Application of salicylic acid, long-acting nitrification inhibitor and preparation method

Abstract

The invention discloses application of salicylic acid as a protective agent of a nitrification inhibitor 3, 4-dimethyl pyrazole phosphate, a long-acting nitrification inhibitor prepared from salicylic acid and 3, 4-dimethyl pyrazole phosphate and a preparation method of the long-acting nitrification inhibitor. According to the invention, salicylic acid has inhibition and protection effects on decomposition of DMPP, and the combination of salicylic acid and DMPP can effectively prolong the nitration inhibition performance of DMPP.

Description

Technical Field

[0001] The invention relates to the field of nitrogen fertilizer nitrification inhibitors, and in particular to use of salicylic acid as a protective agent for nitrification inhibitors, a long-acting nitrification inhibitor and a preparation method thereof. Background Art

[0002] Stable fertilizers are fertilizers that add urease inhibitors and (or) nitrification inhibitors during the production process to regulate the microbial and enzyme activities in the soil that affect the conversion of fertilizer nitrogen, thereby achieving high efficiency and long-term nitrogen. The application of stable fertilizers can effectively increase the retention of ammonium nitrogen in the soil, improve nitrogen utilization by 20%-38%, and reduce the emission of different forms of nitrogen such as ammonia and nitrate to the atmosphere and water environment by 25%-71%. Nitrification inhibitors are the core of stable fertilizers, which can greatly improve the utilization rate of nitrogen fertilizers, reduce nitrate leaching and gas emissions such as nitrous oxide. DMPP (3,4-dimethylpyrazole phosphate) is a nitrification inhibitor that is currently used more frequently. However, DMPP is easily disturbed by the soil environment, especially pH. It is easy to decompose in an alkaline environment, causing inactivation and unable to play its role. my country has a variety of soil types, among which alkaline soils exist in large areas. Therefore, the development of DMPP protective agents to improve its effect in alkaline soils has very high application value. Summary of the invention

[0003] One of the purposes of the present invention is to provide the use of salicylic acid as a protective agent for nitrification inhibitor DMPP. Salicylic acid, molecular weight 138.122, CAS number 69-72-7. Melting point 158 ​​to 161 ° C, boiling point 336.3 ° C, density 1.375 g / cm3, appearance white crystalline powder. The acid strength of salicylic acid aqueous solution is close to acetic acid. The present invention finds that salicylic acid can effectively protect DMPP in alkaline soil, slow down the decomposition of DMPP and make it fully exert its function as a nitrification inhibitor.

[0004] Another object of the present invention is to provide a long-acting nitrification inhibitor, which is made of the following components by weight: 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate.

[0005] The present invention also provides a method for preparing the above-mentioned long-acting nitrification inhibitor, comprising the following steps:

[0006] Step 1: dissolving 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate in ethanol to obtain a mixed solution;

[0007] Step 2: heating and drying the mixed solution while stirring until the water content of the material is 3.0% w / w to obtain a dried material;

[0008] Step 3: The dried material is crushed by a mechanical crusher to obtain a long-acting nitrification inhibitor.

[0009] Preferably, in step 1, 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate are dissolved in 10-15 parts of ethanol to obtain a mixed solution;

[0010] In step 2, the mixed solution is heated to 60-70° C. and dried under normal pressure while being stirred until the moisture content of the material reaches 3.0% w / w to obtain a dried material;

[0011] In the step 3, the dried material is crushed by a mechanical crusher to a particle size of ≤1 mm, and then crushed by an air flow vortex micronizer to 0.05-0.075 mm to obtain a long-acting nitrification inhibitor.

