilized by the roots and leaves of crops. Compared with traditional compound fertilizers, water-soluble fertilizers have the advantages of comprehensive nutrients, fast absorption, high utilization rate, and easy use. Therefore, they have been widely used in modern agricultural production.

[0003] However, the water-soluble fertilizers disclosed in the current related technologies have low water retention performance and are difficult to fully play their role under conditions of drought or poor soil water retention capacity. Summary of the invention

[0004] The technical task of the present invention is to address the above shortcomings and provide a water-soluble fertilizer based on nanocomposite hydrogel and a preparation method thereof, which has the advantages of high water retention performance and significantly increased plant height, pod number, 100-grain weight and yield of crops.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A water-soluble fertilizer based on nanocomposite hydrogel is prepared from 25-35 parts of nanocomposite hydrogel, 20-35 parts of ammonium sulfate, 35-55 parts of potassium dihydrogen phosphate, 0.5-1.5 parts of gibberellins, 1-3 parts of chelated medium elements and 1-3 parts of chelated trace elements as raw materials.

[0007] In some embodiments, the nanocomposite hydrogel is prepared from 2.5-5 parts of carboxylated mushroom residue cellulose nanofibers, 2.5-5 parts of nanoemulsion, 2 parts of epichlorohydrin and 100 parts of deionized water as raw materials.

[0008] In some embodiments, the nanocomposite hydrogel is prepared from 2.5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nanoemulsion, and 2 parts of epichlorohydrin as raw materials.

[0009] In some embodiments, the nanocomposite hydrogel is prepared from 5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nanoemulsion, and 2 parts of epichlorohydrin as raw materials.

[0010] In some embodiments, the nanocomposite hydrogel is prepared from 5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nanoemulsion, and 2.5 parts of epichlorohydrin as raw materials.

[0011] In some embodiments, the carboxylated mushroom residue cellulose nanofibers are prepared from mushroom residue fibers, 2,2,6,6-tetramethylpiperidinium oxide, sodium bromide and 10% sodium hypochlorite as raw materials. The specific preparation method is as follows: mushroom residue fibers, 2,2,6,6-tetramethylpiperidinium oxide, sodium bromide and 10% sodium hypochlorite are mixed, stirred at 25°C and 500rpm for 1.5h, 0.5M sodium hydroxide is used to adjust the pH to a constant 10.0, filtered and washed, and then centrifuged at 10000rpm and 4°C for 30min, the precipitate after centrifugation is freeze-dried at -25°C for 3h, and crushed to obtain the carboxylated mushroom residue cellulose nanofibers, wherein the ratio of the added amounts of mushroom residue fibers, 2,2,6,6-tetramethylpiperidinium oxide, sodium bromide and 10% sodium hypochlorite is 5g:1.6g:10g:500ml.

[0012] In some embodiments, the nanoemulsion is prepared from microalgae oil, Tween 80, anhydrous ethanol and deionized water as raw materials. The specific preparation method is as follows: 0.15 parts of microalgae oil, 1.5 parts of Tween 80, 1.5 parts of anhydrous ethanol and 96.85 parts of deionized water are mixed, emulsified for 30 minutes at 25±2°C and 500rpm with a magnetic stirrer, and the nanoemulsion is obtained after ultrasonic oscillation for 20 minutes.

[0013] In some embodiments, the preparation method of the mushroom residue fiber is as follows: dissolve the mushroom residue in deionized water, stir for 10 minutes under a constant temperature magnetic stirrer at 200°C and 500rpm, then add 2% sodium chlorite solution, bleach at 80°C for 2 hours, adjust the pH to 4.0, filter and collect the residue, wash the residue with deionized water until the pH is 7.0, dry and crush to obtain the mushroom residue fiber, wherein the ratio of the added amount of mushroom residue, deionized water and 2% sodium chlorite solution is 1g:20ml:20ml.

