Cold-resistant fertilizer for fruits and vegetables and preparation method thereof

Abstract

The present application relates to the technical field of fertilizer, especially to a cold-resistant fertilizer for fruits and vegetables and a preparation method thereof. The cold-resistant performance of dry peanut shells, dry sugarcane residues and mung bean straw crop wastes is mined, and the traditional low-value agricultural and forestry solid wastes are innovatively applied to the prevention and control of fruit and vegetable cold damage at low temperature, so that the resource value of the wastes can be maximized, and the conversion and application value is high. The dry peanut shells, dry sugarcane residues and mung bean straw fermentation liquor are reasonably compounded, so that the fruits and vegetables can be prevented and repaired from cold damage at low temperature, and the cold damage can be resisted, and the cold-resistant fertilizer is suitable for a variety of low-temperature sensitive fruits and vegetables such as strawberries, peppers and Chinese cabbages, and has wide applicability.

Description

Technical Field

[0001] This invention relates to the field of fertilizer technology, and in particular to a cold-resistant fertilizer for fruits and vegetables and its preparation method. Background Technology

[0002] Low-temperature chilling injury is a typical meteorological disaster in agricultural production, specifically referring to the latent physiological damage caused to crops during the growing season under relatively low temperatures above 0℃. It is also the core manifestation of damage caused by early spring frosts. The critical temperature for crop chilling injury can be as high as nearly 20℃. In the early stages of damage, the plants do not show obvious frostbite spots, making it highly insidious and difficult to detect in the early stages. By the time visible symptoms such as flower drop, stunted growth, stunted growth, and deformed fruit appear, the physiological damage is irreversible, severely affecting crop yield and market quality. Low-temperature chilling injury mainly disrupts the normal physiological metabolism of plants through three major pathways: weakening crop photosynthetic efficiency, inhibiting root vitality and nutrient absorption capacity, and hindering the transport and distribution of photosynthetic products and mineral nutrients. It is a major cause of reduced yield and deterioration in quality of shallow-rooted, low-temperature-sensitive fruits and vegetables such as strawberries, peppers, and cabbage in early spring.

[0003] Currently, the mainstream prevention and control methods for early spring frost and seedling stage low-temperature damage are divided into three categories: physical protection, chemical agents, and cold-resistant fertilizers, but all of them have obvious shortcomings: First, physical covering and insulation measures are costly to purchase and manually lay covering materials such as film and non-woven fabric. A large amount of disposable plastic film is difficult to degrade naturally and will cause white pollution of soil if left in the field for a long time, which is not conducive to the development of green agriculture. Secondly, foliar spraying of chemical antifreeze agents often involves the addition of synthetic antifreeze agents and plant growth regulators. Frequent application can easily lead to excessive pesticide residues in fruits and vegetables. At the same time, exogenous chemical substances can damage the native microbial community in the soil, and long-term use can easily lead to soil compaction and soil fertility decline. Third, existing publicly available cold-resistant fertilizers are highly targeted and have a narrow range of applications, suitable only for single types of crops, and lack versatility. For example, patent CN120483815A, "A Special Foliar Fertilizer for Improving the Cold Resistance of Durian Seedlings and Its Preparation Method and Application," is only for durian seedlings; CN121488681A, "A Method for Applying Cold-Resistant Water-Soluble Fertilizer," is only for head lettuce; and CN119874441A, "A Foliar Fertilizer Formula for Improving the Cold Resistance of Tobacco Seedlings," is only for tobacco seedlings.

[0004] my country's agricultural production generates a large amount of crop waste, such as straw and other agricultural and forestry waste. While some studies have explored the cold-resistance properties of rice straw returned to the field, research on the cold resistance of other crop wastes is scarce. In most regions, broad bean straw, planted in autumn and harvested in spring, can be enriched with cold-induced proteins, proline, and antioxidant active substances after low-temperature acclimatization, possessing potential physiological regulatory functions for cold resistance. Other crop wastes, such as peanut shells and sugarcane bagasse, are produced in large quantities and are highly renewable. However, research into the cold-resistance functions of these specific crop wastes is currently lacking.

[0005] Therefore, it is of great significance and application value to fully explore the cold-resistant application value of agricultural waste and develop cold-resistant fertilizers that can overcome low-temperature damage and are also applicable to a variety of low-temperature sensitive fruits and vegetables. Summary of the Invention

[0006] Based on the above background, this invention provides a cold-resistant fertilizer for fruits and vegetables and its preparation method. The fertilizer prepared by this invention makes full use of agricultural waste such as broad bean straw, dried peanut shells and dried sugarcane bagasse to construct a multi-level synergistic cold-resistant system. It can not only effectively overcome the cold damage problems of fruits and vegetables in early spring low temperature and late spring, but also be suitable for the cultivation of various low-temperature sensitive fruits and vegetables such as strawberries, peppers, and cabbage, with significant effects on improving quality and efficiency.

