Saline-alkali soil conditioner and application thereof

Abstract

The invention belongs to the field of organic fertilizer and microbial fertilizer manufacturing, and particularly relates to a saline-alkali soil conditioner and application thereof in the technical field of saline-alkali soil conditioning. The invention provides a saline-alkali soil conditioner. The saline-alkali soil conditioner comprises the following components: a nitrogen fertilizer, a phosphate fertilizer and a synergist. Urea and ammonium sulfate in nitrogen fertilizer of the saline-alkali soil conditioner cooperate with acidizing rhizosphere to promote rhizosphere salinity reduction, different types of phosphatic fertilizers are mixed to improve the fertilizer efficiency of phosphatic fertilizers in salinized soil, and a carbon source and a synergist are matched to strengthen the microbial function of the soil. When the soil conditioner is applied, the activity of soil microorganisms can be stimulated, the soil acidity and alkalinity can be improved, and nutrient turnover can be promoted. When the conditioner disclosed by the invention is applied to the salinized soil, the contents of nitrogen, phosphorus and potassium at the overground part of crops can be increased, and the growth of the crops is promoted.

Description

Technical Field

[0001] The invention belongs to the field of organic fertilizer and microbial fertilizer manufacturing, and specifically relates to a saline-alkali soil improver and application thereof in the technical field of saline-alkali soil conditioning. Background Art

[0002] At present, the agricultural sector is facing problems such as a shortage of freshwater resources, a reduction in the quantity and quality of arable land, and a serious shortage of reserve arable land resources. As an important reserve arable land resource, saline-alkali land has great development and utilization value and broad room for value-added. In areas with shallow groundwater, the soil has obvious seasonal salt return characteristics, and it is difficult to remove the salt in the arable layer; in areas with scarce freshwater resources, the management method of saline-alkali land such as large water pressure salt is difficult to sustain. High soil salt content causes crop ion poisoning, osmotic stress, and nutritional imbalance, resulting in reduced yield and quality. Excessive application of chemical fertilizers also poses the risk of groundwater pollution. Achieving the improvement of saline-alkali land production capacity, environmental friendliness, and resource efficiency through nutritional conditioning is a new way to achieve green and sustainable utilization of saline-alkali arable land.

[0003] At present, conditioners are mainly used to repair and adjust soil properties. The product types are single and there are limitations. Conventional conditioners mainly contain calcium preparations, acidic substances and organic matter. Applying gypsum to increase the Ca content of saline-alkali soil 2+ Content accelerated Na + The leaching of organic matter can promote the formation of saline-alkali soil aggregate structure, but it is easy to cause soil compaction problems; the application of organic fly ash and sludge promotes the formation of saline-alkali soil aggregate structure, but it is also easy to cause the negative effect of excessive heavy metals in the soil. Soil conditioners also include natural inorganic raw materials, organic matter, waste, natural polymer compounds, artificial synthetics, natural-synthetic copolymers and biological types, which can improve soil structure, improve soil physical and chemical properties, and increase soil nutrients. However, the above-mentioned improvers are mainly used for soil improvement, and have not exerted the biological potential of crops and soil microorganisms in salt tolerance and yield increase. Summary of the invention

[0004] The purpose of the present invention is to provide a saline-alkali soil conditioner and its application. The soil conditioner of the present invention can stimulate the activity of soil microorganisms, improve soil pH, and promote nutrient turnover. Applying the soil conditioner of the present invention on salinized soil can increase the nitrogen, phosphorus, and potassium content of the aboveground parts of plants and promote crop growth.

[0005] The present invention provides a saline-alkali soil conditioner, comprising the following components: nitrogen fertilizer, phosphate fertilizer and synergist; the nitrogen fertilizer comprises urea and ammonium sulfate; the phosphate fertilizer comprises monoammonium phosphate, ammonium polyphosphate and urea phosphate; the synergist comprises a carbon source, a nitrification inhibitor and a biostimulant;

[0006] The carbon source comprises at least one of molasses, glucose and citric acid;

[0007] The nitrification inhibitor comprises at least one of 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole phosphate;

[0008] The biostimulant includes at least one of quercetin, luteolin and myristic acid.

[0009] As a preferred solution, the carbon source includes molasses and glucose, and the mass ratio of molasses to glucose is 384-456:6.6.

[0010] As a preferred solution, the nitrification inhibitor includes 3,4-dimethylpyrazole phosphate.

