A fertilization method for okra planting

Abstract

A kind of fertilization method for okra planting, during the fruiting period of okra, water and fertilizer mixture required for the growth of okra in the fruiting stage is sent to the soil in the root area of okra in the form of multiple topdressing using drip irrigation system, and the raw materials of each water and fertilizer mixture include, by weight: 18-20 parts of nitrogen, phosphorus and potassium compound fertilizer, 0.4-0.6 parts of water-soluble amino acid fertilizer, 0.8-1.2 parts of microbial agent, and the balance is water. The fertilization method uses the fertilization mode of increasing the application of special fertilizer (self-made water and fertilizer mixture) and reducing the application of conventional fertilizer, which can effectively slow down the aging of okra fruits and prolong the harvesting period of okra fruits (i.e. prolong the shelf life) to create higher production efficiency. Especially during the fruiting period of okra, the soil element nutrition is optimized in the form of multiple topdressing and through the synergistic effect of the film mulching drip irrigation system, which can significantly improve the nutritional quality of okra fruits (i.e. fruit pods) and delay the aging process, and the effect of soil environment regulation is remarkable.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically to a fertilization method for okra cultivation. Background Technology

[0002] Okra is an annual herbaceous plant belonging to the Malvaceae family and the genus Abelmoschus. Its pods are the main edible part, harvested primarily as young pods during the hot season. Due to its wide adaptability and high economic value, okra has become a specialty vegetable and is cultivated throughout China in recent years. Our research group (the inventors' team) conducted extensive cultivation experiments on okra in western Fujian province, studying its plant growth characteristics, fruit commercial characteristics, and yield traits. Previous research indicates that the harvest period for young okra pods is very short, generally 6-7 days after flowering in western Fujian. If harvested in time, the pods quickly age, becoming coarse and tough, rendering them inedible. The main reason for okra pod aging is the continuous increase in cellulose content. In agricultural production, to ensure okra yield and quality, growers need to harvest okra pods promptly. However, high labor costs and labor shortages pose challenges. Therefore, slowing down okra pod aging and extending shelf life has become an urgent problem to be solved in okra production.

[0003] Currently, reports on alleviating okra fruit fibrosis (i.e., aging) mostly focus on post-harvest treatment or hormone therapy. However, there are few reports on slowing down fruit fibrosis from the perspective of okra cultivation fertilization, and fertilization mainly relies on conventional chemical fertilizers. Therefore, in order to slow down okra fruit aging and extend its shelf life, this application provides a fertilization method for okra cultivation. The aim is to extend the harvest period (i.e., extend the shelf life) of okra fruits through fertilization (i.e., topdressing), thereby creating higher production efficiency for future use of topdressing to delay okra aging and extend the fresh consumption period. Summary of the Invention

[0004] This invention provides a fertilization method for okra cultivation to overcome the shortcomings of existing okra cultivation methods, such as the short harvest period of young okra fruits and the easy aging of okra fruits.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A fertilization method for okra cultivation: During the fruiting period of okra, a drip irrigation system is used to deliver a water-fertilizer mixture required for the growth of okra in the fruiting stage to the soil in the root zone of okra in multiple top dressings. Each water-fertilizer mixture contains the following raw materials by weight: 18-20 parts of nitrogen, phosphorus and potassium compound fertilizer, 0.4-0.6 parts of amino acid water-soluble fertilizer, 0.8-1.2 parts of microbial inoculant, and the remainder is water.

[0006] Furthermore, the nitrogen-phosphorus-potassium compound fertilizer is a water-soluble nitrogen-phosphorus-potassium compound fertilizer, and the nitrogen, phosphorus and potassium nutrient contents of the water-soluble nitrogen-phosphorus-potassium compound fertilizer are 18% nitrogen, 9% phosphorus and 18% potassium, respectively.

[0007] Furthermore, the microbial agent is Genleshi compound microbial agent, which contains a variety of beneficial live bacteria (such as methyltrophic Bacillus, Bacillus licheniformis, etc.), plant active substances (such as humic acid, alginic acid, polyglutamic acid, plant polysaccharides, etc.) and mineral nutrients (such as nitrogen, phosphorus, potassium and trace elements such as calcium, magnesium, iron, molybdenum, zinc, and boron).

[0008] Furthermore, during the okra seedling stage, a seedling vigor and root potential stimulation treatment is adopted. Specifically, in the seedling cultivation stage from seed sowing to transplanting, a specially formulated compound seedling substrate is used. This compound seedling substrate is based on conventional peat moss, vermiculite, and perlite, with 5%-10% well-rotted high-quality organic fertilizer, 1%-3% seaweed fertilizer, and 0.5%-1% compound probiotic agent added by weight as a fertilizer substrate. When the seedlings grow to 2-3 true leaves, foliar spraying is used to apply amino acid water-soluble fertilizer at a concentration of 300-500 times, once every 7-10 days, for 2-3 consecutive times.

