Liquid fertilizer and its preparation method and application

Abstract

The application belongs to the technical field of agricultural fertilizer, and particularly relates to a liquid fertilizer, a preparation method and application thereof. The application discloses a liquid fertilizer for effectively improving the growth of crops in saline-alkali soil. The liquid fertilizer comprises, in parts by weight, 5-25 parts of polyglutamic acid fermentation liquor, 0-1.5 parts of microbial inoculum, 50-90 parts of plant extract, 5-25 parts of nutrient substance, 0.1-0.3 parts of suspending aid and 0.1-0.3 parts of preservative. The application realizes the breakthrough in the comprehensive performance of the saline-alkali soil improver through the innovative combination of specific components and processes, realizes the biomass growth of crops in saline-alkali soil, and reduces the production cost.

Description

Technical Field

[0001] This invention belongs to the field of agricultural fertilizer technology, specifically relating to a liquid fertilizer, its preparation method, and its application. Background Technology

[0002] Soil salinization has become a major soil degradation problem threatening global food security. Due to soil salinity stress, crops generally face problems such as hindered root water absorption, reduced soil nutrient availability, and disordered plant physiological metabolism, leading to significant inhibition of growth and development and even crop failure. This not only reduces land productivity but also directly challenges arable land preservation and food security. Even more serious is the rapid development of secondary salinization, causing a considerable amount of farmland to degrade or be abandoned due to intensified soil salinization and alkalization.

[0003] While many traditional soil improvement technologies exist to address this issue, they generally suffer from bottlenecks such as high investment, high energy consumption, short-term effectiveness, and difficulty in sustainability. Water conservancy engineering improvements (such as ditching for salt drainage and freshwater salt suppression) are extremely costly and water-intensive, making them unsustainable in areas with scarce freshwater resources and posing a risk of "salinization." Physical improvements (such as topsoil application and deep tillage) involve large-scale engineering projects and high transportation costs, making them suitable only for small-scale applications. Chemical amendments (such as gypsum and desulfurized gypsum) require large quantities, have slow effects, and excessive application can lead to secondary environmental problems such as soil compaction or heavy metal accumulation. Biological improvements (such as planting salt-tolerant plants) have long cycles and slow effects, failing to quickly meet the needs of agricultural production. The combined use of these technologies often results in improvement costs reaching several thousand yuan per acre.

[0004] In contrast, liquid fertilizers offer a simplified and precise new approach to saline-alkali land improvement. Their flexible formulations allow for targeted enhancement of salt-reducing and alkali-suppressing components such as organic acids and biostimulants. Their fully water-soluble nature enables seamless integration with fertigation systems, allowing for precise application to the root zone via drip irrigation or sprinkler irrigation, avoiding the laborious task of trenching. They are fast-acting, highly efficient, delivering nutrients directly to the rhizosphere and distributing evenly with water, saving labor and time. The combination of organic and inorganic components provides immediate relief from salt stress while continuously fostering soil health. Most importantly, liquid fertilizers overcome the limitations of traditional solid fertilizers in saline-alkali soils, which are prone to fixation and difficult to diffuse, enabling a modern operational model of "small amounts, multiple times, and precise control."

[0005] Therefore, developing a specialized liquid fertilizer for saline-alkali land improvement has become a key technological requirement to overcome the bottlenecks of existing technologies, such as high cost, complex operation, and long lead time. This type of fertilizer technology is expected to enable the effective utilization of saline-alkali land resources, which is of great significance for ensuring the reserve of arable land resources, improving comprehensive grain production capacity, and promoting sustainable agricultural development. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a liquid fertilizer, comprising, by weight:

[0007] 5-25 parts polyglutamic acid fermentation broth, 50-90 parts plant extract, 0-1.5 parts microbial agent, 5-25 parts nutrients, 0.1-0.3 parts suspending agent, and 0.1-0.3 parts preservative.

[0008] Furthermore, the liquid fertilizer, by weight, comprises:

[0009] 15-25 parts polyglutamic acid fermentation broth, 50-70 parts plant extract, 0.5-1.5 parts microbial agent, 8-15 parts nutrients, 0.2-0.3 parts suspending agent, and 0.2-0.3 parts preservative.