[0011] As a preferred solution, the mass parts of the nitrogen fertilizer are 419-503 parts, the mass parts of the phosphate fertilizer are 103-115 parts, and the mass parts of the synergist are 394-466 parts.

[0012] As a preferred solution, the mass ratio of urea to ammonium sulfate in the nitrogen fertilizer is 55-229:190-448; the mass ratio of monoammonium phosphate, urea phosphate and ammonium polyphosphate in the phosphate fertilizer is 57-101:9-26:5-20; the mass ratio of the carbon source, nitrification inhibitor and biostimulant in the synergist is 390-463:0.4-12:3.3.

[0013] As a preferred solution, the mass ratio of myristic acid, quercetin and luteolin in the biostimulant is 1.3:1:1.

[0014] The present invention also provides the use of the saline-alkali soil conditioner described in the above scheme in soil improvement and / or promoting plant growth.

[0015] As a preferred solution, the soil includes saline-alkali soil; and the plants include one or more of corn, wheat, sunflower and cotton.

[0016] The present invention also provides a method for improving soil and / or promoting plant growth, comprising the following steps: applying the saline-alkali soil conditioner described in the above scheme to the soil to be improved.

[0017] As a preferred solution, the application method includes base application or drip irrigation.

[0018] Beneficial effects:

[0019] The present invention provides a saline-alkali soil conditioner, comprising the following components: nitrogen fertilizer, phosphorus fertilizer and synergist; the nitrogen fertilizer comprises urea and ammonium sulfate; the phosphorus fertilizer comprises monoammonium phosphate, ammonium polyphosphate and urea phosphate; the synergist comprises a carbon source, a nitrification inhibitor and a biostimulant; the carbon source comprises at least one of molasses, glucose and citric acid; the nitrification inhibitor comprises at least one of 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole phosphate; the biostimulant comprises at least one of quercetin, luteolin and myristic acid. In the saline-alkali soil conditioner of the present invention, urea and ammonium sulfate cooperate with each other, increase the solubility of phosphorus in the soil through acidification, promote the reduction of rhizosphere salt, mix quick-acting phosphorus fertilizer, acidic phosphorus fertilizer and slow-release phosphorus fertilizer to improve the fertilizer efficiency of phosphorus fertilizer in salinized soil, and strengthen the soil microbial function by matching carbon source and biostimulant. Applying the soil conditioner of the present invention can stimulate soil microbial activity, improve soil pH and promote nutrient turnover. Applying the conditioner of the present invention to salinized soil can increase the nitrogen, phosphorus and potassium content of wheat and corn plants and promote crop growth. The results of the embodiment show that compared with the comparative example 1 of applying high phosphorus fertilizer, the application of the soil conditioner of the present invention can stimulate soil microbial activity, promote nutrient turnover, significantly reduce soil pH, increase soil alkaline phosphatase activity by 36%, increase nitrogen content of the aboveground part of the plant by 103%, increase phosphorus content by 194%, and increase potassium content by 84%. DETAILED DESCRIPTION

[0020] The invention provides a saline-alkali soil conditioner, comprising the following components: a nitrogen fertilizer, a phosphorus fertilizer and a synergist; the nitrogen fertilizer comprises urea and ammonium sulfate; the phosphorus fertilizer comprises monoammonium phosphate, ammonium polyphosphate and urea phosphate; the synergist comprises a carbon source, a nitrification inhibitor and a biostimulant; the carbon source comprises at least one of molasses, glucose and citric acid; the nitrification inhibitor comprises at least one of 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole phosphate; the biostimulant comprises at least one of quercetin, luteolin and myristic acid.

[0021] The nitrogen fertilizer of the present invention comprises urea and ammonium sulfate, and the mass parts of the nitrogen fertilizer are preferably 419 to 503 parts. In the present invention, the mass ratio of urea to ammonium sulfate in the nitrogen fertilizer is preferably 55 to 229:190 to 448. The ammonium sulfate in the nitrogen fertilizer of the present invention can not only supplement the nitrogen and sulfur elements in the soil, but also acidify the root zone of crops, increase salt leaching, and promote the absorption and utilization of phosphorus and trace elements by plants. The compound application of ammonium sulfate and urea increases the solubility of phosphorus in the soil through acidification, improves the utilization rate of phosphorus, and the saline-alkali soil conditioner of the present invention can reduce the application amount of phosphorus fertilizer.

