Soil conditioner for promoting mineralization of organic nitrogen in soil and preparation method thereof

Abstract

The invention discloses a soil conditioner for promoting mineralization of organic nitrogen in soil and a preparation method of the soil conditioner, and belongs to the technical field of agricultural fertilizers. The soil conditioner is prepared from the following raw materials in parts by weight: 67 to 73 parts of oyster shell powder, 1 to 7 parts of bacillus subtilis SCK6 fungicide, 15 to 16 parts of calcium magnesium phosphate fertilizer, 7 to 8 parts of humic acid and 2 parts of carboxymethyl cellulose. The preparation method specifically comprises the following steps: (1) weighing the raw materials; and (2) mixing the raw materials, adding water, uniformly mixing and stirring, granulating, drying, cooling and screening to obtain the feed additive. The calcined oyster shells are matched with the bacillus subtilis SCK6 fungicide, the calcium magnesium phosphate fertilizer, the humic acid and the carboxymethyl cellulose for use, so that the pH value of the soil can be quickly increased, organic nitrogen phosphorus phosphorite of the soil is promoted, and the method has very important significance for realizing reduction and synergism of nitrogen phosphorus fertilizers. Moreover, the soil conditioner has the characteristics of low cost, lasting improvement effect, environmental friendliness and the like, and has popularization and application values in the technical field of soil improvement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of agricultural fertilizers, and more particularly to a soil conditioner for promoting soil organic nitrogen mineralization and a preparation method thereof. BACKGROUND

[0002] The abundant rainfall and climate conditions of the same period of heat and rain in southern China provide good basic conditions for agricultural development. However, the abundant water also accelerates the leaching of soil exchangeable base cations, increases exchangeable acid, and accelerates the soil acidification process. In addition, due to the large amount of nitrogen fertilizer used in China, H + The contribution to acidification is large, which further leads to the acidification of cultivated soils in southern China. Taking Fujian Province as an example, the soil in the province is mainly strongly acidic soil, accounting for as high as 74.2%, with an average pH value of only 5.36, which is at the lowest level in the country; compared with the second soil survey, the acidification degree of cultivated soil in Fujian Province increased by 22.2%. Soil acidification has become a major problem widely concerned by soil, ecological environment and other disciplines. On the one hand, soil acidification will change the soil micro-ecological environment, affect crop growth, and also lead to imbalance of microbial community structure, which is prone to soil-borne diseases of crops; on the other hand, soil acidification will also affect the activity of heavy metals in soil, and thus affect the safety of agricultural products.

[0003] In addition, the large amount of nitrogen and phosphorus fertilizer input makes the nitrogen and phosphorus enrichment phenomenon of cultivated soil obvious. Studies have shown that since the second national soil survey, the total nitrogen and phosphorus of cultivated land has shown a trend of enrichment. Taking Fujian Province as an example, the total nitrogen enrichment area accounts for 52.49% of the total cultivated land area in the province, and the effective phosphorus enrichment area accounts for 97.24% of the total cultivated land area in the province. However, although the nitrogen and phosphorus in the soil are greatly enriched, the soil is still "fertile but lean", and a large amount of nitrogen and phosphorus fertilizer still needs to be applied to maintain crop yield.

[0004] On the other hand, the annual production of oyster shells in coastal areas of China is extremely high, and a large amount of oyster shells are discarded every year, causing serious environmental pollution.

[0005] Therefore, how to develop a soil conditioner that can improve the mineralization rate of soil organic nitrogen, improve the acid-base property of soil, improve the utilization rate of nutrients and be beneficial to the growth of plants is a problem that those skilled in the art need to solve. SUMMARY

[0006] Therefore, the purpose of the present application is to provide a soil conditioner for promoting soil organic nitrogen mineralization and a preparation method thereof to solve the problems in the prior art.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: The application discloses a soil modifier for promoting soil organic nitrogen mineralization, which comprises the following raw materials in parts by weight: oyster shell powder 67-73 parts, bacillus subtilis SCK6 microbial agent 1-7 parts, calcium-magnesium phosphate fertilizer 15-16 parts, humic acid 7-8 parts and carboxymethyl cellulose 2 parts.

[0008] Preferably, the application discloses a soil modifier for promoting soil organic nitrogen mineralization, which comprises the following raw materials in parts by weight: oyster shell powder 70 parts, bacillus subtilis SCK6 microbial agent 3 parts, calcium-magnesium phosphate fertilizer 16 parts, humic acid 8 parts and carboxymethyl cellulose 2 parts.

