Organic conditioner for coastal saline-alkali soil as well as preparation method and field application thereof

Abstract

The invention discloses an organic conditioner for coastal saline-alkali soil as well as a preparation method and field application thereof, relates to the technical field of coastal saline-alkali soil improvement, and solves the problems that due to the influence of typical characteristics such as heavy soil, poor structure and strong capillary rising effect of the coastal saline-alkali soil, the improvement treatment technology takes effect slowly, is easy to repeat and is high in cost. Comprising the following raw materials in parts by weight: 20-30 parts of an organic solid waste material, 10-15 parts of natural clay minerals, 2-4 parts of urea, 4-5 parts of calcium superphosphate, 1-2 parts of diammonium phosphate and 2-4 parts of a liquid binder. Rich organic matters and mineral components are utilized, the soil structure can be effectively improved, the water and fertilizer retention capacity of soil is enhanced, and plant growth is promoted by relieving poison of salt and alkali to plant roots.

Description

Technical Field

[0001] The present invention relates to the technical field of coastal saline-alkali land improvement, and specifically to an organic conditioner for coastal saline-alkali land, a preparation method thereof, and field application. Background Art

[0002] Affected by the intersection of the sea and land, the soil water and salt in coastal saline-alkali land interact frequently. The soil has high salt content, is prone to recurrence, has a compact structure, poor air permeability, low nutrient content and is difficult to be utilized by plants. These characteristics lead to low water and fertilizer retention capacity of the soil, restricting the normal growth and development of plants. At present, the main technical approaches for coastal saline-alkali land improvement are as follows: one is through engineering technical measures such as subsurface pipe drainage for desalination, deep tillage for soil improvement, and construction of irrigation and drainage systems; the second is through chemical improvement with biomass materials such as desulfurized gypsum and humus; the third is through biological improvement by planting salt-tolerant plants such as Suaeda glauca and Tamarix chinensis.

[0003] However, affected by the typical characteristics of coastal saline-alkali land such as heavy soil texture, poor structure, and strong capillary rise effect, the improvement and treatment technologies all have problems of slow effect, easy recurrence, and high cost;

[0004] Engineering technical measures all have high construction costs, complex maintenance, and are restricted by fresh water resources. It is difficult for engineering measures to fully play the role of effective salt washing and rapid desalination. Chemical technical measures such as desulfurized gypsum, phosphogypsum, and salt replacement agents require large-scale continuous application, with high costs, and the replaced salts need to be effectively discharged, otherwise it will lead to secondary salinization. Using biological improvement technologies such as salt-tolerant plants, green manure crops, or microbial materials has the problem of slow effect and requires a long time to significantly improve soil conditions;

[0005] Especially for the currently relatively effective microbial inoculant improvement measures, the key is to inoculate beneficial bacteria groups that decompose organic matter, fix nitrogen, dissolve phosphorus and potassium, regulate the soil pH value through metabolites, secrete organic acids to neutralize soil alkalinity, and at the same time decompose organic matter to improve soil structure and permeability;

[0006] However, the activity of microorganisms is affected by various factors such as temperature, humidity, and soil type, and the effect may vary due to different environmental conditions. In the complex water-salt environment of coastal saline-alkali land, the dry-wet alternation and water-salt interaction are strong, and the microbial habitat fluctuates greatly, which will limit the role of exogenous microorganisms, and thus the improvement effect of microbial improvement materials in coastal saline-alkali land is not obvious; therefore, it does not meet the existing needs, and for this reason, we propose an organic conditioner for coastal saline-alkali land, a preparation method thereof, and field application. Summary of the Invention

[0007] The object of the present invention is to provide an organic conditioner for coastal saline-alkali land, a preparation method thereof and field application, so as to solve the problems of slow effect, easy recurrence and high cost existing in the improvement and treatment technologies under the influence of typical characteristics such as heavy soil texture, poor structure and strong capillary rise in coastal saline-alkali land soil as mentioned in the above background art.

