A gamma-aminobutyric acid-containing navel orange foliar fertilizer and application thereof

Abstract

This invention relates to the field of agricultural fertilizer technology, specifically to a foliar fertilizer for navel oranges containing γ-aminobutyric acid (GABA) and its application. The foliar fertilizer comprises the following components in parts by weight: 10-25 parts GABA; 5-12.5 parts citric acid; 5-12.5 parts potassium citrate; 5-10 parts boric acid; 5-10 parts zinc sulfate; 0.5-2.5 parts sodium selenite; and water to 100 parts. The foliar fertilizer for navel oranges provided by this invention has advantages such as synergistic effects, environmental friendliness, precise and significant effects, and good stability. It can efficiently supplement trace elements and promote the overall quality improvement of fruits, meeting the requirements of green agriculture and possessing significant industrial application value and practical significance.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer technology, specifically to a foliar fertilizer for navel oranges containing γ-aminobutyric acid and its application. Background Technology

[0002] As a globally important economic citrus fruit, the quality of navel oranges (including appearance, color, sugar-acid ratio, vitamin C content, and enrichment level of functional nutrients) directly determines their market value and industrial benefits. In the cultivation and management of navel oranges, the scientific supplementation of micronutrients is a key link in ensuring normal tree growth and promoting fruit quality. Currently, micronutrient fertilizers used in agricultural production are mostly in inorganic salt form, such as zinc sulfate, boric acid, and sodium selenite. However, these traditional micronutrient fertilizers have significant technical limitations in practical application: on the one hand, inorganic micronutrients are easily fixed or adsorbed after being applied to the soil, significantly reducing their effectiveness; on the other hand, when foliar sprayed, inorganic ions have limited ability to penetrate the cuticle, resulting in low absorption and utilization rates. Therefore, compensatory measures such as increasing the dosage or frequency of application are often required in production, which not only wastes fertilizer and increases production costs but may also lead to soil environmental pollution risks.

[0003] To overcome the bottleneck of low absorption and utilization rates of inorganic micronutrient fertilizers, the industry has developed chelated micronutrient fertilizers using synthetic chelating agents such as EDTA (ethylenediaminetetraacetic acid) and EDDHA (ethylenediamine di-o-hydroxyphenylacetic acid) as carriers. These products protect metal ions from precipitation through chelation, thus improving the bioavailability of micronutrients to some extent. However, synthetic chelating agents also have drawbacks: their production costs are high, increasing farmers' input; more importantly, these chemical chelating agents degrade slowly in the natural environment, and long-term application may lead to their accumulation in the soil, posing potential environmental safety risks and contradicting the concepts of green agriculture and sustainable development.

[0004] In recent years, as consumer demands for fruit quality have increased, intrinsic fruit quality (such as sugar-acid ratio, vitamin C content, and enrichment of functional components) has gradually become a core indicator for evaluating fruit marketability. However, current foliar fertilizer product development focuses primarily on nutrient supplementation and yield improvement, with relatively weak technologies for precise nutrient regulation during critical fruit quality formation periods. In particular, functional fertilizer products that can systematically improve the overall quality of fruit are still rare. Summary of the Invention

[0005] Based on the above-mentioned technical deficiencies, the present invention aims to provide a foliar fertilizer for navel oranges containing γ-aminobutyric acid and its application, which is used to accurately and efficiently improve the quality of navel oranges. It is characterized by being completely organic, easily absorbed, having significant effects, and being environmentally friendly.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a foliar fertilizer for navel oranges containing γ-aminobutyric acid, comprising the following components in parts by weight: 10-25 parts γ-aminobutyric acid (GABA); 5-12.5 parts citric acid; 5-12.5 parts potassium citrate; 5-10 parts boric acid; 5-10 parts zinc sulfate; 0.5-2.5 parts sodium selenite; water to 100 parts.