[0022] The phosphate fertilizer of the present invention includes monoammonium phosphate, ammonium polyphosphate and urea phosphate, and the mass parts of the phosphate fertilizer are preferably 103-115 parts; in the present invention, the mass ratio of monoammonium phosphate, urea phosphate and ammonium polyphosphate in the phosphate fertilizer is preferably 57-101:9-26:5-20. The phosphate fertilizer of the present invention adopts the combination of quick-acting state and slow-release state, coordinates the phosphorus nutrient cycle of saline-alkali land, so as to achieve the effect of reducing loss and increasing efficiency, which can not only reduce the amount of phosphate fertilizer converted into invalid phosphorus in saline-alkali soil, but also reduce the burden of environmental pollution. At the same time, the selection of diversified phosphate fertilizer can also improve plant productivity. The monoammonium phosphate in the phosphate fertilizer of the present invention is a high-quality compound fertilizer containing nitrogen and phosphorus and being acidic in the soil. It has high fertilizer efficiency and fast release of phosphate fertilizer. After being applied to calcareous soil, it can significantly improve the mobility and effectiveness of phosphorus in the soil and improve the effective utilization rate of soil phosphorus. The urea phosphate in the phosphate fertilizer of the present invention is a complex compound made by the equiproportional reaction of phosphoric acid and urea, which can effectively reduce the soil pH. The drip application of urea phosphate has a stronger acidification effect than monoammonium phosphate and ammonium polyphosphate. Urea phosphate will be rapidly hydrolyzed after being applied to the soil, and the soil pH will be significantly reduced from 7.54 to 7.40. The ammonium polyphosphate in the phosphate fertilizer of the present invention can significantly promote the nutrient absorption of plants. The ammonium polyphosphate fertilizer greatly increases the content of soil phosphorus and effective Fe, Mn and Zn, and reduces the amount of phosphorus fixed by the soil. The phosphate fertilizer of the present invention adopts the combination of fast-acting state, acidic state and slow-release state, coordinates the phosphorus nutrient cycle of saline-alkali land, reduces the loss and increases the efficiency, and can not only reduce the amount of phosphate fertilizer converted into invalid phosphorus in saline-alkali soil, but also, at the same time, the selection of diversified phosphate fertilizer can also increase the soil phosphorus supply intensity and promote plant growth.

[0023] The synergist of the present invention includes a carbon source, a nitrification inhibitor and a biostimulant, and the mass parts of the synergist are preferably 394 to 466 parts, and the mass ratio of the carbon source, the nitrification inhibitor and the biostimulant in the synergist of the present invention is preferably 390 to 463:0.4 to 12:3.3. The synergist in the saline-alkali soil conditioner of the present invention plays a huge contribution to the activation of inactive phosphorus in the soil. Suitable carbon sources and biostimulants promote the growth and reproduction of microorganisms, improve the activity of soil microorganisms, and phosphate-dissolving bacteria secrete a variety of organic acids and protons, which can reduce the environmental pH to dissolve inorganic phosphorus, secrete alkaline phosphatase to dissolve organic phosphorus, thereby increasing the content of available phosphorus in the soil. Nitrification inhibitors can reduce the conversion of ammonium nitrogen fertilizers to nitrate nitrogen, so that the effect of ammonium nitrogen acidifying the rhizosphere can be maintained for a longer time and at a higher intensity.

[0024] The carbon source of the present invention includes at least one of molasses, glucose and citric acid, and may include molasses and citric acid. In the present invention, when the carbon source includes molasses and citric acid, the mass ratio of molasses to citric acid in the carbon source is preferably 384-456:6.6; when the carbon source includes glucose and citric acid, the mass ratio of glucose to citric acid in the carbon source is preferably 288-317:6.6.

[0025] The nitrification inhibitor of the present invention includes at least one of 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole phosphate. In a specific embodiment, the nitrification inhibitor can be 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide, or 3,4-dimethylpyrazole phosphate. In the present invention, when the nitrification inhibitor is 2-chloro-6-(trichloromethyl)pyridine, the mass ratio of the carbon source, nitrification inhibitor and biostimulant in the synergist of the present invention is preferably 390-463:7-12:3.3; when the nitrification inhibitor is dicyandiamide, the mass ratio of the carbon source, nitrification inhibitor and biostimulant in the synergist of the present invention is preferably 390-463:8.4-12:3.3; when the nitrification inhibitor is 3,4-dimethylpyrazole phosphate, the mass ratio of the carbon source, nitrification inhibitor and biostimulant in the synergist of the present invention is preferably 390-463:0.4-0.9:3.3.

