Decomposing agent for straw in-situ returning to field in saline-alkali soil and preparation method of decomposing agent

Abstract

The invention provides a decomposition agent for straw saline-alkali soil in-situ field returning and a preparation method thereof. The decomposition agent comprises clostridium butyricum powder, streptomyces albidoflavus powder and a salvia miltiorrhiza aqueous extract. The preparation process of the radix salviae miltiorrhizae aqueous extract comprises the following steps: preparing radix salviae miltiorrhizae aqueous slurry; performing enzymolysis on the pulp by using cellulase, pectinase and protease; and carrying out reflux extraction for 1 hour, filtering the enzymatic hydrolysate, adding water into the filter residue, carrying out reflux extraction, carrying out vacuum concentration on the filtrate B, and drying the paste to obtain the salvia miltiorrhiza aqueous extract. The radix salviae miltiorrhizae aqueous extract in the decomposition agent can protect the clostridium butyricum and the streptomyces albidoflavus in the stress environment of the saline-alkali soil and reduce the influence of the environment on propagation of the clostridium butyricum and the streptomyces albidoflavus, so that the adaptability of the clostridium butyricum and the streptomyces albidoflavus to the saline-alkali soil can be improved, and the purpose of rapidly and efficiently decomposing the straws is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of returning crop straw to fields, and in particular to a decomposing agent used for returning straw to fields in situ in saline-alkali land and a preparation method thereof. Background Art

[0002] Saline-alkali land mainly contains carbonates, chlorides, sulfates, sodium ions, potassium ions, etc. These ions form salts and gradually gather in the soil, causing the soil to become compacted and the osmotic pressure to increase. Among them, the soil's moisture retention capacity becomes poor after compaction, and even sowing or planting seedlings will make it difficult for them to survive. When the osmotic pressure increases, the crop roots cannot absorb water from the soil, and even the water in the crops will penetrate into the soil through the roots, causing the crops to wilt and die.

[0003] Saline-alkali land has its own characteristics. The following problems mainly exist after returning the straw to the fields: the high osmotic pressure of saline-alkali land makes it difficult for microorganisms to decompose the straw after it is returned to the fields, resulting in longer decomposition time and incomplete decomposition. Planting crops again when the straw is not completely decomposed is not conducive to seed germination and root formation. It can be seen that it is particularly important to improve the decomposition efficiency and shorten the decomposition time when returning crop straw to the fields in saline-alkali land. Summary of the invention

[0004] In view of this, the present invention provides a decomposing agent for in-situ returning of straw to saline-alkali land and a preparation method thereof. The decomposing agent comprises Clostridium butyricum powder, Streptomyces albicans powder and Salvia miltiorrhiza water extract; wherein the Salvia miltiorrhiza water extract can protect Clostridium butyricum and Streptomyces albicans in the stress environment of saline-alkali land, reduce the impact of the environment on the proliferation of Clostridium butyricum and Streptomyces albicans, thereby improving the adaptability of Clostridium butyricum and Streptomyces albicans to saline-alkali land, thereby achieving the purpose of quickly and efficiently decomposing straw.

[0005] The technical solution of the present invention is as follows: A decomposing agent for returning straw to saline-alkali land in situ, comprising the following components in parts by weight: 35-45 parts of Clostridium butyricum powder, 20-30 parts of Streptomyces albiflorus powder, and 25-45 parts of Salvia miltiorrhiza aqueous extract; The preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, take Danshen, cut into sections with a length of 3-5 mm, crush and add water; the weight ratio of Danshen to water is 1:10-15, mix well to obtain slurry; s2, adjusting the pH of the slurry to 3.7-4.1 with formic acid, and then adding cellulase, pectinase and protease to the slurry, the addition amount of cellulase is 4.8-5.2u / g, the addition amount of pectinase is 2.0-2.4u / g, and the addition amount of protease is 1.2-1.7u / g; heating, controlling the slurry temperature to 40-43°C, maintaining for 2.5-3.0h, and obtaining an enzymolysis solution; s3, using sodium hydroxide to adjust the pH of the enzymatic hydrolyzate to 6.1-6.5, then reflux extraction for 1 hour, filter, and collect filtrate A; add water to the filter residue, the weight ratio of salvia miltiorrhiza to water is 1:10-15; reflux extraction for 1 hour, filter, and collect filtrate B; s4, concentrating the filtrate B under reduced pressure to obtain a paste; drying the paste to obtain a Salvia miltiorrhiza aqueous extract.