[0010] Furthermore, the liquid fertilizer, by weight, comprises:

[0011] 15 parts polyglutamic acid fermentation broth, 70 parts plant extract, 0.5 parts microbial agent, 15 parts nutrients, 0.2 parts suspending agent, and 0.2 parts preservative.

[0012] Furthermore, the microbial agent is Bacillus licheniformis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus megaterium; the plant extract is starch biochemical solution, wood vinegar solution, and seaweed solution; the nutrients are urea ammonium nitrate solution and potassium dihydrogen phosphate; the suspending agent is xanthan gum and magnesium aluminum silicate; and the preservative is ascorbic acid.

[0013] Preferably, the microbial agent is Bacillus subtilis, the plant extract is seaweed extract, the nutrient is urea ammonium nitrate solution and potassium dihydrogen phosphate in a mass ratio of 5:3, and the suspending agent is xanthan gum.

[0014] Furthermore, the effective viable count of the Bacillus subtilis is not less than 2 × 10⁻⁶. 11 CFU / g.

[0015] The present invention also provides a method for preparing the liquid fertilizer, wherein the polyglutamic acid fermentation broth, plant extract, nutrients, suspending agent and preservative are mixed evenly according to the formula, and after emulsification, a suspension is formed. Microbial agent is added to the suspension according to the weight parts and mixed evenly to obtain the liquid fertilizer.

[0016] The present invention also provides the application of the liquid fertilizer in the cultivation of crops in saline-alkali land.

[0017] Specifically, for saline-alkali soils or secondary salinized soils, the liquid fertilizer can be diluted 100-1000 times and applied via drip irrigation or fertigation. The application frequency is 1-3 times per growing season, with each application amount (based on the original liquid) being 5-20 kg / mu.

[0018] Preferably, the crop is bok choy or sunflower.

[0019] The advantages of this invention over the prior art are as follows:

[0020] This invention achieves a breakthrough in the comprehensive performance of saline-alkali soil conditioners through an innovative combination of specific components and processes. It employs a synergistic bacterial protection system of seaweed extract and Bacillus subtilis, ensuring a stable viable bacterial count of 10 × 10⁻⁶ bacteria during a 180-day storage period. 8 With a CFU / mL concentration exceeding 96%, the viable bacterial count reached 96%. Using polyglutamic acid fermentation broth to chelate salt ions and seaweed extract to promote root development, the fresh weight of pakchoi in potted plants in saline-alkali soil increased to 6.92 g / plant, and the root length reached 17.73 cm. A low-sedimentation suspension system was constructed using xanthan gum, and ascorbic acid was used for selective antibacterial activity, improving storage stability while ensuring microbial activity. This invention achieves increased crop biomass in saline-alkali land and reduces production costs. Detailed Implementation

[0021] The objectives, technical solutions, and advantages of the present invention will be further described in detail below with reference to specific embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0022] Example 1 Screening of plant extracts and microbial agents

[0023] The basic formula for liquid fertilizer is made by mixing 15 parts by weight of polyglutamic acid fermentation liquid, 70 parts by weight of plant extract, 0.5 parts by weight of microbial agent, and 15 parts by weight of nutrients evenly.

[0024] The polyglutamic acid fermentation broth was produced by Gansu Dabeinong Bioengineering Co., Ltd., with a polyglutamic acid content of 7% and a molecular weight of 80,000-100,000. The polyglutamic acid fermentation broth uses Bacillus licheniformis as the substrate bacteria, and the production process is as follows: Materials are requisitioned and prepared according to the production order; raw and auxiliary materials with qualified particle size are screened, and those that do not are returned. Primary and secondary seed cultures are carried out sequentially. The culture medium is sterilized at 0.10±0.01MPa and 115±2℃ for 25±5min, cooled to 37±2℃ for inoculation, and cultured until the bacterial morphology is normal, free of contaminants, and OD≥4 before transfer. During the fermentation stage, the culture medium and feed solution are sterilized at 0.13±0.05MPa and 125±5℃, and transferred at a 10% inoculation rate. It is cultured for 50-60 hours under specified conditions, including 37±2℃ and tank pressure of 0.02~0.05MPa. After successful fermentation, the product is transferred to the tank. Strict aseptic technique and process parameters are maintained throughout the process to ensure quality traceability.