[0012] The present invention has the following beneficial effects: according to the alkaline soil characteristics and the mechanism of DMPP decomposition under alkaline conditions, multiple materials that may have the ability to control the decomposition of DMPP are theoretically screened out, and then the effect and strength of these materials on the control of DMPP decomposition are studied through indoor simulation tests, and the toxicity, stability and current economic cost of each material are analyzed, and finally, through continuous plot and field tests, it is verified that salicylic acid is one of the relatively ideal nitrification inhibitor protective materials. The present invention finds that salicylic acid has an inhibitory and protective effect on the decomposition of DMPP, and the combination of salicylic acid and DMPP can effectively prolong the nitrification inhibition performance of DMPP. DETAILED DESCRIPTION

[0013] The present invention is further described below by specific implementation methods, and the following percentages are by weight:

[0014] 1. Sample Preparation

[0015] At room temperature, 40 grams of salicylic acid and 10 grams of DMPP are dissolved in 150 grams of ethanol, heated and dried while stirring, the temperature is maintained at 60°C-70°C, the ethanol is evaporated and recycled, and the material is dried to a moisture content of 3.0%, the material is crushed to a particle size of ≤1mm by a mechanical pulverizer, and then crushed to 0.05-0.075mm by an air vortex micro-powder machine to obtain a mixture of salicylic acid and DMPP A; at room temperature, 10 grams of DMPP are dissolved in 150 grams of ethanol, heated and dried while stirring, the temperature is maintained at 60°C-70°C, the ethanol is evaporated and recycled, and the material is dried to a moisture content of 3.0%, the material is crushed to a particle size of ≤1mm by a mechanical pulverizer, and then crushed to 0.05-0.075mm by an air vortex micro-powder machine to obtain material B; 47 grams of 85% phosphoric acid and 10 grams of DMPP are dissolved in 100 grams of 85°C water, stirred for 5-8 minutes, and the temperature is raised to room temperature. The mixture was heated and dried under pressure while stirring, the temperature was maintained at 95°C-97°C, and the material was dried to a moisture content of 3.0% to obtain a viscous mixture C; 40 g of salicylic acid and 10 g of DMPP were dissolved in 150 g of 85°C water, stirred for 5-8 minutes, the temperature was increased to normal pressure, the mixture was heated and dried while stirring, the temperature was maintained at 95°C-97°C, and the material was dried to a moisture content of 3.0%, the material was crushed with a mechanical crusher to a particle size of ≤1 mm, and then crushed with an air vortex micro-powder machine to a particle size of 0.05-0.075 mm to obtain a mixture D of salicylic acid and DMPP; 10 g of DMPP was dissolved in 85°C water, stirred for 5-8 minutes, the temperature was increased to normal pressure, the mixture was heated and dried while stirring, the temperature was maintained at 95°C-97°C, and the material was dried to a moisture content of 3.0%, the material was crushed with a mechanical crusher to a particle size of ≤1 mm, and then crushed with an air vortex micro-powder machine to a particle size of 0.05-0.075 mm to obtain a material E.

[0016] 2. Indoor simulation test:

[0017] Soil from the tillage layer of 0-20cm was collected from the farmland in Dongning Village, Huanghekou Town, Kenli District, Dongying City, Shandong Province, brought back to the laboratory, mixed evenly, and measured its pH value as 7.9 using a "Lemagnetic" acidometer pH meter S-25. The soil sample was air-dried to a moisture content of about 3.0%, and 18 portions of soil were taken, each 600.0 grams, of which 9 portions: 9 portions of material B 0.060 grams were weighed, first mixed evenly with 5 grams of soil, then mixed evenly with the remaining 595 grams of soil, placed in a culture pot, and water was added to a content of 18.0%; the other 9 portions: 9 portions of material A 0.30 grams were weighed, first mixed evenly with 5 grams of soil, then mixed evenly with the remaining 595 grams of soil, placed in a culture pot, and water was added to a content of 18.0%. All 18 treated samples were placed in a constant temperature incubator, maintained at a temperature of 30.0℃, and water was regularly added according to weight loss every day. The content of DMPP in the soil was measured on the 3rd, 5th, and 10th days respectively. During the determination, the soil sample in the culture pot was poured out and mixed, 5.0 g of the soil sample was taken into a shaking bottle, 50.0 ml of deionized water was added, and the mixture was shaken at 180 r / min for 2 h, and centrifuged at 1000 r / min. The clarified liquid was taken and the DMPP content was determined at a detection wavelength of 224 nm using a liquid chromatograph. At the same time, the DMPP aqueous solution was used for detection and analysis, and a standard curve was drawn. For each test, destructive sampling was used for the treatment of DMPP and DMPP+salicylic acid, and three soil samples from each culture pot were taken for testing, and the average was taken. The results are shown in Table 1.