[0006] By rolling, the salvia miltiorrhiza can be split along the fiber direction when it has a certain length. After contacting with water, the salvia miltiorrhiza with a certain weight settles inside the water, which is more conducive to water infiltration into the interior of the salvia miltiorrhiza. Salvia miltiorrhiza is a plant of the Lamiaceae family. Salvia miltiorrhiza Bge . The dried roots and rhizomes of . The use of cellulase, pectinase and protease can destroy the cell wall of Salvia miltiorrhiza, which is conducive to the release of starch, salvianolic acid and glycosides in the cell and their entry into the enzymatic solution; the use of reflux extraction can further release the substances in Salvia miltiorrhiza and increase the content of starch, salvianolic acid and glycosides in the water extract of Salvia miltiorrhiza; after the water extract of Salvia miltiorrhiza is dried and mixed with Clostridium butyricum powder and Streptomyces albicans powder, the presence of starch can protect Clostridium butyricum and Streptomyces albicans, Try to avoid the stress caused by the environment after it is put into saline-alkali land, so that it can propagate rapidly. As the propagation proceeds, the adaptation of Clostridium butyricum and Streptomyces albus flavus gradually increases, thereby achieving the purpose of quickly and efficiently decomposing straw. At the same time, the phenolic acids in the water extract of Salvia miltiorrhiza can affect the propagation environment, further facilitating the rapid propagation of Clostridium butyricum and Streptomyces albus flavus. Glycosides can chelate some metal ions in saline-alkali land, avoiding stress on Clostridium butyricum and Streptomyces albus flavus cells.

[0007] Preferably, the decomposing agent for returning straw to saline-alkali land in situ comprises the following components in parts by weight: 40 parts of Clostridium butyricum powder, 25 parts of Streptomyces albiflorus powder, and 35 parts of Salvia miltiorrhiza water extract.

[0008] Preferably, the effective viable count of Clostridium butyricum powder is 1 billion to 1.2 billion / g, and the effective viable count of Streptomyces albus flavus powder is 1.5 billion to 2 billion / g.

[0009] The preparation method of the above-mentioned decomposing agent is as follows: Step 1, preparing Clostridium butyricum powder, Activation of strains: Take Clostridium butyricum, inoculate it on solid medium A by streak method, and culture it anaerobically at 30-32℃ for 24-36h; Cultivation: Take the activated strain and inoculate it into seed culture medium A, then culture it anaerobically at 30-32℃ for 36-48h to obtain culture medium A; Fermentation: inoculate the culture solution A into the fermentation medium A at an inoculation rate of 2%, the culture temperature is 30±1°C, and the culture is carried out anaerobically for 3-5 days to obtain the fermentation solution A; After the fermentation liquid A is dried, Clostridium butyricum powder is obtained; Step 2, preparing Streptomyces albicans powder, Strain activation: Take Streptomyces albiflorus and inoculate it on solid medium B by streak method, and culture it at 27-29℃ for 2-3 days; Cultivation: Take the activated strain and inoculate it into seed culture medium B, then culture it with shaking at 27-29°C for 1-2 days to obtain culture medium B; Fermentation: inoculate the culture fluid B into the fermentation medium B at an inoculation rate of 3%, culture at a temperature of 27±1°C, and culture under stirring conditions for 3-5 days to obtain fermentation fluid B; After the fermentation liquid B is dried, Streptomyces albicans powder is obtained; Step three, adding Clostridium butyricum powder, Streptomyces albiflorus powder and Salvia miltiorrhiza water extract into a mixing device and mixing to obtain a decomposing agent; and vacuum-storing the decomposing agent to obtain a product.

[0010] Preferably, in step 1, the solid culture medium A comprises 4 g / L yeast extract, 6 g / L beef extract, 8 g / L peptone, 6 g / L glucose, 0.3 g / L cysteine ​​hydrochloride, 2 g / L potassium chloride, 2 g / L potassium bicarbonate, and 10 g / L agar; Seed culture medium A, beef extract 13g / L, yeast extract powder 6g / L, peptone 9g / L, glucose 10g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L; Fermentation medium A, beef extract 11g / L, yeast extract 6g / L, peptone 8g / L, glucose 9g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L.

[0011] Preferably, in step 2, the solid culture medium B comprises 4 g / L yeast powder, 4 g / L glucose, 2 g / L ammonium chloride, 0.7 g / L potassium dihydrogen phosphate, 0.25 g / L magnesium sulfate, 0.1 g / L sodium chloride, and 10 g / L agar; Seed culture medium B, yeast powder 4g / L, glucose 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.0g / L, magnesium sulfate 0.25g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 7.5g / L; Fermentation medium B, yeast extract 5g / L, molasses 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.5g / L, magnesium sulfate 0.3g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 8.5g / L.