[0014] In some embodiments, the chelated secondary elements are chelated magnesium and chelated calcium, with a mass ratio of 1:1; the chelated trace elements are chelated boron, chelated zinc, and chelated iron, with a mass ratio of 1:2:1.

[0015] In some embodiments, the method comprises the following steps: dissolving the carboxylated mushroom residue cellulose nanofibers in deionized water, stirring evenly at 80°C, adding the epichlorohydrin, continuing stirring under a magnetic stirrer, then adding the nanoemulsion and stirring evenly, standing at room temperature for 2 hours, washing with deionized water for 3 to 5 times, and freeze-drying at -25°C for 12 hours to obtain a nanocomposite hydrogel; dissolving ammonium sulfate, potassium dihydrogen phosphate, chelated medium elements, chelated trace elements, and gibberellin in deionized water, stirring at 35°C for 15 minutes, then adding the nanocomposite hydrogel and stirring thoroughly, freeze-drying at -20°C for 24 hours, and crushing to obtain a water-soluble fertilizer based on the nanocomposite hydrogel.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are:

[0017] By introducing carboxylated mushroom residue cellulose nanofibers, the water solubility and stability of water-soluble fertilizers can be improved, which is beneficial for crops to better absorb and utilize nutrients in the soil; the nanocomposite hydrogel prepared using carboxylated mushroom residue cellulose nanofibers and nanoemulsion significantly improves the swelling and water retention properties of water-soluble fertilizers; the application of water-soluble fertilizers based on nanocomposite hydrogels can significantly increase the plant height, number of pods, 100-grain weight and yield of crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is an electron micrograph of the ultrastructure of the nanocomposite hydrogel prepared in Example 2 of the present application.

[0020] Figure 2 This is a schematic diagram of the preparation method of this application. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] Embodiment 1:

[0024] (1) Preparation of mushroom residue fiber

[0025] Dissolve 25 g of mushroom residue in 500 ml of deionized water, stir for 10 min under a constant temperature magnetic stirrer at 200 ° C and 500 rpm, then add 500 ml of 2% sodium chlorite solution, bleach at 80 ° C for 2 h, adjust the pH to 4.0, filter and collect the residue, wash the residue with deionized water until the pH is 7.0, and then dry and crush to obtain mushroom residue fiber.

[0026] (2) Preparation of carboxylated mushroom residue cellulose nanofibers

[0027] 5 g of mushroom residue fiber, 1.6 g of 2,2,6,6-tetramethylpiperidinium oxide, 10 g of sodium bromide and 500 ml of 10% sodium hypochlorite were mixed, stirred at 25°C and 500 rpm for 1.5 h, 0.5 M sodium hydroxide was used to adjust the pH to 10.0, filtered and washed, and centrifuged at 10000 rpm and 4°C for 30 min. The precipitate after centrifugation was freeze-dried at -25°C for 3 h and crushed to obtain carboxylated mushroom residue cellulose nanofibers.

[0028] (3) Preparation of nanoemulsion

[0029] 0.15 parts of microalgae oil, 1.5 parts of Tween 80, 1.5 parts of anhydrous ethanol and 96.85 parts of deionized water were mixed, emulsified for 30 minutes at 25±2°C and 500 rpm with a magnetic stirrer, and then subjected to ultrasonic oscillation for 20 minutes to obtain a nanoemulsion.

[0030] (4) Preparation of nanocomposite hydrogel

[0031] Dissolve 2.5 parts of carboxylated mushroom residue cellulose nanofibers in 100 parts of deionized water, stir evenly at 80°C, add 2 parts of epichlorohydrin, continue stirring under a magnetic stirrer, then add 5 parts of nanoemulsion and stir evenly, let stand at room temperature for 2 hours, wash with deionized water 3 to 5 times, and freeze-dry at -25°C for 12 hours to obtain a nanocomposite hydrogel.