[0008] To achieve the above object, the present invention provides the following technical solution: An organic conditioner for coastal saline-alkali land is made from raw materials including the following weight components: 20 - 30 parts of organic solid waste materials, 10 - 15 parts of natural clay minerals, 2 - 4 parts of urea, 4 - 5 parts of superphosphate, 1 - 2 parts of diammonium phosphate, and 2 - 4 parts of liquid binder.

[0009] Preferably, the organic solid waste materials include soybean protein isolate residue, the natural clay minerals include natural bentonite, and the raw materials include the following weight components: 20 parts of soybean protein isolate residue, 15 parts of natural bentonite, 2.5 parts of urea, 5 parts of superphosphate, 1.2 parts of diammonium phosphate, and 2 parts of liquid binder.

[0010] Preferably, the natural clay minerals further include attapulgite, the organic solid waste materials further include distiller's grains, and the liquid binder is deionized water.

[0011] A preparation method of an organic conditioner for coastal saline-alkali land includes the following steps:

[0012] Step 1: Mix the urea, superphosphate, and diammonium phosphate granules to obtain granular fertilizer complex.

[0013] Step 2: Dry the organic solid waste materials until the water content < 10%, grind and sieve them to 100 meshes.

[0014] Step 3: Grind and sieve the natural clay mineral materials to 150 meshes, and mix them evenly with the ground and sieved organic solid waste materials to obtain a primary dry material mixture.

[0015] Step 4: Add the granular fertilizer complex to the primary dry material mixture, use the liquid binder to wrap and adsorb the primary dry material mixture on the surface of the granular fertilizer complex to form a coating, granulate and shape it, then dry it until the water content < 10% to obtain the organic conditioner.

[0016] Preferably, the drying temperature in Step 2 is 50 - 60°C.

[0017] Preferably, the drying temperature in Step 4 is 30 - 50°C.

[0018] A field application of an organic conditioner for coastal saline-alkali land is characterized in that: the organic conditioner is applied before spring sowing and autumn sowing in coastal saline-alkali land.

[0019] Preferably, the dosage of the organic conditioner is 50-200 kg / mu, and it needs to be adjusted according to the specific conditions of the soil salt content and soil bulk density in the farmland.

[0020] Preferably, after the completion of the preliminary land preparation such as soil moisture preservation and land leveling, the organic conditioner is evenly spread on the soil surface by a disc fertilizer spreader or other granular fertilizer spreaders, and then plowed by a moldboard turning plow with an operation depth > 30 cm to fully mix the soil with a thickness of 30 cm with the organic conditioner particles evenly; then rotary tillage is carried out by a rotary tiller until it reaches the sowing standard.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] Aiming at the key problems of the coastal saline-alkali soil such as heavy soil texture, poor structure, strong capillary rise effect, and low nutrient content, the present invention provides an organic conditioner for coastal saline-alkali soil, a preparation method and field application thereof. The provided organic conditioner can effectively improve the soil structure, enhance the water and fertilizer retention capacity of the soil by using its rich organic matter and mineral components, and promote the growth of plants by alleviating the toxicity of salt and alkali to plant roots. In particular, it can be used for the improvement and treatment of coastal saline-alkali soil with the whole salt gradient, for soil structure improvement, rapid fertility improvement and crop yield increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a bar chart of the plant height comparison of sweet sorghum of the present invention;

[0024] Figure 2 It is a bar chart of the stem diameter comparison of sweet sorghum of the present invention;

[0025] Figure 3 It is a bar chart of the chlorophyll content comparison of sweet sorghum of the present invention;

[0026] Figure 4 It is a bar chart of the comparison of the change of soil water content of the present invention;

[0027] Figure 5 It is a bar chart of the comparison of the change of soil salt content of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0029] Please refer to Figures 1 to 5, an embodiment provided by the present invention: an organic conditioner for coastal saline-alkali soil, its preparation method and field application, which are made from raw materials including the following weight components: 20-30 parts of organic solid waste materials, 10-15 parts of natural clay minerals, 2-4 parts of urea, 4-5 parts of superphosphate, 1-2 parts of diammonium phosphate, and 2-4 parts of liquid binder.