[0009] Furthermore, during the okra planting period, an early treatment for constructing the microecology of the okra root zone soil is adopted. Specifically, at the bottom of the dug planting hole, conventional compound fertilizer is first applied as base fertilizer and mixed slightly with the bottom soil; then, 50-100 grams of granular bio-organic fertilizer per hole is thoroughly mixed with the soil in the hole; finally, the seedlings with their soil clumps are planted into this mixed soil.

[0010] Furthermore, during the mid-stage of seedling growth, physiological resistance and metabolic reserve induction treatments are employed. Specifically, after the seedlings have recovered from transplanting and entered the rapid vegetative growth period, foliar nutrition and signal induction are carried out. The method of foliar nutrition and signal induction is as follows: a mixture of 0.1% sugar alcohol calcium solution, 0.05% potassium silicate solution, and 0.0075% brassinolide solution is sprayed on the leaves at a rate of 30-40 liters per acre. Generally, foliar spraying is carried out in the evening on a sunny day.

[0011] By adopting the above technical solution, the beneficial effects of this invention are as follows: This fertilization method, which uses a fertilization pattern of increasing the application of special fertilizer (self-made water-fertilizer mixture) and reducing the application of conventional chemical fertilizers, can effectively slow down the aging of okra fruits, extend the harvest period of okra fruits (i.e., extend the shelf life), and create higher production efficiency. Especially during the fruiting period of okra, by using multiple topdressings and optimizing soil element nutrition through synergy with the drip irrigation system under the film, it can significantly improve the nutritional quality of okra fruits (i.e., pods) and delay the aging process, while also having a significant effect on regulating the soil environment. Attached Figure Description

[0012] Figure 1 The effect of different treatments on the cellulose content of okra pods.

[0013] Figure 2 The effects of different treatments on changes in enzyme activity related to okra fruit development, including Figure 2-1 , Figure 2-2 and Figure 2-3 .

[0014] Figure 3 The effects of different treatments on the changes in quality content during the development of okra fruit, including Figure 3-1 , Figure 3-2 and Figure 3-3 . Detailed Implementation

[0015] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0016] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: Example 1

[0017] A fertilization method for okra cultivation involves a seedling strengthening and root potential activation treatment during the seedling stage. Specifically, from seed sowing to transplanting, a specially formulated compound seedling substrate is used. This substrate is based on conventional peat moss, vermiculite, and perlite, with 5%-10% well-rotted high-quality organic fertilizer, 1%-3% seaweed fertilizer, and 0.5%-1% compound probiotic agent (including Bacillus subtilis, Bacillus mucilaginosus, etc.) added by weight as a fertilizer mix. When the seedlings have grown to 2-3 true leaves, a foliar spray of 300-500 times diluted amino acid water-soluble fertilizer (total amino acid content ≥100g / L) is applied every 7-10 days for 2-3 consecutive applications. This stimulation treatment can effectively stimulate the metabolic activity of seedling leaves and roots, enhance nitrogen assimilation capacity, and cultivate robust seedlings with high root vigor and strong stress resistance.

[0018] When okra is in the planting stage, an early treatment for constructing the microecological system of the okra root zone is adopted. Specifically, at the bottom of the dug planting hole, first apply a conventional compound fertilizer as a base fertilizer. This conventional compound fertilizer is an NPK 15-15-15 compound fertilizer, with a dosage of 28-32 kg per acre, and mix it slightly with the base soil. Then, add 50-100 grams of granular bio-organic fertilizer per hole. The parameters of this granular bio-organic fertilizer are: organic matter content ≥45%, effective live bacteria count ≥200 million / g, and rich in functional bacteria such as Trichoderma and Actinomycetes, and mix it thoroughly with the soil in the hole. Finally, plant the seedling with its soil ball into this mixed soil. The purpose of this treatment is to introduce high concentrations of beneficial functional microorganisms into the root surface and rhizosphere soil at the very beginning of crop root colonization, along with abundant organic matter, thereby rapidly forming a "protective" microenvironment that is conducive to root growth, continuously activates soil nutrients, and inhibits soil-borne pathogens. This lays a solid soil biological foundation for the healthy growth and efficient nutrient utilization of the plant throughout its entire growth period.

