A slow-release fertilizer suitable for Hainan lateritic soil

Abstract

This invention discloses a slow-release fertilizer suitable for lateritic soils in Hainan, comprising a fertilizer core and a coating layer; the fertilizer core comprises the following raw materials in parts by weight: 10-20 parts isobutylene diurea, 1-3 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1-3 parts dicyandiamide DCD, 20-30 parts humic acid, and 30-50 parts organic fertilizer; the coating layer comprises the following raw materials in parts by weight: 5-10 parts natural nanotube halloysite, 3-5 parts bentonite, 5-10 parts cyclodextrin, 1-3 parts polyglutamic acid, 1-3 parts wood vinegar, and 5-10 parts polyacrylamide. The isobutylene diurea, humic acid, and organic fertilizer of this invention can effectively replenish organic matter and nitrogen in iron-aluminate soil, maintain soil nitrogen levels, and effectively control the conversion of ammonium nitrogen to nitrate nitrogen in lateritic soil, thereby reducing nitrogen loss and achieving a stable supply of nitrogen. In addition, polyglutamic acid and polyacrylamide have strong water retention capacity, and the fertilizer core is coated with a coating layer to achieve slow release and water retention.

Description

Technical Field

[0001] This invention belongs to the field of fertilizer technology, specifically relating to a slow-release fertilizer suitable for lateritic soil in Hainan. Background Technology

[0002] Lateritic red soil is a strongly acidic iron-aluminum soil that has undergone intense iron-aluminum enrichment and bioaccumulation processes under tropical rainforests or monsoon forests. It features a layer of dead leaves and branches, a dark reddish-brown surface layer, and a brick-red iron-aluminum residual layer (B layer). The soil in Hainan's lateritic red soil region is deep, sandy in texture, easy to cultivate, and suitable for a wide range of crops. However, irrigation water is insufficient, and drought is a frequent threat, leading to severe nutrient loss and very low nutrient content, particularly phosphorus and potassium deficiencies. This results in poor crop growth and low yields. There are no fertilizers specifically formulated for the soil type of Hainan's lateritic red soil region on the market; therefore, fertilizers tailored to the specific soil conditions of Hainan's lateritic red soil region are needed to improve crop yields. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention provides a slow-release fertilizer suitable for Hainan lateritic soil, so as to provide a slow-release fertilizer tailored to the soil characteristics of Hainan lateritic soil region.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is to provide a slow-release fertilizer suitable for Hainan lateritic soil, comprising a fertilizer core and a coating layer;

[0005] The fertilizer core comprises the following raw materials in parts by weight: 10-20 parts of isobutylene diurea, 1-3 parts of 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1-3 parts of dicyandiamide DCD, 20-30 parts of humic acid, and 30-50 parts of organic fertilizer.

[0006] The coating layer comprises the following raw materials in parts by weight: 5-10 parts of natural halloysite nanotubes, 5-10 parts of cyclodextrin, 1-3 parts of polyglutamic acid, 1-3 parts of wood vinegar, and 5-10 parts of polyacrylamide.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the organic fertilizer is coconut coir, soybean meal, or cottonseed meal.

[0009] Furthermore, the fertilizer core comprises the following raw materials in parts by weight: 15 parts isobutylene diurea, 2 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1 part dicyandiamide DCD, 25 parts humic acid, and 40 parts organic fertilizer.

[0010] Furthermore, the coating layer comprises the following raw materials in parts by weight: 8 parts of natural halloysite nanotubes, 8 parts of cyclodextrin, 3 parts of polyglutamic acid, 2 parts of wood vinegar, and 8 parts of polyacrylamide.

[0011] Furthermore, the cyclodextrin is one of β-cyclodextrin, hydroxypropyl β-cyclodextrin, α-cyclodextrin, and γ-cyclodextrin.

[0012] This invention also provides a method for preparing the above-mentioned slow-release fertilizer suitable for Hainan lateritic soil, the method comprising:

[0013] Isobutylidene diurea, 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, dicyandiamide DCD, humic acid and organic fertilizer are mixed evenly and then granulated to obtain fertilizer core.

[0014] Natural halloysite nanotubes were impregnated in dilute hydrochloric acid, followed by filtration, washing, and drying to obtain activated halloysite nanotubes.

[0015] Cyclodextrin, polyglutamic acid, wood vinegar, and polyacrylamide were dissolved in an organic solvent, and then the activated nanotube halloysite was added and heated to obtain the coating material.

