Potassium sulfate fertilizer and marking method thereof

Abstract

The invention discloses a potassium sulfate fertilizer and a marking method thereof. The marking method comprises the following steps: S1, mixing rubidium sulfate and potassium sulfate powder to obtain a mixed reagent; s2, preparing the rubidium sulfate and potassium sulfate mixed reagent into a saturated solution; s3, heating and evaporating the saturated solution to obtain marked potassium sulfate fertilizer particles. The physical and chemical properties of the obtained marked potassium sulfate fertilizer test product are similar to those of the existing potassium sulfate fertilizer, replacement of fertilizer application can be realized, a soil potassium source and a fertilizer potassium source can be distinguished, the absorption and utilization effects of crops on different potassium sources are further determined, and a more reliable method is provided for reasonable application of the potassium fertilizer.

Description

Technical Field

[0001] The invention relates to a potassium sulfate fertilizer and a marking method thereof, belonging to the technical field of fertilizer detection. Background Art

[0002] Potassium (K) is an essential mineral element for plants and plays an important role in plant growth and development. Tobacco is one of the important economic crops in my country and a typical K-loving crop. Generally, within a reasonable content range that does not cause K toxicity, the higher the K content, the better the quality of tobacco. The K content of high-quality tobacco should generally be higher than 2.5%. The average potassium content of tobacco leaves in my country is generally 1% to 2%, which is significantly lower than the international level. Therefore, increasing the K content in tobacco is of great significance to promoting the development of tobacco in my country.

[0003] The lack of K in the cultivation soil is the main reason that limits tobacco yield and quality. The preferred solution is to apply potassium fertilizer. Potassium sulfate is a commonly used potassium fertilizer in tobacco cultivation in my country. It is used as an effective supplement to tobacco production because of its high potassium content, good solubility and high cost-effectiveness. However, the current application of potassium sulfate in my country is not scientific. There is an over-application of potassium sulfate in many tobacco-growing areas. The imbalance of elements not only affects the quality of tobacco but also causes serious harm to soil health. In order to ensure the sustainable development of agricultural ecology, the rational application of potassium fertilizer is urgent.

[0004] At present, the method for determining the appropriate amount of potassium fertilizer is mostly based on presetting different conventional application amounts, and then multiple comparisons and verifications are carried out in field tests to select the most suitable application amount. The experimental process of this method is cumbersome and its widespread use will cause waste of potassium sulfate. This method belongs to the experimental trial method and lacks in-depth scientific explanation. In contrast, the difference subtraction method is used as the absorption and utilization rate of fertilizer K by applying the appropriate amount of potassium fertilizer and not applying potassium fertilizer. The difference subtraction method is simple to operate and has certain scientificity. However, this method ignores the complex mutual influence between fertilizer K and soil K. From the source, the amount of difference subtraction does not come entirely from fertilizer. There is a promoting effect of fertilizer K on soil K, and then the contribution of soil K during fertilization is different from the contribution of soil K when not fertilizing, thereby causing errors in the utilization of fertilizer K. The applicant believes that the rational application of potassium fertilizer should first clarify the absorption and utilization effect of plants on different K sources (such as soil K source, fertilizer K source), and the direct method to effectively distinguish different potassium sources is to mark the potassium source. In element labeling experiments, the isotope of the element is generally used for tracing. However, for the element K, its isotope 40 K has a long half-life (about 124.8 million years) and 42 The half-life of K is too short (about 12 hours) and is not suitable for tracer experiments. Therefore, from the perspective of practical application, we should find other ways to achieve the labeling of fertilizer K.

[0005] Rubidium labeling uses the trace element rubidium (Rb) as a marker to track and study individual organisms. Rubidium is a natural, non-radioactive element with similar chemical properties to potassium (K), so it can be absorbed in organisms and simulate the behavior of potassium. Currently, rubidium labeling mainly involves watering the root zone of crops with a solution containing rubidium or applying / spraying it on the leaves. However, this method carries the risk of rubidium being washed away and leached with precipitation, so it is mostly used for indoor cultivation; at the same time, its dissolution rate is quite different from that of potassium fertilizer, and it cannot match the release time of potassium fertilizer well, resulting in the inability to indicate the nutrient absorption of long-growing period crops during the growth stage. Summary of the invention

[0006] The first purpose of the present invention is to provide a potassium sulfate fertilizer labeling method to solve the problem in the prior art that it is impossible to accurately, quickly and cheaply judge the utilization of potassium fertilizer crops.