[0032] Embodiment 2:

[0033] The difference from Example 1 is that the added amount of carboxylated mushroom residue cellulose nanofibers is 5 parts, and the rest is the same as Example 1, which will not be repeated here.

[0034] Embodiment 3:

[0035] The difference from Example 1 is that the added amounts of carboxylated mushroom residue cellulose nanofibers and nanoemulsion are 5 parts and 2.5 parts respectively, and the rest are the same as Example 1 and will not be described again here.

[0036] The swelling performance and water retention performance of the nanocomposite hydrogel prepared in Examples 1-3 were analyzed by the following specific methods:

[0037] Analysis of the swelling performance of nanocomposite hydrogels: Weigh the same mass of nanocomposite hydrogels in each group, dry them at 40°C and weigh them, which is recorded as m0 (g). Then, immerse the dried nanocomposite hydrogels completely in deionized water to allow them to swell fully. Use filter paper to absorb the water on the surface of the swollen hydrogels and weigh them, which is recorded as m1 (g). Three parallels are used in each group. Swelling rate (SR) calculation formula:

[0038]

[0039] In vitro water retention performance of nanocomposite hydrogels: Weigh the same mass of hydrogels in swelling equilibrium in each group in a culture dish, recorded as m1 (g), and weigh the weight of the hydrogels after placing them in a constant temperature and humidity environment at 25°C for 12 hours, recorded as m (g), with three parallels in each group. Water retention rate (WR) calculation formula:

[0040]

[0041] Water holding performance of nanocomposite hydrogel in soil: 50g of dry sandy soil and the same mass of hydrogel were weighed in a 250mL beaker, recorded as M1 (g), and then 30mL of deionized water was added. After being placed in a constant temperature and humidity environment at 25℃ for 12h, the beaker was weighed, recorded as M2 (g). Each group of experiments was conducted in triplicate. Soil water holding rate (WH) calculation formula:

[0042]

[0043] Table 1 shows the results of the analysis of the swelling performance and water retention performance of the nanocomposite hydrogel. It can be seen from Table 1 that the swelling rate, water retention rate and soil water retention rate of the nanocomposite hydrogel prepared in Example 2 are significantly higher than those in Example 1 and Example 3. The improvement of the swelling rate lays a good foundation for the subsequent water retention and soil water retention performance. It can more effectively retain water in an in vitro environment, further enhancing the ability to bind water. At the same time, the hydrogel has better compatibility and interaction with the soil, and can more efficiently regulate the soil moisture condition. Figure 1 The ultrastructure electron microscopic image of the nanocomposite hydrogel prepared in Example 2 is shown. The nanocomposite hydrogel has a relatively tight network and relatively small and uniform pores.

[0044] Table 1 Nanocomposite hydrogel performance analysis results (P < 0.05)

[0045]

[0046] Embodiment 4:

[0047] The nanocomposite hydrogel prepared in Example 2 is used to prepare a water-soluble fertilizer, and the specific steps are as follows:

[0048] 24 parts of ammonium sulfate, 50 parts of potassium dihydrogen phosphate, 0.5 parts of chelated magnesium, 0.5 parts of chelated calcium, 0.75 parts of chelated boron, 1.5 parts of chelated zinc, 0.75 parts of chelated iron and 1 part of gibberellin were dissolved in deionized water, stirred at 35°C for 15 minutes, then 25 parts of the nanocomposite hydrogel prepared in Example 2 were added, stirred thoroughly, freeze-dried at -20°C for 24 hours, and crushed to obtain a water-soluble fertilizer based on the nanocomposite hydrogel.

[0049] Embodiment 5:

[0050] 28 parts of ammonium sulfate, 45 parts of potassium dihydrogen phosphate, 1.5 parts of chelated medium elements, 2 parts of chelated trace elements, and 1.5 parts of gibberellins were dissolved in deionized water, and 30 parts of the nanocomposite hydrogel prepared in Example 2 were added after stirring. The other steps were the same as those in Example 4 and will not be repeated here.

