Method for preparing slow-release fertilizer based on organic nitrification inhibitor, prepared slow-release nitrogen fertilizer and application

Abstract

The invention discloses a method for preparing a slow-release fertilizer based on an organic nitrification inhibitor, a prepared slow-release nitrogen fertilizer and application, and the method comprises the following steps: drying trimmed tea tree branches and leaves, crushing, sieving with a 10-mesh sieve, adding 85-95% ethanol to extract tea polyphenol, extracting for 24-48 hours, carrying out plate-frame pressure filtration solid-liquid separation, volatilizing ethanol in an extracting solution at a high temperature to obtain tea polyphenol, and drying to obtain the slow-release nitrogen fertilizer based on the organic nitrification inhibitor. Tea polyphenol and urea are mixed according to the ratio of 1: 200-1000 and then extruded and granulated, extracted residues are extruded and granulated, and the granulated residues and the prepared urea are mixed according to the ratio of 5-10: 1 to form the organic and inorganic slow-release nitrogen fertilizer with the nitrification inhibitor function. By adopting the method, the function of the tea polyphenol in the tea tree branches and leaves for inhibiting nitrification can be effectively exerted, the utilization efficiency of urea is improved, the environmental risk is reduced, and agricultural wastes are comprehensively utilized; the decomposition speed of tea tree branch and leaf residues obtained after tea polyphenol extraction is high, the soil environment can be effectively improved, and plant growth can be adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of fertilizer production, and in particular to a method for preparing a slow-release fertilizer based on an organic nitrification inhibitor, the prepared organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function, and its application in improving soil environment and regulating plant growth. Background Art

[0002] In the soil, microorganisms convert ammonium nitrogen into nitrate nitrogen through nitrification. The nitrate nitrogen produced is not easily adsorbed by soil particles, and nitrate nitrogen also produces nitrous oxide through denitrification, thus causing a large amount of nitrogen loss. Therefore, how to reduce nitrification, especially the conversion of nitrogen in fertilizers into nitrate nitrogen, is the key to improving crop nutrient utilization and fertilizer utilization.

[0003] Nitrification inhibitors refer to a class of chemical substances that can inhibit the biological conversion process of ammonium nitrogen into nitrate nitrogen. The current mainstream industrial products of nitrification inhibitors include 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide, 3,4-dimethylpyrazole phosphate, guanylthiourea (ASU), 2-methyl-4,6-bis(trichlorotoluene)-triazine (MDCT), 2-sulfathiazole (ST), etc. Although nitrification inhibitors are beneficial to reduce nitrogen leaching losses and nitrous oxide emissions, they have not been widely used due to factors such as cost, process and their own impact on the environment. It is necessary to find some biological nitrification inhibitors that have good nitrification inhibition effects without polluting the environment.

[0004] my country's tea plantation area ranks first in the world, reaching 3 million hectares. Pruning tea trees every year will produce a large amount of branches and leaves (500-1500kg / ha), and this type of waste has not been effectively utilized as a resource. Tea tree branches and leaves contain about 18-34% tea polyphenols. In the soil, low concentrations of tea polyphenols stimulate the growth of microorganisms, while high concentrations of tea polyphenols inhibit the growth of microorganisms and have a significant inhibitory effect on soil nitrification. Therefore, efficient use of tea polyphenols in tea trees can effectively inhibit soil nitrification and improve fertilizer utilization. In addition, because tea tree branches and leaves contain a large amount of tea polyphenols, it is difficult to decompose quickly in the soil. How to efficiently utilize the tea polyphenols and promote the decomposition of tea tree branches and leaves is of great significance to maintaining soil fertility and improving nutrient utilization. Summary of the invention

[0005] The invention provides a method for preparing a slow-release fertilizer based on an organic nitrification inhibitor, the prepared organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function, and the application of the slow-release fertilizer in improving soil environment and regulating plant growth.

[0006] A method for preparing a slow-release fertilizer based on an organic nitrification inhibitor comprises the following steps:

[0007] (1) Pretreatment of tea leaves: drying, crushing and sieving the pruned tea leaves;

[0008] (2) Extraction of tea polyphenols: adding ethanol solution to the sieved powder to extract tea polyphenols, and then subjecting the powder to plate and frame filter press for solid-liquid separation. After evaporation of ethanol in the extract, tea polyphenols are obtained. The residue after extraction is extruded and granulated to obtain residue particles.