[0007] The second purpose of the present invention is to provide a potassium sulfate fertilizer. The application of the potassium sulfate labeled fertilizer not only meets the growth and nutrient absorption characteristics of tobacco, but also can clarify the utilization of different potassium sources by crops. It is highly targeted and practical and has broad application prospects.

[0008] The technical solution of the present invention is:

[0009] In a first aspect, the present invention provides a method for labeling potassium sulfate fertilizer, comprising the following steps:

[0010] S1, weighing rubidium sulfate and potassium sulfate powder according to the mass ratio;

[0011] S2, preparing a saturated potassium sulfate solution by weighing rubidium sulfate and potassium sulfate powder;

[0012] S3, heating the solution to evaporate it to obtain labeled potassium sulfate fertilizer particles.

[0013] Preferably, in step S1, the mass ratio of rubidium sulfate to potassium sulfate in the mixed reagent is 1:19 to 1:9.

[0014] Preferably, in step S2, a saturated potassium sulfate solution is prepared according to the mass of potassium sulfate, and then the weighed rubidium sulfate is added and stirred until it becomes clear.

[0015] Preferably, in step S3, a mold plate is placed in the solution, a plurality of hemispherical grooves with a diameter of 3-5 mm are provided in the plate (the hemispherical grooves in the mold plate can be set according to needs), the temperature range is set to 40°C to 50°C for heating and evaporation, and after the crystals are condensed and fully covered in the hemispherical grooves, they are immediately taken out and replaced with a new mold to continue condensation, thereby obtaining marked potassium sulfate fertilizer particles.

[0016] In a second aspect, the present invention provides a potassium sulfate fertilizer, wherein labeled potassium sulfate fertilizers having different mass ratios of rubidium sulfate to potassium sulfate are prepared according to the above-mentioned potassium sulfate fertilizer labeling method, and labeled fertilizers having a dissolution rate similar to that of existing potassium sulfate are screened to be used as a substitute. Specifically, the labeled potassium sulfate fertilizer particles are screened and the dissolution rate is compared with that of existing potassium sulfate fertilizers. If the dissolution rate of the labeled potassium sulfate fertilizers of various particle sizes is not equivalent to that of the existing potassium sulfate, the mixed mass ratio of rubidium sulfate to potassium sulfate powder is adjusted until a labeled fertilizer having a dissolution rate similar to that of the existing potassium sulfate is obtained as a substitute for the existing potassium sulfate.

[0017] Preferably, 3-5 mm labeled potassium sulfate granules with 5% or 10% rubidium sulfate addition are selected to replace the existing 3-5 mm granular potassium sulfate fertilizer.

[0018] Technical principle of the present invention: The core principle of the present invention is that "potassium sulfate particles containing different proportions of rubidium sulfate have extremely similar solubility to pure potassium sulfate particles, and the plant absorption behavior of rubidium ions and potassium ions in the soil is consistent." Rubidium (Rb) and potassium (K) are elements of the same main group, with very similar chemical properties, similar atomic outer electron structures, similar ion radii, and only one electron in the outermost layer. They almost have isotopic characteristics, so Rb is used instead of K to study the fate of K element. 86 As a radioactive element, Rb has high experimental requirements and is complex to implement. With the advancement of Rb measurement and analysis technology, non-radioactive Rb is now used for K tracing research. When the Rb concentration is increased in the soil, plants will absorb a large amount of Rb instead of K. The high absorption of Rb may be due to the compensation of the low concentration of K in the soil. Therefore, we believe that the transfer of Rb and K from the soil and their transport mechanisms in plants are similar. Since the K element in plant tissues only comes from soil K and fertilizer K, the sum of the absorption ratios of soil K and fertilizer K is 1. The Rb / K ratio of fertilizer can be known by labeling potassium fertilizer with rubidium, and the proportion of potassium fertilizer absorbed in plant tissues can be calculated by combining the Rb / K ratio of soil and plants. Based on this principle, the present invention labels potassium sulfate with rubidium sulfate to solve the problem of unclear absorption and utilization effects of crops on different K sources from the source, providing technical support for the precise application of potassium fertilizers.

