Application of nano-zinc molybdate in promoting crop growth and absorption of nitrogen, phosphorus and potassium

Abstract

The application relates to application of nano zinc molybdate in promoting crop growth and nitrogen, phosphorus and potassium absorption. In view of the problems of low utilization efficiency of traditional molybdenum fertilizer and molybdenum deficiency in some tobacco planting areas in China, the nano zinc molybdate is dissolved in deionized water and subjected to ultrasonic dispersion treatment; when tobacco grows to the 4-5 leaf stage, foliar spraying is carried out, spraying is carried out once every 3 days, the spraying amount is 30 mL per tobacco plant each time, and the tobacco grows to the rosette stage; in the spraying process, the pot mouth is covered with transparent plastic to avoid contact between the nano particles and the soil medium. The nano molybdenum fertilizer can also significantly improve the transport capacity of molybdenum elements in tobacco, promote the transport of molybdenum elements from the roots to the aboveground parts, and further optimize the absorption and utilization efficiency of nutrients. The application provides a new technical approach for high-yield and high-quality cultivation of tobacco, and has important application value and popularization prospect.

Description

TECHNICAL FIELD

[0001] The application relates to the field of nano-fertilizers, and particularly relates to application of a nano-zinc molybdate in promoting crop growth and nitrogen, phosphorus and potassium accumulation. BACKGROUND

[0002] Molybdenum is an essential nutrient element for plant growth and development, and plays a crucial role in biological nitrogen fixation, nitrate assimilation, plant hormone synthesis and active oxygen metabolism in plants. In agricultural production, the application of molybdenum fertilizer has a significant effect on improving the yield and quality of various crops. However, the utilization efficiency of traditional molybdenum fertilizer is often limited, mainly due to its low solubility and difficulty in being effectively absorbed and utilized by plants. In addition, the soil in some parts of China has different degrees of molybdenum deficiency, with the average content of total molybdenum being 1.7 mg / kg, and the effective molybdenum content being lower than the critical value of molybdenum deficiency (0.15 mg / kg), which further limits the growth and yield improvement of crops.

[0003] Taking flue-cured tobacco as an example, as an economic crop with high demand for molybdenum, its yield and quality are closely related to the absorption and utilization of molybdenum element. The yield of tobacco leaves mainly depends on the dry matter accumulation of tobacco plants, and the quality is closely related to the absorption of nutrients such as nitrogen, phosphorus and potassium in tobacco plants and their distribution in the body of tobacco plants. Nitrogen is an important chemical element that constitutes various organs of tobacco plants, and promotes the growth and development of roots, stems and leaves of tobacco plants, which is of great significance to improve the yield and quality of tobacco leaves. Phosphorus is involved in the synthesis of important substances such as phosphoric acid, phospholipids, phytic acid and nucleoprotein in tobacco plants, can promote nitrogen metabolism and carbohydrate synthesis and transport, and increase the sugar content in tobacco leaves, which is essential for improving the color and aroma of tobacco. Potassium is a quality element of tobacco, which can improve the aroma quality, aroma amount, eating taste and burning property of tobacco by promoting protein metabolism and various enzyme reaction processes in tobacco plants, and reduce the content of nicotine, nicotine and cyanide in tobacco leaves, thereby reducing the harm to human body. Molybdenum element plays an important role in promoting nitrogen metabolism, phosphorus utilization and potassium absorption of tobacco, thereby directly affecting the yield and quality of tobacco. However, due to the limitations of traditional molybdenum fertilizer, the growth of tobacco is often restricted by molybdenum deficiency.

[0004] In fact, the influence of molybdenum on various crops is crucial. For example, in leguminous plants, molybdenum is an important part of nitrogenase and is crucial to the process of biological nitrogen fixation; in gramineous crops, molybdenum is involved in the reduction process of nitrate nitrogen, affecting the absorption and utilization of nitrogen; in various fruit and vegetable crops, molybdenum can promote photosynthesis of plants and improve the yield and quality of fruits. Therefore, improving the utilization efficiency of molybdenum fertilizer and solving the problem of soil molybdenum deficiency are of great significance to promote the growth and yield improvement of various crops.