[0019] When okra seedlings are in the mid-growth stage, physiological resistance and metabolic reserve induction treatment is employed. Specifically, after the transplanting recovery period and during the rapid vegetative growth phase (approximately 15-20 days after transplanting), foliar nutrition and signal induction are performed. This is done by mixing a 0.1% sugar alcohol calcium solution, a 0.05% potassium silicate solution, and a 0.0075% brassinolide solution and spraying the mixture on the leaves at a rate of 30-40 liters per acre. Foliar spraying is generally carried out in the evening on a sunny day. In this induction treatment, the supplementation of silicon and calcium aims to strengthen the cell wall structure of okra seedlings, providing material reserves for the future robustness of fruit cells and stabilizing cell membrane structure. The low concentration of brassinolide, as a highly effective plant growth regulator, aims to gently activate the okra seedlings' own stress-resistance metabolic pathways, regulate endogenous hormone balance, enhance their tolerance to okra seedling stress, and potentially positively regulate physiological processes related to delayed senescence.

[0020] When okra is in its fruiting stage, a drip irrigation system is used to deliver the necessary water-fertilizer mixture to the soil around the okra roots in multiple applications. Each application of the water-fertilizer mixture consists of the following components by weight: 18-20 parts nitrogen-phosphorus-potassium (NPK) compound fertilizer, 0.4-0.6 parts amino acid water-soluble fertilizer, 0.8-1.2 parts microbial inoculant, and the remainder is water. The dilution ratio is 500-1000 times (optimal ratio is 800 times). The NPK compound fertilizer is a water-soluble NPK compound fertilizer with nitrogen, phosphorus, and potassium content of 18% nitrogen, 9% phosphorus, and 18% potassium (also known as NPK (18-9-18)). The microbial agent mentioned is Genleshi compound microbial agent, which contains a variety of beneficial live bacteria (such as methyltrophic Bacillus, Bacillus licheniformis, etc.), plant active substances (such as humic acid, alginic acid, polyglutamic acid, plant polysaccharides, etc.), and mineral nutrients (such as nitrogen, phosphorus, potassium, and trace elements such as calcium, magnesium, iron, molybdenum, zinc, and boron). The topdressing is applied three times, starting on July 3rd each year using a drip irrigation system, once every 10 days, for a total of three applications. This fertilization pattern, which increases the application of special fertilizer (a self-made water-fertilizer mixture) and reduces the application of conventional chemical fertilizers, effectively slows down the aging of okra fruits, extends the harvest period (i.e., extends shelf life), and creates higher production efficiency.

[0021] The drip irrigation system described is existing technology. Existing drip irrigation under mulch film is a water-saving agricultural irrigation method that combines drip irrigation with mulch film covering. It involves laying drip irrigation tape (capillary tubes) under the mulch film, integrating drip irrigation with the mulch film. Liquid (such as water or nutrient solution) is delivered evenly and accurately directly to the soil near the crop roots through the outlet in the form of droplets for the crop to absorb and utilize. The structure and working principle of the drip irrigation system will not be described in detail here.