[0007] The technical solution of the present invention: A cold-resistant fertilizer for fruits and vegetables, by weight, is composed of the following raw materials: 10-25 parts dried peanut shells, 15-50 parts dried sugarcane bagasse, 15-30 parts macronutrient fertilizer, 5-10 parts chelated micronutrient fertilizer, 1-3 parts boric acid, and 8-35 parts broad bean straw fermentation liquid. Based on the total amount of raw materials used in preparation, the macro-element fertilizer is composed of 10-15 parts of potassium dihydrogen phosphate, 3-10 parts of potassium nitrate and 2-5 parts of urea. The chelated micronutrient fertilizer is composed of chelated calcium, chelated magnesium, and chelated zinc with EDTA as the chelating agent.

[0008] Furthermore, based on the total amount of raw materials used in preparation, the chelated trace element fertilizer is composed of 2-4 parts of chelated calcium, 1-3 parts of chelated magnesium, and 1-3 parts of chelated zinc.

[0009] Furthermore, the preparation of the broad bean straw fermentation liquid includes the following steps: a. Select dry broad bean stalks, crush them, soak them in clean water at room temperature, and then drain them; b. After adding broad bean straw, fermentation agent and water into the fermentation tank, ferment at a constant temperature of 28-32℃ with ventilation for 5-8 days. During the fermentation process, control the moisture content of the material to be 58%-62% and maintain the oxygen concentration in the fermentation tank at 8%-12%. Stir once every 18-24 hours. c. After fermentation is complete, filter to remove solid residue and collect the filtrate, which is the broad bean straw fermentation liquid.

[0010] Further, in step b, the feed is prepared with a mass ratio of broad bean straw:water:fermentation agent of 100:(200-500):(2-5), and the viable count of the fermentation agent is not less than 1×10⁻⁶. 10 CFU / g.

[0011] Furthermore, the fermentation agent is composed of Bacillus subtilis and Lactobacillus plantarum in a live bacteria mass ratio of (1-3):1.

[0012] Furthermore, the broad bean straw is broad bean straw that has undergone low-temperature acclimatization during autumn sowing and spring harvesting after at least 20 consecutive days with an average daily temperature below 10°C.

[0013] Based on the same inventive concept, the present invention also provides a method for preparing a cold-resistant fertilizer for fruits and vegetables, characterized by comprising the following steps: 1) Crush the dried peanut shells and dried sugarcane bagasse separately and mix them together. Add water at a solid-liquid ratio of 1:(15-20) (g / ml). Then, reflux and extract at a constant temperature of 65-80℃ for 2-3 times, each extraction lasting 80-120 minutes. 2) After combining the extracts, solid-liquid separation is performed to obtain filtrate and filter residue. The filtrate is concentrated to a solid content of 10-30%. 3) After drying the filter residue to a moisture content of ≤12%, immerse the filter residue in a citric acid aqueous solution, stir at room temperature, and then dry it again to obtain dry base residue; 4) Mix the broad bean straw fermentation liquid and the concentrated filtrate from step 2), and homogenize to obtain a composite active liquid; 5) Add the dry base residue obtained in step 3), macro-element fertilizer, chelated micro-element fertilizer and boric acid into the compound active liquid, stir evenly, and obtain fertilizer; 6) Fertilizer can be prepared into 2-4mm fertilizer granules using a room temperature extrusion granulation process.

[0014] Furthermore, the dried bagasse in step 1) is bagasse with residual sugar content ≤1% after desugaring treatment.

[0015] Based on the same inventive concept, this invention also provides the application of the aforementioned cold-resistant fertilizer for fruits and vegetables in low-temperature protection and / or frost damage repair of low-temperature sensitive fruits and vegetables.

[0016] Furthermore, the fruits and vegetables mentioned include strawberries, peppers, and cabbage.

[0017] The beneficial effects achieved by this invention are as follows: This invention explores the cold resistance properties of dried peanut shells, dried sugarcane bagasse, and broad bean straw, and innovatively applies traditional low-value agricultural and forestry solid waste to the prevention and control of low-temperature chilling injury in fruits and vegetables. This can maximize the resource value of waste and has great transformation and application value.

[0018] This invention rationally combines dried peanut shells, dried sugarcane bagasse, and fermented broad bean straw liquid, which can not only synergistically prevent and repair low-temperature damage to fruits and vegetables and resist chilling injury, but is also suitable for a variety of low-temperature sensitive fruits and vegetables such as strawberries, peppers, and cabbage, and has a wide range of applications.