[0009] In the application, the oyster shell powder and the calcium-magnesium phosphate fertilizer provide sufficient nutrients for the soil and supplement the calcium, magnesium and phosphate fertilizer which are deficient in the acid soil. On the one hand, the oyster shell presents a porous structure after calcination, which can improve the stability of soil aggregates by reducing the dispersion of clay particles, make the soil loose and porous, increase the soil aeration and water permeability, and be beneficial to the growth and respiration of plants and beneficial microorganisms. On the other hand, the main component of the oyster shell is calcium carbonate, which is alkaline and can react with hydrogen ions in the acid soil to improve the pH value of the soil and create a suitable environment for the growth of plants and beneficial microorganisms. The improvement of the pH value of the acid soil can affect the activity of urease and promote the mineralization of soil organic nitrogen. In addition, the growth of ammonia-oxidizing bacteria is stimulated after the pH value is improved, thereby promoting the conversion of nitrogen elements to nitrate nitrogen. In addition, the improvement of the pH value creates a more suitable survival environment for bacillus subtilis, which has the ability of nitrogen fixation, phosphorus solubilization and potassium solubilization, and can form a thin biological membrane at the root of crops for long-term colonization in the rhizosphere, stimulate the growth of crops and protect the crops from external pressure. Moreover, bacillus subtilis can secrete cellulase, protease and beta-glucanase, etc., to further promote the mineralization of organic nitrogen and improve the nitrogen fertilizer utilization rate of the soil. Furthermore, bacillus subtilis can synthesize secondary metabolites, hormones, cell wall degrading enzymes and antioxidants, inhibit pathogenic bacteria and enhance the ability of plants to resist diseases. The addition of humic acid and carboxymethyl cellulose improves the water retention and stability of the modifier, provides nutrients and carbon sources for bacillus subtilis and enhances the survival rate of bacillus subtilis in the modifier. The application effectively overcomes the problems of soil acidification, soil compaction, environmental pollution and low fertilizer utilization rate caused by the large-scale application of chemical fertilizers.

[0010] Further, the preparation method of the oyster shell powder is as follows: the oyster shell is cleaned, dried, calcined and crushed to obtain the oyster shell powder.

[0011] The above-mentioned further beneficial effect is that the content of calcium carbonate in the oyster shell is as high as more than 90%, and the oyster shell also contains trace elements and organic matter. The oyster shell is made into the soil modifier in the application, which not only has the ability of water and fertilizer retention and air permeability, can significantly improve the soil quality, but also can promote the growth of microorganisms and help the crops to increase yield.

[0012] Further, the calcination temperature is 700-900 DEG C, the calcination time is 1-2 h, and the crushing degree is 20-60 meshes.

[0013] The further beneficial effect of the above is that the particle of the oyster shell powder after crushing is large, the porous structure of the oyster shell is preserved, so that it has strong adsorption, water retention, fertilizer retention and air permeability, and can not only adjust the pH value of the soil, but also has the effects of drought resistance and fertilizer retention.

[0014] Further, the effective viable cell number of the above Bacillus subtilis SCK6 microbial agent is 2x10 8 -1x10 9 Individuals / g.

[0015] The further beneficial effect of the above is that the oyster shell powder and the microbial agent are matched in the present application, which can promote the mineralization of soil organic nitrogen, improve the absorption and utilization efficiency of nitrogen elements by plants, and achieve the effects of yield increase and fertilizer reduction.

[0016] Further, the preparation method of the culture medium of the above Bacillus subtilis SCK6 microbial agent is as follows: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, 15-20 g of agar, 1000 mL of deionized water, and adjusting the pH to 7.0-7.2.

[0017] Further, the fineness of the calcium-magnesium phosphate fertilizer is 20-60 meshes, and the P2O5 content is ≥16%.

[0018] Further, the purity of the humic acid is ≥80%.

[0019] A preparation method of the above soil amendment for promoting soil organic nitrogen mineralization, specifically comprising the following steps: (1) The raw materials are weighed according to the weight fraction of the soil amendment; (2) The raw materials are mixed, water is added, and the mixture is uniformly mixed, granulated, dried, cooled, and sieved to obtain the soil amendment for promoting soil organic nitrogen mineralization (granular).

[0020] Further, in the above step (2), the water content of the mixture is 10%-15% after adding water.

[0021] According to the above technical solution, compared with the prior art, the beneficial effects of the present application are as follows: 1. The soil amendment of the present application has the functions of providing nutrients (phosphorus, calcium, magnesium, organic matter, etc.), improving the pH value of the soil, improving the soil texture, and adsorbing heavy metals in the soil.

[0022] 2、The soil improver of the present application, because the oyster shell powder has a higher pH value, and the bacillus subtilis SCK6 has a higher alkali resistance, and the humic acid and the carboxymethyl cellulose provide sufficient nutrients and carbon sources for the bacillus subtilis, and the humic acid and the carboxymethyl cellulose increase the air permeability and the water retention of the bacillus subtilis, and are suitable for the growth of the bacillus subtilis. Meanwhile, the oyster shell powder, the bacillus subtilis, the calcium magnesium phosphate fertilizer, the humic acid and the carboxymethyl cellulose coordinate through multiple pathways to adjust the pH value of the soil and balance the soil nutrients.