[0022] Soil, as the core carrier of crop nutrient supply, directly affects the nitrogen and carbon metabolism of plants through the activities of urease and sucrase. Insufficient nitrogen supply accelerates the decomposition of pod protein and indirectly promotes cellulose accumulation. Therefore, the inventors and their team selected 'fruit okra' as the material and conducted research on topdressing during the fruiting stage of fruit okra. The fruit okra is a variety of okra. Simultaneously, pod aging-related indicators (such as cellulose content, aging rate, and metabolic enzyme activity), nutritional quality, and soil physicochemical and enzyme activities of fruit okra were measured to clarify the synergistic regulatory effect of topdressing on 'soil environment-plant metabolism-pod aging / quality', providing a theoretical basis for delaying okra aging through fertilization methods in production. The research steps of this topdressing method are as follows: 1. Materials and Methods 1.1 Experimental Materials and Design The field trial was conducted from April to August 2024 at the Longmen Base of the Longyan Municipal Institute of Agricultural Sciences. A randomized block design was used, with 5 treatments, each replicated 3 times, for a total of 15 plots, surrounded by protective rows. The experimental beds were 1.1 meters wide with furrows, using a double-row planting pattern. The okra was planted with a spacing of 40cm × 60cm, with 30 plants per plot. The tested variety was 'Fruit Okra', sown on April 18, 2024, and seedlings of uniform growth were selected for transplanting on May 16. Before transplanting, 1000 kg / 667 m² of Jiangping organic fertilizer (organic matter ≥45%, N-P2O5-K2O ≥5%) and 25 kg / 667 m² of calcium magnesium phosphate fertilizer (P2O5 ≥18%) were incorporated into the soil and mixed thoroughly. Apply as base fertilizer; Sakefu compound fertilizer (N-P2O5-K2O=15-15-15) 30kg / 667m² 2 Calcium magnesium phosphate fertilizer (P2O5≥18%) 25kg / 667m 2 Planting and management practices followed the standard practices for okra production. A drip irrigation system was used, with drip tape laid between two rows of plants on the raised bed at 30cm intervals. The dripper flow rate was 2L / h, and irrigation was synchronized with topdressing. Starting July 3rd, a fertigation system was used to apply fertilizer every 10 days for a total of 3 applications. The experiment included 5 treatments (each applied per 667m²). 2 Dosage), CK: Traditional topdressing control (Sakefu water-soluble fertilizer, N-P2O5-K2O=18-9-18, 30kg / 667m 2 T1: Sake-rich water-soluble fertilizer (N-P2O5-K2O=18-9-18, 30kg / 667m³) 2 ) + urea (N≥46%, 2kg / 667m 2 T2: Sake-rich water-soluble fertilizer (N-P2O5-K2O=18-9-18, 2kg / 667m³) 2 + Amino acid-containing water-soluble fertilizer (total amino acid content ≥230g / L, 500x dilution) + Genleshi (live bacteria count ≥2 billion / ml, 1L / 667m³) 2 T3: Sake-rich water-soluble fertilizer (N-P2O5-K2O=18-9-18, 20kg / 667m³) 2 ) + Alginic acid-containing organic water-soluble fertilizer (organic matter 45.0-55.0%, 1500 times dilution) + Genleshi (live bacteria count ≥2 billion / ml, 1L); T4: Sakefu water-soluble fertilizer (N-P2O5-K2O=18-9-18, 20kg / 667m 2 ) + Chitosan (purity ≥90%, 2kg / 667m 2 ) + Genleshi (live bacteria count ≥ 2 billion / ml, 1L / 667m 2The concentration settings were based on the results of previous pretreatment studies.

[0023] 1.2 Soil physicochemical properties at the experimental site The basic physicochemical properties of the tested soil were: pH 5.23, organic matter 31.47 g / kg. -1 Total nitrogen 1.45 g•kg -1 Total potassium 16.48 g•kg -1 Alkaline nitrogen uptake: 152.65 mg / kg -1 Available phosphorus 64.8 mg•kg -1 And readily available potassium 257.63 mg•kg -1 .

[0024] 1.3 Sample Collection and Index Measurement Soil samples from the 0-30cm layer were collected at multiple points in the experimental area using the "S"-shaped method. The soil samples were then mixed thoroughly to form a composite sample. The physicochemical properties of the soil in each plot were then determined.

[0025] Because the nutrient supply from a single topdressing is easily affected by external environmental factors, and the initial soil fertility of the experimental plots is uneven, which may further aggravate the differences in nutrient absorption by plants, ultimately leading to unstable differences in fruit indicators among different treatments, to ensure the reliability of the experimental results, pods were collected on August 7th at the peak fruiting stage, 4, 5, 6, 7, 8, and 9 days after flowering. Ten pods were randomly collected from each treatment to determine the nutritional quality of the pods (soluble sugar, soluble protein, total flavonoids, etc.), aging-related indicators (cellulose content, aging rate), and the activity of cellulose metabolic enzymes (CesA, Kor, β-GC). Cauliflower was planted in the experimental field as the previous crop. Soil samples were taken after cauliflower harvest (April 10th) to determine relevant indicators, and again 10 days after the last topdressing (August 9th) for soil sampling. Quality determination: The determination of plant soluble protein (sPRO), soluble sugar, total flavonoids (TFH), vitamin C, cellulose content, cellulose synthase (CesA), cellulase (Kor), and β-glucosidase (β-GC) was performed using a kit from Tianjin Kevino Biotechnology Co., Ltd. Fresh okra was washed, boiled in boiling water for 2 minutes, and then cooled to an edible temperature. Samples were randomly arranged. Aged okra was defined as okra with some fruit fibers that were difficult to chew; the aging rate was calculated as (aged samples / total number of samples) * 100%. See Table 1 below.

[0026] 1.4 Data Processing and Analysis Data statistics and analysis were performed using WPS Office 2023 and SPSS Statistics 26.0 software. Duncan's new multiple range method was used to compare the significance of differences between treatments.

[0027] 2 Results and Analysis 2.1 Synergistic effects of different treatments on the senescence process of okra pods and cellulose metabolic enzymes The effects of different treatments on the aging rate of okra pods are shown in Table 1 above. As can be seen from Table 1, 7 days after flowering is the key turning point for pod aging: the aging rate of the CK treatment increases rapidly from 7 days after flowering, while the aging process of the T1, T2 and T3 treatments is significantly delayed, with the aging rate still at 0% at 7 days after flowering. The T2 treatment has the best effect, with the lowest aging rate of only 10.00% at 8 days after flowering. At 9 days after flowering, the aging rate of the other four treatments is 100.00%, while the fruit aging rate of the T2 treatment is 50.00%, which is at least 2 days later than that of the CK treatment.