[0030] The organic solid waste materials include soybean protein isolate residue, and the natural clay minerals include natural bentonite. The optimal ratio of the organic conditioner for coastal saline-alkali soil includes raw materials with the following weight components: 20 parts of soybean protein isolate residue, 15 parts of natural bentonite, 2.5 parts of urea, 5 parts of superphosphate, 1.2 parts of diammonium phosphate, and 2 parts of liquid binder.

[0031] Organic solid waste materials refer to organic wastes generated during processes such as agriculture, forestry, and food processing, such as straw, livestock and poultry manure, food residues, fallen leaves, etc. As soil improvement materials, their main characteristics are high organic matter content, containing abundant organic substances such as carbon, nitrogen, and phosphorus; these materials are usually renewable agricultural by-products or wastes, rich in resources, environmentally friendly and sustainable. They have the functions of increasing the organic matter content of the soil, increasing the soil aggregate structure, improving the soil structure, enhancing the air permeability and water retention of the soil, and reducing soil compaction; at the same time, they can provide nutrients for soil microorganisms, promote the reproduction of microorganisms, enhance the biological activity and nutrient cycling ability of the soil; gradually release nutrients such as nitrogen, phosphorus, and potassium necessary for plants, providing continuous nutrient supply;

[0032] The organic solid waste materials used are soybean protein isolate residue and distiller's grains that are relatively easy to obtain in the regions where the coastal saline-alkali soil in our country is located;

[0033] Soybean protein isolate residue is the high-moisture residue by-product remaining after the low-temperature meal is leached with an alkaline aqueous solution, acid-precipitated, separated, and spray-dried to obtain soybean protein isolate products during soybean protein production. Its solid yield is similar to that of the protein product, and it is usually in powder form or wet paste form. The proportion of protein in soybean protein isolate residue is equivalent to that of soybean meal, with a crude protein content in the range of 45-50%, a crude fiber content in the range of 5-15%, and at the same time, there are a small amount of crude fat, various minerals such as calcium and magnesium, and a small amount of starch, etc. As the main source of organic matter, soybean protein isolate residue can, on the one hand, increase the organic matter content of the soil, improve the soil structure, promote microbial activities, and enhance soil fertility; on the other hand, due to the presence of residual proteins, amino acids, and minerals, it can be used as a raw material for organic fertilizers to slowly release nutrients and continuously supply the nutrients required for plant growth.

[0034] Distillers grains are by-products generated during the brewing process and are the residual solid substances after fermentation. It is the residue after fermentation and distillation of grains such as sorghum, rice, wheat, and corn, usually in a moist paste or dry granular form. It mainly includes 10 - 15% of incompletely fermented starch, 20% of cellulose and hemicellulose, 15 - 20% of residual grain protein, as well as fermentation microorganisms and metabolites such as alcohol, yeast, and lactic acid bacteria. On the one hand, distillers grains are rich in organic matter and can be used as soil conditioners to increase the organic matter content of the soil, improve soil structure and fertility; on the other hand, during the decomposition process of organic substances such as cellulose in distillers grains, organic colloids will be formed, enhancing the adhesion of soil particles and improving soil structure.

[0035] Natural clay mineral materials refer to hydrated aluminosilicate minerals with a layered structure and are the main mineral components that make up clay rocks and soils. They mainly include kaolinite, montmorillonite, palygorskite, illite, chlorite, etc. Clay minerals have unique crystal structures and physical and chemical properties: small grain size (generally <2mm), large specific surface area; widespread isomorphous substitution, charged layer plates or end faces, with strong electrostatic interactions and cation exchangeability; characteristics such as aluminol and silanol groups at end face sites and surfaces. The interlayer domain of clay minerals has characteristics such as interlayer exchange, adsorption, catalysis, aggregation, and pillaring, and is a good place for chemical reactions, and finally forms different types of clay minerals, including montmorillonite, kaolinite, illite, attapulgite, halloysite, and sepiolite, etc. Due to containing residual proteins, amino acids, and minerals, it can be used as a raw material for organic fertilizers to slowly release nutrients and continuously supply the nutrients required for plant growth.

