CN113880666B - Mineral-based soil conditioner for improving coastal saline soil and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of crop planting, in particular to a mineral-based soil conditioner for improving coastal saline soil and a preparation method thereof. The invention provides a mineral-based soil conditioner for improving coastal saline soil and a preparation method thereof, aiming at the problem that the yield of planted rice is still to be improved after a soil conditioner in the prior art is applied to saline-alkali soil such as coastal soil, and the mineral-based soil conditioner comprises urea, a water-retaining agent, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate and modified zeolite which is subjected to thermal modification. The soil conditioner prepared by thermally modifying the zeolite and mixing the zeolite with other components can greatly improve the yield of the planted rice when being applied to the coastal soil.

Description

Mineral-based soil conditioner for improvement of coastal saline soil and preparation method thereof

technical field

The invention relates to the technical field of crop planting, in particular to a mineral-based soil conditioner for coastal saline soil improvement and a preparation method thereof.

Background technique

The area of saline soil in the world is about 1 billion hectares; the area of saline soil in my country is about 34.6 million hectares, of which there are about 2.4 million hectares of coastal saline soil. Due to the high salinity of the soil, the lack of fresh water resources and low nutrients, the growth of crops has been seriously affected, and the development of agriculture in coastal areas has been severely limited. Applying soil conditioner to improve saline soil is an economical and convenient method. It can improve soil physical and chemical properties, enhance soil and water retention capacity, reduce salinity stress in saline-alkali soil, and improve crop yield and quality. At present, the commonly used conditioners mainly include polymers, organic wastes, calcium-containing minerals, etc. However, after these soil conditioners are applied to saline-alkaline soils such as tidal flat soils, the yield of rice planted still needs to be improved.

In response to this problem, people have also carried out exploratory research in long-term production and living practices. For example, a Chinese invention patent application discloses a soil conditioner [application number: 201610587532.9], which includes mineral materials, activators A, microbial inoculum, activator B, enzyme preparation for providing nutrition for the microbial inoculum; the mineral material includes zeolite, attapulgite, sepiolite; the main component of the activator A is organic acid; the bacterial strain contained in the microbial bacterial agent is Bacillus subtilis.

This invention uses minerals + microbial agents + enzymes to add activators such as organic acids to the minerals, which can effectively absorb the salt in the soil and neutralize OH ^- at the same time, which can effectively reduce the salinity of the soil, but its composition is complex , is not easy to configure, and after actual use, it is found that its effect still needs to be further improved.

Contents of the invention

The object of the present invention is to address the above-mentioned problems and provide a mineral-based soil conditioner for improvement of coastal saline soil that can increase rice yield.

Another object of the present invention is to provide a method for preparing a mineral-based soil conditioner for coastal saline soil improvement that can increase rice production.

A mineral-based soil conditioner for coastal saline soil improvement, including urea and water retention agent, and also includes calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate and thermally modified modified zeolite.

In the above-mentioned ore-based soil conditioner for coastal saline soil improvement, the soil conditioner comprises 400-600 parts by mass of modified zeolite, 100-150 parts of urea, 100-150 parts of superphosphoric acid Calcium, 60-100 parts of water retaining agent, 30-80 parts of ammonium sulfate, 15-50 parts of ferrous sulfate and 50-100 parts of bentonite.

In the above-mentioned ore-based soil conditioner for seaside saline soil improvement, the soil conditioner includes 500 parts by mass of modified zeolite, 125 parts of urea, 125 parts of superphosphate, 80 parts of water-retaining agent, 55 parts of ammonium sulfate, 30 parts of ferrous sulfate and 75 parts of bentonite.

In the above-mentioned ore-based soil conditioner for coastal saline soil improvement, the modified zeolite is modified through the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 30-60min;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: calcining the solid phase obtained in step 2 at 450-550°C for 20-40min to obtain a modified zeolite.

In the above mineral-based soil conditioner for improvement of coastal saline soil, the modifying agent includes aluminum sulfate, magnesium sulfate and phosphoric acid.

In the above-mentioned ore-based soil conditioner for coastal saline soil improvement, the components of the zeolite and modifier include 400-600 parts by mass of zeolite, 60-80 parts of aluminum sulfate, 50-150 parts parts of magnesium sulfate and 100-300 parts of phosphoric acid.

In the above-mentioned ore-based soil conditioner for coastal saline soil improvement, the components of the zeolite and modifier include 500 parts by mass of zeolite, 70 parts of aluminum sulfate, 100 parts of magnesium sulfate and 200 parts by mass. parts of phosphoric acid.

In the above mineral-based soil conditioner for improvement of coastal saline soil, the solvent is deionized water.