[0028] Instruction manual attached Figure 1 The effect of different treatments on the cellulose content of okra pods. Figure 1 The results show that the cellulose content of okra pods exhibits a similar trend, gradually increasing with fruit development and ripening. The cellulose content of all five treatments reaches its highest value on the 9th day after flowering, specifically CK 277.42 mg / g. -1 T1263.09mg•g -1 T2236.57mg•g -1 T3256.46mg•g -1 and T4280.28mg•g -1 . Figure 1 In the T1 treatment, the cellulose content of the pods was lower than that of the CK treatment 4-9 days after flowering, indicating that the application of a small amount of urea can improve the tenderness of the pods. In the T2 treatment, the increase in cellulose content was slower than that of the other treatments 5-8 days after flowering, with an increase of only 3.27%. Combined with the aging rate results in Table 1, the T2 treatment significantly slowed down the aging of the pods compared to the CK. In the T3 treatment, the cellulose content was slightly higher than that of the CK 4-5 days after flowering, and lower than that of the CK 6-9 days after flowering. In the T4 treatment, the cellulose content was slightly lower than that of the CK 8 days after flowering, and higher than that of the CK at other times.

[0029] Instruction manual attached Figure 2 To investigate the effects of different treatments on the changes in enzyme activity related to okra fruit development, the following study was conducted. Figure 2 (like Figure 2-1 As shown in the figure, the activity of cellulose synthase (CesA) gradually increased with the development and maturation of okra pods. The CesA activity of all five treatments reached its peak on the 9th day after flowering, with the values ​​of CK 3.16 U•L. -1 T13.33U•L -1 T23.41U•L -1 T33.28U•L -1 and T42.99U•L -1During different stages of the late flowering period, the CesA activity of treatments T1-T3 was higher than that of the control (CK) treatment, with the T2 treatment showing the highest overall CesA activity. Further analysis of the growth rate showed that the CesA activity growth rate of the T2 treatment was 23.5% lower than that of the CK treatment from 5-8 days after flowering; and the CesA activity growth rate of the CK treatment accelerated significantly from 7 days after flowering, while the growth rate of the T2 treatment remained gradual. This gradual growth trend effectively reduced the accumulation of cellulose in the pods, laying the foundation for delaying aging.

[0030] like Figure 2-2 As shown, cellulase (Kor) activity also gradually increased with pod development and maturation. The Kor activity of all five treatments reached its highest value on the 9th day after flowering, which was 2.35 U•L for CK. -1 T12.32U•L -1 T22.52U•L -1 T32.48U•L -1 and T42.25U•L -1 In terms of aging regulation, although the T1 and T3 treatments could maintain a 0% aging rate 7 days after flowering and play a certain role in delaying aging, the aging rate rose to 100% 9 days after flowering, and the regulation effect on cellulose metabolic enzymes was significantly weaker than that of the T2 treatment. The T4 treatment, due to excessively high Kor activity, accelerated the decomposition of the pod cell wall, resulting in an aging rate of 100% 8 days after flowering, and its aging process was faster than that of the CK.

[0031] As shown in Figure 2-3, the activity of β-glucosidase (β-GC) showed the opposite trend to the two enzymes mentioned above, gradually decreasing as the pods matured. The β-GC activity in all five treatments reached its peak on the fourth day after flowering. During the critical period of 5-9 days after flowering, the β-GC activities of treatments T1, T2, and T3 were all higher than the control (CK) treatment, with the advantage of treatment T2 being particularly significant. From 7 to 9 days after flowering, the β-GC activity of treatment T2 was 12.8%–18.5% higher than that of CK. This difference may be because treatment T2, by increasing β-GC activity, accelerated the decomposition of synthesized cellulose in the pods, thereby further reducing the degree of fibrosis and synergistically delaying pod aging.

[0032] 2.2 Effects of different treatments on the physicochemical properties and enzyme activity of okra rhizome soil Table 2 below shows the effects of different treatments on the physicochemical properties of okra rhizome soil.