[0012] Compared with the prior art, the beneficial effects of the present invention are: (1) In the present invention, the water extract of Salvia miltiorrhiza used is rich in starch, salvianolic acid and glycosides, which can protect Clostridium butyricum and Streptomyces albus flavus in the stress environment of saline-alkali land, reduce the impact of the environment on the proliferation of Clostridium butyricum and Streptomyces albus flavus, thereby improving the adaptability of Clostridium butyricum and Streptomyces albus flavus to saline-alkali land, and thus achieve the purpose of quickly and efficiently decomposing straw.

[0013] (2) When the decomposing agent of the present invention was used and the straw was returned to the field in situ, for wheat straw, the residual rate of the straw was less than 50% after 30 days of decomposition, while the straw participation rates of the control group and the comparison group after 30 days of decomposition were greater than 50%. It can be seen that the decomposing agent of the present invention can quickly start to decompose the wheat straw, and the effect is significant. For corn straw, the residual rate of the straw was less than 50% after 120 days of decomposition, while the straw participation rates of the control group and the comparison group after 120 days of decomposition were greater than 70%. It can be seen that the decomposing agent of the present invention can quickly start to decompose the corn straw, and the effect is significant. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0015] Unless otherwise specified, the reagents and bacterial powders used in this example are all commercially available products.

[0016] Example 1 A decomposing agent for returning straw to saline-alkali land in situ, comprising the following components by weight: 40kg of Clostridium butyricum powder, 25kg of Streptomyces albiflorus powder, and 35kg of Salvia miltiorrhiza aqueous extract; The preparation method of the above-mentioned decomposing agent is as follows: Step 1, preparing Clostridium butyricum powder, Strain activation: Take Clostridium butyricum, inoculate it on solid medium A by streak method, and culture it anaerobically at 31℃ for 30h; Cultivation: Take the activated strain and inoculate it into seed culture medium A, then culture it anaerobically at 31°C for 40 hours to obtain culture medium A; Fermentation: inoculate the culture solution A into the fermentation medium A at an inoculation rate of 2%, the culture temperature is 30°C, and the culture is carried out anaerobically for 4 days to obtain the fermentation solution A; After the fermentation liquid A is dried, Clostridium butyricum powder is obtained, and the effective live bacteria count of the powder is 1.1 billion / g; Solid medium A, yeast extract 4g / L, beef extract 6g / L, peptone 8g / L, glucose 6g / L, cysteine ​​hydrochloride 0.3g / L, potassium chloride 2g / L and potassium bicarbonate 2g / L, agar 10g / L; Seed culture medium A, beef extract 13g / L, yeast extract powder 6g / L, peptone 9g / L, glucose 10g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L; Fermentation medium A, beef extract 11g / L, yeast extract 6g / L, peptone 8g / L, glucose 9g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L; Step 2, preparing Streptomyces albicans powder, Strain activation: Take Streptomyces albicans and inoculate it on solid medium B by streak method, and culture it at 28℃ for 2 days; Cultivation: Take the activated strain and inoculate it into seed culture medium B, then culture it with shaking at 28°C for 1.5 days to obtain culture medium B; Fermentation: inoculate the culture fluid B into the fermentation medium B at an inoculation rate of 3%, culture at a temperature of 27°C, and culture under stirring conditions for 4 days to obtain fermentation fluid B; After the fermentation liquid B was dried, Streptomyces albicans powder was obtained, and the effective viable bacteria count of the powder was 1.8 billion / g; Solid culture medium B, yeast powder 4g / L, glucose 4g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 0.7g / L, magnesium sulfate 0.25g / L, sodium chloride 0.1g / L, agar 10g / L; Seed culture medium B, yeast powder 4g / L, glucose 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.0g / L, magnesium sulfate 0.25g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 7.5g / L; Fermentation medium B, yeast extract 5g / L, molasses 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.5g / L, magnesium sulfate 0.3g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 8.5g / L; Step 3, the preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, take Danshen, cut into sections with a length of 3-5 mm, crush and add water; the weight ratio of Danshen to water is 1:12, and mix well to obtain slurry; s2, adjusting the pH of the slurry to 3.9 with formic acid, and then adding cellulase, pectinase and protease to the slurry, the addition amount of cellulase is 5.0u / g, the addition amount of pectinase is 2.2u / g, and the addition amount of protease is 1.5u / g; heating, controlling the slurry temperature to 41°C, maintaining for 2.7h, and obtaining an enzymatic hydrolyzate; s3, using sodium hydroxide to adjust the pH of the enzymatic hydrolyzate to 6.3, then reflux extraction for 1 hour, filter, and collect filtrate A; add water to the filter residue, the weight ratio of Danshen to water is 1:12 based on Danshen; reflux extraction for 1 hour, filter, and collect filtrate B; s4, concentrating the filtrate B under reduced pressure to obtain a paste; drying the paste to obtain a Salvia miltiorrhiza aqueous extract; Step 4: Add Clostridium butyricum powder, Streptomyces albiflorus powder and Salvia miltiorrhiza water extract into the mixing device of Example 1 according to the ratio and mix them to obtain a decomposing agent; and store the decomposing agent in a vacuum to obtain a product.

