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

Abstract

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

[0002] Improving the utilization rate of nitrogen fertilizer is an important challenge facing my country's agricultural sector. Stable fertilizers 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 and improve the nitrogen utilization rate by 20%-38%, while reducing 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 widely used. However, DMPP is easily disturbed by the soil environment, especially the 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 soil exists in large areas, mainly concentrated in the coastal areas of the eastern north, saline-alkali land in the Songnen Plain in the northeast, and saline soil in the semi-desert inland area. The land with agricultural production value and affected by saline-alkali obstacles exceeds 500 million mu. Therefore, the development of DMPP protective agent to improve its effect in alkaline soil has very high application value. Summary of the invention

[0003] One of the purposes of the present invention is to provide the use of L-malic acid as a protective agent for nitrification inhibitor DMPP. L-malic acid is an organic acid found in fruits such as apples and grapes, and has the advantages of strong acidity, safety, and good stability. CAS No.: 97-67-6, density: 1.595 g / cm 3 , melting point: 101-103°C, boiling point: 306.4°C, flash point: 153.4°C, refractive index: 1.529, 1% solution pH is 2.4. The present invention finds that L-malic 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 L-malic 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 L-malic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate in water 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 L-malic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate are dissolved in 8-15 parts of water to obtain a mixed solution;

[0010] In the step 2, the mixed solution is heated to 90° C.-95° C., and is dried under normal pressure while being stirred until the moisture content of the material reaches 3.0% w / w, thereby obtaining 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 L-malic acid is one of the relatively ideal nitrification inhibitor protective materials. The present invention finds that L-malic acid has an inhibitory and protective effect on the decomposition of DMPP, and the combination of L-malic 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 L-malic acid and 10 grams of DMPP are dissolved in 80 grams of water, stirred evenly, and then heated and dried under normal pressure while stirring, maintaining the temperature at 85°C-90°C, and drying to a moisture content of 3.0%; the material is crushed with a mechanical crusher to a particle size of ≤1mm, and then crushed with an air vortex micronizer to 0.05-0.075mm to obtain a material A of L-malic acid and DMPP; at room temperature, 10 grams of DMPP are dissolved in 80 grams of water, stirred evenly, and then heated and dried under normal pressure while stirring, maintaining the temperature at 85°C-90°C, and drying to a moisture content of 3.0%; the material is crushed with a mechanical crusher to a particle size of ≤1mm, and then crushed with an air vortex micronizer to a particle size of 0.05-0.075mm to obtain a material A of L-malic acid and DMPP; at room temperature, 10 grams of DMPP are dissolved in 80 grams of water, stirred evenly, and then heated and dried under normal pressure The material B was obtained by stirring and drying under pressure while maintaining the temperature at 85°C-90°C, and drying the material 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 flow vortex micronizer to 0.05-0.075 mm to obtain material B. 47 g of 85% phosphoric acid and 10 g of DMPP were dissolved in 73 g of water, stirred evenly, and dried under normal pressure while stirring and drying the material to a moisture content of 3.0% while maintaining the temperature at 85°C-90°C to obtain a viscous mixture C.

[0016] 2. Indoor simulation test

[0017] Soil from the tillage layer of 0-20cm was collected from the farmland in Liming Village, Balang Town, Qianguo County, Jilin Province, brought back to the laboratory, mixed evenly, and the pH was measured to be 8.1 using a "Leij" 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 500.0 grams, of which 9 portions: 9 portions of material B 0.045 grams were weighed, first mixed evenly with 5 grams of soil, then mixed evenly with the remaining 495 grams of soil, placed in a culture pot, and water was added to the content of 20.0%; the other 9 portions: 9 portions of material A 0.225 grams were weighed, first mixed evenly with 5 grams of soil, then mixed evenly with the remaining 495 grams of soil, placed in 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 33.0℃, and water was regularly replenished 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, pour out the soil sample in the culture pot and mix it evenly, take 5.0g of the soil sample in a shaking bottle, add 50.0ml of deionized water, shake at 200r / min for 2h, centrifuge at 1000r / min, take the clarified liquid, use a liquid chromatograph to determine the DMPP content at a detection wavelength of 224nm, and at the same time use the DMPP aqueous solution for detection and analysis to draw a standard curve. For each test, DMPP and DMPP+L-malic acid treatments were destructively sampled, and three soil samples from each culture pot were tested and the average was taken.

[0018] Table 1 Effect of L-malic acid on DMPP decomposition at different time points

[0019] Content (mg / kg) Day 3 Day 5 Day 10 DMPP 62.9 47.7 29.2 DMPP+L-malic acid 71.6 63.9 40.5

[0020] It can be seen from Table 1 that L-malic acid showed a good inhibitory effect on the degradation of DMPP in alkaline soil from the third day. This helps to reduce the dosage of DMPP and prolong the regulatory effect of DMPP on nitrogen transformation in the middle and late stages.

[0021] 3. Comparative test

[0022] Soil from the tillage layer of 0-20 cm was collected from the farmland in Liming Village, Balang Town, Qianguo County, Jilin Province, brought back to the laboratory, mixed evenly, and the pH value was measured using a "Leci" acidometer pH meter S-25 to find that it was 8.1. 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 B 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 A 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 viscous mixture 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%. 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. 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 using a liquid chromatograph at a detection wavelength of 224 nm. At the same time, the DMPP aqueous solution was used for detection and analysis, and a standard curve was drawn. 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 L-malic acid and phosphoric acid on the decomposition of DMPP at different time points

[0024] Content (mg / kg) Day 2 Day 3 DMPP 49.3 38.2 DMPP+L-malic acid 61.2 47.2 DMPP+phosphoric acid 48.4 39.0

[0025] It can be seen from Table 2 that at the culture temperature of 40°C, L-malic acid showed a good protective effect, while phosphoric acid, which is more acidic than L-malic acid, did not show any effect. The reason may be that the dissolution rate of phosphoric acid in the soil solution is much faster than that of L-malic acid, causing the separation of phosphoric acid and DMPP, and failing to provide a protective effect.