[0033] Table 2 shows that the effects of different topdressing treatments on the improvement of soil physicochemical indicators in the okra root zone varied, but all treatments improved basic soil fertility: In terms of total nitrogen content, treatments T1, T2, and T4 increased by 1.16%, 1.55%, and 0.39% compared to the control (CK), respectively, with T2 showing the most significant improvement; total potassium content was most significantly improved in treatment T3, increasing by 23.77% compared to CK, far exceeding other treatments; in terms of available phosphorus content, the differences between topdressing treatments (T2-T4) and CK were all statistically significant, indicating that topdressing effectively replenishes soil phosphorus; in terms of available potassium content, treatment T4 performed exceptionally well, significantly increasing by 9.30% compared to CK, providing sufficient support for plant potassium absorption; alkaline nitrogen content showed the most significant improvement in treatment T2, significantly increasing by 6.66% compared to CK, enhancing soil nitrogen supply efficiency; in terms of organic matter content, treatments T1-T4 showed significant improvements compared to CK... The increases were 3.87%, 10.61%, 5.17%, and 8.86%, respectively. Although the differences between each treatment and the control (CK) were not statistically significant, the T2 treatment showed the largest increase. In summary, different topdressing treatments can improve soil physicochemical properties and basic soil fertility by increasing the content of nitrogen, potassium, phosphorus, and other nutrients in the soil, as well as the accumulation of organic matter, thereby promoting the nutrient reserves in the okra root zone to varying degrees.

[0034] Table 3 below shows the effects of different treatments on soil enzyme activity in the rhizosphere of okra.

[0035] Table 3 shows that the effects of topdressing treatments on the regulation of soil enzyme activities in the okra rhizosphere varied. Regarding soil urease activity, treatment T1 showed no significant difference from the control (CK), while treatments T2, T3, and T4 were significantly higher than the CK, with treatments T2 and T3 showing the most significant improvement, enhancing soil nitrogen conversion efficiency. As for sucrase activity, all topdressing treatments (T1-T4) showed no significant difference from the CK, indicating that the activity of this enzyme was less affected by the tested topdressing method. Soil cellulase activity did not show significant differences between any treatment and the CK, indicating that topdressing had a limited regulatory effect on this enzyme. Catalase activity reflects the intensity of soil microbial activity; treatment T3 showed a significant increase of 135.53% in catalase activity compared to the CK, while treatments T2 and T4, although not showing a significant difference, also showed some improvement, indicating that topdressing can enhance soil ecological function by activating soil microbial activity. In summary, different topdressing treatments can increase the activity of soil enzymes in the rhizosphere of okra to varying degrees, with more significant effects on the regulation of urease and catalase, providing biological support for soil nutrient transformation and plant absorption.

[0036] 2.3 Effects of different treatments on the changes in quality content during the development of okra fruit Instruction manual attached Figure 3 To investigate the effects of different treatments on the changes in quality content during the development of okra fruits, the following study was conducted. Figure 3 (like Figure 3-1 As shown in the figure, the trends of soluble protein content in okra pods were basically similar across the five treatments, showing an initial increase followed by a decrease. The soluble protein content reached its maximum value on the 7th day after flowering in all five treatments, at 1396.07 ng•g. -1 1295.82 ng•g -1 1503.76ng•g -1 1646.71ng•g -1 and 1674.56ng•g -1 The content of T1 treatment was lower than that of CK treatment only on day 7 after flowering, and higher than that of CK treatment at all other stages after flowering. The content of T2, T3 and T4 treatments was higher than that of CK treatment from day 4 to day 9 after flowering, with the content of T4 treatment being the highest at all stages.

[0037] like Figure 3-2 The results show that the soluble sugar content in the pods of all five treatments initially increased and then decreased during development. In the early stages of development, soluble sugars accumulated continuously. As the fruit further developed, the soluble sugar content gradually increased, and then decreased as the fruit began to age. In the control (CK) treatment, the soluble sugar content reached its maximum of 3207.58 μg / g on day 5 after flowering. -1 Treatments T1, T2, and T3 reached their maximum values ​​on day 6 after flowering, at 3311.41, 2836.78, and 3410.29 ug•g, respectively. -1 In the T4 treatment, the peak value of soluble sugars appeared no later than day 7 after flowering, and the highest value was 3355.91 ug•g. -1 .

[0038] like Figure 3-3 The results show that the total flavonoid content during pod development exhibits a similar trend, initially increasing and then decreasing. The total flavonoid content in treatments T2, T3, and T4 was higher than the control at all stages. In treatment T1, the total flavonoid content was lower than the control 4-7 days after flowering, but higher than the control 8-9 days after flowering. The highest total flavonoid content in treatments T2-T4 was 0.25 mg / g at 6 days after flowering. -1 0.25 mg•g -1 and 0.28 mg•g -1 .

[0039] 3. Discussion Chemical fertilizers play a crucial role in increasing plant yields, contributing between 40% and 50%.

