Improver suitable for fertility improvement of barren soil

Abstract

The invention relates to the technical field of soil improvement, in particular to a modifier suitable for fertility improvement of barren soil. The modifier is obtained by modifying bentonite with vinyl trichlorosilane and dimethyl silane glycol and then crosslinking the modified bentonite with acrylic acid, polyethylene glycol allyl ether and humic acid. The modifier can effectively adjust the pH value of the acid soil to maintain the pH value at a neutral level, and can remarkably improve the field moisture capacity, the soil organic matter content and the content of soil aggregates with the particle size larger than 0.25 mm.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to an improver suitable for fertilizing poor soil. Background Art

[0002] Soil is the foundation of agricultural production, and its fertility level directly affects the growth and yield of crops. However, due to low organic matter content, loose structure, poor water and fertilizer retention capacity, poor soil can hardly meet the needs of crop growth, which seriously restricts the development of agricultural production. Especially in acidic or alkaline soils, the deviation of soil pH from the neutral range will significantly affect the effectiveness of soil nutrients, resulting in the inability of crops to absorb nutrients normally and growth inhibition. Studies have shown that most crops can only grow well in a soil environment close to neutral, while overly acidic or overly alkaline soils are not conducive to the normal growth of crops. Therefore, how to adjust the soil pH to maintain it at a neutral level has become an important research direction for improving poor soils.

[0003] In addition, the field water holding capacity of poor soil is low, and water is easily lost, resulting in water shortage of crops and affecting their growth. Improving the water retention capacity of soil can not only reduce the frequency of irrigation, but also provide a continuous water supply for crops and improve the growth environment of crops. At the same time, the organic matter content of poor soil is low, and the soil fertility is insufficient, making it difficult to provide sufficient nutrient sources for crops. Therefore, increasing the content of soil organic matter is a key measure to improve soil fertility and soil quality. Summary of the invention

[0004] In view of this, the object of the present invention is to provide an improver suitable for fertilizing poor soil, so as to adjust the pH value of the poor soil to maintain it at a neutral level, and to improve its water retention capacity and organic matter content.

[0005] Based on the above purpose, the present invention provides an improver suitable for improving fertility of poor soil, which is prepared by the following steps:

[0006] (1) dispersing bentonite in toluene, ultrasonicating for 0.5-2h, adding vinyl trichlorosilane and dimethyl silanediol, heating to 95-105°C, stirring for reaction for 20-30h, cooling, filtering, washing, and drying at 55-65°C for 20-30h to obtain vinyl bentonite;

[0007] (2) adding acrylic acid and polyethylene glycol allyl ether to deionized water, stirring for 20-40 minutes, then adding vinyl bentonite, ultrasonicating for 20-40 minutes, dropping an aqueous solution of ammonium persulfate, heating to 65-75° C., stirring for reaction for 4-6 hours, cooling, filtering, washing with deionized water, and drying at 75-85° C. for 20-30 hours to obtain modified bentonite;

[0008] (3) Add modified bentonite and humic acid to N,N-dimethylacetamide, ultrasonicate for 0.5-2h, then add diphenylmethane diisocyanate, heat to 65-75°C, stir to react for 20-30h, filter, wash with deionized water, dry at 75-85°C for 20-30h, crush, and pass through a 80-120 mesh sieve to obtain an improver suitable for fertilizing poor soil.

[0009] Preferably, the density of the bentonite is 2-3 g / cm 3 .

[0010] Preferably, in step (1), the weight ratio of bentonite, toluene, vinyltrichlorosilane and dimethylsilanediol is 8-12:80-120:0.5-1.5:0.2-0.7.

[0011] Preferably, in step (2), the weight ratio of acrylic acid, polyethylene glycol allyl ether, deionized water, vinyl bentonite and aqueous ammonium persulfate solution is 3-8:1-3:50-150:8-12:0.5-2.

[0012] Preferably, the concentration of the ammonium persulfate aqueous solution in step (2) is 3wt%-8wt%.