In the above-mentioned mineral-based soil conditioner for seashore saline soil improvement, the ratio of the mass of the solvent to the total mass of the zeolite and the modifying agent is 50:1.

A method for preparing a mineral-based soil conditioner for coastal saline soil improvement as described above, comprising the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 30-60min;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 450-550° C. for 20-40 minutes to obtain a modified zeolite;

Step 4: Add the modified zeolite prepared in Step 3, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate, urea and water retaining agent into the mixer according to the predetermined ratio, fully stir and mix, and granulate in the granulator , to obtain finished products for soil conditioners.

Compared with the prior art, the present invention has the advantages of:

1. In the present invention, the soil conditioner prepared by thermally modifying zeolite and then mixing it with other components has good adsorption capacity for sodium ions and ammonium ions, and can greatly improve the quality of rice planted when applied to tidal flat soil. Yield.

2. The components used in the present invention are all simple and easy to obtain, the configuration steps are simple, the production cost is low, and it is suitable for large-scale popularization and use.

Description of drawings

Figure 1 is a schematic diagram of the adsorption capacity of modified zeolites of different particle sizes to sodium ions;

Fig. 2 is the scanning electron micrograph of modified zeolite;

Fig. 3 is the scanning electron micrograph of zeolite;

Figure 4 is a schematic diagram of the adsorption capacity of modified zeolite made at different calcination temperatures to sodium ions;

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1

This embodiment provides a mineral-based soil conditioner for seaside saline soil improvement, including 400 parts by mass of modified zeolite, 150 parts of urea, 150 parts of superphosphate, 100 parts of water-retaining agent, 80 parts of parts of ammonium sulfate, 50 parts of ferrous sulfate and 100 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 30 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 550° C. for 40 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 600 parts, the aluminum sulfate of 60 parts, the magnesium sulfate of 50 parts and the phosphoric acid of 100 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Deionized water is pure water from which impurities in the form of ions have been removed. The definition of "deionization" stipulated by the International Organization for Standardization ISO/TC 147 is: "Deionized water completely or incompletely removes ionized substances." Today's technology is mainly produced by RO reverse osmosis.

Water retaining agent is a super absorbent resin, which is a functional polymer material with particularly strong water absorption capacity. Non-toxic and harmless, it releases and absorbs water repeatedly, so people in agriculture compare it to a "miniature reservoir". At the same time, it can also absorb fertilizers and pesticides and release them slowly to increase fertilizer and drug effects.

Example 2

This embodiment provides a mineral-based soil conditioner for improvement of coastal saline soil, including 600 parts by mass of modified zeolite, 100 parts of urea, 100 parts of superphosphate, 60 parts of water-retaining agent, 30 parts 15 parts of ammonium sulfate, 15 parts of ferrous sulfate and 50 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 60 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 450° C. for 20 minutes to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 400 parts, the aluminum sulfate of 80 parts, the magnesium sulfate of 150 parts and the phosphoric acid of 300 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Example 3

This embodiment provides a mineral-based soil conditioner for seaside saline soil improvement, including 500 parts by mass of modified zeolite, 125 parts of urea, 125 parts of superphosphate, 80 parts of water-retaining agent, 55 parts 30 parts of ammonium sulfate, 30 parts of ferrous sulfate and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts, the magnesium sulfate of 100 parts and the phosphoric acid of 200 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Example 4

This embodiment provides a method for preparing a mineral-based soil conditioner for seashore saline soil improvement, comprising the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 30 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 550° C. for 40 minutes to obtain a modified zeolite;

Step 4: Add the modified zeolite prepared in Step 3, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate, urea and water-retaining agent into the mixer according to a predetermined ratio, stir and mix well, and prepare the soil conditioner finished product.

Example 5

This embodiment provides a method for preparing a mineral-based soil conditioner for seashore saline soil improvement, comprising the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 60 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 450° C. for 20 minutes to obtain a modified zeolite;

Step 4: Add the modified zeolite prepared in Step 3, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate, urea and water-retaining agent into the mixer according to a predetermined ratio, stir and mix well, and prepare the soil conditioner finished product.

Example 6

This embodiment provides a method for preparing a mineral-based soil conditioner for seashore saline soil improvement, comprising the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 minutes to obtain a modified zeolite;

Step 4: Add the modified zeolite prepared in Step 3, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate, urea and water-retaining agent into the mixer according to a predetermined ratio, stir and mix well, and prepare the soil conditioner finished product.