[0019] Beneficial effects of the present invention:

[0020] 1) The rubidium sulfate-labeled potassium sulfate fertilizer provided by the present invention can distinguish the sources of soil potassium and fertilizer potassium for crops, clarify the absorption and utilization effects of different potassium sources by crops, and make the application amount of potassium fertilizer more targeted, more scientific and reasonable.

[0021] 2) The method for marking potassium sulfate fertilizer provided by the present invention is different from the previous method of directly marking by watering the crop root zone with a solution containing rubidium element or applying / spraying it on the leaf surface. The method of the present invention obtains marked potassium sulfate fertilizer particles by mixing rubidium sulfate and potassium sulfate according to a mass ratio, which reduces the amount of rubidium sulfate added and saves money. At the same time, the dissolution rate is similar to that of existing potassium sulfate, greatly prolongs the nutrient release time, and can match the release time of potassium fertilizer, which can indicate the nutrient absorption of long-growth period crops during the growth stage; in addition, the marked potassium sulfate fertilizer reduces the risk of leaching, not only serves as a marker, but also can effectively meet the application needs of tobacco field fertilizers, and is of great practical application significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram for screening labeled fertilizers to replace existing potassium sulfate;

[0023] Figure 2 The rubidium sulfate-labeled potassium sulfate fertilizer obtained after evaporation in the mold (the mold is only for display, and the spacing will be adjusted in actual application to make the mold grooves more dense);

[0024] Figure 3 The crystal particles are taken out from the mold. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0026] Example 1

[0027] A method for labeling potassium sulfate fertilizer comprises the following steps:

[0028] S1, after rubidium sulfate and potassium sulfate powder are passed through a 100-mesh sieve, 1 g of rubidium sulfate and 19 g of potassium sulfate are mixed (rubidium sulfate accounts for 5% of the total mass);

[0029] S2, add 171.2 g of pure water to 19 g of potassium sulfate and stir to prepare a saturated solution of potassium sulfate, then add 1 g of rubidium sulfate and stir until the solution is clear;

[0030] S3, pour the clarified solution into a 250 mL beaker, then put it into a mold, put the beaker into a water bath for heating and evaporation, set the temperature to 50°C until the solution is evaporated, and remove the crystal particles in the groove of the mold to obtain the rubidium sulfate-labeled potassium sulfate fertilizer;

[0031] S4, taking out the crystal particles and sieving them to obtain particle sizes of <2 mm, 2-3 mm, 3-5 mm and >5 mm, and storing them in a dark, dry and cool place.

[0032] Example 2

[0033] A method for labeling potassium sulfate fertilizer comprises the following steps:

[0034] S1, after passing rubidium sulfate and potassium sulfate powder through a 100-mesh sieve, weigh 2 g of rubidium sulfate and 18 g of potassium sulfate respectively (rubidium sulfate accounts for 10% of the total mass);

[0035] S2, add 162.2 g of pure water to 18 g of potassium sulfate and stir to prepare a saturated solution of potassium sulfate, then add 1 g of rubidium sulfate and stir until the solution is clear;

[0036] S3, pour the clarified solution into a 250 mL beaker, then put it into a mold, put the beaker into a water bath for heating and evaporation, set the temperature to 50°C until the solution is evaporated, and remove the crystal particles in the groove of the mold to obtain the rubidium sulfate-labeled potassium sulfate fertilizer;

[0037] S4, taking out the crystal particles and sieving them to obtain particle sizes of <2 mm, 2-3 mm, 3-5 mm and >5 mm, and storing them in a dark, dry and cool place.

[0038] 1. Chemical property analysis

[0039] The dissolution rates of the labeled potassium sulfate fertilizer particles and the existing potassium sulfate are compared to obtain the labeled potassium sulfate fertilizer having similar physical and chemical properties to the existing potassium sulfate.

[0040] The dissolution rates of the labeled potassium sulfate fertilizer granules in Example 1 and Example 2 were compared with those of the existing potassium sulfate in 0.01 M CaCl2 solutions at 5, 15, and 25° C. Since the slow-release fertilizer takes a long time to dissolve, in order to shorten the dissolution time and facilitate comparison of the dissolution effect, the fertilizer granules of the same mass were weighed at the same stirring rate (45 rpm). Table 1-1 shows the dissolution time of the existing potassium sulfate fertilizer granules of different particle sizes at different temperatures and the labeled potassium sulfate fertilizer granules (Note: under the same dissolution conditions, the particles with a particle size of <2 mm and 2-3 mm dissolve too quickly and are not comparable to the existing potassium sulfate, so only the dissolution data of the particles with a particle size of 3-5 mm and >5 mm are taken for display).