[0009] (3) Tea polyphenols and urea are mixed and extruded into granules to obtain tea polyphenol granules. The residue granules are mixed with the tea polyphenol granules to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

[0010] In step (1), the pruned tea tree branches and leaves are dried and crushed and passed through a 5-20 mesh sieve.

[0011] In step (2), the ethanol solution is an ethanol aqueous solution with a volume percentage of 85-95%.

[0012] In step (2), the time for extracting tea polyphenols is 24-48 hours.

[0013] In step (3), the mixing mass ratio of the tea polyphenols to the urea is 1:200-1000.

[0014] In step (3), the mass ratio of the residue particles to the tea polyphenol particles is 5-10:1.

[0015] The organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function prepared by the method. The application of the organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function in improving soil environment and regulating plant growth. The present invention exerts the function of tea polyphenols in inhibiting nitrification, improves urea utilization efficiency, reduces environmental risks, effectively improves soil environment, and regulates plant growth.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The method of the present invention comprises: drying and crushing the pruned tea tree branches and leaves, passing through a 10-mesh sieve, adding 85-95% ethanol to extract tea polyphenols, extracting for 24-48 hours, and separating the solid and liquid by plate-frame filter pressing, preparing tea polyphenols after high-temperature volatilization of the ethanol in the extract, mixing the tea polyphenols with urea at a ratio of 1:200-1000 and then extruding into granules, extruding and granulating the residue after extraction, and mixing with the prepared urea at a ratio of 5-10:1 to form an organic and inorganic slow-release nitrogen fertilizer with the function of nitrification inhibitor. By adopting this method, the function of tea polyphenols in tea tree branches and leaves to inhibit nitrification can be effectively exerted, environmental risks can be reduced, agricultural waste can be comprehensively utilized, the tea tree branch and leaf residue after tea polyphenols are extracted can decompose quickly, and the soil environment can be effectively improved and plant growth can be regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a technical mechanism diagram of the method for preparing slow-release fertilizer based on organic nitrification inhibitor of the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise specified in the examples, all percentages are by mass.

[0020] like Figure 1 As shown, a method for preparing a slow-release fertilizer based on an organic nitrification inhibitor has the following steps:

[0021] (1) Pretreatment of tea leaves: drying and crushing the pruned tea leaves through a 10-mesh sieve;

[0022] (2) Extraction of tea polyphenols: adding 85-95% by volume ethanol to extract tea polyphenols, extracting for 24-48 hours and then performing solid-liquid separation by plate and frame filter pressing, and obtaining tea polyphenols after ethanol in the extract is evaporated at high temperature;

[0023] (3) tea polyphenols and urea are mixed at a ratio of 1:200-1000 and then extruded into granules; the residue after extraction is extruded into granules and mixed with the prepared urea at a ratio of 5-10:1 to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function;

[0024] Example 1

[0025] The pruned tea leaves and branches are dried and crushed to pass through a 10-mesh sieve, and 85% volume percent ethanol is added to extract tea polyphenols. After extraction for 24 hours, the solid-liquid separation is carried out by plate and frame filter pressing. The ethanol in the extract is evaporated at high temperature to obtain tea polyphenols. The tea polyphenols are mixed with urea at a ratio of 1:200 and extruded into granules. The residue after extraction is extruded and granulated, and mixed with the prepared urea at a ratio of 5:1 to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

[0026] Example 2

[0027] The pruned tea leaves and branches are dried and crushed to pass through a 10-mesh sieve, and 85% volume percent ethanol is added to extract tea polyphenols. After extraction for 24 hours, the solid-liquid separation is carried out by plate and frame filter pressing. The ethanol in the extract is evaporated at high temperature to obtain tea polyphenols. The tea polyphenols are mixed with urea at a ratio of 1:1000 and extruded into granules. The residue after extraction is extruded and granulated, and mixed with the prepared urea at a ratio of 5:1 to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