Comparative example 1

This comparative example provides a kind of soil conditioner, comprises the zeolite that mass parts are respectively 500 parts, the urea of 125 parts, the superphosphate of 125 parts, the water-retaining agent of 80 parts, the ammonium sulfate of 55 parts, the sulfurous acid sulfite of 30 parts iron and 75 parts of bentonite.

Comparative example 2

This comparative example provides a soil conditioner, comprising 500 parts by mass of modified zeolite, 125 parts of urea, 125 parts of superphosphate, 80 parts of water-retaining agent, 55 parts of ammonium sulfate, 30 parts of Ferrous sulfate and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts and the magnesium sulfate of 100 parts, solvent is deionized water, the quality of solvent and the total amount of zeolite and modifying agent The mass ratio is 50:1.

Comparative example 3

This comparative example provides a kind of soil conditioning agent, comprises the modified zeolite of 500 parts respectively in mass parts, the urea of 125 parts, the calcium superphosphate of 125 parts, the water retaining agent of 80 parts, the ammonium sulfate of 55 parts, the Ferrous sulfate and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts, the magnesium sulfate of 100 parts and the hydrochloric acid of 200 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Comparative example 4

This comparative example provides a kind of soil conditioning agent, comprises the modified zeolite of 500 parts respectively in mass parts, the urea of 125 parts, the calcium superphosphate of 125 parts, the water retaining agent of 80 parts, the ammonium sulfate of 55 parts, the Ferrous sulfate and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts, the magnesium sulfate of 100 parts and the acetic acid of 200 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Comparative example 5

This comparative example provides a kind of soil conditioning agent, comprises the modified zeolite of 500 parts respectively in mass parts, the urea of 125 parts, the calcium superphosphate of 125 parts, the water retaining agent of 80 parts, the ammonium sulfate of 55 parts, the Ferrous sulfate and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifier comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts, the magnesium sulfate of 100 parts and the citric acid of 200 parts, solvent is deionized water, the quality of solvent and zeolite The ratio to the total mass of modifier is 50:1.

Comparative example 6

This comparative example provides a soil conditioner, including 500 parts by mass of modified zeolite, 125 parts of urea, 125 parts of superphosphate, 80 parts of water retaining agent and 75 parts of bentonite.

Modified zeolites are modified by the following steps:

Step 1: Take zeolite, modifier and solvent, dissolve the modifier into the solvent, add zeolite, and heat to reflux for 45 minutes;

Step 2: After naturally cooling to room temperature, filter to separate the solid and liquid phases;

Step 3: Calcining the solid phase obtained in Step 2 at 500° C. for 30 min to obtain a modified zeolite.

Wherein, the component of zeolite and modifying agent comprises the zeolite that mass parts are respectively 500 parts, the aluminum sulfate of 70 parts, the magnesium sulfate of 100 parts and the phosphoric acid of 200 parts, solvent is deionized water, the quality of solvent and zeolite and The total mass ratio of modifiers is 50:1.

Application example 1

A test field was selected in the Cixi Binhai flat area, and the soil salt content was measured to be 0.6%, which was divided into seven parts with equal areas and named as test field 1-7;

Soil conditioner 1 was obtained with the component ratio recorded in Example 3;

Soil conditioner 2 was obtained with the component ratio recorded in Comparative Example 1;

Soil conditioner 3 was obtained with the component ratio recorded in Comparative Example 2;

Soil conditioner 4 was obtained with the component ratio recorded in Comparative Example 3;

Soil conditioner 5 was obtained with the component ratio recorded in Comparative Example 4;

Soil conditioner 6 was obtained with the component ratio recorded in Comparative Example 5;

Soil conditioner 7 was obtained with the component ratio recorded in Comparative Example 6;

Add soil conditioners 1-7 of equal mass to test fields 1-7 respectively, and then add rice seeds of equal amount respectively, and the rice variety is Xiushui 134. Cultivate in the same way for 140 days, weigh the rice yield in each test field after harvest, the results are shown in the table below:

Result analysis: as can be seen from the above table, the rice yield of experimental field 1 is obviously higher than that of experimental field 2-7, so the soil conditioner provided by the invention can greatly improve the rice yield, and has reached the expected purpose of the present invention.

Application example 2

Based on the composition of the components described in Example 3, the only difference is that the particle diameters of the modified zeolite are 10 mesh, 20 mesh, 60 mesh, 100 mesh and 200 mesh respectively to prepare conditioner 1-5, and then at 25 ° C The zeolite (ie, not calcined at 500°C) was used as a control to prepare comparative conditioners 1-5. Both conditioner 1-5 and comparison conditioner 1-5 were added to 150mL water samples with a mass concentration of 1g·L ^-1 NaCl solution, and then the flask was placed in the shaking box, and the temperature was 200r·min at 25°C. ^-1 Shake for 24 hours, after standing still, filter with 0.45 μm filter membrane, take the supernatant and measure the Na ⁺ content on a flame photometer respectively. The adsorption results of various conditioners are shown in Fig. 1.