[0036] The natural clay mineral materials used in the present invention are attapulgite and bentonite with relatively low costs. Attapulgite is a special natural clay mineral mainly composed of magnesium-rich aluminosilicate minerals. It is famous for its unique fibrous structure and excellent adsorption performance and is widely used in multiple fields. The particles of attapulgite are fibrous or needle-like, and this unique structure endows it with good adsorption performance and a high specific surface area; at the same time, it has extremely strong adsorption ability and can adsorb a variety of gases, liquids, and solutes, especially suitable for adsorbing oils, organic pollutants, and heavy metals, etc.; it has strong acid and alkali resistance and can maintain stability under various harsh environmental conditions. The fibrous structure of attapulgite can promote the aggregation between soil particles to form a stable aggregate structure, and this aggregate structure enhances the air permeability and water retention of the soil and reduces soil compaction; attapulgite has a high cation exchange capacity (CEC) and can effectively adsorb harmful salts such as sodium ions (Na+) in the soil, reducing the mobility of these salts in the soil and the concentration at the plant roots;

[0037] Bentonite is a natural clay mineral mainly composed of montmorillonite, with a layered structure. When it absorbs water, the interlayer distance increases, causing the volume of bentonite to expand significantly. Bentonite particles have a strong bonding ability under wet conditions and can adsorb and exchange a large number of cations, such as calcium, sodium, magnesium, etc. Bentonite has a strong water absorption and swelling ability. After absorbing water in the soil, the gaps between particles increase, forming a better aggregate structure, which helps to improve soil aeration and water permeability, prevent soil compaction; it not only increases the soil's water retention capacity but also reduces water evaporation.

[0038] The liquid binder is deionized water.

[0039] A preparation method of an organic conditioner for coastal saline-alkali land includes the following steps:

[0040] Step 1: Mix urea, superphosphate, and diammonium phosphate granules to obtain a granular fertilizer complex;

[0041] Step 2: Dry the organic solid waste material at a drying temperature of 50 - 60 °C until the water content < 10%, grind and sieve it to 100 mesh;

[0042] Step 3: Grind and sieve the natural clay mineral material to 150 mesh and mix it evenly with the ground and sieved organic solid waste material to obtain a primary dry material mixture;

[0043] Step 4: Add the granular fertilizer complex to the primary dry material mixture, use a liquid binder to wrap and adsorb the primary dry material mixture on the surface of the granular fertilizer complex to form a coating, granulate and shape it, then dry it at a drying temperature of 30 - 50 °C until the water content < 10% to obtain the organic conditioner.

[0044] Field application of the organic conditioner for coastal saline-alkali land. The organic conditioner provided by the present invention is applied before spring sowing and autumn sowing in coastal saline-alkali land;

[0045] The dosage of the organic conditioner is 50 - 200 kg / mu and needs to be adjusted according to the specific conditions of the soil salt content and soil bulk density of the farmland;

[0046] After the completion of pre-land preparation such as soil moisture preservation and land leveling, the organic conditioner is evenly spread on the soil surface by a disc fertilizer applicator or other granular fertilizer applicators;

[0047] Subsequently, a moldboard plow is used for plowing, and the operation depth > 30 cm is required to make the soil with a thickness of 30 cm fully mixed evenly with the organic conditioner particles;

[0048] Then a rotary tiller is used for rotary tillage until it reaches the sowing standard.

[0049] Regarding the organic conditioner provided by the present invention, relevant field trials were carried out in a typical area of coastal saline-alkali land, Dongying City, Shandong Province;

[0050] The test site is in Huanghekou Town, Kenli District, Dongying City, Shandong Province (118°55’E, 37°42’N), which belongs to the core area of the Yellow River Delta region; it belongs to the warm temperate semi-humid continental monsoon climate zone with distinct seasons. The main soil types are saline-alkali soil and salinized fluvo-aquic soil. The physical and chemical properties of the soil before the test are shown in Table 1:

[0051] Table 1 Physical and chemical properties of the soil before the test

[0052]