[0041] Table 1-1 Dissolution time of reagent particles of different particle sizes at different temperatures

[0042]

[0043] As can be seen from the above table, when the rubidium sulfate content is 5%, the dissolution time of the 3-5mm test product and the 3-5mm spherical potassium sulfate particles is basically similar; when the rubidium sulfate content is 10%, the dissolution time of the test product particles with a particle size of >5mm is basically similar to that of the 3-5mm granular potassium sulfate fertilizer at the same temperature. In summary, the 3-5mm labeled potassium sulfate test product with a 5% rubidium sulfate addition can be optimally replaced with the existing 3-5mm granular potassium sulfate fertilizer, and the 3-5mm labeled potassium sulfate test product with a 10% rubidium sulfate addition can also be generally replaced with the existing 3-5mm granular potassium sulfate fertilizer.

[0044] 2. Accuracy analysis

[0045] 2.1 Potted plant experiment

[0046] Example 1 and Example 2 were applied to potted plant experiments to further verify the accuracy of the rubidium-labeled potassium sulfate granular fertilizer in obtaining the utilization of potassium fertilizer. It should be noted that due to the high price of rubidium sulfate, the direct application of Example 1 and Example 2 is too costly and not conducive to promotion. Therefore, in the actual potted plant experiment, Example 1 and Example 2 need to be mixed with ordinary potassium sulfate at a ratio of 1:100 before application, and the labeling effect is not affected by dilution.

[0047] 2.1.1 Test materials

[0048] The soil used in the potted experiment was collected from the Qianxi Linquan Science and Technology Park of Bijie Tobacco Company in Guizhou Province. The existing potassium sulfate selected in the experiment was Stanley potassium sulfate type compound fertilizer, and the tobacco variety was Yunyan 87.

[0049] 2.1.2 Experimental design

[0050] The pot experiment (flower pot diameter * bottom diameter * pot height is 27.5×22×31cm) was carried out in the Science and Technology Park of China Agricultural University. Each pot was filled with 10kg of soil. After the tobacco seedlings emerged, they were transplanted and one plant was planted in each pot.

[0051] Four treatments were set up in the experiment, CK: no fertilization; T1: application of existing potassium sulfate fertilizer; T2: application of labeled potassium sulfate fertilizer with 0.05% rubidium sulfate addition (100 times dilution of abundance in Example 1); T3: application of labeled potassium sulfate fertilizer with 0.1% rubidium sulfate addition (100 times dilution of abundance in Example 2). Each treatment was repeated 4 times, N: P2O5: K2O = 10: 7: 21, and the fertilizer application amount is shown in Table 2-1. The fertilizer in each treatment was applied once as a base fertilizer before transplanting.

[0052] Table 2-1 Specific fertilizer amounts for different treatments

[0053] deal with <![CDATA[N(kg / hm 2 )]]> <![CDATA[P2O5(kg / hm 2 )]]> <![CDATA[K2O(kg / hm 2 )]]> <![CDATA[Rb(kg / hm 2 )]]> CK 104 73 0 0 T1 104 73 220 0 T2 104 73 219.89 0.11 T3 104 73 219.79 0.22

[0054] 2.1.3 Sample collection and determination

[0055] Soil samples: Collect 1kg of soil from the 0-10cm surface layer in the potted plants, air-dry and pass through a 2mm sieve. Take 5g of air-dried soil and put it into a 200mL centrifuge tube. Add 25mL of 1M ammonium acetate (pH 7) and put it into a shaker. Oscillate at 100rpm for 30min. Then put it into a centrifuge and centrifuge at 2000rpm for 10min. Pour out the supernatant and add 25mL of 1M ammonium acetate (pH 7). Repeat the operation. Filter the mixture with whatman42 filter paper to obtain the supernatant. Use inductively coupled plasma mass spectrometry to determine the K and Rb contents.