[0025] The plant extracts were selected from one of the following: starch biochemical solution, wood vinegar solution, and seaweed solution; the microbial agents were selected from one of the following: commercially available Bacillus licheniformis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus megaterium, with an effective viable count of not less than 2 × 10⁻⁶. 11 CFU / g, all strains mentioned above are commercially available products; nutrients are urea ammonium nitrate solution and potassium dihydrogen phosphate in a mass ratio of 5:3. Liquid fertilizers containing different plant extracts and microbial agents were prepared, with other raw materials remaining constant. The changes in the number of viable bacteria in the resulting liquid fertilizers under natural conditions were monitored, and the effects of different plant extracts and microbial agents on potted Chinese cabbage under salt stress were verified.

[0026] Specifically, the raw materials were weighed according to their weight, stirred evenly, and liquid fertilizer was prepared. The number of viable bacteria in the obtained liquid fertilizer was measured, bottled, sealed, and placed under natural conditions. The number of viable bacteria was measured at 30d, 60d, 90d, 120d, 150d, and 180d, and the results are shown in Table 1.

[0027] Table 1 Screening results of agricultural microbial agents

[0028]

[0029] To verify the application effects of liquid fertilizers prepared with different plant extracts and microbial agents, a pot experiment was conducted using Chinese cabbage as the test crop. The pots used were 10cm high and 12cm wide, and the growing medium was a commercial substrate. Chinese cabbage seedlings were raised in plastic seedling trays with the substrate. After one true leaf emerged, healthy seedlings with uniform growth were transplanted. Each treatment was repeated 5 times. On the day of transplanting, each pot was watered with 30mL of water. Fertilizer was applied 2 days after the seedlings had recovered. The tested liquid fertilizer was diluted 300 times, and 50mL of the diluted solution was applied to the roots of each pot. This was repeated every 7 days for a total of 2 applications over a period of 28 days.

[0030] Based on the growth indicators of pak choi (as shown in Table 2), the pak choi in the group with added seaweed extract exhibited the most vigorous growth, the highest above-ground fresh weight, and the longest root system. In comparison, the starch biochemical solution and wood vinegar solutions also showed some effect, but not as significant as the seaweed extract. Considering the results in Tables 1 and 2, Bacillus subtilis was selected as the type of agricultural microbial agent to be added, and seaweed extract was chosen as the optimal choice for plant extract.

[0031] Table 2. Screening results of plant extracts and microbial agents

[0032]

[0033] Example 2: Screening of suspending agents and preservatives

[0034] The basic formula for the liquid fertilizer consists of 15 parts by weight of polyglutamic acid fermentation broth, 70 parts by weight of seaweed extract, 0.5 parts by weight of Bacillus subtilis, and 15 parts by weight of nutrients, all mixed evenly. To optimize product performance, while strictly maintaining the total amount of the above-mentioned basic raw materials and the emulsification preparation method using an emulsifying pump, the types and amounts of suspending agents and preservatives were screened.

[0035] Suspension agent screening: One of xanthan gum (0.2 parts by weight), magnesium aluminum silicate (0.5 parts by weight), polyethylene glycol (2 parts by weight), and sodium carboxymethyl cellulose (0.5 parts by weight) was selected and added to the base fertilizer to prepare four liquid fertilizer samples independently. A blank control group without any additives was also set up. The performance of the suspension agents was evaluated by comparing the dispersibility, sedimentation volume, and viscosity of each group of samples (results are shown in Table 3). At the same time, to evaluate the performance of the preservatives, 0.5 parts by weight of various candidate preservatives (potassium sorbate, sodium benzoate, ascorbic acid, and Kathon) were added to all the above-mentioned fertilizer samples that had undergone suspension treatment (including the four samples containing suspension agents and the blank control group) for testing.

[0036] The number of fungi and the number of viable Bacillus subtilis in each group of samples with added preservatives were determined. Then, the samples were placed in a constant temperature incubator at 37℃ for 14 days. After the culture was completed, the number of fungi and the number of viable Bacillus subtilis in each group of samples were determined again (the results are shown in Table 4). This was to evaluate the preservative effect of different preservatives under different suspension backgrounds and their impact on the activity of the strains.