[0026] The biostimulant of the present invention includes at least one of quercetin, luteolin and myristic acid, preferably quercetin, luteolin and myristic acid. In the present invention, the mass ratio of myristic acid, quercetin and luteolin in the biostimulant is 1.3:1:1. The quercetin and luteolin of the present invention can stimulate the spore germination of arbuscular mycorrhizal fungi in the soil, and myristic acid can provide nutrition for the infection of arbuscular mycorrhizal fungi in the soil, helping arbuscular mycorrhizal fungi to colonize in the root system better and faster, thereby helping plants to better absorb nitrogen and phosphorus nutrients.

[0027] The present invention also provides the use of the saline-alkali soil conditioner described in the above scheme in soil improvement and / or promoting plant growth. In the present invention, the soil preferably includes saline-alkali soil; the plant preferably includes one or more of corn, wheat, sunflower and cotton.

[0028] The present invention also provides a method for improving soil and / or promoting plant growth, comprising: applying the saline-alkali soil improver described in the above scheme to the soil to be improved.

[0029] In the present invention, the saline-alkali soil conditioner is preferably applied by basal application or drip irrigation.

[0030] When the application method of the present invention is preferably base application, the mass ratio of urea to ammonium sulfate is 55-229:344-448; the mass ratio of monoammonium phosphate, urea phosphate and ammonium polyphosphate is 57-76:14-26:16-20; the mass ratio of the carbon source, nitrification inhibitor and biostimulant is 390.6-419.6:0.7-0.9:3.3; the mass ratio of molasses and citric acid in the carbon source is 384-413:6.6; the nitrification inhibitor includes 3,4-dimethylpyrazole phosphate; the mass ratio of myristic acid, quercetin and luteolin in the biostimulant is 1.3:1:1.

[0031] In order to further illustrate the present invention, a saline-alkali soil conditioner and its application provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0032] In a specific embodiment of the present invention, monoammonium phosphate contains 12% nitrogen and 61% P2O5, urea phosphate contains 17% nitrogen and 44% P2O5, ammonium polyphosphate contains 18% nitrogen and 58% P2O5, urea contains 21% nitrogen, and ammonium sulfate contains 46% nitrogen.

[0033] Example 1

[0034] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0035] Urea 126g, ammonium sulfate 344g, monoammonium phosphate 76g, urea phosphate 14g, ammonium polyphosphate 16g, molasses 413g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.7g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0036] Example 2

[0037] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0038] Urea 55g, ammonium sulfate 448g, monoammonium phosphate 57g, urea phosphate 14g, ammonium polyphosphate 16g, molasses 384g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.9g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0039] Example 3

[0040] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0041] Urea 229g, ammonium sulfate 190g, monoammonium phosphate 101g, urea phosphate 9g, ammonium polyphosphate 5g, molasses 456g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.4g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0042] Comparative Example 1

[0043] In g as mass parts, a saline-alkali soil conditioner was prepared according to the following components as a high-phosphorus control group:

[0044] Urea 722g, potassium dihydrogen phosphate 278g.

[0045] Comparative Example 2

[0046] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0047] Urea 137g, ammonium sulfate 353g, monoammonium phosphate 42g, urea phosphate 23g, ammonium polyphosphate 12g, molasses 423g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.7g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0048] Comparative Example 3

[0049] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0050] Urea 72g, ammonium sulfate 459g, monoammonium phosphate 58g, urea phosphate 4g, ammonium polyphosphate 4g, molasses 393g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 1.2g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0051] Comparative Example 4

[0052] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0053] Urea 171g, ammonium sulfate 442g, monoammonium phosphate 98g, urea phosphate 8g, ammonium polyphosphate 6g, molasses 265g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.9g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0054] Comparative Example 5

[0055] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0056] Urea 79g, ammonium sulfate 563g, monoammonium phosphate 74g, urea phosphate 21g, ammonium polyphosphate 10g, molasses 241g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 1.2g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0057] Comparative Example 6

[0058] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0059] Urea 303g, ammonium sulfate 252g, monoammonium phosphate 74g, urea phosphate 27g, ammonium polyphosphate 31g, molasses 302g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.5g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0060] Comparative Example 7

[0061] In g as mass parts, a saline-alkali soil conditioner is prepared according to the following components:

[0062] Urea 244g, ammonium sulfate 195g, monoammonium phosphate 58g, urea phosphate 13g, ammonium polyphosphate 10g, molasses 469g, citric acid 6.6g, 3,4-dimethylpyrazole phosphate 0.4g, myristic acid 1.3g, quercetin 1.0g, luteolin 1.0g.