[0013] Preferably, in step (3), the weight ratio of modified bentonite, humic acid, N,N-dimethylacetamide and diphenylmethane diisocyanate is 8-12:1-3:40-60:0.2-1.

[0014] Preferably, the purity of the humic acid is ≥90%.

[0015] Beneficial effects of the present invention:

[0016] The improver for poor soil fertilization provided by the present invention can effectively adjust the pH value of acidic soil to maintain it at a neutral level. Soil pH is closely related to the effectiveness of soil nutrients and crop growth. Most crops can grow well in a soil environment close to neutral, while overly acidic soil is not conducive to the normal growth of crops. The present invention provides a more suitable growth environment for crops by adjusting the soil pH value.

[0017] Secondly, the amendment significantly increased the field water holding capacity and soil organic matter content. The increase in field water holding capacity helps to improve soil water retention, reduce water loss, and provide a continuous water supply for crops; while the increase in organic matter content can improve soil fertility and provide a rich source of nutrients for crop growth. In addition, the amendment effectively increased the content of soil aggregates with a particle size greater than 0.25 mm. Aggregates with a particle size greater than 0.25 mm are of great significance to soil structure and nutrient storage. They not only enhance the soil's ability to resist erosion, but also improve the soil's aeration and stability, thereby further optimizing the soil environment.

[0018] The present invention constructs a stable hydrophilic cross-linked network through the synergistic effect of acrylic acid, polyethylene glycol allyl ether and humic acid. The network enhances the water retention capacity of the soil, promotes the adsorption of organic matter and the formation of aggregates; on the other hand, it improves the stability and aeration of the soil structure, provides excellent soil conditions for the healthy growth of crops, and is particularly suitable for fertilizing and improving poor soils. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0020] In the specific implementation mode of the present invention, the bentonite was purchased from Haoyuan Bentonite Factory in Fangzi District, Weifang City, with a specification of HY-002 and a density of 2.6 g / cm 3 Humic acid was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a product number of H108498 and a purity of ≥90%.

[0021] Embodiment 1:

[0022] (1) 8 g of bentonite was dispersed in 80 g of toluene, and ultrasonicated for 0.5 h. Then, 0.5 g of vinyl trichlorosilane and 0.2 g of dimethylsilanediol were added, and the temperature was raised to 95° C., and the mixture was stirred for reaction for 20 h. The mixture was cooled, filtered, washed with acetone, and dried at 55° C. for 20 h to obtain vinyl bentonite.

[0023] (2) 3 g of acrylic acid and 1 g of polyethylene glycol allyl ether were added to 50 g of deionized water, stirred for 20 min, then 8 g of vinyl bentonite was added, ultrasonicated for 20 min, 0.5 g of a 3 wt% aqueous solution of ammonium persulfate was added dropwise, the temperature was raised to 65° C., stirred for reaction for 4 h, cooled, filtered, washed with deionized water, and dried at 75° C. for 20 h to obtain modified bentonite;

[0024] (3) Add 8 g of modified bentonite and 1 g of humic acid to 40 g of N,N-dimethylacetamide, ultrasonicate for 0.5 h, then add 0.2 g of diphenylmethane diisocyanate, heat to 65 °C, stir and react for 20 h, filter, wash with deionized water, dry at 75 °C for 20 h, crush, and pass through an 80-mesh sieve to obtain an improver suitable for fertilizing poor soil.

[0025] Embodiment 2:

[0026] (1) Dispersing 10 g of bentonite in 100 g of toluene, ultrasonicating for 1 h, adding 1 g of vinyl trichlorosilane and 0.5 g of dimethylsilanediol, heating to 100 ° C., stirring for reaction for 24 h, cooling, filtering, washing with acetone, and drying at 60 ° C. for 24 h to obtain vinyl bentonite;

[0027] (2) 5 g of acrylic acid and 2 g of polyethylene glycol allyl ether were added to 100 g of deionized water, stirred for 30 min, then 10 g of vinyl bentonite was added, ultrasonicated for 30 min, 1 g of 5 wt% ammonium persulfate aqueous solution was added dropwise, the temperature was raised to 70° C., stirred for reaction for 5 h, cooled, filtered, washed with deionized water, and dried at 80° C. for 24 h to obtain modified bentonite;

[0028] (3) Add 10 g of modified bentonite and 2 g of humic acid to 50 g of N,N-dimethylacetamide, ultrasonicate for 1 h, then add 0.5 g of diphenylmethane diisocyanate, heat to 70 °C, stir and react for 24 h, filter, wash with deionized water, dry at 80 °C for 24 h, crush, and pass through a 100-mesh sieve to obtain an improver suitable for fertilizing poor soil.