[0037] Based on the performance indicators of each group of samples in Table 3, 0.2 parts by weight of xanthan gum, when used as a suspending agent, resulted in the best dispersibility, smallest sedimentation volume, and moderate viscosity in the liquid fertilizer, making it the optimal choice for this liquid fertilizer suspending agent.

[0038] Table 4 shows that none of the samples had initial fungal infection before culture. After 14 days of constant temperature culture at 37℃, the total fungal count in all samples with added ascorbic acid remained <10 CFU / mL, while samples with added potassium sorbate, sodium benzoate, and Kathon, as well as the blank control group, all showed varying degrees of fungal growth. The total fungal count in the blank control group reached 87 CFU / mL, indicating that ascorbic acid has a significant inhibitory effect on fungal contamination, and its preservative and antibacterial effects are significantly better than other candidate preservatives. Meanwhile, the viable count retention rate of Bacillus subtilis in samples with added ascorbic acid was over 97%, with virtually no adverse effect on the activity of the target strain; while the viable count retention rate of Bacillus subtilis in samples with added potassium sorbate, Kathon, and sodium benzoate was below 90%, and the viable count retention rate of Bacillus subtilis in samples without added preservatives was below 80%.

[0039] Based on the above results, as shown in Tables 3 and 4, 0.2 parts by weight of xanthan gum and 0.5 parts by weight of ascorbic acid were ultimately selected as the best choices for the suspending agent and preservative of this liquid fertilizer.

[0040] Table 3. Screening results of suspension additives

[0041]

[0042] Table 4 Preservative Screening Results

[0043]

[0044] Example 3

[0045] This embodiment provides a suspension liquid fertilizer that effectively improves crop growth in saline-alkali soil, made from the following raw materials in parts by weight: 15 parts by weight of polyglutamic acid fermentation liquid, 70 parts by weight of plant extract, 0.5 parts by weight of microbial agent, 15 parts by weight of nutrients, 0.2 parts by weight of suspending agent, and 0.2 parts by weight of preservative.

[0046] The plant extract is seaweed extract; the microbial agent is Bacillus subtilis, and the minimum number of viable bacteria in the Bacillus subtilis is 2 × 10⁻⁶. 11 CFU / g; the nutrient is prepared by urea ammonium nitrate solution and potassium dihydrogen phosphate in a mass ratio of 5:3; the suspending agent is xanthan gum; the preservative is ascorbic acid.

[0047] The above-mentioned method for preparing a suspension liquid fertilizer that effectively improves crop growth in saline-alkali soil includes the following steps:

[0048] (1) Add 15 parts by weight of polyglutamic acid fermentation liquid, 70 parts by weight of seaweed liquid and 15 parts by weight of nutrients to the mixing tank in sequence, stirring while adding until uniform;

[0049] (2) Add 0.2 parts by weight of ascorbic acid to the above-mentioned well-mixed liquid raw materials while stirring until uniform;

[0050] (3) Weigh 0.2 parts by weight of xanthan gum and slowly add it to the above mixture while stirring until it is uniform;

[0051] (4) The above mixture is circulated and emulsified for 2 hours using an emulsification pump to obtain a uniform suspension;

[0052] (5) Add the Bacillus subtilis in the specified weight to the above suspension while stirring until uniform, and the suspension fertilizer is obtained.

[0053] Example 4

[0054] The raw materials and quantities used in this embodiment are the same as those in Embodiment 3, the only difference being that the polyglutamic acid fermentation broth is 25 parts by weight and the nutrients are 5 parts by weight.

[0055] Example 5

[0056] The raw materials and quantities used in this embodiment are the same as those in Embodiment 3, the only difference being that: the polyglutamic acid fermentation broth is 5 parts by weight, the seaweed broth is 90 parts by weight, and the nutrients are 5 parts by weight.

[0057] Example 6

[0058] The raw materials and quantities used in this embodiment are the same as those in Embodiment 3, the only difference being that: the polyglutamic acid fermentation broth is 24 parts by weight, the seaweed broth is 50 parts by weight, the microbial agent is 1.5 parts by weight, and the nutrients are 25 parts by weight.

[0059] Comparative Example 1

[0060] The raw materials and quantities used in this embodiment are the same as those in Embodiment 3, the only difference being that Bacillus subtilis is not included.

[0061] Comparative Example 2

[0062] The comparative example uses the same raw materials and amounts as Example 3, the only difference being that it does not include polyglutamic acid fermentation broth.