[0053] Around the preparation method of the organic conditioner provided by the present invention, a total of 4 organic conditioners were obtained, namely DGA (distillers grains + attapulgite + urea + superphosphate + diammonium phosphate), DGB (distillers grains + bentonite + urea + superphosphate + diammonium phosphate), WLA (soybean protein waste + attapulgite + urea + superphosphate + diammonium phosphate), and WLB (soybean protein waste + bentonite + urea + superphosphate + diammonium phosphate);

[0054] At the same time, 4 treatments, namely CF (urea + superphosphate + diammonium phosphate), OM (urea + superphosphate + diammonium phosphate + manure source fermented organic fertilizer), DG (distillers grains + urea + superphosphate + diammonium phosphate), and WL (soybean protein waste + urea + superphosphate + diammonium phosphate), were set as controls;

[0055] The specific test settings are shown in Table 2:

[0056] Table 2 Test treatments

[0057]

[0058] The test adopted a one-crop-a-year system. The test crop was a highly salt-tolerant forage crop, sweet sorghum. The test variety was Zhongketian F428, and the seeding density was 6,000 - 6,500 plants per mu. The land was prepared in late April, sweet sorghum was sown on May 9, and harvested on September 29;

[0059] Results and analysis of the field trial:

[0060] Plant height of sweet sorghum: As Figure 1As shown, compared with CF, all treatments could increase plant height, with WLB being the best. At the 6-leaf stage, the plant height showed as WLB > DGA > DGB > WL > OM > WLA > DG > CF. However, only the plant height of WLB was significantly higher than that of CF, and there were no significant differences for the other treatments compared with CF. At the 12-leaf stage, the plant height showed as WLB > WLA > DGA > DGB > WL > OM > CF > DG. The plant heights of WLB, WLA, and DGA were significantly higher than that of CF, and the plant height of DG was significantly lower than that of CF. There were no significant differences for the other treatments compared with CF. At the 16-leaf stage, the plant height showed as WLB > WLA > WL > DG > DGA > OM > DGB > CF. The plant heights of WLB, WLA, and DGA were significantly higher than that of CF, and there were no significant differences for the other treatments compared with CF.

[0061] Sweet sorghum stem diameter: As Figure 2 shown, compared with CF, only WLB significantly increased the stem diameter, and there were no significant differences for the other treatments compared with CF. At the 6-leaf stage, the stem diameter showed as WLB > DGA > WL > WLA > OM > DGB > CF > DG; at the 12-leaf stage, the stem diameter showed as WLB > DGB > DGA > WL > DG > WLA > OM > CF; at the 16-leaf stage, the stem diameter showed as WLB > WLA > DGA > DGB > WL > DG > CF > OM.

[0062] Sweet sorghum chlorophyll content: As Figure 3 shown, compared with CF, all treatments could increase SPAD, with WLB being the best. At the 6-leaf stage, the SPAD showed as WLB > OM > WL > DG > DGA > WLA > DGB > CF. However, there were no significant differences in SPAD among all treatments. At the 12-leaf stage, the SPAD showed as WLB > WLA > DGB > OM > DGA > WL > DG > CF. The SPAD values of WLB, WLA, DGB, OM, and DGA were all significantly higher than that of CF, and there were no significant differences for WL and DG compared with CF. At the 16-leaf stage, the SPAD showed as WLB > DGB > WL > WLA > OM > DGA > DG > CF. The SPAD values of WLB and WL were significantly higher than that of CF, and there were no significant differences for the other treatments compared with CF.