[0007] Furthermore, the navel orange foliar fertilizer comprises the following components in parts by weight: γ-Aminobutyric acid: 15-20 parts; citric acid: 7.5-10 parts; potassium citrate: 7.5-10 parts; boric acid: 7-8 parts; zinc sulfate: 7-8 parts; sodium selenite: 1-2 parts; water to 100 parts.

[0008] Gamma-aminobutyric acid (GABA) is a naturally occurring non-protein amino acid that functions as both a metabolite and a signaling molecule in plants. It participates in regulating plant cell pH, maintaining carbon-nitrogen (C / N) balance, modulating defense response systems, and enhancing plant resistance to stress. It also promotes both vegetative and reproductive growth, optimizing nutrient absorption and utilization. Adding GABA to fertilizers significantly promotes root development and overall crop growth. Furthermore, GABA has a systemic promoting effect on late-stage fruit coloring and sugar accumulation. Its mechanisms include inducing ethylene synthesis, promoting the absorption and utilization of minerals such as boron, magnesium, potassium, and molybdenum, thereby increasing the accumulation of anthocyanins and aromatic substances in fruits, ultimately leading to earlier fruit ripening and improved quality.

[0009] In a second aspect, the present invention provides the application of the above-mentioned foliar fertilizer in improving the quality of navel oranges.

[0010] Furthermore, the quality of the navel oranges includes: Vitamin C content, soluble solids, titratable acid, and solid-acid ratio.

[0011] Furthermore, the application includes: during the fruit enlargement period of navel oranges, diluting the foliar fertilizer and spraying it onto the surface of navel orange leaves.

[0012] Furthermore, the fruit enlargement period includes the early stage of fruit enlargement and the middle stage of fruit enlargement.

[0013] The initial stage of fruit enlargement is from June to early July; the middle stage of fruit enlargement is from mid-July to August.

[0014] Furthermore, the application method is as follows: spray once in the early stage of fruit enlargement and once in the middle stage of fruit enlargement.

[0015] Furthermore, the dilution factor is 300 to 500 times.

[0016] Preferably, the dilution factor is 400 times.

[0017] In a third aspect, the present invention provides a method for improving the quality of navel oranges, comprising the following steps: Dilute the above-mentioned navel orange foliar fertilizer 400 times; Spray the diluted solution onto the surface of the navel orange leaves once each during the early and middle stages of fruit enlargement.

[0018] Furthermore, the navel orange variety is 'Newhall' navel orange.

[0019] Compared with existing technologies, this invention aims to provide an organic micronutrient water-soluble fertilizer that combines high absorption efficiency and environmental friendliness, and can significantly improve the overall quality of navel oranges. A corresponding precise application method for this fertilizer in navel orange production is also established, offering the following beneficial effects: (1) Synergistic effect: GABA combined with trace elements (Zn, B, Se) produces unexpected synergistic effects. GABA not only participates in metabolism as a biostimulant, but may also significantly promote the absorption and transport of trace elements by plants, thereby amplifying the fertilizer effect.

[0020] (2) Green and environmentally friendly: The citric acid-potassium citrate system is used as a chelating agent and pH adjuster, replacing the traditional chemically synthesized chelating agent. All components are biodegradable, environmentally friendly, and have no residual risk. At the same time, it provides additional potassium nutrition.

[0021] (3) Significant and precise effects: Targeting the critical period of fruit enlargement in navel oranges, only 1-2 sprays are needed to significantly and quantitatively increase the sugar content and vitamin C content of the fruit, improve the color, and produce selenium-enriched functional fruits, achieving labor-saving, time-saving, efficient and precise nutritional regulation.

[0022] (4) Good stability: The water-soluble fertilizer formula is stable, the components are compatible, and there is no precipitation or stratification during long-term storage. Attached Figure Description

[0023] Figure 1 The effects of existing products and the product of this invention on the development of navel oranges.