[0063] Comparative Example 3

[0064] The comparative example uses the same raw materials and amounts as Example 3, the only difference being that it does not include plant extracts.

[0065] Comparative Example 4

[0066] The comparative example uses the same raw materials and amounts as Example 3, the only difference being that polyglutamic acid is replaced with polyaspartic acid, which has a molecular weight of 80,000-100,000 and a concentration of 7.

[0067] Comparative Example 5

[0068] Weigh out 0.93 parts by weight of water-soluble fertilizer containing macro-elements (N content 19 wt%, P2O5 content 19 wt%, K2O content 19%), 0.06 parts by weight of rhamnolipin, 0.03 parts by weight of trehalose, and 0.02 parts by weight of polyglutamic acid, mix and stir evenly to obtain the final product.

[0069] Experimental Example 1

[0070] The water-soluble fertilizers prepared in Examples 3-6 and Comparative Examples 1-5, and commercially available water-soluble fertilizers containing macro-elements (N, P2O) were compared. 5、A pot experiment was conducted using commercially available K2O (K2O content 170 g / L) as the primary control, with no fertilizer applied as a blank control. The pots used were 10 cm high and 12 cm wide. The test crop was Chinese cabbage, and the test soil was saline-alkali soil from Shandong Province with a pH of 8.42 and a total salt content of 0.20%. Chinese cabbage seedlings were raised in plastic seedling trays using a substrate. After one true leaf emerged, healthy seedlings with uniform growth were transplanted. Each treatment was repeated four times. On the day of transplanting, each pot was watered with 30 mL of water. Fertilizer was applied two days after transplanting. For the example and comparative cases, the water-soluble fertilizer was diluted 300 times, and 50 mL of the diluted solution was applied to the roots of each pot. This was repeated every 7 days for a total of three applications. The blank control group was also watered simultaneously. All other experimental conditions were kept consistent, and the experimental period was 35 days.

[0071] Table 5 Growth of Bok Choy

[0072]

[0073] As shown in Table 5, under the synergistic effect of polyglutamic acid fermentation broth and seaweed extract, the suspended liquid fertilizer of this invention (Examples 3-7) significantly improved the growth promotion effect of pakchoi under salt stress compared to Comparative Examples 1-5 and commercially available water-soluble fertilizers containing macroelements. Among them, Example 3 showed the best overall performance, resulting in a fresh weight of 6.92 g / plant, a plant height of 12.91 cm, and a root length of 17.52 cm for the aboveground parts of pakchoi, representing increases of 196%, 81%, and 62% respectively compared to the blank control, and increases of 101%, 66%, and 37% respectively compared to commercially available water-soluble fertilizers containing macroelements. The efficacy verification of the core components showed that polyglutamic acid fermentation broth was indispensable (its absence reduced fresh weight by 10%, see Comparative Example 1), and seaweed extract was particularly crucial for root development (its absence shortened root length by 15%, see Comparative Example 2). Furthermore, polyglutamic acid could not be replaced by polyaspartic acid (Comparative Example 3 had the worst fertilizer effect). The results confirm that the optimized combination of polyglutamic acid fermentation broth and seaweed extract can significantly improve crop salt tolerance and biomass accumulation, providing an efficient solution for saline-alkali land improvement.

[0074] Experimental Example 2

[0075] Experimental Location: The experiment was conducted at a farm in Yumen City, Jiuquan City, Gansu Province. The soil physicochemical properties of the experimental field were as follows: bulk density 1.35 g / cm³, pH 8.57, water-soluble salt content 5.80 g / kg, organic matter 15.14 g / kg, total nitrogen 0.82 g / kg, available phosphorus 8.75 mg / kg, and available potassium 70.35 mg / kg. The experimental field was flat, and the irrigation facilities met the experimental requirements.

[0076] Test materials: The test product was the water-soluble fertilizer prepared in Example 3, and the test crop was sunflower.