[0018] Table 1 Effect of salicylic acid on DMPP decomposition at different time points

[0019] Content (mg / kg) Day 3 Day 5 Day 10 DMPP 61.3 33.7 25.3 DMPP+Salicylic Acid 71.5 47.2 28.1

[0020] It can be seen from Table 1 that at a culture temperature of 30°C, starting from the third day, salicylic acid showed a good inhibitory effect on the decomposition of DMPP, greatly prolonging the action time of DMPP, so that DMPP was at a higher concentration and could maintain its stable effect state.

[0021] 3. Comparative test

[0022] Soil from the tillage layer of 0-20 cm was collected from the farmland in Dongning Village, Huanghekou Town, Kenli District, Dongying City, Shandong Province, brought back to the laboratory, mixed evenly, and the pH value was measured to be 7.9 using a "Leci" acidometer pH meter S-25. The soil sample was air-dried to a moisture content of about 3.0%. 18 portions of 500.0 g soil were taken, of which 6 portions: 6 portions of material E were weighed, each portion of 0.050 g, first mixed with 5 g soil, then mixed with the remaining 495 g soil, put into a culture pot, and water was added to the content of 20.0%; 6 portions: 6 portions of material C were weighed, each portion of 0.25 g, first mixed with 5 g soil, then mixed with the remaining 495 g soil, put into a culture pot, and water was added to the content of 20.0%; 6 portions: 6 portions of material D were weighed, each portion of 0.25 g, first mixed with 5 g soil, then mixed with the remaining 495 g soil, put into a culture pot, and water was added to the content of 20.0%. All 18 treated samples were placed in a constant temperature incubator, maintained at a temperature of 40.0 ° C, and water was regularly added according to weight loss every day. The content of DMPP in the soil was measured on the 2nd and 3rd days respectively. During the determination, the soil sample in the culture pot was poured out and mixed, 5.0 g of the soil sample was taken into a shaking bottle, 50.0 ml of deionized water was added, and the mixture was shaken at 180 r / min for 2 h, centrifuged at 1000 r / min, and the clarified liquid was taken. The DMPP content was determined at a detection wavelength of 224 nm using a liquid chromatograph, and the DMPP aqueous solution was used for detection and analysis to draw a standard curve. For each test, all treatments were destructively sampled, and three soil samples from each culture pot were taken for testing, and the average was taken. The results are shown in Table 2.

[0023] Table 2 Effects of salicylic acid and phosphoric acid on the decomposition of DMPP at different time points

[0024] Content (mg / kg) Day 2 Day 3 DMPP 47.2 31.6 DMPP+Salicylic Acid 56.3 40.4 DMPP+phosphoric acid 48.9 30.7

[0025] It can be seen from Table 2 that at a culture temperature of 40°C, salicylic acid showed a good protective effect, while an equal amount of phosphoric acid showed no effect. The reason may be that the dissolution rate of phosphoric acid in the soil solution is much faster than that of salicylic acid, causing the separation of phosphoric acid and DMPP, and failing to provide a protective effect.