[0017] Comparative Example 1 The difference from Example 1 is that the process of step 3 is as follows: Step 3, the preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, same as in Example 1; s2, same as in Example 1; s3, same as in Example 1; s4, add ethanol to the filtrate B until the ethanol content is 70%, let it stand for 12 hours, take the supernatant, recover the ethanol under reduced pressure, and concentrate it to a paste, dry the paste to obtain the Salvia miltiorrhiza aqueous extract.

[0018] Example 2 A decomposing agent for returning straw to saline-alkali land in situ, comprising the following components by weight: 35kg of Clostridium butyricum powder, 20kg of Streptomyces albiflorus powder, 45kg of Salvia miltiorrhiza aqueous extract; The preparation method of the above-mentioned decomposing agent is as follows: Step 1, preparing Clostridium butyricum powder, Activation of strains: Take Clostridium butyricum, inoculate it on solid medium A by streak method, and culture it anaerobically at 30℃ for 36h; Cultivation: Take the activated strain and inoculate it into seed culture medium A, then culture it anaerobically at 30°C for 48 hours to obtain culture medium A; Fermentation: inoculate the culture solution A into the fermentation medium A at an inoculation rate of 2%, culture at a temperature of 29°C, and culture anaerobically for 5 days to obtain the fermentation solution A; After the fermentation liquid A is dried, Clostridium butyricum powder is obtained, and the effective viable bacteria count of the powder is 1 billion / g. The composition of solid culture medium A is the same as that of Example 2; The composition of seed culture medium A is the same as that of Example 2; The composition of fermentation medium A is the same as that of Example 2; Step 2, preparing Streptomyces albicans powder, Strain activation: Take Streptomyces albicans and inoculate it on solid medium B by streak method, and culture it at 27℃ for 3 days; Cultivation: Take the activated strain and inoculate it into seed culture medium B, then culture it with shaking at 27°C for 2 days to obtain culture medium B; Fermentation: inoculate the culture fluid B into the fermentation medium B at an inoculation rate of 3%, culture at a temperature of 26°C, and culture under stirring conditions for 5 days to obtain fermentation fluid B; After the fermentation liquid B was dried, Streptomyces albicans powder was obtained, and the effective live bacteria count of the powder was 1.5 billion / g.

[0019] The composition of the solid culture medium B is the same as that of Example 2; the composition of the seed culture medium B is the same as that of Example 2; the composition of the fermentation culture medium B is the same as that of Example 2; Step 3, the preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, take Danshen, cut into sections with a length of 3-5 mm, crush and add water; the weight ratio of Danshen to water is 1:10, and mix well to obtain slurry; s2, adjusting the pH of the slurry to 3.7 with formic acid, and then adding cellulase, pectinase and protease to the slurry, the addition amount of cellulase is 4.8u / g, the addition amount of pectinase is 2.0u / g, and the addition amount of protease is 1.2u / g; heating, controlling the slurry temperature to 40°C, maintaining for 3.0h, and obtaining an enzymatic hydrolyzate; s3, using sodium hydroxide to adjust the pH of the enzymatic hydrolyzate to 6.1, then reflux extraction for 1 hour, filter, and collect filtrate A; add water to the filter residue, the weight ratio of salvia miltiorrhiza to water is 1:10; reflux extraction for 1 hour, filter, and collect filtrate B; s4, concentrating the filtrate B under reduced pressure to obtain a paste; drying the paste to obtain a Salvia miltiorrhiza aqueous extract; Step 4: Add Clostridium butyricum powder, Streptomyces albiflorus powder and Salvia miltiorrhiza water extract into the mixing device of Example 1 according to the ratio and mix them to obtain a decomposing agent; and store the decomposing agent in a vacuum to obtain a product.