[0024] Figure 2 The specific results of the effects of the examples and comparative examples on the quality of navel oranges are as follows; among them, Figure 2 (A) shows the results of soluble solids determination; Figure 2 (B) shows the results of titratable acid determination; Figure 2 (C) shows the results of vitamin C content determination; Figure 2(D) represents the results of the solid-acid ratio determination; T1 represents treatment 1, T2 represents treatment 2, T3 represents treatment 3, T4 represents treatment 4, T5 represents treatment 5, T6 represents treatment 6, T7 represents treatment 7, T8 represents treatment 8, and T9 represents treatment 9. Detailed Implementation

[0025] The following detailed embodiments further illustrate the present invention, but should not be construed as limiting the invention. Simple modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are all within the scope of the invention; unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0026] In the embodiments of this invention, the foliar fertilizer formulas for navel oranges used in the experiments were all selected from navel orange trees with the same tree shape and were tested in navel orange orchards in Ganzhou City, Jiangxi Province.

[0027] The navel orange variety used in this embodiment of the invention is the 'Newhall' navel orange.

[0028] In this embodiment of the invention, zinc sulfate is preferably zinc sulfate heptahydrate; sodium selenite is a commonly used feed-grade or industrial-grade raw material; and water is preferably deionized water or clean soft water.

[0029] Example 1 (Preferred Formula) This example aims to prepare a foliar fertilizer with the best overall effect.

[0030] Weigh out 200 kg of γ-aminobutyric acid (GABA), 100 kg of citric acid, 100 kg of potassium citrate, 80 kg of zinc sulfate heptahydrate (equivalent to approximately 18 kg of pure Zn content), and 20 kg of sodium selenite (equivalent to approximately 9 kg of pure Se content). First, dissolve the above materials thoroughly in 500-600 L of deionized water in a stirring container. Then, add 80 kg of boric acid (equivalent to approximately 14 kg of pure B content) to the solution and continue stirring until completely dissolved. Finally, bring the volume to 1000 L with deionized water to obtain a homogeneous and transparent liquid. After filtration and packaging, the foliar fertilizer product of this invention is obtained.

[0031] Example 2 This example aims to prepare a foliar fertilizer of another concentration to verify the applicability of the technical solution of the present invention.

[0032] Weigh out 150 kg of γ-aminobutyric acid (GABA), 75 kg of citric acid, 75 kg of potassium citrate, 70 kg of zinc sulfate heptahydrate (equivalent to approximately 15.8 kg of pure Zn content), and 10 kg of sodium selenite (equivalent to approximately 4.5 kg of pure Se content). First, dissolve the above materials thoroughly in 500-600 L of deionized water in a stirring container. Then, add 70 kg of boric acid (equivalent to approximately 12.3 kg of pure B content) to the solution and continue stirring until completely dissolved. Finally, bring the volume to 1000 L with deionized water to obtain a homogeneous and transparent liquid. After filtration and packaging, the foliar fertilizer product of this invention is obtained.

[0033] Test case 1. Navel orange trees of similar age, growth vigor, and fruit load were selected as experimental subjects. The experiment consisted of 9 treatment groups, each with 3 replicates, arranged in a randomized block design. The specific fertilization regimens for each treatment group are as follows: Treatment 1 (Example 1): The foliar fertilizer prepared in Example 1 was diluted 400 times and sprayed once each during the early stage and middle stage of fruit enlargement of navel orange ('Newhall' navel orange).

[0034] Treatment 2 (Example 2): The foliar fertilizer prepared in Example 2 was diluted 400 times and sprayed once each during the early stage and middle stage of fruit enlargement of navel orange ('Newhall' navel orange).

[0035] Treatment 3 (Comparative Example 1): No GABA was added to the foliar fertilizer components; the remaining components were the same as in Example 1. The application method was the same as in Example 1.

[0036] Treatment 4 (Comparative Example 2): Citric acid was not added to the foliar fertilizer components; the remaining components were the same as in Example 1. The application method was the same as in Example 1.