[22] To achieve high yields, growers often resort to excessive fertilizer application. However, this overuse of chemical fertilizers can lead to various problems such as reduced quality, decreased fertilizer utilization, and exacerbated continuous cropping obstacles. This study investigated a topdressing treatment combining reduced chemical fertilizer application with increased application of special fertilizers. The results showed that the T2-T4 treatment (reduced application of 20% of the chemical fertilizer, combined with water-soluble fertilizers containing amino acids, seaweed extract, and chitin + Root-Plant Solution) not only optimized soil nutrient levels through synergy with the drip irrigation system, but also significantly improved the nutritional quality of pods and slowed down the aging process. Furthermore, it demonstrated significant effects in regulating the soil environment. Specific analysis follows: Drip irrigation's uniform water supply avoids soil compaction caused by traditional irrigation. Combined with mulching to reduce water evaporation, it improves soil aeration, creating suitable conditions for microbial activity (such as urease synthesis) and indirectly enhancing the effect of topdressing. From the perspective of soil elemental nutrition, the T2-T4 treatments, through the drip irrigation system under mulch, precisely delivered fertilizer to the root zone, reducing nutrient leaching loss. Even with a 20% reduction in chemical fertilizer application, it still significantly increased the content of key soil nutrients. The T2 treatment showed significantly higher levels of available nitrogen and phosphorus compared to the control (CK), providing a stable supply for plant nitrogen and phosphorus absorption. The T3 and T4 treatments showed significantly higher levels of total potassium (H) and available potassium compared to the CK, effectively supplementing the potassium needed for okra growth. Furthermore, while the organic matter content of the soil in the T2-T4 treatments was not statistically significant compared to the CK, it still demonstrated an effect on soil carbon accumulation, consistent with the research finding that "the application of organic fertilizer can increase soil organic matter content."

[0040] From the perspective of soil environmental regulation, the uniform water supply characteristics of the drip irrigation system under the mulch film avoid soil compaction caused by traditional irrigation. Combined with the reduction of water evaporation due to mulch film covering, it significantly improves soil aeration, creating suitable conditions for soil microbial activity. The T2 treatment showed increased soil urease activity, which accelerates the conversion of soil organic nitrogen to available nitrogen, further enhancing soil nitrogen supply efficiency. The T3 treatment showed significantly higher catalase activity than the control (CK). Catalase activity is a core indicator reflecting the intensity of soil microbial activity; its increase indicates enhanced soil microbial community activity, promoting soil organic matter decomposition and nutrient cycling. Simultaneously, the soil sucrase and cellulase activities in the T2-T4 treatments were all higher than those in the pure fertilizer treatments (CK and T1), further confirming the optimizing effect of reducing chemical fertilizer application and applying functional organic fertilizer on the soil enzyme system. This demonstrates that this topdressing model is scientifically sound in improving the soil environment, creating a healthy root zone environment for okra growth. Therefore, reducing chemical fertilizers and applying organic fertilizers during topdressing has a more positive effect on improving the soil nutrient retention capacity of okra, the accumulation of soil organic matter, and the regulation of soil microorganisms and enzyme activity.

[0041] In terms of delaying pod aging, the T1-T3 treatments effectively delayed pod aging through the synergistic effect of regulating the balance of cellulose metabolic enzymes and the soil environment, with the T2 treatment showing the best effect. Looking at aging indicators, the pod aging rate of the control (CK) reached 10.00% 7 days after flowering, while the T1-T3 treatments remained at 0%; 9 days after flowering, the aging rate of the T2 treatment was only 50.00%, delaying aging by at least 2 days compared to the CK, and the pod cellulose content was reduced by 14.7% compared to the CK. From the perspective of the regulatory mechanism, on the one hand, the T2 treatment achieved a dual regulation of cellulose "reduced synthesis + accelerated degradation" by inhibiting the growth rate of cellulose synthase (CesA) activity and increasing β-glucosidase (β-GC) activity; on the other hand, the optimization of the soil environment provided support for delaying aging. The increased soil urease activity of the T2 treatment ensured a continuous supply of nitrogen, avoiding pod protein decomposition and compensatory cellulose accumulation due to nitrogen deficiency, while improved soil aeration reduced premature plant aging, further delaying the pod aging process. Example 2