[0005] In recent years, nanotechnology has been increasingly applied in the field of agriculture. Nano-fertilizers, with their unique physical and chemical properties such as high specific surface area, good dispersibility, and slow nutrient release characteristics, have significantly improved the bioavailability of nutrients. Previous studies have shown that nano-molybdenum fertilizer exhibits obvious advantages in promoting crop growth, improving yield and quality. However, the application of nano-molybdenum fertilizer in the production of various crops is still insufficient, especially in addressing soil molybdenum deficiency and improving molybdenum absorption and utilization efficiency of crops.

[0006] Therefore, to address the low utilization efficiency of traditional molybdenum fertilizer and the soil molybdenum deficiency in some areas, it is of great significance to develop efficient nano-molybdenum fertilizer and explore its application potential in the production of various crops. By introducing nano-molybdenum fertilizer, it is expected to solve the above problems, further promote the nutrient absorption efficiency of crops, improve the yield and quality of crops, and provide a new technical approach for the sustainable development of agricultural production. SUMMARY

[0007] The present application aims to solve the problems of low utilization efficiency of traditional molybdenum fertilizer and soil molybdenum deficiency in some areas of China, and proposes a new type of nano-molybdenum fertilizer and its application method. The main component of the nano-molybdenum fertilizer is nano-zinc molybdate. Through pot experiment verification, the nano-molybdenum fertilizer shows significant advantages in promoting crop growth and nitrogen, phosphorus, and potassium accumulation.

[0008] In view of the deficiencies of the prior art, the present application provides an application of nano-zinc molybdate in promoting crop growth efficiency and nitrogen, phosphorus, and potassium accumulation. The nano-zinc molybdate is Zn9Mo8O 33 NPs.

[0009] The average particle size of the nano-zinc molybdate Zn9Mo8O 33 NPs is 5-50 nm.

[0010] The average particle size of the nano-zinc molybdate Zn9Mo8O 33 NPs is 25.15 nm.

[0011] The crop is flue-cured tobacco.

[0012] The nano-zinc molybdate is used for the following purposes: increasing the plant height, maximum leaf length, maximum leaf width, fresh weight of aboveground part, dry weight of aboveground part, dry weight of underground part, and fresh weight of underground part of flue-cured tobacco;

[0013] increasing the total sugar content of flue-cured tobacco leaves;

[0014] improving the nitrogen content and nitrogen accumulation of flue-cured tobacco leaves and transporting them to the leaves;

[0015] improving the phosphorus accumulation of flue-cured tobacco leaves, the phosphorus distribution rate of flue-cured tobacco leaves, and promoting the transportation of phosphorus from stems to leaves;

[0016] Improve the potassium content of flue-cured tobacco leaves, the potassium accumulation of leaves, and the potassium transport from stems to leaves.

[0017] The nano-molybdenum fertilizer is applied by the following ways:

[0018] Step 1: Dissolve the nano-molybdenum fertilizer in deionized water;

[0019] Step 2: When the flue-cured tobacco grows to the 4-5 leaf stage, carry out foliar spraying, spray every 3 days, and the spraying amount is 30 mL per flue-cured tobacco plant each time, and spray 3 times in total;

[0020] Step 3: During the spraying process, cover the pot opening with transparent plastic to avoid the nano-molybdenum fertilizer solution from contacting the soil medium.

[0021] The concentration of the nano-molybdenum fertilizer solution is 50-500 ppm.

[0022] In step 2, spray 15 mL in the morning and 15 mL in the evening.