[0019] This invention modifies the filter residue of peanut shells and sugarcane bagasse, which are rich in cellulose and lignin after extraction, using citric acid. The modified filter residue has an increased number of hydroxyl and carboxyl active functional groups on its surface, which can improve the cation exchange capacity and adsorption performance of the filter residue. It can not only reliably and stably load macroelements (P, K, and N) and microelements (Ca, Mg, and Zn, etc.), but also achieve long-term slow release of macroelements and microelements at low temperatures. The modified filter residue can also improve soil aggregate structure and water and fertilizer retention capacity, regulate the rhizosphere microenvironment, and promote root development at low temperatures. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0022] The fermentation agent used in the following examples consists of Bacillus subtilis and Lactobacillus plantarum in a live bacteria mass ratio of 2:1, and the live bacteria count of the fermentation agent is 1×10⁻⁶. 11 CFU / g.

[0023] The Bacillus subtilis used in the following examples was purchased from the China General Microbiological Culture Collection Center, with accession number CGMCC 1.14985 and accession date of December 10, 2014 (12 / 10 / 2014). Lactobacillus plantarum was purchased from the China General Microbiological Culture Collection Center, with accession number CGMCC 1.1856 and accession date of July 12, 1995 (7 / 13 / 1995).

[0024] The preparation of the broad bean straw fermentation liquid used as the raw material includes the following steps: a. Select dry broad bean stalks, crush them to 30 mesh, manually remove mud, sand, mold and impurities, soak them in clean water at room temperature for 30 minutes, and drain until there is no free water. b. Add the dried broad bean straw, water and fermentation agent to the fermentation tank at a mass ratio of 100:300:2, wherein the fermentation agent is composed of Bacillus subtilis and Lactobacillus plantarum at a live bacteria mass ratio of 2:1. c. Ferment at a constant temperature of 30±2℃ in the fermentation tank (circulate for 30 minutes of ventilation followed by 90 minutes of standing) for 8 days. During the fermentation process, the moisture content of the material is controlled at 58% to 62%, and the oxygen concentration in the fermentation tank is kept stable at 8% to 12%. The material is stirred once every 24 hours. d. After fermentation is complete, filter to remove solid residue and collect the filtrate, which is the broad bean straw fermentation liquid.

[0025] Example 1: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 20 parts dried peanut shells, 30 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 18 parts broad bean straw fermentation liquid. In this embodiment, broad bean stalks obtained from open-field planting in autumn and spring harvest at a broad bean planting base in Anqing City, Anhui Province in 2024 were selected. After harvesting, the broad bean stalks were vacuum-dried at 50±3℃ until the moisture content was ≤12% to facilitate storage and transportation.

[0026] Based on the total amount of raw materials used in preparation, the macro-element fertilizer is composed of 14 parts potassium dihydrogen phosphate, 8 parts potassium nitrate, and 6 parts urea. The chelated micronutrient fertilizer is composed of 4 parts chelated calcium, 3.5 parts chelated magnesium, and 1.5 parts chelated zinc, all chelated with EDTA as the chelating agent.

[0027] The preparation of the cold-resistant fertilizer includes the following steps: 1) After crushing the dried peanut shells and dried sugarcane bagasse separately and passing them through a 30-mesh sieve, mix them together, add water at a solid-liquid ratio of 1:20 (g / ml), and reflux extract at a constant temperature of 65±5℃ 3 times, each extraction lasting 80-120 minutes. The moisture content of the dried peanut shells and dried sugarcane bagasse is ≤12%, which facilitates their preservation and transportation.

[0028] The dried sugarcane bagasse is sugarcane bagasse with residual sugar ≤1% after desugaring treatment. The sugarcane bagasse comes from a sugar factory. The sugarcane bagasse is first washed with water in a countercurrent to remove surface soluble sugars, so that the residual sugar mass fraction is ≤1%, and then dried with hot air at low temperature (55℃) to obtain dried sugarcane bagasse.

[0029] 2) After combining the extracts, solid-liquid separation was performed to obtain filtrate and filter residue. The filtrate was concentrated under vacuum (45±2℃) to a solid content of 20wt%. 3) After drying the filter residue at a constant temperature of 45±2℃ until the moisture content is ≤12%, the filter residue is immersed in a 3wt% citric acid aqueous solution with a solid-liquid ratio of 1:8 (g / ml), stirred at low speed (150rpm) at room temperature for 60 min, and dried at a constant temperature of 45±2℃ until constant weight to obtain dry base residue. 4) Mix the broad bean straw fermentation liquid and the concentrated filtrate from step 2), and homogenize to obtain a composite active liquid; 5) Add the dry base residue obtained in step 3), macro-element fertilizer, chelated micro-element fertilizer and boric acid into the compound active liquid, stir evenly, and obtain fertilizer. 6) Fertilizer can be prepared into 2-4mm fertilizer granules using a room temperature extrusion granulation process.

[0030] Example 2: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 20 parts dried peanut shells, 30 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 8 parts broad bean straw fermentation liquid; Other matters not covered herein are the same as in Example 1.