[0063] Sweet sorghum biomass and forage quality: In the analysis of the aboveground dry matter weight of sweet sorghum, the results showed that different soil conditioners had a significant impact on the accumulation of dry matter. Compared with the CF treatment, all treatments could increase the total fresh weight, total dry weight, total carbon and total nitrogen contents. Among them, the WLB treatment showed the best performance in terms of total fresh weight and total dry weight, reaching 1462.5 kg / mu and 484.6 kg / mu respectively; the DGB treatment brought relatively lower total fresh weight (1107.2 kg / mu) and total dry weight (357.8 kg / mu). The trend of the impact of each treatment on total carbon was similar to the changes in total dry weight and total fresh weight, and the order of total carbon content was: WLB > WL > WLA > DG > OM > DGA > DGB > CF. In terms of the accumulation of total nitrogen, the WLB and OM treatments significantly increased the total nitrogen content, while the DG treatment had a poor effect on the accumulation of total nitrogen. The DGB treatment brought the largest crude fiber ratio, which was 68.8%, and WL reduced the crude fiber content by 8.5% compared with CF. Compared with the CF treatment, the WLB, OM, DGA and DGB treatments all brought an increase in the crude fat ratio. Among them, the effects of the OM, DGA and DGB treatments on crude fat were approximately equal, between 3.06% - 3.11%; the DG, WL and WLA treatments brought a decrease in the crude fat ratio.

[0064] Table 3 Sweet sorghum biomass and forage quality

[0065]

[0066] The data in the table are the average values. Different letters after the data in the same column indicate a significant difference at the 5% level. The same applies hereinafter.

[0067] Changes in soil water content: As Figure 4 shown, at the 6 - leaf stage, the soil water content showed DGB > DG > OM > CF > WL > DGA > WLB > WLA, and there was no obvious difference in the soil water content of all treatments. At the 12 - leaf stage, the soil water content showed WLB > DGB > WL > WLA > DG > DGA > OM > CF. Except that there was no obvious difference in the soil water content between OM and CF, the soil water content of the other treatments was significantly higher than that of CF. The soil water content decreased significantly from the 6 - leaf stage to the 12 - leaf stage, indicating that this stage was a period of vigorous crop growth and the water consumption increased sharply. At the 16 - leaf stage, the soil water content showed WLB > DGB > DG > DGA > WL > WLA > OM > CF, and the soil water contents of WLB, DGB and DG were significantly higher than that of CF. Generally speaking, WLB, DGB and DG had a certain water retention capacity, reduced the evaporation and ineffective loss of water, and improved the water use efficiency of crops.

[0068] Changes in soil salt content: As Figure 5As shown, at the 6-leaf stage, the soil salt content showed the order of CF > OM > WL > DG > DGA > WLA > DGB > WLB. There was no significant difference in soil salt content between the OM and WL treatments and CF. The soil salt content of WLB, DGB, WLA, DGA, and DG was significantly lower than that of CF. At the 12-leaf stage, the soil salt content showed the order of CF > OM > DGA > WL > WLA > DG > DGB > WLB. There was no significant difference in soil salt content between the OM treatment and CF, and the soil salt content of the remaining treatments was significantly lower than that of CF. At the 16-leaf stage, the soil salt content showed the order of CF > OM > WL > WLA > DG > DGB > WLB > DGA, and the soil salt content of all treatments was significantly lower than that of CF. From the 6-leaf stage to the 16-leaf stage, the soil salt content of the CF, WLA, and WLB treatments increased, while the soil salt content of the remaining treatments decreased.

[0069] Soil physical and chemical characteristics: As shown in Table 4 below, in the comprehensive analysis of soil properties, we found that different treatment methods had a significant impact on the key indicators of the soil. Compared with the CF treatment, the soil conditioner improved the soil pH and soil bulk density. This led to a change in soil pH towards neutrality. The WLB treatment and the WL treatment brought the largest and smallest pH reduction values, which were 8.3 and 8.5 respectively. Generally, each treatment led to a decrease in soil bulk density, and the WL treatment had the greatest impact on soil bulk density, with a decrease of 6.8%. It is worth noting that the total porosity under each treatment also decreased, and the order from largest to smallest was: CF > OM > DG > WL > DGA > WLA > DGB > WLB. In terms of saturated hydraulic conductivity, the CF treatment had the strongest water conductivity, which was 420.7 mm / d, and the WLB treatment was the weakest, which was 331.3 mm / d.