[0023] The beneficial effects of the present application are: through the pot experiment verification, the nano-molybdenum fertilizer shows significant advantages in promoting the growth of flue-cured tobacco and the absorption and accumulation of nitrogen, phosphorus and potassium. Under the treatment of nano-zinc molybdate, the plant height, leaf length, leaf width and total sugar content of flue-cured tobacco leaves are significantly improved, and the nitrogen, phosphorus and potassium accumulation of flue-cured tobacco leaves is increased by at least 30.61%, 39.94% and 48.78% respectively compared with the control. In addition, the nano-molybdenum fertilizer can also significantly improve the transport capacity of molybdenum elements in flue-cured tobacco, promote the transport of molybdenum elements from the roots to the aboveground parts, and further optimize the absorption and utilization efficiency of nutrients. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The morphology and particle size distribution of the three kinds of nano-molybdenum fertilizers; A-C: TEM images of nano-molybdenum oxide, nano-zinc molybdate and nano-potassium molybdate; D-F: particle size distribution of nano-molybdenum oxide, nano-zinc molybdate and nano-potassium molybdate;

[0025] Figure 2 Effect of different forms of molybdenum fertilizer on the biomass of flue-cured tobacco;

[0026] Figure 3 Effect of different forms of molybdenum fertilizer on the total sugar content of flue-cured tobacco leaves;

[0027] Figure 4 Effect of different forms of molybdenum fertilizer on the nitrogen absorption and transport of flue-cured tobacco;

[0028] Figure 5 Effect of different forms of molybdenum fertilizer on the phosphorus absorption and transport of flue-cured tobacco;

[0029] Figure 6 Effect of different forms of molybdenum fertilizer on the potassium absorption and transport of flue-cured tobacco. DETAILED DESCRIPTION

[0030] The following detailed description of a nano-molybdenum fertilizer and its application method for improving the growth efficiency and nitrogen, phosphorus, and potassium accumulation of flue-cured tobacco, based on specific embodiments, is provided only to illustrate the invention in more detail and should not be construed as limiting the invention in any way.

[0031] The flue-cured tobacco variety used in the following examples is "Yunyan 87," which was provided by Wengfu Group Co., Ltd. Nano-molybdenum fertilizer mainly includes nano-molybdenum oxide (MoO3NPs) and nano-zinc molybdate (Zn9Mo8O). 33 Both the NPs and nano-potassium molybdate (K2MoO4NPs) were provided by Sino-Australian Nanomaterials Technology Co., Ltd.

[0032] The soil samples used in the following examples were collected from Xinzhou District, Wuhan City, Hubei Province. This soil is a typical molybdenum-deficient acidic yellow-brown soil. Its physicochemical properties are as follows: pH value 4.69, organic matter content 18.06 g kg⁻¹, available potassium content 62.47 mg kg⁻¹, available phosphorus content 7.42 mg kg⁻¹, alkaline nitrogen content 72.8 mg kg⁻¹, while available molybdenum content is only 0.10 mg kg⁻¹, indicating a significant molybdenum deficiency in this soil. This unique soil condition provides an ideal control environment for this invention's study on the promoting effect of nano-molybdenum fertilizer on flue-cured tobacco growth and nutrient absorption, highlighting the unique advantages of nano-molybdenum fertilizer in improving molybdenum-deficient soil and enhancing crop yield and quality.

[0033] Example 1

[0034] This embodiment is used to illustrate the characterization of the nano-molybdenum fertilizer involved in the present invention.

[0035] In practice, 10 mg of nano molybdenum fertilizer was dissolved in 50 mL of anhydrous ethanol, and ultrasonically treated for 30 min. The suspension was then collected using a copper mesh for electron microscopy and allowed to air dry naturally before being sent to the electron microscopy platform of Huazhong Agricultural University to observe its morphology and distribution.

[0036] Transmission electron microscopy (TEM) characterization results showed that the nano-molybdenum oxide exhibited a sheet-like structure and relatively uniform dispersion. Figure 1 (A) Through statistical analysis of the particle size in the figure, the average particle size of the nano-molybdenum oxide (MoO3) NPs is 10–130 nm, with an average particle size of 38.05 nm. Furthermore, the nano-zinc molybdate exhibits an irregular structural morphology and a slightly aggregated distribution. Figure 1 In section B), based on the particle statistics in the figure, nano-zinc molybdate Zn9Mo8O 33The average particle size of the NPs is 5-50 nm, and the average particle size is 25.15 nm. The nano-potassium molybdate presents a unique droplet structure and a small amount of mesoporous characteristics Figure 1 The average particle size of the NPs is 5-50 nm, and the average particle size is 25.15 nm. The nano-potassium molybdate presents a unique droplet structure and a small amount of mesoporous characteristics

[0037] Example 2

[0038] This example is used to illustrate that the nano-molybdenum fertilizer involved in the present application can improve the growth efficiency and nitrogen, phosphorus and potassium accumulation of flue-cured tobacco at an appropriate concentration.