[0063] Application Example 1

[0064] 1) Soil treatment

[0065] After the soil is air-dried, it is passed through a 2 mm sieve and weighed into bags of 2.5 kg. Based on the mass of each kg of soil, basic nutrients potassium sulfate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, manganese sulfate, and copper sulfate pentahydrate are added according to the K element content of 200 mg / kg, the Mg element content of 50 mg / kg, the Zn element content of 5 mg / kg, the Mn element content of 5 mg / kg, and the Cu element content of 2 mg / kg to obtain the test soil. The basic physical and chemical indicators of the test soil are: available phosphorus 13 mg / kg, pH 7.54, conductivity EC 406 μS / cm, and total salt 1.2 g / kg.

[0066] Before sowing, add 0.5g / kg NaCl in the form of solution to adjust the total salt content of the test soil to 1.7g / kg per kg of soil mass. The soil is fully dried and passed through a 2mm sieve again. After being fully mixed, it is potted. After 30 days of sowing, continue to add 0.3g / kg NaCl to make the total salt content of the soil reach 2g / kg. According to the classification standard of coastal saline-alkali soil ("Saline Soil in China", Wang Zunqin et al., 1993), the soil at this time is slightly salinized soil.

[0067] 2) Plant treatment

[0068] A pot experiment was conducted in the greenhouse of the College of Resources and Environment of China Agricultural University from June to August 2022. The crops planted were wheat and corn, and the application methods were basal application and drip irrigation, with wheat being the planted crop for illustration.

[0069] The wheat variety was Triticum aestivum L.cv Xiaoyan No.60.

[0070] For disinfection and germination of wheat seeds, first take twice the number of seeds needed, add them to 10% hydrogen peroxide and soak them for 15 minutes for sterilization, then rinse the hydrogen peroxide attached to the surface of the seeds with deionized water, and then spread the seeds on a tray with moist filter paper, cover the surface of the seeds with a layer of moist filter paper to keep them moist, and place them in the dark at 28℃ to wait for the seeds to germinate. After culturing for about 12 hours, the embryos can be sown when they turn white.

[0071] Before sowing, the soil water requirement of each potted plant is 450 mL according to 60% of the field water holding capacity. The soil conditioners of Examples 1, 2, 3 and Comparative Examples 2, 3, 4, 5, 6, and 7 are dissolved in 450 mL of water and added to the pot. After the water is completely infiltrated, seeds with uniform length of white embryos are selected for sowing. Eight grains of wheat are sown in each pot, and then covered with soil and covered with plastic film for water and heat preservation. The plastic film is uncovered after 2 to 3 days of seedling emergence. The seedlings are fixed in about a week, and 3 wheat plants are left for the test. The seeds are weighed regularly and water is supplemented according to a weight water content of 18% (about 60% of the field water holding capacity).

[0072] The dosage of the soil conditioner in Examples 1 to 3 and Comparative Examples 2 to 7 is determined based on the application of 75 mg P / kg soil. Based on the mass of the soil, the dosage of the soil conditioner in Examples 1 to 3 is 1.21 g / kg, 1.30 g / kg, and 1.10 g / kg, respectively; the dosage of the soil conditioner in Comparative Examples 2 to 7 is 1.77 g / kg, 1.91 g / kg, 1.13 g / kg, 1.24 g / kg, 0.99 g / kg, and 1.60 g / kg, respectively. The soil conditioners in Examples 1 to 3 and Comparative Examples 2 to 7 are respectively dissolved in 450 mL of deionized water and applied to the slightly salinized soil obtained in step (1) with drip irrigation.

[0073] Comparative Example 1 was set as a high phosphorus control group, recorded as P100, and 100 mg / kg of potassium dihydrogen phosphate and 200 mg / kg of urea were applied per kg of soil mass in terms of P2O5. According to the above addition amounts, the nitrogen and phosphorus fertilizers described in Comparative Example 1 were dissolved in 450 mL of deionized water and applied to the slightly salinized soil obtained in step (1).