[0070] Compared with the CF treatment, the soil conditioner could significantly increase the organic matter content of the soil and its related soil nutrients. The organic matter content increased by 8.9% - 31.3%. Among them, the DG treatment had the least promoting effect on the organic matter content, which was 6.62 g / kg; the WLA treatment had the most significant promoting effect on the organic matter content, which was 7.98 g / kg. In the impact on the total nitrogen content, the WL, WLA, and WLB treatments were generally higher than the DG, DGA, and DGB treatments. The order of total nitrogen content was: WLB > WL > WLA > DGA > DGB > DG > OM > CF. The available nitrogen content under each treatment did not change in the same way as the total nitrogen content. The order of available nitrogen content was: WL > WLB > DG > DGA > WLA > OM > DGB > CF. The change trend of available phosphorus content was similar to that of organic matter and total nitrogen content. The WLB treatment was the treatment method with the strongest and most significant promoting effect on available phosphorus (40.94 mg / kg).

[0071] Table 4 Soil physical and chemical characteristics

[0072]

[0073] It will be apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in all respects, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Accordingly, all changes that fall within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims concerned.

Claims

1. An organic conditioner for coastal saline-alkali land, characterized in that, It is made from raw materials including the following weight components: 20 - 30 parts of organic solid waste materials, 10 - 15 parts of natural clay minerals, 2 - 4 parts of urea, 4 - 5 parts of superphosphate, 1 - 2 parts of diammonium phosphate, and 2 - 4 parts of liquid binder.

2. The organic conditioner for coastal saline-alkali land according to claim 1, wherein: The organic solid waste materials include soybean protein isolate residue, the natural clay minerals include natural bentonite, and the raw materials include the following weight components: 20 parts of soybean protein isolate residue, 15 parts of natural bentonite, 2.5 parts of urea, 5 parts of superphosphate, 1.2 parts of diammonium phosphate, and 2 parts of liquid binder.

3. The organic conditioner for coastal saline-alkali land according to claim 2, wherein: The natural clay minerals also include attapulgite, the organic solid waste materials also include distiller's grains, and the liquid binder is deionized water.

4. A method for preparing the organic conditioner for coastal saline-alkali land according to any one of claims 1-3, characterized in that, It includes the following steps: Step 1: Mix the urea, superphosphate, and diammonium phosphate granules to obtain a granular chemical fertilizer complex. Step 2: Dry the organic solid waste materials until the water content is < 10%, grind and sieve them to 100 mesh. Step 3: Grind and sieve the natural clay mineral materials to 150 mesh, and mix them evenly with the ground and sieved organic solid waste materials to obtain a primary dry material mixture. Step 4: Add the granular chemical fertilizer complex to the primary dry material mixture, use the liquid binder to wrap and adsorb the primary dry material mixture on the surface of the granular chemical fertilizer complex to form a coating, perform granulation and shaping, then dry until the water content is < 10% to obtain an organic conditioner.

5. An organic conditioner for coastal saline-alkali land, its preparation method and field application according to claim 1, characterized in that: The drying temperature in Step 2 is 50 - 60 °C.

6. The organic conditioner for coastal saline-alkali land, its preparation method and field application according to claim 1, characterized in that: The drying temperature in Step 4 is 30 - 50 °C.

7. Field application of the organic conditioner according to any one of claims 1-3 for coastal saline-alkali land, characterized in that: The organic conditioner is used for application before spring sowing and autumn sowing in coastal saline-alkali land.

8. The field application of the organic conditioner for coastal saline-alkali land according to claim 7, characterized in that: The application rate of the organic conditioner is 50 - 200 kg / mu, and it needs to be adjusted according to the specific conditions of the soil salt content and soil bulk density in the farmland.

9. An organic conditioner for coastal saline-alkali land, its preparation method and field application according to claim 1, characterized in that: After the completion of pre-land preparation such as soil moisture preservation and land leveling, the organic conditioner is evenly spread on the soil surface using a disc fertilizer spreader or other granular fertilizer spreaders, and then a moldboard plow is used for plowing, with the operation depth > 30 cm, so that the soil with a thickness of 30 cm is fully mixed evenly with the organic conditioner granules; then a rotary tiller is used for rotary tilling until it reaches the sowing standard.

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