[0031] Example 3: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 20 parts dried peanut shells, 30 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 35 parts broad bean straw fermentation liquid; Other matters not covered herein are the same as in Example 1.

[0032] Example 4: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 20 parts dried peanut shells, 15 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 35 parts broad bean straw fermentation liquid. Other matters not covered herein are the same as in Example 1.

[0033] Comparative Example 1: A cold-resistant fertilizer for fruits and vegetables, which is composed of the following raw materials in parts by weight: 20 parts dried peanut shells, 30 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 18 parts rice straw fermentation liquid. Compared to Example 1, the preparation of the rice straw fermentation liquid in this comparative example is the same as that of the broad bean straw fermentation liquid, except that the broad bean straw is replaced with rice straw.

[0034] Other matters not covered herein are the same as in Example 1.

[0035] Comparative Example 2: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 20 parts dried peanut shells, 30 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, and 1.5 parts boric acid; Compared to Example 1, this comparative example lacks broad bean straw fermentation liquid, and the broad bean straw fermentation liquid is replaced with the same amount of concentrated filtrate from step 2), that is, in step 4), the concentrated filtrate on the original basis is supplemented with the same amount of concentrated filtrate as the broad bean straw fermentation liquid.

[0036] Other matters not covered herein are the same as in Example 1.

[0037] Comparative Example 3: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 50 parts dried peanut shells, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 18 parts broad bean straw fermentation liquid; Compared to Example 1, this comparative example lacks dried sugarcane bagasse, and the corresponding preparation steps only use peanut shells for extraction.

[0038] Other matters not covered herein are the same as in Example 1.

[0039] Comparative Example 4: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 50 parts dried sugarcane bagasse, 28 parts macronutrient fertilizer, 9 parts chelated micronutrient fertilizer, 1.5 parts boric acid, and 18 parts broad bean straw fermentation liquid; Compared to Example 1, this comparative example lacks dried peanut shells, and the corresponding preparation steps only use dried sugarcane bagasse for extraction.

[0040] Other matters not covered herein are the same as in Example 1.

[0041] Comparative Example 5: A cold-resistant fertilizer for fruits and vegetables, the raw materials for its preparation are composed of the following, by weight: 28 parts of macronutrient fertilizer, 9 parts of chelated micronutrient fertilizer, 1.5 parts of boric acid, and 18 parts of broad bean straw fermentation liquid; Compared to Example 1, this comparative example lacks dried peanut shells and dried sugarcane bagasse. The concentrated filtrate from step 3) of Example 1 is replaced with the same amount of broad bean straw fermentation liquid, and the filter residue is replaced with biochar (rice straw base). After the filter residue is treated in step 3), it replaces the dry base residue.

[0042] Other matters not covered herein are the same as in Example 1.

[0043] Crop experiments were conducted using the above examples and their comparative examples.

[0044] Relevant tests in crop experiments ① Chilling injury index = Σ (chilling injury level × number of plants at that level) / (4 × total number of plants surveyed) × 100%; The classification standards for cold damage levels are as follows: Grade 0: No chilling injury, leaves are fully extended and not wilted, flower buds and young fruits are normal; Level 1: Mild chilling injury, with slight curling of leaf margins and minor water loss; flowers and fruits are undamaged. Level 2: Moderate chilling injury, with 1 / 3 to 1 / 2 of the leaves wilting and turning pale, a small number of flowers falling off, and young fruits suffering slight frost damage; Level 3: Severe cold damage, more than 1 / 2 of the leaves wither, a large number of flowers fall off, and young fruits are damaged and sunken by frost. Level 4: Severe chilling injury: The entire plant wilts and dries up, the growing point is damaged, and a large number of fruits fall off.

[0045] ② Relative electrical conductivity of leaves (cell membrane damage rate) The immersion conductivity method was used. 0.2g of fresh functional leaves were taken, the midrib removed, and the leaves were chopped and placed in a test tube containing 20mL of deionized water. The solution was immersed at room temperature in the dark for 12 hours. The initial conductivity S1 of the immersion solution was measured using a conductivity meter. The test tube was then placed in a boiling water bath for 30 minutes, cooled to room temperature, and the final conductivity S2 was measured. Relative conductivity = S1 / S2 × 100%. A higher value indicates more severe cell membrane damage and cytoplasmic leakage, and a higher degree of low-temperature damage to the plant.

[0046] ③ SOD superoxide dismutase activity The NBT photoreduction method was used. 0.2g of fresh leaves were weighed, ground in liquid nitrogen, and then extracted in a pre-cooled phosphate buffer (pH=7.8) in an ice bath. The supernatant crude enzyme solution was obtained by centrifugation. The NBT reaction system was prepared, and the reaction was carried out under light for 20 min. The reaction was terminated in the dark, and the absorbance was measured at 560nm using a spectrophotometer. One enzyme activity unit (U / g·FW) was defined as the inhibition of NBT photoreduction by 50%. Higher enzyme activity indicates a stronger ability of the plant to scavenge superoxide anions and better cold resistance and stress tolerance.