[0039] This example provides a potting test method for foliar spraying of nano-molybdenum fertilizer for flue-cured tobacco, and the specific steps are as follows:

[0040] Test environment and conditions: The test was carried out in the greenhouse of the Potting Field of Huazhong Agricultural University, and the light cycle was controlled to be 16 hours of light and 8 hours of darkness, the temperature was 25°C, and the humidity was 30%.

[0041] Seed germination and transplanting of flue-cured tobacco: The seeds of flue-cured tobacco were placed in a seedling tray filled with vermiculite for germination, and cultured for 45 days. When the seedlings reached two-leaf-one-heart stage, uniform seedlings were selected.

[0042] The selected seedlings were transplanted into pots containing 4 kg of soil (the size of the pot is 15.5 cm in diameter at the top, 12.5 cm in diameter at the bottom, and 17.5 cm in height), and one seedling was planted in each pot.

[0043] Soil fertilization: The amounts of N, P2O5 and K2O added to each 1 kg of soil were 0.24 g, 0.24 g and 0.48 g, respectively. The fertilizers used in the test were superphosphoric acid and potassium sulfate, both of which were of analytical purity (AR). Deionized water was used for irrigation during the growth and development period of tobacco.

[0044] Test treatment and spraying:

[0045] The test was set up with 5 treatment groups: CK (deionized water), T1 ammonium molybdate (ordinary molybdenum fertilizer), T2 nano-molybdenum oxide, T3 nano-zinc molybdate, and T4 nano-potassium molybdate. Each treatment group was set up with 4 replicates.

[0046] The nano-molybdenum fertilizer was suspended in deionized water and ultrasonically dispersed for 30 minutes to ensure that the molybdenum concentration was 200 mg / L (200 ppm).

[0047] When the plants grew to 4-5 leaf stage, foliar spraying treatment was carried out. Spraying was carried out every 3 days, a total of 3 times, and the amount of spraying was 30 mL / day (15 mL in the morning and 15 mL in the evening).

[0048] During the spraying process, the pot opening was covered with transparent plastic to avoid contact between the nano-particles and the soil medium.

[0049] Sampling and analysis:

[0050] When the tobacco seedlings grow to the rosette stage, sampling and subsequent analysis are performed.

[0051] Test items and methods

[0052] Agronomic trait investigation: According to the standard of YC / T 142-2010, the plant height, stem diameter, maximum leaf length, width, and effective leaf number of tobacco were measured.

[0053] Biomass determination: After harvesting the tobacco samples, washing and drying, the fresh weight was recorded; 105℃ fixation for 30 min, drying at 60℃ to constant weight, and recording the dry weight.

[0054] Chlorophyll content determination: Using SPAD-502 chlorophyll meter and 95% ethanol extraction method, the absorbance at wavelengths of 649 nm, 665 nm, and 470 nm was measured, and the contents of chlorophyll a, b, carotenoids, and total chlorophyll were calculated.

[0055] Plant nitrogen, phosphorus, and potassium nutrient determination: Using H2SO4-H2O2 digestion method, the total nitrogen, phosphorus, and potassium contents were determined by flow analyzer and flame photometer, and the element accumulation, distribution rate, and transport coefficient were calculated.

[0056] Plant molybdenum content determination: After sample digestion with HNO3 / HClO4 mixed acid, the molybdenum content was determined by ICP-MS.

[0057] Total sugar content determination: 3,5-dinitrosalicylic acid colorimetric method was used.