[0074] 3) Sample determination

[0075] ① Investigation of plant growth status: Investigation of biomass and degree of yellowing of crop leaves under salt stress. The results are shown in Table 1.

[0076] A. Crop biomass determination: Wheat was harvested 63 days after sowing. The aboveground plants were collected and weighed for fresh weight. The aboveground samples were dried in an oven at 105°C for 30 minutes, and the oven temperature was adjusted to 65°C to 70°C until they were dried to a constant weight. The dry weight was weighed and recorded. The results are shown in Table 1.

[0077] B. Statistics of plant salt stress: The yellowing degree of wheat leaves was counted on the 62nd day after sowing. The wheat plants were statistically subjected to salt damage symptoms, and the yellowing degree of leaves was investigated. The disease index survey method was used to divide the overall yellowing degree of leaves into 5 levels, from 1 to 5, from a small area of ​​leaves slightly yellowing to a large area of ​​leaves severely yellowing and withering. The yellowing degree of wheat leaves was recorded as the salt stress index, and the formula is shown in Formula I:

[0078]

[0079] The salt stress index was calculated according to the formula, and the results are shown in Table 1.

[0080] ② Determination of nitrogen, phosphorus, potassium and sodium content in plant samples

[0081] The dried plants were crushed and passed through a 1 mm sieve. After digestion with concentrated sulfuric acid-hydrogen peroxide, the total nitrogen content was determined by the semi-micro Kjeldahl method, the total phosphorus content was determined by the vanadium molybdenum yellow colorimetry, and the potassium content was determined by flame photometry. The results are shown in Table 1.

[0082] ③ Determination of soil available phosphorus, pH, EC and phosphatase activity

[0083] When harvesting, remove the top 2 cm of soil first, pick out the fine roots from the remaining soil and mix them through a 2 mm sieve. Collect two soil samples by quartering, one stored in a 4 ° C refrigerator and the other air-dried. Take the soil stored at 4 ° C, and use disodium nitrobenzene phosphate as a substrate to determine the activity of soil alkaline phosphatase. Take the air-dried soil, use a soil-water ratio of 1:5 for extraction, and determine the soil pH and EC; the molybdenum antimony colorimetric method is used to determine the soil available phosphorus. The results are shown in Table 1.

[0084] 4) Result analysis

[0085] Table 1 Analysis of wheat results of Examples 1 to 3 and Comparative Examples 1 to 7

[0086]

[0087] Note: The average value refers to the mean of 4 replicates for each treatment. The comparison with P100 refers to the difference between the index of each treatment and the comparative example 1 (excessive phosphate fertilizer treatment); * indicates that there is a significant difference between the soil conditioner treatment and the comparative example 1; - (minus sign) before the number indicates that the mean of the soil conditioner treatment is less than that of the comparative example 1.

[0088] According to Table 1, compared with the application of 100 mg P / kg soil in Comparative Example 1, the application of soil conditioners in saline-alkali soil significantly promoted the growth of wheat. The dry weight of wheat in Example 1, Example 2, and Example 3 increased by 30%, 16%, and 18% respectively compared with Comparative Example 1. The dry weight of wheat in Comparative Example 3, Comparative Example 4, and Comparative Example 5 increased by 15%, 3%, and 18% respectively compared with Comparative Example 1. The average wheat biomass of Examples 1 to 3 is 37% higher than the average wheat biomass of Comparative Examples 2 to 7. After applying the soil conditioners in the examples, the salt stress index of wheat is significantly reduced. Compared with Comparative Example 1, the average salt stress index of Examples 1 to 3 decreased by 27% to 50%, indicating that the degree of salt damage to wheat was significantly reduced after the application of soil conditioners.

[0089] The nitrogen content of the plants treated with the soil conditioners of Example 1, Example 2, and Example 3 increased by 103%, 88%, and 86% compared with that of Comparative Example 1; the nitrogen content of the plants treated with the soil conditioners of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 increased by 71%, 40%, 38%, 76%, 8%, and 35% compared with that of Comparative Example 1. The potassium content of the plants treated with the soil conditioners of Example 1, Example 2, and Example 3 increased by 56%, 69%, and 84% compared with that of Comparative Example 1; the potassium content of the plants treated with the soil conditioners of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 increased by 63%, 43%, 23%, 64%, 1%, and 11% compared with that of Comparative Example 1. The phosphorus content of the plants treated with the soil conditioners of Example 1, Example 2, and Example 3 increased by 103%, 161%, and 194% compared with that of Comparative Example 1; the phosphorus content of the plants treated with the soil conditioners of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 increased by 84%, 0, 44%, 82%, 41%, and 50% compared with that of Comparative Example 1.