[0047] ③ Free proline content The acidic ninhydrin colorimetric method was used. Fresh leaves were extracted with boiling water containing 3% sulfosalicylic acid, and the supernatant was collected by centrifugation. This supernatant was then mixed with ninhydrin and glacial acetic acid and boiled in water for color development. The colored upper layer was extracted with toluene, and the absorbance was measured at a wavelength of 520 nm. The proline content (μg / g) was calculated using a standard curve. Proline is a core osmotic regulator; the higher the content, the stronger the osmotic pressure of the plant cells and the better the resistance to freezing and stress.

[0048] ④Fruit soluble solids (sugar content %) The handheld refractometer was used for testing: mature fruits from the same part of the plant were selected, rinsed with clean water and dried, and the homogeneous juice from the middle of the pulp was cut off and dropped onto the mirror of the refractometer. After calibration and zeroing, the value was read.

[0049] ⑤ Method for detecting vitamin C content in fruits (mg / 100g) The 2,4-dinitrophenylhydrazine colorimetric method was used: fresh fruit pulp samples were accurately weighed, extracted with oxalic acid solution at low temperature, and the supernatant was collected by centrifugation. After the color reaction, the absorbance was measured, and the vitamin C content was calculated by referring to the standard curve. The unit is mg / 100g fresh fruit. The experiment was repeated 3 times.

[0050] All experimental data are expressed as mean ± standard deviation.

[0051] Specific crop experiments will be conducted.

[0052] 1) Strawberry The tested variety, Hongyan strawberry, was selected from robust runner seedlings with four leaves and one bud, free from pests and diseases, and with uniform growth. The seedlings were 45 days old, 8-10 cm tall, with white and well-developed roots and no aging roots. The strawberry seedlings were transplanted into disposable planting cups and managed routinely for 10 days after transplanting. After the growth stabilized and there were no weak or slow-growing seedlings, the uniformly growing plants were selected and grouped into 10 groups of 10 plants each. Each group was subjected to 3 biological replicates.

[0053] Each group was fertilized once, with each plant receiving 3.0 ± 0.3 g of fertilizer.

[0054] The blank control group (CK group) was treated with conventional fertilizer (commercially available general-purpose fruit and vegetable nitrogen-phosphorus-potassium compound fertilizer, 15-15-15).

[0055] Group 1, applying the fertilizer of Example 1.

[0056] Group 2, applying the fertilizer from Example 2.

[0057] Three groups were treated with the fertilizer described in Example 3.

[0058] Four groups were treated with the fertilizer described in Example 4.

[0059] Five groups were treated with the same fertilizer as Comparative Example 1.

[0060] Group 6 was treated with the same fertilizer as control group 2.

[0061] Group 7 was treated with the same fertilizer as control group 3.

[0062] Eight groups were treated with the same fertilizer as control group 4.

[0063] Nine groups were treated with fertilizer of the same ratio as 5.

[0064] After 7 days of fertilization and maintenance, the plants were transferred to an artificial climate chamber and subjected to uniform low-temperature stress: constant temperature of 18-22℃ and normal light management during the day, and controlled temperature of -2-0℃ at night, with continuous low-temperature stress for 12 hours / day for 3 consecutive days.

[0065] After the low-temperature stress ended and the temperature returned to normal, the plants were managed normally for 7 days. The recovery of the plants from frost damage was observed. Samples were taken uniformly, and physiological indicators were measured on the upper functional leaves of the plants. Each treatment was repeated 3 times. The chilling injury grade of each group of plants was calculated and the chilling injury index was calculated. The plants were then managed normally. Flowering, fruit setting, and fruit development were continuously observed. The rate of deformed fruit, single fruit weight, sugar content, vitamin C content, and final yield were calculated. The results are shown in Tables 1 and 2.

[0066] Table 1: Data on various indicators of strawberry after low-temperature stress The p-values ​​between the groups were less than 0.05.

[0067] Table 2: Data on various indicators of strawberry after low-temperature stress The p-values ​​between the groups were less than 0.05. The deformed strawberry fruits in Table 2 were: obviously wedge-shaped fruits with flattened fruit ends and asymmetrical fruit shape; fan-shaped fruits with wide and flat fruit surfaces and obvious fruit distortion; and cockscomb-shaped fruits with fused cracks and severe fruit deformities.