The scanning electron microscopes of the calcined modified zeolite and the uncalcined zeolite are shown in Figure 2 and Figure 3. It can be seen that the structure of the calcined modified zeolite (Fig. 2) changes significantly, and the pores and specific surface area increase, while the pores Salt ions can enter the interior along the micropores of the calcined modified zeolite, which promotes the adsorption of salt ions on the thermally modified zeolite, and the surface boundary membrane resistance of the calcined modified zeolite becomes weaker, improving its adsorption capacity.

Application example 3

Based on the composition of the components described in Example 3, conditioners made from modified zeolites that were not calcined at room temperature, calcined at 200°C, calcined at 300°C, calcined at 400°C, calcined at 500°C and calcined at 600°C, various conditioners Add them to 150mL NaCl solution water samples with a mass concentration of 1g·L ^-1 , then put the flask into a ^shaking box, shake it at 200 r·min The μm filter membrane was suction-filtered, and the supernatant was taken to measure the Na ⁺ content on a flame photometer. The result is shown in Figure 4.

Application example 4

Soil conditioner was prepared with the ratio of components recorded in Example 3. Below in conjunction with concrete pot test and field test the effect of soil conditioner of the present invention is further described.

In the pot test treatment S+NPK, the amount of a soil conditioner for improvement of coastal saline soil is 16.7g.kg ^-1 soil, N, P ₂ O ₅ , K ₂ O are all 0.167g.kg ^{- 1} .

The soil used in the test is Cixi coastal saline soil, the texture is medium loam, the soil salt content of 0-20cm is 4.7g·kg ^-1 , rice variety Yongyou 1540, and brackish water (total salt content 1.9g·L ^-1 ) irrigation. The experiment was divided into pot experiment and plot experiment, both of which had 3 treatments: no fertilizer (CK), single application of NPK fertilizer (NPK), and soil amendment plus NPK fertilizer (S+NPK). Each treatment was repeated 4 times, except for the no-fertilizer treatment, the other two treatments had the same amount of nitrogen, phosphorus and potassium.

In the pot experiment, 15kg of soil was filled in each pot, 250g of soil conditioner was applied to each pot of S+NPK treatment, and 2.5g of N, P ₂ O ₅ , K ₂ O was applied to each pot of NPK treatment and S+NPK treatment. In the plot test, 550kg·hm ^-2 of urea, 750kg·hm ^-2 of superphosphate and 510kg·hm ^-2 of potassium dihydrogen phosphate were applied in NPK treatment; 3000kg·hm ^-2 of soil conditioner and 250kg of urea were applied in S+NPK treatment ·hm ^-2 , calcium superphosphate 450kg·hm ^-2 , potassium dihydrogen phosphate 510kg·hm ^-2 , make N:P ₂ O ₅ :K ₂ O=1:0.5:0.7 for NPK treatment and S+NPK treatment. The plot area is 25m ² .

It can be seen from Table 1 that under the condition of no soil conditioner, there was no significant difference in the total salt content of soil between CK and NPK treatments, but the application of soil conditioner at the soil salt content of 0-5 cm and 5-20 cm in the soil layer ( S+NPK) was significantly lower than the CK and NPK treatments without soil conditioner, and the soil total salt content of the soil layer 20-40cm without soil conditioner (CK, NPK) and with soil conditioner (S+NPK) had no difference Significant differences.

Table 1 Effects of soil conditioners on soil salinity (g·kg ^-1 )

It can be seen from Table 2 that compared with the treatment without soil conditioner (CK, NPK), the application of soil conditioner (S+NPK) increased the soil alkaline nitrogen, available phosphorus and available potassium to varying degrees.

Table 2 Effect of soil conditioner on nutrient content (mg·kg ^-1 ) of 0-20cm soil

The yield-increasing effect of soil conditioner application in coastal saline soil is shown in Tables 3 and 4. Application of soil conditioner in coastal saline soil can increase rice yield. Compared with CK and NPK treatments without soil conditioner, application of soil conditioner (S+NPK ) treatment increased the yield of rice in pot experiments by 125.4% and 64.8% respectively, and the yield of rice in plot experiments increased by 175.0% and 20.1% respectively.

Table 3 Pot test soil conditioner on the impact of rice yield

The impact of table 4 soil amendments on rice yield

Application example 5

In the pot test treatment S+NPK, the amount of a soil conditioner used for coastal saline soil improvement is 1500kg·hm ^-2 (S15), 3000kg·hm ^-2 (S30), 4500kg·hm ^-2 (S45 ).