[0026] 4. Application in large-scale equipment production

[0027] The rotary drum granulation process is used to produce compound fertilizers with a nitrogen, phosphorus and potassium ratio of 28-10-10, and three kinds of fertilizers are produced respectively: (1) conventional compound fertilizer: the raw materials used per ton are 554.3 kg of urea (46%), 227.2 kg of monoammonium phosphate (11-44-0), 166.7 kg of potassium chloride (60%) and 51.8 kg of filler. All the materials are crushed through a 20-mesh sieve, mixed evenly, and put into a rotary drum for granulation, drying, cooling, screening and packaging to obtain conventional compound fertilizer C; (2) conventional compound fertilizer + DMPP: the raw materials used per ton are 554.3 kg of urea (46%), 227.2 kg of monoammonium phosphate (11-44-0), 166.7 kg of potassium chloride (60%), 1.5 kg of material B and 50.3 kg of filler. All the materials are crushed through a 20-mesh sieve. During operation, material B is firstly mixed with 20 times the weight of urea powder, then put into the urea feeding port, mixed evenly, then mixed evenly with monoammonium phosphate, potassium chloride and filler, then put into the drum for granulation, drying, cooling, sieving and packaging, to obtain compound fertilizer D containing DMPP; (3) Conventional compound fertilizer + DMPP + salicylic acid: the raw materials used per ton are urea (46%) 554.3kg, monoammonium phosphate (11-44-0) 227.2kg, potassium chloride (60%) 166.7kg, material A 7.5kg and filler 44.3kg, all of which are crushed through a 20-mesh sieve. During operation, material A is firstly mixed with 10 times the weight of urea powder, then put into the urea feeding port, mixed evenly, then mixed evenly with monoammonium phosphate, potassium chloride and filler, then put into the drum for granulation, drying, cooling, sieving and packaging, to obtain fertilizer E containing DMPP and salicylic acid.

[0028] 5. Community experiment

[0029] The test site is located in Dongning Village, Huanghekou Town, Kenli District, Dongying City, Shandong Province. A plot with uniform soil fertility was selected to plant corn. The soil pH was 7.9. The setting area was 16m 2There were 9 plots (4m*4m), and each treatment was repeated 3 times. (1) Conventional fertilizer: 0.66 kg of urea, 0.27 kg of monoammonium phosphate, and 0.20 kg of potassium chloride were applied to each plot. The three materials were crushed to a particle size of less than 0.1 mm, and then the three materials were mixed evenly, and then mixed evenly with 10 times the weight of dry soil, and evenly spread on the surface, plowed, and sown; (2) Conventional fertilizer + DMPP: 0.66 kg of urea, 0.27 kg of monoammonium phosphate, 0.20 kg of potassium chloride, and 1.80 g of the material B prepared above were applied to each plot. Urea, monoammonium phosphate, and potassium chloride were crushed to a particle size of less than 0.1 mm, and material B was first mixed with urea, and then mixed evenly with the other two materials, and then mixed evenly with 10 times the weight of dry soil, and evenly spread on the surface, plowed, and sown; (3) Conventional fertilizer + DMPP + salicylic acid: 0.66 kg of urea, 0.27 kg of monoammonium phosphate, 0.20 kg of potassium chloride, and the material A prepared above were applied to each plot. 9.0g, crush urea, monoammonium phosphate and potassium chloride to a particle size of less than 0.1mm, first mix A with the three materials evenly, then mix them evenly with 10 times the weight of dry soil, evenly spread them on the surface, plow and sow. No topdressing was required in the later stage of all treatments, and the seeds, pesticides and other management were kept consistent. The amount of nitrate nitrogen and ammonium nitrogen in the soil was determined on the 20th, 80th and 100th days. Use a soil drill to take soil samples from the 0-20cm tillage layer, and use the five-point cross sampling method. Take 5 drills in each plot and take about 300g of soil. Bring the soil samples back to the laboratory, sieve them, mix them, take 5.0g of them, and use 2.00mol·L -1 The corn was extracted with potassium chloride solution and measured with a 3-AA3 flow analyzer. The results are shown in Tables 3 and 4. The yield was measured at harvest time. From the 5th plant in each of the 2 middle ridges of each plot, 5 plants were taken continuously, for a total of 10 plants. The corn was broken off and brought back to the laboratory. It was threshed, air-dried, weighed, and the yield per mu was calculated. The results are shown in Table 5.