[0068] 2) Chili peppers The tested variety, Zunyi Chaotian chili pepper, was selected. Seedlings with five leaves and one bud, uniform growth, no disease or pests, and a seedling age of 35 days were selected. The chili pepper seedlings were transplanted into disposable planting cups. After transplanting, the seedlings were managed routinely for 10 days. After the growth was stable and there were no weak seedlings, the plants with uniform growth were selected and grouped into 10 groups, with 10 plants in each group. Each group was biologically replicated 3 times.

[0069] Apply fertilizer to each group accordingly.

[0070] Each group was fertilized once, with each plant receiving 2.8 ± 0.3 g of fertilizer.

[0071] The blank control group (CK group) was given conventional fertilizer (commercially available general-purpose fruit and vegetable nitrogen-phosphorus-potassium compound fertilizer, 15-15-15).

[0072] Group 1, applying the fertilizer of Example 1.

[0073] Group 2, applying the fertilizer from Example 2.

[0074] Three groups were treated with the fertilizer described in Example 3.

[0075] Four groups were treated with the fertilizer described in Example 4.

[0076] Five groups were treated with the same fertilizer as Comparative Example 1.

[0077] Group 6 was treated with the same fertilizer as control group 2.

[0078] Group 7 was treated with the same fertilizer as control group 3.

[0079] Eight groups were treated with the same fertilizer as control group 4.

[0080] Nine groups were treated with fertilizer of the same ratio as 5.

[0081] After 7 days of fertilization and maintenance, the plants were transferred to an artificial climate chamber and subjected to uniform low-temperature stress: constant temperature of 18-22℃ and normal light management during the day, and controlled temperature of -2-0℃ at night, with continuous low-temperature stress for 12 hours / day for 3 consecutive days.

[0082] After the low-temperature stress ended and the temperature returned to normal, the plants were managed normally for 7 days. The recovery of the plants from frost damage was observed. Samples were taken uniformly, and physiological indicators were measured on the upper functional leaves of the plants. Each treatment was repeated 3 times. The chilling injury grade of each group of plants was calculated and the chilling injury index was calculated. The plants were then managed normally. Flowering, fruit setting, and fruit development were continuously observed. The rate of deformed fruit, single fruit weight, sugar content, vitamin C content, and final yield were calculated. The results are shown in Tables 3 and 4.

[0083] Table 3: Data on various indicators of chili peppers after low-temperature stress The p-values ​​between the groups were less than 0.05.

[0084] Table 4: Data on various indicators of chili peppers after low-temperature stress (Part 2) The p-values ​​between the groups were less than 0.05.

[0085] Table 4 lists the deformed pepper fruits as follows: fruits that are obviously asymmetrical, with slight bending, local depressions, and disordered petal shapes; fruits that are severely bent, wrinkled, flat, and small, with pointed, crooked, or hollow fruits; and fruits whose development is severely hindered, exhibiting stiff, finger-like, cracked, or deformed conjoined fruits.

[0086] 3) Cabbage The tested variety, Xiaoza 56, was selected. The seedlings were 30 days old, with four leaves and one heart, uniform growth, and no disease or pests. The seedlings were transplanted into disposable planting cups and managed routinely for 10 days. After the seedlings had stabilized and there were no weak or slow-growing seedlings, the uniformly growing plants were selected and grouped into 11 groups with 10 plants in each group. Each group was subjected to 3 biological replicates.

[0087] Each group was fertilized once, with each plant receiving 2.2 ± 0.3 g of fertilizer.

[0088] The blank control group (CK group) was given conventional fertilizer (commercially available general-purpose fruit and vegetable nitrogen-phosphorus-potassium compound fertilizer, 15-15-15).

[0089] Group 1, applying the fertilizer of Example 1.

[0090] Group 2, applying the fertilizer from Example 2.

[0091] Three groups were treated with the fertilizer described in Example 3.

[0092] Four groups were treated with the fertilizer described in Example 4.

[0093] Five groups were treated with the same fertilizer as Comparative Example 1.

[0094] Group 6 was treated with the same fertilizer as control group 2.

[0095] Group 7 was treated with the same fertilizer as control group 3.

[0096] Eight groups were treated with the same fertilizer as control group 4.

[0097] Nine groups were treated with fertilizer of the same ratio as 5.

[0098] After 7 days of fertilization and maintenance, the plants were transferred to an artificial climate chamber and subjected to uniform low-temperature stress: constant temperature of 18-22℃ and normal light management during the day, and controlled temperature of -2-0℃ at night, with continuous low-temperature stress for 12 hours / day for 3 consecutive days.

[0099] After the low-temperature stress ended and the temperature returned to normal, the plants were managed normally for 7 days. The recovery of the plants from frost damage was observed. Samples were taken uniformly, and physiological indicators were measured on the upper functional leaves of the plants. Each treatment was repeated 3 times. The chilling injury grade of each group of plants was calculated and the chilling injury index was calculated. The plants were then managed normally. Flowering, fruit setting, and fruit development were continuously observed. The rate of deformed fruit, single fruit weight, sugar content, vitamin C content, and final yield were calculated. The results are shown in Tables 5 and 6.