[0026] 3. Application in large-scale equipment production

[0027] Compound fertilizers with a nitrogen, phosphorus and potassium ratio of 26-12-12 were produced by a room temperature extrusion process, and three kinds of fertilizers were produced respectively: (1) conventional compound fertilizer: the raw materials used per ton were 500.0 kg of urea (46%), 272.7 kg of monoammonium phosphate (11-44-0), 200.0 kg of potassium chloride (60%) and 27.3 kg of filler. All the materials were crushed through a 20-mesh sieve, and then all the materials were mixed evenly, extruded into granules, sieved and packaged to obtain conventional compound fertilizer C; (2) conventional compound fertilizer + DMPP: the raw materials used per ton were 500.0 kg of urea (46%), 272.7 kg of monoammonium phosphate (11-44-0), 200.0 kg of potassium chloride (60%), 1.2 kg of material B and 26.1 kg of filler. All materials were crushed and passed through a 20-mesh sieve, and then material B was first mixed evenly with 10 times the weight of urea powder, and then mixed evenly with the remaining urea, monoammonium phosphate, potassium chloride, and filler, and then extruded granulated, sieved, and packaged to obtain a compound fertilizer D containing DMPP; (3) Conventional compound fertilizer + DMPP + L-malic acid: The raw materials used per ton are 500.0 kg of urea (46%), 272.7 kg of monoammonium phosphate (11-44-0), 200.0 kg of potassium chloride (60%), 6.0 kg of material A, and 21.3 kg of filler. All materials were crushed and passed through a 20-mesh sieve, and then material A was mixed evenly with urea, monoammonium phosphate, potassium chloride, and filler, and then extruded granulated, sieved, and packaged to obtain a fertilizer E containing DMPP and L-malic acid.

[0028] 4. Cell experiment

[0029] The test site is located in Liming Village, Balang Town, Qianguo County, Jilin Province. The plot with uniform soil fertility was selected to plant corn. The soil pH was 8.1. The setting area was 16m 2There were 9 plots (4m*4m), and each treatment was repeated 3 times. (1) Conventional fertilizer: 0.60 kg urea, 0.33 kg monoammonium phosphate, and 0.24 kg 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: 0.60 kg urea, 0.33 kg monoammonium phosphate, 0.24 kg potassium chloride, and 1.44 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 + L-malic acid: 0.60 kg urea, 0.33 kg monoammonium phosphate, 0.24 kg potassium chloride, and the material A prepared above were applied to each plot. 7.2g, 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 will be required in the later stage of all treatments, and seeds, pesticides and other management will remain consistent. The amount of nitrate nitrogen and ammonium nitrogen in the soil was determined on the 20th, 80th and 100th days. During the operation, a soil drill was used to take soil samples from the 0-20cm tillage layer, and a five-point cross sampling method was used. Five drills were taken from each plot, and about 300g of soil was taken. The soil samples were brought back to the laboratory, sieved and mixed, and 5.0g was taken. 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 4 middle ridges of each plot, 5 plants were taken continuously, for a total of 20 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 L-malic acid combined with DMPP on reducing nitrate nitrogen

[0031] Nitrate nitrogen (mg / kg) Day 20 Day 80 Day 100 Conventional fertilization 51.9 29.5 21.8 Conventional fertilization + DMPP 46.2 30.6 22.9 Conventional fertilization + DMPP + L-malic acid 39.3 28.4 17.5

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

[0033] Ammonium nitrogen (mg / kg) Day 20 Day 80 Day 120 Conventional fertilization 31.4 24.0 15.3 Conventional fertilization + DMPP 50.2 32.9 21.1 Conventional fertilization + DMPP + L-malic acid 58.8 37.1 25.9

[0034] Table 5 Effect of L-malic acid combined with DMPP on increasing corn yield

[0035]

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

[0037] 5. Field trials

[0038] The test site is located in Liming Village, Balang Town, Qianguo County, Jilin Province. The soil fertility is uniform and the terrain is flat. The pH of the soil plough layer was measured to be 8.1 before planting. Three treatments were set up: conventional fertilization in treatment 1 (conventional compound fertilizer C prepared above), conventional compound fertilizer + DMPP in treatment 2 (compound fertilizer D prepared above), and conventional compound fertilizer + DMPP + L-malic acid in treatment 3 (compound fertilizer E prepared above), with 3 replicates for each treatment and an area of ​​1 mu for each treatment. All three treatments applied the corresponding fertilizer products at 50 kg per mu of land, plowed, raked, and then applied seed fertilizer with a seeder, sowing and fertilization were completed simultaneously. No more topdressing was done in the later period, and 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 L-malic 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 L-malic acid as a protective agent for nitrification inhibitor 3,4-dimethylpyrazole phosphate.

2. The use according to claim 1, characterized in that L-Malic 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 L-malic 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 L-malic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate in water 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 L-malic acid and 1-2 parts of 3,4-dimethylpyrazole phosphate are dissolved in 8-15 parts of water to obtain a mixed solution; In the step 2, the mixed solution is heated to 90° C.-95° C., and is dried under normal pressure while being stirred until the moisture content of the material reaches 3.0% w / w, thereby obtaining 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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