[0051] Embodiment 6:

[0052] 20 parts of ammonium sulfate, 55 parts of potassium dihydrogen phosphate, 2 parts of chelated medium elements, 1 part of chelated trace elements, and 1 part of gibberellin were dissolved in deionized water, and 30 parts of the nanocomposite hydrogel prepared in Example 2 were added after stirring. The other steps were the same as those in Example 4 and will not be repeated here.

[0053] Embodiment 7:

[0054] 32 parts of ammonium sulfate, 40 parts of potassium dihydrogen phosphate, 2.5 parts of chelated medium elements, 1 part of chelated trace elements, and 0.5 parts of gibberellin were dissolved in deionized water, and 35 parts of the nanocomposite hydrogel prepared in Example 2 were added after stirring. The other steps were the same as those in Example 4 and will not be repeated here.

[0055] Embodiment 8:

[0056] 35 parts of ammonium sulfate, 35 parts of potassium dihydrogen phosphate, 3 parts of chelated medium elements, 1 part of chelated trace elements, and 1 part of gibberellin were dissolved in deionized water, and 25 parts of the nanocomposite hydrogel prepared in Example 2 were added after stirring. The other steps were the same as those in Example 4 and will not be repeated here.

[0057] This application takes soybean crop planting as an example, and the water-soluble fertilizer prepared in Examples 4-8 is applied to the soil planted with soybean crops. The experiment was conducted in Hailun, Heilongjiang. The experiment set up 5 treatment groups and 1 control group, with 1 group per mu, 11 ridges in each group, ridge length 100m, and ridge width 0.6m. During the experiment, except for the different fertilizer composition ratios, the rest of the management was the same. Spraying was carried out in a manner of dissolving 60g of fertilizer per mu in 2L of clean water, and the control group only sprayed 2L of clean water per mu.

[0058] After the planting experiment, the plant height, pod number, 100-grain weight and yield of the crops were measured. Among them, the plant height was measured by selecting 3 plants from each ridge in each group before the soybean matures and is harvested, and the vertical measurement is made from the base of the plant to the highest natural growth point, and the data is recorded and the average is taken; the pod number was measured by selecting 3 plants from each ridge in each group before the soybean matures and is harvested, and the data is recorded and the average is taken; the 100-grain weight was measured by randomly selecting 100 beans from each ridge in each group before the soybean matures and is harvested, and the data is recorded and the average is taken; the yield was measured by randomly selecting 3 ridges of soybeans from each group when the soybeans were harvested, and the average is taken to calculate the yield per mu.

[0059] Table 2 shows the effects of the water-soluble fertilizers prepared in Examples 4-8 on soybean yield indicators. It can be seen from Table 2 that the plant height, number of pods, 100-grain weight and yield of soybeans were significantly improved by applying the water-soluble fertilizers prepared in Examples 4-8 compared with the control group. Among them, Example 6 was significantly higher in plant height, number of pods, 100-grain weight and yield than the other examples. The proportion of each raw material can optimize the soil environment and promote the growth and yield formation of soybeans.

[0060] Table 2 Effects of different fertilization treatments on soybean yield indicators (P<0.05)

[0061]

[0062] Through the above specific implementations, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the above specific implementations. On the basis of the disclosed implementations, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A water-soluble fertilizer based on nanocomposite hydrogel, characterized in that: The water-soluble fertilizer is prepared from 25-35 parts of nano composite hydrogel, 20-35 parts of ammonium sulfate, 35-55 parts of potassium dihydrogen phosphate, 0.5-1.5 parts of gibberellins, 1-3 parts of chelated medium elements and 1-3 parts of chelated trace elements as raw materials.

2. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 1, characterized in that: The nano composite hydrogel is prepared from 2.5-5 parts of carboxylated mushroom residue cellulose nanofibers, 2.5-5 parts of nano emulsion, 2 parts of epichlorohydrin and 100 parts of deionized water as raw materials.

3. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The nanocomposite hydrogel is prepared from 2.5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nanoemulsion and 2 parts of epichlorohydrin as raw materials.

4. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The nano composite hydrogel is prepared from 5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nano emulsion and 2 parts of epichlorohydrin as raw materials.

5. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The nano composite hydrogel is prepared from 5 parts of carboxylated mushroom residue cellulose nanofibers, 5 parts of nano emulsion and 2.5 parts of epichlorohydrin as raw materials.

6. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The carboxylated mushroom residue cellulose nanofibers are prepared from mushroom residue fibers, 2,2,6,6-tetramethylpiperidinyl oxide, sodium bromide and 10% sodium hypochlorite as raw materials, and the specific preparation method is as follows: Mushroom residue fiber, 2,2,6,6-tetramethylpiperidinium oxide, sodium bromide and 10% sodium hypochlorite are mixed, stirred at 25°C and 500rpm for 1.5h, 0.5M sodium hydroxide is used to adjust the pH value to be constant at 10.0, filtered and washed, and then centrifuged at 10000rpm and 4°C for 30min, the precipitate after centrifugation is freeze-dried at -25°C for 3h, and crushed to obtain the carboxylated mushroom residue cellulose nanofibers, wherein the ratio of the added amount of mushroom residue fiber, 2,2,6,6-tetramethylpiperidinium oxide, sodium bromide and 10% sodium hypochlorite is 5g:1.6g:10g:500ml.

7. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The nanoemulsion is prepared from microalgae oil, Tween 80, anhydrous ethanol and deionized water as raw materials, and the specific preparation method is as follows: 0.15 parts of microalgae oil, 1.5 parts of Tween 80, 1.5 parts of anhydrous ethanol and 96.85 parts of deionized water were mixed, emulsified for 30 minutes at 25±2°C and 500 rpm with a magnetic stirrer, and ultrasonically vibrated for 20 minutes to obtain the nanoemulsion.

8. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 6, characterized in that: The preparation method of the mushroom residue fiber is as follows: The mushroom residue is dissolved in deionized water, stirred for 10 minutes under the action of a constant temperature magnetic stirrer at 200°C and 500rpm, then a 2% sodium chlorite solution is added, bleached at 80°C for 2 hours, the pH is adjusted to 4.0, the residue is collected by filtration, the residue is washed with deionized water until the pH is 7.0, and the mushroom residue fiber is obtained after drying and crushing, wherein the added amount ratio of the mushroom residue, deionized water and 2% sodium chlorite solution is 1g:20ml:20ml.

9. A water-soluble fertilizer based on nanocomposite hydrogel according to claim 1, characterized in that: The chelated secondary elements are chelated magnesium and chelated calcium, with a mass ratio of 1:1; the chelated trace elements are chelated boron, chelated zinc and chelated iron, with a mass ratio of 1:2:

1.

10. The method for preparing a water-soluble fertilizer based on nanocomposite hydrogel according to claim 2, characterized in that: The following steps are involved: The carboxylated mushroom residue cellulose nanofibers are dissolved in deionized water, stirred at 80°C, the epichlorohydrin is added, the stirring is continued under a magnetic stirrer, and then the nanoemulsion is added and stirred evenly, the mixture is allowed to stand at room temperature for 2 hours, washed with deionized water for 3 to 5 times, and freeze-dried at -25°C for 12 hours to obtain a nanocomposite hydrogel; Ammonium sulfate, potassium dihydrogen phosphate, chelated medium elements, chelated trace elements and gibberellins are dissolved in deionized water, stirred at 35° C. for 15 minutes, then added with the nanocomposite hydrogel and stirred sufficiently, freeze-dried at -20° C. for 24 hours, and crushed to obtain a water-soluble fertilizer based on the nanocomposite hydrogel.

Images