[0100] Table 5: Data on various indicators of Chinese cabbage after low-temperature stress The p-values ​​between the groups were less than 0.05.

[0101] Table 6: Data on various indicators of Chinese cabbage after low-temperature stress (Part 2) P < 0.05 among the groups. Table 6 shows the grading of cabbage head compactness: Grade 1: extremely loose head, leaves not closed, outer leaves spread out, no head-forming characteristics; Grade 2: loose head, leaves slightly clustered, hollow inside, extremely poor compactness; Grade 3: average head, leaves basically formed, moderate compactness, slightly soft when pressed; Grade 4: compact head, leaves full and regular, firm when pressed, no obvious softness; Grade 5: extremely compact head, dense and full, hard when pressed.

[0102] As shown in Tables 1 to 6, the cold-resistant fertilizers for fruits and vegetables in Examples 1 to 4 all demonstrated significant cold injury prevention and post-freezing repair capabilities for strawberries, peppers, and cabbages—three different families and genera of cold-sensitive fruits and vegetables. Example 1 showed the best cold resistance performance, outperforming the blank control (CK), the other examples, and all comparative examples in all aspects. Regarding physiological indicators of low-temperature stress, compared to the conventional compound fertilizer (CK) group, Example 1 showed a significant decrease in the cold injury index for strawberries, peppers, and cabbages, with a reduction in leaf relative conductivity exceeding 60%. SOD antioxidant enzyme activity and the content of the osmotic regulator proline both increased by more than two times. Relative conductivity directly reflects the degree of cell membrane damage; a significant decrease indicates that the fertilizer can effectively reduce cytoplasmic leakage caused by low temperatures and alleviate irreversible cell membrane damage. The simultaneous and significant increase in SOD and proline confirms that the fertilizer can activate the plant's endogenous stress resistance system, enhance the ability to scavenge reactive oxygen species and regulate cell osmotic activity under low temperatures, and physiologically resist cold injury. In terms of crop yield and crop comparison, the yield per plant of all three crops in Example 1 was significantly increased compared to the control group. Specifically, the rate of deformed fruit in strawberries and peppers decreased significantly, and the firmness of the cabbage head was significantly improved. The soluble solids content of the fruit, vitamin C content, and soluble sugar content of the cabbage were all significantly increased. This indicates that the fertilizer of this invention not only alleviates the physiological damage caused by low-temperature stress but also promotes the accumulation and translocation of photosynthetic products, reducing low-temperature-induced defects such as deformed fruit and loose, non-heading fruit, thus simultaneously increasing yield and improving quality.

[0103] The dosage of broad bean straw fermentation liquid in Examples 1 to 3 increased in a gradient, and the amount of broad bean straw fermentation liquid added affected the strength of the fertilizer's cold resistance. Example 2 had the lowest dosage of broad bean straw fermentation liquid, with its various cold resistance, yield, and quality indicators all lower than Examples 1 and 3. However, more broad bean straw fermentation liquid is not necessarily better. Comparatively, Example 2 showed the best effect. Analysis of Example 3 suggests that the synergistic ratio of active components may have been unbalanced, leading to a decrease in marginal effect. Comparative Examples 3 (lacking sugarcane bagasse) and 4 (lacking peanut shells) showed significantly worse results than Example 1 in all indicators. Both showed increased chilling injury index, decreased stress-resistant substance content, and simultaneous decreases in yield and quality, demonstrating a synergistic effect between dried peanut shells and desweetened sugarcane bagasse. After extraction, the filter residue, modified with citric acid, forms a porous carrier capable of loading large amounts of micronutrients for long-term, slow-release at low temperatures. Compared to conventional fertilizers, this avoids the problem of sudden nutrient release at low temperatures. Furthermore, the cellulose and lignin-degraded polysaccharides carried in the filter residue help stabilize cell structure, further ensuring cold resistance. Comparative Example 1 used rice straw fermentation liquid instead of broad bean straw fermentation liquid. Compared to Example 1, the chilling injury index of the three crops increased significantly, while the SOD and proline contents decreased significantly. Comparative Example 2, which lacked broad bean straw fermentation liquid and only used concentrated filtrate from peanut shells and sugarcane bagasse, resulted in a significant increase in chilling injury damage to all crops, with minimal improvement in quality and yield. Combining Comparative Examples 1 and 2, it is evident that broad bean straw fermentation liquid plays an irreplaceable role in the cold resistance effect of this invention. Comparative Example 5 simultaneously removed peanut shells and sugarcane bagasse, and replaced the citric acid-treated filter residue with biochar modified with citric acid. Its cold resistance and yield-increasing and quality-improving effects were significantly inferior to those of Comparative Examples 1 and 2. However, they were far inferior to those of Example 1. Combining Examples 1, 2, and 5, it can be seen that after the extraction of peanut shells and sugarcane bagasse, the application of citric acid modification of the extract and filter residue has a synergistic effect with the fermentation liquid of broad bean straw.