[0090] The application of conditioners has a significant improvement effect on saline-alkali soil. Under the condition of reducing the amount of phosphorus applied by 25%, the available phosphorus in the soil treated by Example 1, Example 2, and Example 3 only decreased by 0.4-3.6 mg / kg (an average decrease of 4%), and the effectiveness of soil phosphorus remained at a high level. The pH value of the soil treated by the soil conditioners of Example 1, Example 2, and Example 3 was reduced by 0.18, 0.10, and 0.13 units compared with that of Comparative Example 1; the pH value of the soil conditioners of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 was reduced by 0.04, 0.01, 0.07, 0.09, 0.04, and -0.04 units compared with that of Comparative Example 1. The application of conditioners significantly increased the activity of soil alkaline phosphatase. The alkaline phosphatase activity of the soil treated with the soil conditioners of Example 1, Example 2, and Example 3 increased by 33%, 31%, and 36% compared with that of Comparative Example 1; the alkaline phosphatase activity of the soil treated with the soil conditioners of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 increased by 27%, 16%, 5%, -2%, 22%, and 16% compared with that of Comparative Example 1.

[0091] In summary, urea and ammonium sulfate in the saline-alkali soil conditioner of the present invention cooperate with each other, increase the solubility of phosphorus in the soil through acidification, promote the reduction of rhizosphere salinity, mix quick-acting phosphate fertilizer, acidic phosphate fertilizer and slow-release phosphate fertilizer to improve the fertilizer efficiency of phosphate fertilizer in salinized soil, and strengthen the function of soil microorganisms through the combination of carbon source and biostimulant. Applying the soil conditioner of the present invention can stimulate the activity of soil microorganisms, improve soil pH, and promote nutrient turnover. Applying the conditioner of the present invention on salinized soil can increase the nitrogen, phosphorus and potassium content of plants and promote crop growth.

[0092] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A saline-alkali soil conditioner, characterized in that: The invention comprises the following components: nitrogen fertilizer, phosphate fertilizer and synergist; the nitrogen fertilizer comprises urea and ammonium sulfate; the phosphate fertilizer comprises monoammonium phosphate, ammonium polyphosphate and urea phosphate; the synergist comprises carbon source, nitrification inhibitor and biostimulant; The carbon source comprises at least one of molasses, glucose and citric acid; The nitrification inhibitor includes at least one of 2-chloro-6-(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole phosphate; The biostimulant includes at least one of quercetin, luteolin and myristic acid.

2. The saline-alkali soil conditioner according to claim 1, characterized in that The carbon source includes molasses and glucose, and the mass ratio of the molasses to glucose is 384-456:6.

6.

3. The saline-alkali soil conditioner according to claim 1 or 2, characterized in that The nitrification inhibitor includes 3,4-dimethylpyrazole phosphate.

4. The saline-alkali soil conditioner according to claim 1, characterized in that The mass fraction of the nitrogen fertilizer is 419 to 503 parts, the mass fraction of the phosphorus fertilizer is 103 to 115 parts, and the mass fraction of the synergist is 394 to 466 parts.

5. The saline-alkali soil conditioner according to claim 1, characterized in that The mass ratio of urea to ammonium sulfate in the nitrogen fertilizer is 55-229:190-448; the mass ratio of monoammonium phosphate, urea phosphate and ammonium polyphosphate in the phosphate fertilizer is 57-101:9-26:5-20; the mass ratio of carbon source, nitrification inhibitor and biostimulant in the synergist is 390-463:0.4-12:3.

3.

6. The saline-alkali soil conditioner according to claim 1, characterized in that The mass ratio of myristic acid, quercetin and luteolin in the biostimulant is 1.3:1:

1.

7. Use of the saline-alkali soil conditioner according to any one of claims 1 to 6 in soil improvement and / or promotion of plant growth.

8. The use according to claim 7, characterized in that: The soil comprises saline-alkali soil; and the plants comprise one or more of corn, wheat, sunflower and cotton.

9. A method for improving soil and / or promoting plant growth, characterized in that: The following steps are involved: The saline-alkali soil conditioner according to any one of claims 1 to 6 is applied to the soil to be improved.

10. The method according to claim 9, characterized in that The application method includes base application or drip irrigation.

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