[0029] Embodiment 3:

[0030] (1) Disperse 12 g of bentonite in 120 g of toluene, ultrasonicate for 2 h, add 1.5 g of vinyl trichlorosilane and 0.7 g of dimethylsilanediol, heat to 105° C., stir to react for 30 h, cool, filter, wash with acetone, and dry at 65° C. for 30 h to obtain vinyl bentonite;

[0031] (2) 8 g of acrylic acid and 3 g of polyethylene glycol allyl ether were added to 150 g of deionized water, stirred for 40 min, then 12 g of vinyl bentonite was added, ultrasonicated for 40 min, 2 g of 8 wt% ammonium persulfate aqueous solution was added dropwise, the temperature was raised to 75° C., stirred for reaction for 6 h, cooled, filtered, washed with deionized water, and dried at 85° C. for 30 h to obtain modified bentonite;

[0032] (3) Add 12 g of modified bentonite and 3 g of humic acid to 60 g of N,N-dimethylacetamide, ultrasonicate for 2 h, then add 1 g of diphenylmethane diisocyanate, heat to 75 °C, stir and react for 30 h, filter, wash with deionized water, dry at 85 °C for 30 h, crush, and pass through a 120-mesh sieve to obtain an improver suitable for fertilizing poor soil.

[0033] Comparative Example 1:

[0034] The difference between Comparative Example 1 and Example 2 is that: dimethylsilanediol is not added in step (1);

[0035] The specific steps are as follows:

[0036] (1) Dispersing 10 g of bentonite in 100 g of toluene, ultrasonicating for 1 h, adding 1 g of vinyltrichlorosilane, heating to 100 ° C, stirring for reaction for 24 h, cooling, filtering, washing with acetone, and drying at 60 ° C for 24 h to obtain vinyl bentonite;

[0037] (2) 5 g of acrylic acid and 2 g of polyethylene glycol allyl ether were added to 100 g of deionized water, stirred for 30 min, then 10 g of vinyl bentonite was added, ultrasonicated for 30 min, 1 g of 5 wt% ammonium persulfate aqueous solution was added dropwise, the temperature was raised to 70° C., stirred for reaction for 5 h, cooled, filtered, washed with deionized water, and dried at 80° C. for 24 h to obtain modified bentonite;

[0038] (3) Add 10 g of modified bentonite and 2 g of humic acid to 50 g of N,N-dimethylacetamide, ultrasonicate for 1 h, then add 0.5 g of diphenylmethane diisocyanate, heat to 70 °C, stir and react for 24 h, filter, wash with deionized water, dry at 80 °C for 24 h, crush, and pass through a 100-mesh sieve to obtain an improver.

[0039] Comparative Example 2:

[0040] The difference between Comparative Example 2 and Example 2 is that: polyethylene glycol allyl ether is not added in step (2);

[0041] The specific steps are as follows:

[0042] (1) Dispersing 10 g of bentonite in 100 g of toluene, ultrasonicating for 1 h, adding 1 g of vinyl trichlorosilane and 0.5 g of dimethylsilanediol, heating to 100 ° C., stirring for reaction for 24 h, cooling, filtering, washing with acetone, and drying at 60 ° C. for 24 h to obtain vinyl bentonite;

[0043] (2) 5 g of acrylic acid was added to 100 g of deionized water, stirred for 30 min, then 10 g of vinyl bentonite was added, ultrasonicated for 30 min, 1 g of 5 wt% ammonium persulfate aqueous solution was added dropwise, the temperature was raised to 70° C., stirred for reaction for 5 h, cooled, filtered, washed with deionized water, and dried at 80° C. for 24 h to obtain modified bentonite;

[0044] (3) Add 10 g of modified bentonite and 2 g of humic acid to 50 g of N,N-dimethylacetamide, ultrasonicate for 1 h, then add 0.5 g of diphenylmethane diisocyanate, heat to 70 °C, stir and react for 24 h, filter, wash with deionized water, dry at 80 °C for 24 h, crush, and pass through a 100-mesh sieve to obtain an improver.