[0058] Compared with the control group (CK), the maximum leaf length and width of flue-cured tobacco at the rosette stage under T3 (nano zinc molybdate) treatment showed significant growth, with an increase of 23.06% and 22.89%, respectively. It is worth noting that the spraying of molybdenum fertilizer treatment had no significant effect on the stem diameter and effective leaf number of flue-cured tobacco (Table 1). In addition, the effects of different molybdenum fertilizer treatments on the agronomic traits of flue-cured tobacco showed significant differences. Specifically, compared with the traditional ammonium molybdate treatment (T1), spraying nano zinc molybdate (T3) and nano potassium molybdate (T4) showed superior effects on improving key agronomic indicators such as plant height, maximum leaf length, maximum leaf width, and effective leaf number.

[0059] Table 1 Effects of different forms of molybdenum fertilizer on the agronomic traits of flue-cured tobacco

[0060]

[0061] Under the specific treatments T1, T3, and T4, the fresh weight of the aboveground part increased by 17.42%, 33.35%, and 35.21% respectively compared with CK (Figure 2 The underground and aboveground dry weight of flue-cured tobacco under T3 and T4 treatments were significantly higher than that of CK, with an increase of 26.08%, 31.17% and 31.57%, 28.88% respectively Figure 2 The aboveground fresh weight under T3 and T4 treatments was significantly higher than that of CK, with an increase of 13.56% and 15.15% respectively, while the aboveground dry weight was increased by 13.73% and 11.40% respectively. In summary, spraying molybdenum fertilizer can effectively increase the biomass of different parts of flue-cured tobacco, and the effect of T3 and T4 treatments is the most significant.

[0062] Figure 3 The results showed that spraying different types of molybdenum fertilizer could effectively increase the total sugar content of flue-cured tobacco leaves, with an increase range of 2.73% to 22.96%. The application of molybdenum fertilizer also increased the total sugar content of leaves Figure 3 Specifically, the total sugar content of leaves under T1, T2 and T3 treatments was significantly increased by 31.62%, 27.49% and 39.84% respectively, while T4 treatment increased by 7.99%. In summary, spraying molybdenum fertilizer can significantly increase the total sugar content of tobacco leaves, which indicates that molybdenum fertilizer has a positive effect on the carbon metabolism of tobacco leaves.

[0063] Figure 4 The results showed that the nitrogen content of roots under T4 treatment was significantly increased by 48.27%, while the nitrogen content of stems and leaves had no significant difference. Compared with T1, nano-molybdenum fertilizer had little effect on the nitrogen content of roots and stems, and only the nitrogen content of leaves under T3 treatment was significantly increased by 6.68% Figure 4 The nitrogen accumulation of leaves under T3 and T4 treatments was significantly higher than that of other treatments, with an increase of 30.61% and 22.95% respectively compared with CK, and an increase of 18.86% and 11.88% respectively compared with T1 Figure 4

[0064] Compared with CK, the phosphorus content of roots and leaves under molybdenum treatment had no significant change, and only the phosphorus content of stems under T2 treatment was increased by 15.76% Figure 5 The phosphorus accumulation of roots and stems under T4 treatment was the highest, and the phosphorus accumulation of leaves under T3 and T4 treatments was higher, with an increase of 39.94% and 25.64% respectively compared with CK Figure 5

[0065] Figure 6 ​​The results show that under the treatment of molybdenum, the potassium content of tobacco root and stem is significantly higher than that of CK. Under the treatment of T3 and T4, the potassium content of leaf is increased by 14.35% and 10.04% respectively compared with CK. Compared with T1, the potassium content of leaf under T3 treatment is increased by 8.36%. Compared with CK, the potassium accumulation of root and stem under T4 treatment is significantly increased, with an increase of 47.06% and 71.28% respectively; the potassium accumulation of leaf under T1, T3 and T4 treatment is increased by 23.04%, 48.78% and 36.63% respectively. Compared with T1, the potassium accumulation of root under T4 treatment is significantly increased by 38.09%, and the potassium accumulation of leaf under T3 treatment is significantly increased by 20.92% Figure 6

[0066] In the production process of flue-cured tobacco, T3 treatment (i.e. nano zinc molybdate treatment) shows significant advantages compared to other molybdenum fertilizer treatments. Specifically, nano zinc molybdate not only significantly improves the biomass accumulation of flue-cured tobacco, but also greatly promotes the absorption and accumulation of key nutrient elements such as nitrogen, phosphorus and potassium in flue-cured tobacco, thereby optimizing the yield and quality of flue-cured tobacco.