[0077] Experimental Design: The experiment included three treatments: Treatment 1 served as the control group, receiving conventional fertilization management; Treatment 2 received conventional fertilization management plus a commercially available water-soluble fertilizer containing polyglutamic acid (polyglutamic acid ≥15g / L, organic matter ≥100g / L); and Treatment 3 received conventional fertilization management plus the tested product. Specific fertilizer application rates for each treatment are shown in Table 6. Except for basal fertilizer, all fertilizers applied at other times were administered via drip irrigation. Before drip irrigation, all fertilizers were thoroughly dissolved in the fertilizer tank, with a dilution ratio controlled at 500 times. Each treatment was replicated three times, with randomly assigned plots, each plot covering 1 acre. Other field management practices remained consistent across all treatments.

[0078] Table 6 Fertilizer application rates for each treatment

[0079]

[0080] At sunflower harvest time, five plants were randomly selected from each plot to measure plant height, stem diameter, flower head diameter, and fresh weight of seeds per flower head. The results are shown in Table 7. Compared with treatment 1 (control group), the application of commercially available polyglutamic acid-containing water-soluble fertilizer and the tested product both increased sunflower plant height, stem diameter, flower head diameter, and fresh weight of seeds per flower head. Treatment 3 (application of the tested product) showed the best results, with plant height increasing by 6.36%, stem diameter by 13.87%, flower head diameter by 9.03%, and fresh weight of seeds per flower head by 11.69% compared to treatment 1. These results indicate that the application of the tested product on the basis of conventional fertilization can significantly promote the growth of sunflower plants in saline-alkali soil and increase seed yield. This demonstrates that the product has a significant yield-increasing and efficiency-enhancing effect on sunflowers under saline-alkali conditions, effectively improving planting benefits and providing support for sunflower cultivation in saline-alkali land.

[0081] Table 7. Sunflower growth under each treatment

[0082]

[0083] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A liquid fertilizer, characterized in that, By weight, it includes: 5-25 parts polyglutamic acid fermentation broth, 50-90 parts plant extract, 0-1.5 parts microbial agent, 5-25 parts nutrients, 0.1-0.3 parts suspending agent, and 0.1-0.3 parts preservative.

2. The liquid fertilizer according to claim 1, characterized in that, By weight, it includes: 15-25 parts polyglutamic acid fermentation broth, 50-70 parts plant extract, 0.5-1.5 parts microbial agent, 8-15 parts nutrients, 0.2-0.3 parts suspending agent, and 0.2-0.3 parts preservative.

3. The liquid fertilizer according to claim 2, characterized in that, By weight, it includes: 15 parts polyglutamic acid fermentation broth, 70 parts plant extract, 0.5 parts microbial agent, 15 parts nutrients, 0.2 parts suspending agent, and 0.2 parts preservative.

4. The liquid fertilizer according to any one of claims 1 to 3, characterized in that, The plant extracts are starch biochemical solution, wood vinegar solution, and seaweed solution; the microbial agents are Bacillus licheniformis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus megaterium; the nutrients are urea ammonium nitrate solution and potassium dihydrogen phosphate; the suspending agents are xanthan gum, polyvinyl alcohol, polyethylene glycol, magnesium aluminum silicate, and sodium hydroxymethyl cellulose; and the preservatives are ascorbic acid, Kathon, sodium benzoate, and potassium sorbate.

5. The liquid fertilizer according to claim 4, characterized in that, The microbial agent is Bacillus subtilis, the plant extract is seaweed extract, the nutrient is urea ammonium nitrate solution and potassium dihydrogen phosphate in a mass ratio of 5:3, and the suspending agent is xanthan gum.

6. The liquid fertilizer according to claim 5, characterized in that, The effective viable count of the Bacillus subtilis is not less than 2 × 10⁻⁶. 11 CFU / g.

7. The method for preparing the liquid fertilizer according to any one of claims 1 to 3, characterized in that, The polyglutamic acid fermentation broth, plant extracts, nutrients, suspending agents, and preservatives are mixed evenly according to the specified ratio. After emulsification, a suspension is formed. Microbial agents are added to the suspension according to the specified weight and mixed evenly to obtain the final product.

8. The application of the liquid fertilizer according to any one of claims 1 to 3 in the cultivation of crops in saline-alkali land.

9. The application according to claim 8, characterized in that, Dilute the liquid fertilizer 100-1000 times and apply it to crops via drip irrigation or fertigation. Apply the liquid fertilizer 1-3 times per growing season, and apply 5-20 kg / mu.

10. The application according to claim 8, characterized in that, The crop in question is either bok choy or sunflower.

Images