[0028] Example 3

[0029] The pruned tea leaves and branches are dried and crushed to pass through a 10-mesh sieve, and 85% volume percent ethanol is added to extract tea polyphenols. After extraction for 24 hours, the solid-liquid separation is carried out by plate and frame filter pressing. The ethanol in the extract is evaporated at high temperature to obtain tea polyphenols. The tea polyphenols are mixed with urea at a ratio of 1:600 ​​and extruded into granules. The residue after extraction is extruded and granulated, and mixed with the prepared urea at a ratio of 5:1 to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

[0030] Example 4

[0031] The pruned tea leaves and branches are dried and crushed to pass through a 10-mesh sieve, and 85% volume percent ethanol is added to extract tea polyphenols. After extraction for 24 hours, the solid-liquid separation is carried out by plate and frame filter pressing. The ethanol in the extract is evaporated at high temperature to obtain tea polyphenols. The tea polyphenols are mixed with urea at a ratio of 1:200 and extruded into granules. The residue after extraction is extruded and granulated, and mixed with the prepared urea at a ratio of 5:1 to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

[0032] Comparative Example 1

[0033] Dry the pruned tea tree branches and leaves, crush them through a 10-mesh sieve, and add them directly to the soil.

[0034] Comparative Example 2

[0035] Dry the pruned tea tree branches and leaves, crush them through a 10-mesh sieve, mix them with urea at a ratio of 1:200, and add them to the soil.

[0036] After the corresponding slow-release nitrogen fertilizer, tea tree branches and leaves, and tea tree branches and leaves and urea in the above examples and comparative examples were added to the soil for 4 days, the soil CO2 emission was measured to characterize the decomposition rate of tea tree branches and leaves, and the soil nitrate nitrogen content was detected to characterize the soil nitrification rate. The results show that after ethanol extraction, the decomposition rate of tea tree branches and leaves residues (Examples 1-4) is significantly higher than that of the unextracted treatment (Comparative Example 1), increasing by 17-35%, indicating that the tea tree branches and leaves after the extraction of tea polyphenols can be quickly decomposed and utilized by microorganisms, and can provide an effective carbon source available to microorganisms for the soil. In Examples 1-4, the nitrate nitrogen content in the soil is significantly lower than that in Comparative Example 2 (reduced by 27-45%), and the higher the ratio of tea polyphenols to urea, the better the effect of inhibiting nitrification (45% reduction in Example 4 and 27% reduction in Example 1).

Claims

1. A method for preparing a slow-release fertilizer based on an organic nitrification inhibitor, characterized in that: The following steps are involved: (1) Pretreatment of tea leaves: drying, crushing and sieving the pruned tea leaves; (2) Extraction of tea polyphenols: adding ethanol solution to the sieved powder to extract tea polyphenols, and then subjecting the powder to plate and frame filter press for solid-liquid separation. After evaporation of ethanol in the extract, tea polyphenols are obtained. The residue after extraction is extruded and granulated to obtain residue particles. (3) Tea polyphenols and urea are mixed and extruded into granules to obtain tea polyphenol granules. The residue granules are mixed with the tea polyphenol granules to form an organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function.

2. The method for preparing a slow-release fertilizer based on an organic nitrification inhibitor according to claim 1, characterized in that: In step (1), the pruned tea tree branches and leaves are dried and crushed and passed through a 5-20 mesh sieve.

3. The method for preparing a slow-release fertilizer based on an organic nitrification inhibitor according to claim 1, characterized in that: In step (2), the ethanol solution is an ethanol aqueous solution with a volume percentage of 85-95%.

4. The method for preparing a slow-release fertilizer based on an organic nitrification inhibitor according to claim 1, characterized in that: In step (2), the time for extracting tea polyphenols is 24-48 hours.

5. The method for preparing a slow-release fertilizer based on an organic nitrification inhibitor according to claim 1, characterized in that: In step (3), the mixing mass ratio of the tea polyphenols to the urea is 1:200-1000.

6. The method for preparing a slow-release fertilizer based on an organic nitrification inhibitor according to claim 1, characterized in that: In step (3), the mass ratio of the residue particles to the tea polyphenol particles is 5-10:

1.

7. An organic or inorganic slow-release nitrogen fertilizer having the function of a nitrification inhibitor prepared according to the method of any one of claims 1 to 6.

8. Use of the organic and inorganic slow-release nitrogen fertilizer with nitrification inhibitor function according to claim 7 in improving soil environment and regulating plant growth.

Images