[0042] This embodiment is basically the same as Embodiment 1 in its implementation, except that during the fruiting period of okra, a drip irrigation system is used to deliver the water-fertilizer mixture required for the growth of okra in the fruiting stage to the soil in the root zone of okra in multiple top dressings. Each water-fertilizer mixture contains, by weight, 18-20 parts of high-potassium nitrogen-phosphorus-potassium water-soluble fertilizer (15-5-30), 0.4-0.6 parts of humic acid water-soluble fertilizer, 0.8-1.2 parts of granular microbial fertilizer, and the remainder is water. The dilution ratio is 500 times. The nitrogen, phosphorus, and potassium nutrient content of the high-potassium nitrogen-phosphorus-potassium water-soluble fertilizer is 15% nitrogen, 5% phosphorus, and 30% potassium (also known as NPK (15-5-30)). The granular microbial fertilizer comprises, by weight, 55 parts of well-rotted sheep manure, 3 parts of Bacillus subtilis (20 billion / g), 1 part of Trichoderma harzianum (5 billion / g), 8 parts of potassium humate (humic acid ≥50%), 1 part of borax (B ≥11%), 0.5 parts of zinc sulfate (Zn ≥22%), 8 parts of bentonite, and 1 part of maltodextrin. Example 3

[0043] This embodiment is basically the same as Embodiment 1 in its implementation, except that during the fruiting period of okra, a drip irrigation system is used to deliver the water-fertilizer mixture required for okra growth during the fruiting stage to the soil in the root zone of the okra multiple times. Each water-fertilizer mixture, by weight, includes: 18-20 parts water-soluble NPK compound fertilizer, 0.4-0.6 parts amino acid water-soluble fertilizer, 0.4-0.6 parts seaweed extract water-soluble fertilizer, 0.8-1.2 parts microbial inoculant, 1.8-2.2 parts chitosan, and the remainder is water. The dilution ratio is 1000 times. The seaweed extract water-soluble fertilizer is emphasized for its more significant effect on the okra plant's resistance to stress and fruit retention. The chitosan is emphasized for delaying leaf aging, preventing diseases, and protecting against high-temperature stress, thus avoiding the problem of rapid fruit decay after 2-3 harvests of okra.

[0044] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A fertilization method for okra cultivation, characterized in that: During the fruiting period of okra, a drip irrigation system is used to deliver the water-fertilizer mixture required for the growth of okra in the fruiting stage to the soil in the root zone of okra in multiple top dressings. Each water-fertilizer mixture contains the following raw materials by weight: 18-20 parts of nitrogen, phosphorus and potassium compound fertilizer, 0.4-0.6 parts of amino acid water-soluble fertilizer, 0.8-1.2 parts of microbial agent and the remainder is water.

2. The fertilization method for okra cultivation according to claim 1, characterized in that: The nitrogen-phosphorus-potassium compound fertilizer is a water-soluble nitrogen-phosphorus-potassium compound fertilizer, and the nitrogen, phosphorus and potassium nutrient contents of the water-soluble nitrogen-phosphorus-potassium compound fertilizer are 18% nitrogen, 9% phosphorus and 18% potassium.

3. The fertilization method for okra cultivation according to claim 1, characterized in that: The microbial agent is Genleshi compound microbial agent, which contains a variety of beneficial live bacteria, plant active substances and mineral nutrients.

4. The fertilization method for okra cultivation according to claim 1, characterized in that: During the okra seedling stage, a seedling strengthening and root potential stimulation treatment is adopted. Specifically, in the seedling cultivation stage from seed sowing to transplanting, a specially formulated compound seedling substrate is used. This compound seedling substrate is based on conventional peat moss, vermiculite, and perlite, with 5%-10% well-rotted high-quality organic fertilizer, 1%-3% seaweed fertilizer, and 0.5%-1% compound probiotic agent added by weight as fertilizer substrate. When the seedlings grow to 2-3 true leaves, foliar spraying is used to apply amino acid water-soluble fertilizer at a concentration of 300-500 times, once every 7-10 days, for 2-3 consecutive times.

5. The fertilization method for okra cultivation according to claim 1, characterized in that: During the okra planting period, an early treatment for constructing the microecology of the okra root zone soil is adopted. Specifically, at the bottom of the dug planting hole, conventional compound fertilizer is first applied as base fertilizer and mixed slightly with the bottom soil. Then, 50-100 grams of granular bio-organic fertilizer per hole is thoroughly mixed with the soil in the hole. Finally, the seedlings with soil balls are planted into this mixed soil.

6. The fertilization method for okra cultivation according to claim 1, characterized in that: During the mid-stage of seedling growth, physiological resistance and metabolic reserve induction treatments are employed. Specifically, after the seedlings have recovered from transplanting and entered the rapid vegetative growth period, foliar nutrition and signal induction are carried out. The method of foliar nutrition and signal induction is as follows: 0.1% sugar alcohol calcium solution, 0.05% potassium silicate solution and 0.0075% brassinolide solution are mixed and sprayed on the leaves at a rate of 30-40 liters per acre. Generally, foliar spraying is carried out in the evening on a sunny day.

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