[0023] 3、The soil improver of the present application can promote the organic nitrogen mineralization capacity of the soil, and solve the "contradictory phenomenon" that the soil with a high content of organic nitrogen still needs to be maintained by a large amount of nitrogen fertilizer.

[0024] 4、The soil improver of the present application can promote the organic nitrogen mineralization of the soil, provide sufficient calcium elements, neutralize the acid soil, adjust the pH value, improve the soil structure, improve the soil fertility, and enhance the ability of the plant to resist diseases and pests.

[0025] 5、The present application has very important significance for realizing the nitrogen and phosphorus fertilizer reduction and efficiency increase, and reducing the ecological risk of nitrogen and phosphorus, by improving the soil environment, promoting the organic nitrogen and phosphorus mineralization, and exerting the nutrient supply potential of the soil nitrogen and phosphorus library. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0027] In the following embodiments, the preparation method of the oyster shell powder is as follows: in order to determine the optimal calcination temperature, the oyster shell is cleaned, dried, forged at a high temperature of 800 DEG C in a muffle furnace for 2 hours, and then crushed through a 20 mesh sieve to obtain the oyster shell powder.

[0028] The effective viable count of the bacillus subtilis SCK6 inoculant is 1x10 9 The preparation method of the culture medium is as follows: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, 15 g of agar, 1000 mL of deionized water, pH is adjusted to 7.2, and sterilized at 121 DEG C for 15 min to obtain the culture medium.

[0029] The fineness of the calcium magnesium phosphate fertilizer is 20 mesh, and the P2O5 content is 18%.

[0030] The purity of the humic acid is 80%. Example 1

[0031] The soil improver for promoting soil organic nitrogen mineralization comprises the following raw materials by weight: oyster shell powder 73 g, bacillus subtilis SCK6 inoculant 1 g, calcium magnesium phosphate 16 g, humic acid 8 g, and carboxymethyl cellulose 2 g. The preparation method of the soil improver for promoting soil organic nitrogen mineralization comprises the following steps: (1) weighing each raw material; (2) mixing each raw material, adding water to the mixture to a water content of 15%, uniformly mixing and stirring, granulating, drying, cooling, screening, and preparing the soil improver for promoting soil organic nitrogen mineralization into granules with a diameter of 5 mm, cooling, and bagging. Example 2

[0032] The soil improver for promoting soil organic nitrogen mineralization comprises the following raw materials by weight: oyster shell powder 70 g, bacillus subtilis SCK6 inoculant 4 g, calcium magnesium phosphate 16 g, humic acid 8 g, and carboxymethyl cellulose 2 g. The preparation method of the soil improver for promoting soil organic nitrogen mineralization comprises the following steps: (1) weighing each raw material; (2) mixing each raw material, adding water to the mixture to a water content of 15%, uniformly mixing and stirring, granulating, drying, cooling, screening, and preparing the soil improver for promoting soil organic nitrogen mineralization into granules with a diameter of 5 mm, cooling, and bagging. Example 3

[0033] The soil improver for promoting soil organic nitrogen mineralization comprises the following raw materials by weight: oyster shell powder 67 g, bacillus subtilis SCK6 inoculant 7 g, calcium magnesium phosphate 16 g, humic acid 8 g, and carboxymethyl cellulose 2 g. (1) weighing each raw material; (2) mixing each raw material, adding water to the mixture to a water content of 15%, uniformly mixing and stirring, granulating, drying, cooling, screening, and preparing the soil improver for promoting soil organic nitrogen mineralization into granules with a diameter of 5 mm, cooling, and bagging.

[0034] Comparative Example 1

[0035] No improver is added.

[0036] Comparative Example 2

[0037] The only difference from Example 1 is that the oyster shell powder is replaced by quicklime.

[0038] Comparative Example 3

[0039] The difference from Example 1 is that no bacillus subtilis SCK6 inoculant is added.

[0040] Performance test

[0041] The test soil is collected from Baisha Town, Minhou County, Fuzhou City, Fujian Province (26°12'38''N, 119°04'04''E), and the soil type is yellow soil, which belongs to subtropical monsoon humid climate, the average annual temperature is 20.4℃, and the average annual precipitation is 1782mm. The basic physicochemical properties are as follows: pH value 5.89, nitrate nitrogen 2.09mg·kg -1 , ammonium nitrogen 8.53mg·kg -1 , alkali-hydrolyzable nitrogen 73.88mg·kg -1 , available phosphorus 43.23mg·kg -1 , available potassium 9.09mg·kg -1 , organic matter 20.39g·kg -1 , total nitrogen 1.39g·kg -1 .