The soil used in the test was clay loam in Daixi Rocket Salt Field, the soil salt content was 6g·kg ^-1 , the rice variety was Yongyou 1540, and it was irrigated with brackish water (total salt content 2.7g·L ^-1 ). There were 4 treatments in the plot test: single application of nitrogen, phosphorus and potassium fertilizer (CK); the dosage of soil conditioner was 1500kg·hm ^-2 (S15), 3000kg·hm ^-2 (S30), 4500kg·hm ^-2 (S45). Apply N255kg·hm ^-2 per treatment, the ratio of nitrogen, phosphorus and potassium application is N:P ₂ O ₅ :K ₂ O=1:0.5:0.7, and the fertilizers are urea, superphosphate and potassium dihydrogen phosphate, 4 times per treatment repeat. The plot area is 30m ² .

Table 5 Effects of different dosages of soil conditioners on rice yield

It can be seen from Table 5 that among the four treatments, the rice yield treated with 3000 kg·hm ^-2 (S30) of soil conditioner in coastal saline soil was the highest, which was 23.6% higher than that of the control (CK) which only applied nitrogen, phosphorus and potassium fertilizers. Soil conditioner application rate of 1500kg·hm ^-2 (S15) and 4500kg·hm ^-2 (S45) increased yield by 5.9% and 6.1%, so it can be determined that the application rate of soil conditioner in coastal saline soil is 3000kg·hm ^-2 is the best for high yield of rice. Best dosage.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the present invention or go beyond the definition of the appended claims range.

Claims (7)

1. A mineral-based soil conditioner for improving coastal saline soil comprises urea and a water-retaining agent, and is characterized in that: also comprises calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate and modified zeolite subjected to thermal modification;

the modified zeolite is modified by the following steps:

the method comprises the following steps: dissolving zeolite, modifier and solvent in the solvent, adding zeolite, and heating and refluxing for 30-60min;

step two: naturally cooling to room temperature, and filtering to separate solid phase from liquid phase;

step three: calcining the solid phase obtained in the step two at 450-550 ℃ for 20-40min to obtain modified zeolite;

the modifier comprises aluminum sulfate, magnesium sulfate and phosphoric acid;

the soil conditioner comprises, by mass, 400-600 parts of modified zeolite, 100-150 parts of urea, 100-150 parts of calcium superphosphate, 60-100 parts of a water retaining agent, 30-80 parts of ammonium sulfate, 15-50 parts of ferrous sulfate and 50-100 parts of bentonite.

2. The mineral-based soil conditioner for coastal saline soil improvement of claim 1, wherein: the soil conditioner comprises, by mass, 500 parts of modified zeolite, 125 parts of urea, 125 parts of calcium superphosphate, 80 parts of water-retaining agent, 55 parts of ammonium sulfate, 30 parts of ferrous sulfate and 75 parts of bentonite.

3. The mineral-based soil conditioner for coastal saline soil improvement of claim 1, wherein: the components of the zeolite and the modifier comprise, by mass, 400-600 parts of zeolite, 60-80 parts of aluminum sulfate, 50-150 parts of magnesium sulfate and 100-300 parts of phosphoric acid.

4. The mineral-based soil conditioner for coastal saline soil improvement of claim 3, wherein: the components of the zeolite and the modifier comprise, by mass, 500 parts of zeolite, 70 parts of aluminum sulfate, 100 parts of magnesium sulfate and 200 parts of phosphoric acid.

5. The mineral-based soil conditioner for improving coastal saline soil of claim 1, wherein: the solvent is deionized water.

6. The mineral-based soil conditioner for coastal saline soil improvement of claim 1, wherein: the ratio of the mass of the solvent to the total mass of zeolite and modifier is 50.

7. A method for preparing the mineral-based soil conditioner for coastal saline soil improvement as claimed in any one of claims 1 to 6, comprising the steps of:

the method comprises the following steps: dissolving zeolite, modifier and solvent in the solvent, adding zeolite, and heating and refluxing for 30-60min;

step two: naturally cooling to room temperature, and filtering to separate solid phase from liquid phase;

step three: calcining the solid phase obtained in the step two at 450-550 ℃ for 20-40min to obtain modified zeolite;

step four: and (3) adding the modified zeolite prepared in the third step, calcium superphosphate, bentonite, ammonium sulfate, ferrous sulfate, urea and a water-retaining agent into a stirrer according to a predetermined proportion, fully stirring and uniformly mixing, and granulating in a granulator to obtain a finished product of the soil conditioner.

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