[0016] The fertilizer core is obtained by coating it with the aforementioned coating material.

[0017] Furthermore, the process parameters for the heat treatment include: a heating temperature of 40–50°C and a heating time of 8–10 hours.

[0018] The beneficial effects of this invention are as follows: Isobutyl diurea, humic acid, and organic fertilizer can effectively replenish organic matter and nitrogen in iron-aluminate soil, maintain soil nitrogen levels, and the low solubility of isobutyl diurea in water can effectively control nitrogen release. Simultaneously, the combined action of isobutyl diurea and polyacrylamide can improve soil structure, increase soil aggregates, and improve crop yield. 3,4-Dimethyl-1H-pyrazole dihydrogen phosphate and dicyandiamide (DCD) can effectively control the conversion of ammonium nitrogen to nitrate nitrogen in lateritic soil, thereby achieving a stable nitrogen supply, reducing nitrate nitrogen leaching and nitrogen oxide emissions, and improving fertilizer utilization. This invention also utilizes the tubular structure of halloysite, the excellent water absorption properties of cyclohexane, the good bactericidal and growth-promoting functions of wood vinegar, and the network structure of polyglutamic acid and polyacrylamide solution to form a coating layer, thus achieving slow release, water retention, and growth-promoting effects. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0021] The specific embodiments of the present invention will be described in detail below.

[0022] Example 1

[0023] A slow-release fertilizer suitable for Hainan lateritic soil comprises the following raw materials in parts by weight: 15 parts isobutylene diurea, 2 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1 part dicyandiamide (DCD), 25 parts humic acid, 40 parts soybean meal, 8 parts natural nanotube halloysite, 8 parts hydroxypropyl β-cyclodextrin, 3 parts polyglutamic acid, 2 parts wood vinegar, and 8 parts polyacrylamide;

[0024] The above-mentioned method for preparing slow-release fertilizer suitable for Hainan lateritic soil includes:

[0025] (1) Mix isobutylene diurea, 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, dicyandiamide DCD, humic acid and soybean meal evenly, and then granulate to obtain fertilizer core;

[0026] (2) Natural nanotube halloysite was immersed in 10% dilute hydrochloric acid at 50°C for 45 minutes, then filtered, washed and dried in sequence to obtain activated nanotube halloysite.

[0027] Cyclodextrin, polyglutamic acid, wood vinegar, and polyacrylamide were dissolved in ethanol, and then activated nanotube halloysite was added and heated at 45°C for 9 hours to obtain the coating material.

[0028] The fertilizer core is placed in a coating machine and coated with a coating material to obtain the final product.

[0029] Example 2

[0030] A slow-release fertilizer suitable for Hainan lateritic soil comprises the following raw materials in parts by weight: 10 parts isobutylene diurea, 1 part 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 3 parts dicyandiamide (DCD), 20 parts humic acid, 30 parts cottonseed meal, 5 parts natural nanotube halloysite, 5 parts hydroxypropyl β-cyclodextrin, 2 parts polyglutamic acid, 1 part wood vinegar, and 5 parts polyacrylamide.

[0031] The above-mentioned method for preparing slow-release fertilizer suitable for Hainan lateritic soil includes:

[0032] (1) Mix isobutylene diurea, 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, dicyandiamide DCD, humic acid and soybean meal evenly, and then granulate to obtain fertilizer core;

[0033] (2) Natural nanotube halloysite was immersed in dilute hydrochloric acid with a mass fraction of 8% at 40°C for 60 minutes, and then filtered, washed and dried in sequence to obtain activated nanotube halloysite.

[0034] Cyclodextrin, polyglutamic acid, wood vinegar, and polyacrylamide were dissolved in ethanol, and then activated nanotube halloysite was added and heated at 40°C for 10 hours to obtain the coating material.

[0035] The fertilizer core is placed in a coating machine and coated with a coating material to obtain the final product.

[0036] Example 3

[0037] A slow-release fertilizer suitable for Hainan lateritic soil comprises the following raw materials in parts by weight: 20 parts isobutylene diurea, 3 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 2 parts dicyandiamide (DCD), 30 parts humic acid, 50 parts cottonseed meal, 10 parts natural nanotube halloysite, 10 parts hydroxypropyl β-cyclodextrin, 1 part polyglutamic acid, 2 parts wood vinegar, and 10 parts polyacrylamide.