[0045] Comparative Example 3:

[0046] The difference between Comparative Example 3 and Example 2 is that: diphenylmethane diisocyanate is not added in step (3);

[0047] The specific steps are as follows:

[0048] (1) Dispersing 10 g of bentonite in 100 g of toluene, ultrasonicating for 1 h, adding 1 g of vinyl trichlorosilane and 0.5 g of dimethylsilanediol, heating to 100 ° C., stirring for reaction for 24 h, cooling, filtering, washing with acetone, and drying at 60 ° C. for 24 h to obtain vinyl bentonite;

[0049] (2) 5 g of acrylic acid and 2 g of polyethylene glycol allyl ether were added to 100 g of deionized water, stirred for 30 min, then 10 g of vinyl bentonite was added, ultrasonicated for 30 min, 1 g of 5 wt% ammonium persulfate aqueous solution was added dropwise, the temperature was raised to 70° C., stirred for reaction for 5 h, cooled, filtered, washed with deionized water, and dried at 80° C. for 24 h to obtain modified bentonite;

[0050] (3) Add 10 g of modified bentonite and 2 g of humic acid to 50 g of N,N-dimethylacetamide, ultrasonicate for 1 h, heat to 70 °C, stir and react for 24 h, filter, wash with deionized water, dry at 80 °C for 24 h, crush, and pass through a 100-mesh sieve to obtain an improver.

[0051] Performance Testing:

[0052] Test soil: selected from a place in Jiangxi Province, the basic physical and chemical properties are as follows: field water holding capacity 18.45%, organic matter 7.58g / kg, pH 5.56, soluble salt concentration 2.84g / kg, total nitrogen 0.54g / kg, total phosphorus 0.12g / kg, total potassium 0.38g / kg, available nitrogen 70.23mg / kg, available phosphorus 6.59mg / kg and available potassium 53.25mg / kg.

[0053] Pot experiment: The test soil without any improved material was used as the control, and 3 replicates were set for each formulation. The pot experiment was carried out using a plastic paper pot. 30 g of the improver prepared in the embodiment and the comparative example was applied to the soil for the pot experiment. Each pot was filled with 1500 g of the test soil. After saturation with water, it was placed under natural conditions for natural sedimentation for 120 days, and the soil was taken out to test the physical and chemical properties of the soil. The results are shown in Table 1.

[0054] Table 1 Performance test results

[0055]

[0056] Data Analysis:

[0057] From the data of Examples 1-3 and the control group in Table 1, it can be seen that the modifier prepared by the present invention can effectively increase the soil pH and maintain it at a neutral level. The soil acidity and alkalinity are closely related to the soil nutrient form, and have a very important influence on the effectiveness of soil nutrients and the growth of crops. Most crops can only grow well in a soil environment close to neutrality, and the field water holding capacity and organic matter content are greatly improved. The increase in field water holding capacity helps to improve the water retention of the soil, reduce water loss, and provide a continuous water supply for crops; while the increase in organic matter content can improve soil fertility and provide a rich source of nutrients for crop growth. At the same time, the modifier prepared by the present invention effectively increases the content of particles with a diameter of more than 0.25 mm in soil aggregates. Aggregates with a particle size greater than 0.25 mm are of great significance to soil structure and soil nutrients. They can not only enhance the soil's anti-erosion ability, but also improve the soil's aeration and nutrient storage capacity, thereby further optimizing the soil environment.