[0030] Table 3 Effect of salicylic acid combined with DMPP on reducing nitrate nitrogen

[0031] Nitrate nitrogen (mg / kg) Day 20 Day 80 Day 100 Conventional fertilization 42.3 29.5 18.2 Conventional fertilization + DMPP 33.6 25.1 22.1 Conventional fertilization + DMPP + salicylic acid 30.9 22.5 24.3

[0032] Table 4 Effect of salicylic acid combined with DMPP on increasing soil ammonium nitrogen

[0033] Ammonium nitrogen (mg / kg) Day 20 Day 80 Day 120 Conventional fertilization 26.1 15.8 14.0 Conventional fertilization + DMPP 32.7 23.8 20.5 Conventional fertilization + DMPP + salicylic acid 37.3 31.9 25.6

[0034] Table 5 Effect of salicylic acid combined with DMPP on increasing corn yield

[0035]

[0036] In summary, compared with the use of DMPP alone, DMPP protected by salicylic acid showed good effects in reducing soil nitrate nitrogen, increasing ammonium nitrogen and increasing corn yield.

[0037] 6. Field trials

[0038] The test site is located in Dongning Village, Huanghekou Town, Kenli District, Dongying City, Shandong Province. The soil fertility is uniform and the terrain is flat. The pH of the soil plough layer was measured to be 7.9 before planting. Three treatments were set up: treatment 1 conventional fertilization (conventional compound fertilizer C prepared above), treatment 2 conventional compound fertilizer + DMPP (compound fertilizer D prepared above), treatment 3 conventional compound fertilizer + DMPP + salicylic acid (compound fertilizer E prepared above), each treatment 3 replicates, each treatment area 1 mu, the previous crop is wheat. The three treatments all applied the corresponding fertilizer products at 50 kg per mu of land, and the furrows were opened and sown after wheat harvesting. The seed fertilizer was applied with the sowing machine, and sowing and fertilization were completed simultaneously. In the later period, no topdressing was done, and the weeding, spraying and other measures were kept consistent. At the harvesting period, a harvester was used, and each replicate was harvested separately, and the weight was weighed after drying and dehydration to obtain the actual yield. The average yield of the three replicates was the final data, and the results are shown in Table 6.

[0039] Table 6 Effect of salicylic acid combined with DMPP on increasing corn yield

[0040]

[0041] The above embodiments are intended to illustrate the present invention rather than to limit it. Under the concept of the present invention, technical solutions that have not been substantially changed are still protected by the present invention.

Claims

1. Use of salicylic acid as a protective agent for the nitrification inhibitor 3,4-dimethylpyrazole phosphate.

2. The use according to claim 1, characterized in that Salicylic acid is used to slow down the decomposition of the nitrification inhibitor 3,4-dimethylpyrazole phosphate in alkaline soils.

3. A long-acting nitrification inhibitor, characterized in that The invention is prepared from the following components by weight: 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate.

4. The method for preparing the long-acting nitrification inhibitor according to claim 3, characterized in that The steps include: Step 1: dissolving 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate in ethanol to obtain a mixed solution; Step 2: heating and drying the mixed solution while stirring until the water content of the material is 3.0% w / w to obtain a dried material; Step 3: The dried material is crushed by a mechanical crusher to obtain a long-acting nitrification inhibitor.

5. The preparation method according to claim 4, characterized in that: In the step 1, 3-5 parts of salicylic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate are dissolved in 10-15 parts of ethanol to obtain a mixed solution; In step 2, the mixed solution is heated to 60-70° C. and dried under normal pressure while being stirred until the moisture content of the material reaches 3.0% w / w to obtain a dried material; In the step 3, the dried material is crushed by a mechanical crusher to a particle size of ≤1 mm, and then crushed by an air flow vortex micronizer to 0.05-0.075 mm to obtain a long-acting nitrification inhibitor.

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