[0067] From the perspective of biomass accumulation, the fresh weight and dry weight of flue-cured tobacco above ground under T3 treatment are significantly increased, which are increased by 33.35% and 29.95% respectively compared with the control group (see the results in the specific embodiment). This indicates that nano zinc molybdate significantly promotes the growth and development of flue-cured tobacco above ground, laying a solid foundation for high yield.

[0068] In terms of nutrient absorption and accumulation, the accumulation of nitrogen, phosphorus and potassium in flue-cured tobacco leaf under T3 treatment is increased by at least 30.61%, 39.94% and 48.78% respectively compared with the control group (see the data in the specific embodiment). The accumulation of these key nutrients directly improves the intrinsic quality of tobacco leaf. The increase of nitrogen element promotes the growth and development of various organs of tobacco plant, the accumulation of phosphorus element improves the color and aroma of flue-cured tobacco, and the increase of potassium element significantly enhances the aroma quality, aroma amount and combustion of flue-cured tobacco, while reducing the content of harmful substances.

[0069] Especially worth mentioning is that nano zinc molybdate also significantly improves the transport capacity of molybdenum element in flue-cured tobacco, promoting the transport of molybdenum element from root to above ground (see the specific embodiment). This efficient nutrient transport mechanism enables flue-cured tobacco to make full use of soil nutrient resources, further improving the utilization efficiency of nutrients.

[0070] ​In summary, T3 treatment (nano zinc molybdate) provides strong technical support for high yield and quality cultivation of flue-cured tobacco by significantly improving biomass accumulation, promoting absorption and accumulation of key nutrients, and unique advantages in nutrient transport. This finding not only solves the problem of low utilization efficiency of traditional molybdenum fertilizer and soil molybdenum deficiency in some tobacco-growing areas, but also injects new vitality into the sustainable development of the flue-cured tobacco industry.

[0071] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary and that certain changes and modifications can be made thereto without departing from the principles and spirit of the application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. An application of nano-zinc molybdate in promoting crop growth efficiency and nitrogen, phosphorus, and potassium accumulation, characterized in that, The chemical formula of the nano-zinc molybdate is Zn9Mo8O. 33 The average particle size of NPs, nano zinc molybdate is 5–50 nm.

2. The application according to claim 1, characterized in that, The nano zinc molybdate Zn9Mo8O 33 The average particle size of the NPs is 25.15 nm.

3. The application according to claim 1, characterized in that, The crop in question is flue-cured tobacco.

4. The application according to claim 3, characterized in that, The nano-zinc molybdate is used for the following purposes: increasing the plant height, maximum leaf length, maximum leaf width, above-ground fresh weight, above-ground dry weight, underground dry weight, and underground fresh weight of flue-cured tobacco. Increase the total sugar content of flue-cured tobacco leaves; Increase the nitrogen content and nitrogen accumulation in flue-cured tobacco leaves and promote nitrogen translocation within the leaves; Increase phosphorus accumulation in flue-cured tobacco leaves, phosphorus allocation rate in leaves, and promote phosphorus translocation from stems to leaves; Increase the potassium content and potassium accumulation in flue-cured tobacco leaves, and promote the translocation of potassium from the stem to the leaves.

5. The application according to claim 3, characterized in that, The nano-molybdenum fertilizer is applied in the following manner: Step 1: Dissolve the nano-molybdenum fertilizer in deionized water; Step 2: When the flue-cured tobacco grows to the 4-5 leaf stage, spray the leaves once every 3 days, with each spraying amount being 30mL per plant, for a total of 3 sprays.

6. The application according to claim 5, characterized in that, The concentration of the nano-molybdenum fertilizer solution is 50–500 ppm.

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