[0056] Plant samples: Wash and dry the tobacco plants harvested at maturity, bake them in an oven at 70°C for 72 hours until constant weight, and crush them through a 2mm sieve. Take 2.5g of the sample and heat it in an oven at 105°C for 2 hours, cool it in a dryer, weigh it to determine the oven-dried weight, and then burn it in a muffle furnace at 500°C. Dissolve the ash in 5mL 0.6M HCl solution, dilute it with 10ml deionized water, and filter it through pre-wet Whatman 541 paper into a 50ml volumetric flask. After the crucible is thoroughly rinsed, wash the filter paper three times and make up to volume with deionized water. The K and Rb contents of the plants were determined using an inductively coupled plasma mass spectrometer.

[0057] 2.1.4 Calculation formula

[0058]

[0059] 2.2 Results and Analysis

[0060] As shown in Table 2-2, the soil Rb / K ratios in each treatment were similar, and the Rb / K ratios in plants were T3>T2>T1>CK. In fertilizer, the Rb / K ratio in T3 treatment was significantly higher than that in T2. ​​In addition, the potassium fertilizer utilization rate in T1 was significantly higher than that in T2 and T3, while the apparent potassium fertilizer utilization rates in T2 and T3 treatments were both lower than 30%, with no significant difference.

[0061] Table 2-2 Differences in Rb / K ratios and potash fertilizer utilization rates of crops under different treatments

[0062]

[0063] 2.3 Conclusion

[0064] The calculation results of the utilization rate by the labeling method and the agronomic formula method are significantly different, and there is no significant difference between Example 1 and Example 2. The main reason is that the agronomic apparent utilization rate method does not take into account the complex interaction between fertilizer K and soil K, which will interfere with the calculation of the utilization efficiency of fertilizer K. Only through labeling technology can we clearly distinguish fertilizer K from soil K, so as to accurately obtain the proportion of crop K absorbed from fertilizer. In summary, through potted plant experiments, we believe that Example 1 and Example 2 can replace the existing sulfuric acid and potassium sulfate fertilizers.

[0065] 3. Security Analysis

[0066] In plant physiology, the binding sites on the plasma membrane are difficult to distinguish between Rb + and K + Therefore, Rb is widely used as a tracer of K. However, when the externally added Rb increases the Rb content in the soil, the plants preferentially absorb Rb and reduce the absorption of K, which will cause the problem of slow plant growth. Therefore, we will control the amount of Rb added to avoid Rb stress on the plants, 75mg / L (1L per 1m 2 ) is the content value that produces Rb stress effect, and Example 1 and Example 2 are far below this value, so they can be used in actual application without affecting plants and the environment.

[0067] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for labeling potassium sulfate fertilizer, characterized in that: The following steps are involved: S1, weighing rubidium sulfate and potassium sulfate powder according to the mass ratio; S2, preparing a saturated potassium sulfate solution by weighing rubidium sulfate and potassium sulfate powder; S3, heating the solution to evaporate it to obtain labeled potassium sulfate fertilizer particles.

2. The potassium sulfate fertilizer labeling method according to claim 1, characterized in that: In step S1, the mass ratio of rubidium sulfate to potassium sulfate is in the range of 1:19 to 1:

9.

3. The potassium sulfate fertilizer labeling method according to claim 1, characterized in that: In step S2, a saturated potassium sulfate solution is prepared according to the mass of potassium sulfate, and then the weighed rubidium sulfate is added, and stirred until it becomes clear.

4. The potassium sulfate fertilizer labeling method according to claim 1, characterized in that: In step S3, a mold plate is placed in the solution. The plate is provided with a plurality of hemispherical grooves with a diameter of 3-5 mm. The temperature range is set to 40°C to 50°C for heating and evaporation. The crystals are taken out immediately after condensation and covering the hemispherical grooves.

5. A potassium sulfate fertilizer, characterized in that: The potassium sulfate fertilizer labeling method according to any one of claims 1 to 4 is used to prepare labeled potassium sulfate fertilizers with different mass ratios of rubidium sulfate to potassium sulfate, and labeled fertilizers with a similar dissolution rate to existing potassium sulfate are screened and obtained as substitutes.

6. The potassium sulfate fertilizer according to claim 5, characterized in that Choose 3-5mm marked potassium sulfate granules with 5% or 10% rubidium sulfate addition to replace the existing 3-5mm granular potassium sulfate fertilizer.

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