[0058] It can be seen from the data of Example 2 and Comparative Example 1 in Table 1 that the addition of dimethylsilanediol can effectively improve the field water holding capacity and increase the content of particles with a diameter greater than 0.25 mm in soil aggregates. This is because dimethylsilanediol can cross-link with vinyltrichlorosilane and intercalate into the interlayer structure of bentonite, which helps acrylic acid, polyethylene glycol allyl ether and humic acid to construct a hydrophilic cross-linked network, thereby effectively improving the water retention capacity of the soil and enhancing the stability of the aggregate structure.

[0059] It can be seen from the data of Example 2 and Comparative Example 2 in Table 1 that the addition of polyethylene glycol allyl ether promotes field water holding capacity, organic matter content, and content of aggregates > 0.25 mm. This is mainly because polyethylene glycol allyl ether provides cross-linking sites and constructs a cross-linking network on the one hand, and provides a hydrophilic polyethylene glycol main chain structure on the other hand, which increases the hydrophilicity of the cross-linking network. The improvement of the overall network hydrophilicity not only enhances the water retention capacity of the soil, but also promotes the adsorption of organic matter and the formation of aggregates, thereby improving the soil structure and nutrient effectiveness, and providing a better soil environment for crop growth.

[0060] From the data of Example 2 and Comparative Example 3, it can be seen that the addition of diphenylmethane diisocyanate helps to improve the field water holding capacity and the content of aggregates > 0.25 mm. This is because diphenylmethane diisocyanate acts as a bridge, allowing humic acid and modified bentonite to build a suitable hydrophilic network. On the one hand, the hydrophilic network enhances the water retention capacity of the soil, allowing water to be more effectively adsorbed and retained; on the other hand, it helps the agglomeration of soil particles, increases the content of aggregates with a particle size > 0.25 mm, and improves the stability and air permeability of the soil structure. The formation of this network structure not only improves the water holding capacity of the soil, but also enhances the soil's anti-erosion ability and nutrient storage capacity, providing a better soil environment for the healthy growth of crops.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0062] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modifier suitable for improving poor soil fertility, characterized in that: Prepared by the following steps: (1) dispersing bentonite in toluene, ultrasonicating for 0.5-2h, adding vinyl trichlorosilane and dimethyl silanediol, heating to 95-105°C, stirring for reaction for 20-30h, cooling, filtering, washing, and drying at 55-65°C for 20-30h to obtain vinyl bentonite; (2) adding acrylic acid and polyethylene glycol allyl ether to deionized water, stirring for 20-40 minutes, then adding vinyl bentonite, ultrasonicating for 20-40 minutes, dropping an aqueous solution of ammonium persulfate, heating to 65-75° C., stirring for reaction for 4-6 hours, cooling, filtering, washing with deionized water, and drying at 75-85° C. for 20-30 hours to obtain modified bentonite; (3) Add modified bentonite and humic acid to N,N-dimethylacetamide, ultrasonicate for 0.5-2h, then add diphenylmethane diisocyanate, heat to 65-75°C, stir to react for 20-30h, filter, wash with deionized water, dry at 75-85°C for 20-30h, crush, and pass through a 80-120 mesh sieve to obtain an improver suitable for fertilizing poor soil.

2. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: The density of the bentonite is 2-3 g / cm 3 .

3. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: In the step (1), the weight ratio of bentonite, toluene, vinyltrichlorosilane and dimethylsilanediol is 8-12:80-120:0.5-1.5:0.2-0.

7.

4. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: In the step (2), the weight ratio of acrylic acid, polyethylene glycol allyl ether, deionized water, vinyl bentonite and ammonium persulfate aqueous solution is 3-8:1-3:50-150:8-12:0.5-2.

5. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: The concentration of the ammonium persulfate aqueous solution in step (2) is 3wt%-8wt%.

6. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: In the step (3), the weight ratio of modified bentonite, humic acid, N,N-dimethylacetamide and diphenylmethane diisocyanate is 8-12:1-3:40-60:0.2-1.

7. The improver suitable for improving poor soil fertility according to claim 1, characterized in that: The purity of the humic acid is ≥90%.

Images