[0042] The soil is screened through a 2mm sieve to remove stones and plant roots for indoor simulation test. Before the formal test, the screened soil is cultured and activated to activate the soil microbial activity. The soil of the above-mentioned examples 1-3 and comparative examples 1-3 is cultured with the soil amendment, and the soil moisture content is adjusted to 60% of the maximum water holding capacity.

[0043] The test is measured after 7 days, and the results are shown in Table 1.

[0044] Table 1: Data of soil amendment culture test of examples 1-3 and comparative examples 1-3 Group pH Ammonium nitrogen (mg / kg) Nitrate nitrogen (mg / kg) Nitrogen mineralization rate [mg / (kg·d)] Example 1 6.25 10.97 39.27 5.66 Example 2 6.08 8.55 37.71 5.09 Example 3 6.03 7.42 33.43 4.32 Control Example 1 5.53 3.02 31.08 3.35 Control Example 2 7.63 15.64 28.61 4.80 Control Example 3 6.22 3.34 32.17 3.56 As can be seen from Table 1, the soil nutrients change among different treatments, and the soil pH value increases significantly with the addition of soil amendment. From the soil ammonium nitrogen, nitrate nitrogen and nitrogen mineralization rate, it can be seen that the improvement effect of example 1-3 is better than that of comparative example 1-3, especially example 1, ammonium nitrogen 10.97mg·kg -1 , nitrate nitrogen 39.27mg·kg -1 , and the nitrogen mineralization rate reaches 5.66mg / (kg·d).

[0045] In summary, the oyster shell after calcination and bacillus subtilis SCK6 microbial agent, calcium magnesium phosphate fertilizer, humic acid and carboxymethyl cellulose are used together, which can quickly improve the soil pH value, promote the mineralization of soil organic nitrogen and phosphorus, and has very important significance for realizing the reduction and efficiency of nitrogen and phosphorus fertilizer. Moreover, the soil amendment has the characteristics of low cost, long-lasting improvement effect and environmental protection, and has popularization and application value in the field of soil improvement technology.

[0046] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil amendment to promote mineralization of soil organic nitrogen, characterized in that, The soil improver comprises the following raw materials in parts by weight: oyster shell powder 67-73 parts, bacillus subtilis SCK6 microbial agent 1-7 parts, calcium-magnesium phosphate fertilizer 15-16 parts, humic acid 7-8 parts and carboxymethyl cellulose 2 parts.

2. The soil amendment to promote mineralization of soil organic nitrogen according to claim 1, characterized in that, The soil improver comprises the following raw materials in parts by weight: oyster shell powder 67-73 parts, bacillus subtilis SCK6 microbial agent 1-7 parts, calcium-magnesium phosphate fertilizer 15-16 parts, humic acid 7-8 parts and carboxymethyl cellulose 2 parts.

3. The soil amendment to promote mineralization of soil organic nitrogen according to claim 1 or 2, characterized in that, The preparation method of the oyster shell powder is as follows: the oyster shell is cleaned, dried, calcined and crushed to obtain the oyster shell powder.

4. The soil amendment to promote mineralization of soil organic nitrogen according to claim 3, characterized in that, The calcination temperature is 700-900 DEG C and the calcination time is 1-2 h; the crushing is to 20-60 mesh.

5. The soil amendment to promote mineralization of soil organic nitrogen according to claim 1 or 2, characterized in that, The effective viable cell number of the Bacillus subtilis SCK6 microbial inoculant is 2×10 8 -1×10 9 cells / g.

6. The soil amendment to promote mineralization of soil organic nitrogen according to claim 5, characterized in that, The preparation method of the culture medium of the bacillus subtilis SCK6 microbial agent is as follows: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, 15-20 g of agar and 1000 mL of deionized water are used, and the pH is adjusted to 7.0-7.

2.

7. The soil amendment to promote mineralization of soil organic nitrogen according to claim 1 or 2, characterized in that, The fineness of the calcium-magnesium phosphate fertilizer is 20-60 mesh, and the P2O5 content is greater than or equal to 16%.

8. The soil amendment to facilitate the mineralization of soil organic nitrogen according to claim 1 or 2, characterized in that, The purity of the humic acid is greater than or equal to 80%.

9. A method of preparing a soil amendment for promoting mineralization of soil organic nitrogen as claimed in any one of claims 1 to 8, characterized in that, The method comprises the following steps: (1) the raw materials are weighed according to any one of claims 1-8; (2) the raw materials are mixed, water is added, and the mixture is stirred, granulated, dried, cooled and sieved to obtain the soil improver for promoting soil organic nitrogen mineralization.

10. The method of claim 9, wherein the soil amendment is prepared by mixing the soil amendment with the soil. In step (2), the water content of the mixture is 10%-15%. ​