[0037] Treatment 5 (Comparative Example 3): No potassium citrate was added to the foliar fertilizer components; the remaining components were the same as in Example 1. The application method was the same as in Example 1.

[0038] Treatment 6 (Comparative Example 4): The foliar fertilizer contained only boric acid, zinc sulfate, and sodium selenite (inorganic salt control group), and did not contain GABA, citric acid, or potassium citrate. The application method was the same as in Example 1.

[0039] Treatment 7 (Comparative Example 5): Spray commercially available Prefon Abao-Zinc-Boron Fertilizer (mainly containing boron and zinc) according to the recommended dosage and timing in the product instructions.

[0040] Treatment 8 (Comparative Example 6): Sprayed with an equal amount of water as a blank control group.

[0041] Treatment 9 (Comparative Example 7): The same foliar fertilizer as in Example 1 was sprayed, but the application time was different. It was sprayed twice during the physiological fruit drop period.

[0042] The specific component concentrations of the foliar fertilizer in each treatment group are detailed in the table below (Table 1).

[0043] Table 1. Concentration of main components of foliar fertilizer in each treatment group (g / L) Components (g / L) Process 1 Process 2 Process 3 Process 4 Process 5 Process 6 Process 7 Process 8 Process 9 GABA 200 150 / 200 200 / (Commercially available fertilizer) / 200 Citric acid 100 75 100 / 100 / - / 100 Potassium citrate 100 75 100 100 / / - / 100 Boric acid (as B) 14 12.3 14 14 14 14 - / 14 Zinc sulfate (as Zn) 18 15.8 18 18 18 18 - / 18 Sodium selenite (as Se) 9 4.5 9 9 9 9 - / 9 Note: " / " indicates that no component was added, and "-" indicates that the component is unknown or does not exist.

[0044] 2. Measurement Indicators and Methods During the ripening period of navel oranges, 10 fruits were randomly collected from different locations on each tree in each treatment group, and the samples were mixed for quality index determination. The measurement indicators and methods included: vitamin C content (2,6-dichlorophenolindophenol titration method), soluble solids content (handheld refractometer method), and titratable acid content (NaOH titration method), and the solids-acid ratio (soluble solids / titratable acid) was calculated.

[0045] 3. Results and Analysis The results of the quality determination of navel oranges in each treatment group are detailed in Table 2 below.

[0046] Table 2. Effects of different treatments on the quality of navel oranges Processing Group soluble solids % Vitamin C content (mg / 100g) Titrateable acid % solid acid ratio Process 1 (Example 1) 13.9 ± 0.2 a 49.5 ± 0.8 a 0.60 ± 0.02 c 23.4 ± 0.4 a Process 2 (Example 2) 13.8 ± 0.2 a 49.3 ± 0.7 a 0.61 ± 0.02 c 22.7 ± 0.5 a Treatment 3 (Comparative Example 1) 12.9 ± 0.4 ab 46.1 ± 0.3 b 0.67 ± 0.04 bc 19.3 ± 0.4 b Treatment 4 (Comparative Example 2) 12.9 ± 0.3 b 46.4 ± 0.8 b 0.67 ± 0.02 bc 19.2 ± 0.4 b Treatment 5 (Comparative Example 3) 13.2 ± 0.3 ab 46.3 ± 1.4 b 0.70 ± 0.02 ab 18.8 ± 0.7 b Treatment 6 (Comparative Example 4) 12.8 ± 0.4 b 43.7 ± 0.5 c 0.65 ± 0.02 bc 19.7 ± 0.6 b Treatment 7 (Comparative Example 5) 12.7 ± 0.4 b 43.6 ± 0.8 c 0.69 ± 0.02 ab 18.5 ± 0.8 b Treatment 8 (Comparative Example 6) 11.6 ± 0.6 c 42.1 ± 0.6 c 0.76 ± 0.03 a 15.4 ± 0.5 c Treatment 9 (Comparative Example 7) 13.2 ± 0.3 ab 47.4 ± 1.0 ab 0.66 ± 0.04 bc 20.0 ± 0.7 b Note: Multiple comparisons were performed using Turkey's HSD, with different letters in the same column indicating significant differences.