[0104] When this cold-resistant fertilizer is applied to large-scale farmland planting, it should be applied in a single, concentrated application 6-10 days before a cold snap or late spring frost. Throughout the entire growth period, it is mainly used during the seedling stage, budding stage, and the early fruit expansion stage, which are sensitive to low temperatures. Application is done by single-sided trenching around the roots. Dig a shallow trench 8-10 cm deep 10-15 cm away from the outer edge of the plant roots, evenly spread the fertilizer, cover with soil, lightly press, and water lightly. The recommended application rate is 28-30 kg / mu (approximately 0.067 hectares).

[0105] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A cold-resistant fertilizer for fruits and vegetables, characterized in that, The raw materials for its preparation consist of the following components in parts by weight: 10-25 parts dried peanut shells, 15-50 parts dried sugarcane bagasse, 15-30 parts macronutrient fertilizer, 5-10 parts chelated micronutrient fertilizer, 1-3 parts boric acid, and 8-35 parts broad bean straw fermentation liquid. Based on the total amount of raw materials used in preparation, the macro-element fertilizer is composed of 10-15 parts of potassium dihydrogen phosphate, 3-10 parts of potassium nitrate and 2-5 parts of urea. The chelated micronutrient fertilizer is composed of chelated calcium, chelated magnesium, and chelated zinc using EDTA as a chelating agent. The preparation of the broad bean straw fermentation liquid includes the following steps: a. Select dry broad bean stalks, crush them, soak them in clean water at room temperature, and then drain them; b. After adding broad bean straw, fermentation agent and water into the fermentation tank, ferment at a constant temperature of 28-32℃ for 5-8 days with ventilation. During the fermentation process, control the moisture content of the material to be 58%-62% and maintain the oxygen concentration in the fermentation tank at 8%-12%. Stir once every 18-24 hours. c. After fermentation is complete, filter to remove solid residue and collect the filtrate, which is the broad bean straw fermentation liquid; The broad bean straw mentioned refers to broad bean straw that has undergone low-temperature acclimatization during autumn sowing and spring harvesting after at least 20 consecutive days of average daily temperature below 10℃.

2. The cold-resistant fertilizer for fruits and vegetables according to claim 1, characterized in that, Based on the total amount of raw materials used in preparation, the chelated micronutrient fertilizer is composed of 2-4 parts of chelated calcium, 1-3 parts of chelated magnesium, and 1-3 parts of chelated zinc.

3. The cold-resistant fertilizer for fruits and vegetables according to claim 1, characterized in that, In step b, the mass ratio of broad bean straw: water: fermentation agent is 100:(200-500):(2-5).

4. The cold-resistant fertilizer for fruits and vegetables according to claim 3, characterized in that, The fermentation agent is composed of Bacillus subtilis and Lactobacillus plantarum in a live bacteria mass ratio of (1-3):

1.

5. A method for preparing a cold-resistant fertilizer for fruits and vegetables according to any one of claims 1 to 4, characterized in that, Includes the following steps: 1) Crush the dried peanut shells and dried sugarcane bagasse separately and mix them together. Add water at a solid-liquid ratio of 1:(15-20) (g / ml). Then, reflux and extract at a constant temperature of 65-80℃ for 2-3 times, each extraction lasting 80-120 minutes. 2) After combining the extracts, solid-liquid separation is performed to obtain filtrate and filter residue. The filtrate is concentrated to a solid content of 10-30%. 3) After drying the filter residue to a moisture content of ≤12%, immerse the filter residue in a citric acid aqueous solution, stir at room temperature, and then dry it again to obtain dry base residue; 4) Mix the broad bean straw fermentation liquid and the concentrated filtrate from step 2), and homogenize to obtain a composite active liquid; 5) Add the dry base residue obtained in step 3), macro-element fertilizer, chelated micro-element fertilizer and boric acid into the compound active liquid, stir evenly, and obtain fertilizer; 6) Fertilizer can be prepared into 2-4mm fertilizer granules using a room temperature extrusion granulation process.

6. The method for preparing a cold-resistant fertilizer for fruits and vegetables according to claim 5, characterized in that, The dried sugarcane bagasse in step 1) is sugarcane bagasse with residual sugar content ≤1% after sugar removal treatment.

7. The application of the cold-resistant fertilizer for fruits and vegetables according to any one of claims 1 to 6 in the low-temperature protection and / or frost damage repair of low-temperature sensitive fruits and vegetables.

8. The application according to claim 7, characterized in that, The fruits and vegetables mentioned include strawberries, peppers, and cabbage.

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