[0038] The above-mentioned method for preparing slow-release fertilizer suitable for Hainan lateritic soil includes:

[0039] (1) Mix isobutylene diurea, 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, dicyandiamide DCD, humic acid and soybean meal evenly, and then granulate to obtain fertilizer core;

[0040] (2) Natural nanotube halloysite was immersed in 15% dilute hydrochloric acid at 60°C for 30 minutes, then filtered, washed and dried in sequence to obtain activated nanotube halloysite.

[0041] Cyclodextrin, polyglutamic acid, wood vinegar, and polyacrylamide were dissolved in ethanol, and then activated nanotube halloysite was added and heated at 50°C for 8 hours to obtain the coating material.

[0042] The fertilizer core is placed in a coating machine and coated with a coating material to obtain the final product.

[0043] Comparative Example 1

[0044] The wrapping layer in Example 1 is removed, and the rest is the same as in Example 1.

[0045] Comparative Example 2

[0046] The polyacrylamide in Example 1 was removed, and the rest was the same as in Example 1.

[0047] Comparative Example 3

[0048] The 3,4-dimethyl-1H-pyrazole dihydrophosphate in Example 1 was removed, and the rest was the same as in Example 1.

[0049] Field experiment: Six mu of adjacent fields in Hainan lateritic soil were selected, all planted with mangoes. Seedlings that were free from pests and diseases, had strong disease resistance, and high yields were selected. Slow-release fertilizers suitable for Hainan lateritic soils, obtained from Examples 1-3 and Comparative Examples 1-3, were applied respectively. The period from planting to harvest was one experimental cycle.

[0050] Application method: Apply 1.5 kg of fertilizer per plant per year (the slow-release fertilizers obtained from Examples 1-3 and Comparative Examples 1-3 suitable for Hainan lateritic soil).

[0051] Table 1 Mango yield obtained from field experiments of this invention

[0052] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Yield per mu 3658kg 3591kg 3624kg 2942kg 3026kg 3017kg

[0053] As shown in Table 1, the slow-release fertilizer of the present invention can effectively increase the yield of mangoes in the lateritic soil region of Hainan.

[0054] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A slow-release fertilizer suitable for Hainan lateritic soil, characterized in that, Includes fertilizer core and coating layer; The fertilizer core is composed of the following raw materials in parts by weight: 10-20 parts isobutylene diurea, 1-3 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1-3 parts dicyandiamide DCD, 20-30 parts humic acid, and 30-50 parts organic fertilizer. The coating layer is composed of the following raw materials in parts by weight: 5-10 parts of natural halloysite nanotubes activated by dilute hydrochloric acid, 5-10 parts of cyclodextrin, 1-3 parts of polyglutamic acid, 1-3 parts of wood vinegar and 5-10 parts of polyacrylamide. The organic fertilizer is coconut coir, soybean meal, or cottonseed meal; the cyclodextrin is one of β-cyclodextrin, hydroxypropyl β-cyclodextrin, α-cyclodextrin, and γ-cyclodextrin.

2. The slow-release fertilizer suitable for Hainan lateritic soil according to claim 1, characterized in that: The fertilizer core is composed of the following raw materials in parts by weight: 15 parts isobutylene diurea, 2 parts 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, 1 part dicyandiamide DCD, 25 parts humic acid, and 40 parts organic fertilizer.

3. The slow-release fertilizer suitable for Hainan lateritic soil according to claim 1, characterized in that: The coating layer is composed of the following raw materials in parts by weight: 8 parts of natural halloysite nanotubes activated by dilute hydrochloric acid, 8 parts of cyclodextrin, 3 parts of polyglutamic acid, 2 parts of wood vinegar and 8 parts of polyacrylamide.

4. The method for preparing slow-release fertilizer suitable for Hainan lateritic soil according to any one of claims 1 to 3, characterized in that, The method includes: Isobutylidene diurea, 3,4-dimethyl-1H-pyrazole dihydrogen phosphate, dicyandiamide DCD, humic acid and organic fertilizer are mixed evenly and then granulated to obtain fertilizer core. Natural halloysite nanotubes were impregnated in dilute hydrochloric acid, and then filtered, washed and dried sequentially to obtain natural halloysite nanotubes activated by dilute hydrochloric acid. Cyclodextrin, polyglutamic acid, wood vinegar, and polyacrylamide were dissolved in an organic solvent, and then the natural nanotube halloysite activated by dilute hydrochloric acid was added and heated to obtain the coating material. The process parameters of the heat treatment included: heating temperature of 40-50℃ and heating time of 8-10h. The fertilizer core is obtained by coating it with the aforementioned coating material.