[0047] 4. Conclusion From Table 2, Figure 2 It can be seen that treating different varieties of navel oranges with different concentrations of foliar fertilizer resulted in varying degrees of improvement in fruit quality, including vitamin C content, soluble solids, titratable acid, and solid-acid ratio (treatments 1-2).

[0048] Compared with the blank control (Comparative Example 6), after applying the foliar fertilizers of Examples 1-2 of this invention, the vitamin C content, soluble solids, total sugar content, and solid-acid ratio of navel orange fruits were significantly increased, while the titratable acid content was significantly decreased. This indicates that this invention can comprehensively and significantly improve the internal quality of navel oranges.

[0049] Compared with commercially available products (Comparative Example 5) Figure 1 Compared to commercially available micronutrient fertilizers, Example 1 outperforms them in all quality indicators, particularly in improving vitamin C, soluble solids, and the acid-to-vitamin ratio, demonstrating the superiority of this invention in improving quality.

[0050] Compared with the comparative examples (Comparative Examples 1-4) that lacked components: whether GABA, citric acid, potassium citrate, or all three were lacking (Comparative Example 4), all quality indicators of the navel oranges were lower than those in Example 1. This fully demonstrates that there is a significant synergistic effect between GABA, citric acid, potassium citrate, and trace elements, which together constitute the complete technical solution of this invention.

[0051] Compared to Comparative Example 7, which had a different application period: even when the product of this invention was applied outside the fruit enlargement period (such as during the physiological fruit drop period), its effect on improving fruit quality was far superior to the blank control, but still slightly lower than Example 1, which was applied precisely during the fruit enlargement period. This indicates that spraying during the fruit enlargement period is the optimal window for achieving quality improvement, demonstrating the ingenuity and practicality of the "precise application method" of this invention.

[0052] In summary, this invention, through the scientific combination of specific functional active substances (GABA), organic acid adjuvants (citric acid and its potassium salt) and trace elements, combined with precise application timing, has achieved unexpected technical effects in improving the overall quality of navel oranges, demonstrating significant creativity and broad application value.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A foliar fertilizer for navel oranges containing γ-aminobutyric acid, characterized in that, The components comprise the following parts by weight: γ-Aminobutyric acid 10-25 parts; citric acid 5-12.5 parts; potassium citrate 5-12.5 parts; boric acid 5-10 parts; zinc sulfate 5-10 parts; sodium selenite 0.5-2.5 parts; Add water to make 100 parts.

2. The application of the foliar fertilizer as described in claim 1 in improving the quality of navel oranges.

3. The application according to claim 2, characterized in that, The quality of the navel oranges includes: Vitamin C content, soluble solids, titratable acid, and solid-acid ratio.

4. The application according to claim 2, characterized in that, The application includes: during the fruit enlargement period of navel oranges, diluting the foliar fertilizer and spraying it onto the surface of the navel orange leaves.

5. The application according to claim 2, characterized in that, The fruit enlargement period includes the early stage of fruit enlargement and the middle stage of fruit enlargement.

6. The application according to claim 2, characterized in that, Spray once during the early stage of fruit enlargement and once during the middle stage of fruit enlargement.

7. The application according to any one of claims 2 to 6, characterized in that, The dilution factor is 300 to 500 times.

8. A method for improving the quality of navel oranges, characterized in that, Includes the following steps: Dilute the foliar fertilizer for navel oranges according to claim 1 by 400 times; spray the diluted solution onto the surface of the navel orange leaves once each during the early and middle stages of fruit enlargement.

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