[0020] Example 3 A decomposing agent for returning straw to saline-alkali land in situ, comprising the following components by weight: 45kg of Clostridium butyricum powder, 30kg of Streptomyces albiflorus powder, and 25kg of Salvia miltiorrhiza aqueous extract; The preparation method of the above-mentioned decomposing agent is as follows: Step 1, preparing Clostridium butyricum powder, Strain activation: Take Clostridium butyricum, inoculate it on solid medium A by streak method, and culture it anaerobically at 32℃ for 24h; Cultivation: Take the activated strain and inoculate it into seed culture medium A, then culture it anaerobically at 32°C for 36 hours to obtain culture medium A; Fermentation: inoculate the culture fluid A into the fermentation medium A at an inoculation rate of 2%, the culture temperature is 31°C, and the anaerobic culture is performed for 3 days to obtain the fermentation fluid A; After the fermentation liquid A is dried, Clostridium butyricum powder is obtained, and the effective live bacteria count of the powder is 1.2 billion / g; The composition of solid culture medium A is the same as that of Example 2; The composition of seed culture medium A is the same as that of Example 2; The composition of fermentation medium A is the same as that of Example 2; Step 2, preparing Streptomyces albicans powder, Strain activation: Take Streptomyces albicans and inoculate it on solid medium B by streak method, and culture it at 29℃ for 2 days; Cultivation: Take the activated strain and inoculate it into seed culture medium B, then culture it with shaking at 29°C for 1 day to obtain culture medium B; Fermentation: inoculate the culture fluid B into the fermentation medium B at an inoculation rate of 3%, culture at a temperature of 28°C, and culture under stirring conditions for 3 days to obtain fermentation fluid B; After the fermentation liquid B is dried, Streptomyces albicans powder is obtained, and the effective viable bacteria count of the powder is 2 billion / g; In step 2, the composition of solid culture medium B is the same as that in Example 2; The composition of seed culture medium B is the same as that of Example 2; The composition of fermentation medium B is the same as that of Example 2; Step 3, the preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, take Danshen, cut into sections with a length of 3-5 mm, crush and add water; the weight ratio of Danshen to water is 1:15, mix well to obtain slurry; s2, adjusting the pH of the slurry to 4.1 with formic acid, and then adding cellulase, pectinase and protease to the slurry, the addition amount of cellulase is 5.2u / g, the addition amount of pectinase is 2.4u / g, and the addition amount of protease is 1.7u / g; heating, controlling the slurry temperature to 43°C, maintaining for 2.5h, and obtaining an enzymatic hydrolyzate; s3, using sodium hydroxide to adjust the pH of the enzymatic hydrolyzate to 6.5, then reflux extraction for 1 hour, filter, and collect filtrate A; add water to the filter residue, the weight ratio of Danshen to water is 1:15 based on Danshen; reflux extraction for 1 hour, filter, and collect filtrate B; s4, concentrating the filtrate B under reduced pressure to obtain a paste; drying the paste to obtain a Salvia miltiorrhiza aqueous extract; Step 4: according to the ratio, add Clostridium butyricum powder, Streptomyces albiflorus powder and Salvia miltiorrhiza water extract into a mixing device and mix them to obtain a decomposing agent; and store the decomposing agent in a vacuum to obtain a product.

[0021] test The test site is located in Zhaoyuan City, Shandong Province (120°08′~120°38′ east longitude, 37°05′~37°33′ north latitude). The soil is brown soil and it belongs to the warm temperate continental monsoon climate. It is cold in winter and hot in summer, but rarely cold or hot. It is suitable in spring and autumn, with distinct four seasons and sufficient sunlight. The annual average sunshine hours are 2503.2 hours, the annual average temperature is 11.5℃, the lowest extreme temperature in history is -18.5℃, and the precipitation is about 30 mm, accounting for about 4.5% of the annual precipitation, which is the season with the least precipitation in the whole year. The winter is often dry and cold, with little rain and snow, which is the characteristic of the winter climate. It is a typical wheat-corn double-cropping area.

[0022] The straw decomposition rate is mainly determined by the weight loss rate method and the tensile capacity determination method. That is, the mass difference and tensile force value difference of the straw during the decomposition process are used to obtain the straw residual rate and tensile force value respectively to illustrate the decomposition rate. The lower the straw residual rate and tensile force value, the more thorough the decomposition.

[0023] At the same time, the soil cellulase activity was measured. The higher the enzyme activity, the stronger the ability of soil microorganisms (indigenous microorganisms and exogenously added decomposing microorganisms) to decompose straw, and the faster the straw decomposes.

[0024] Straw residual rate (%) = remaining straw dry weight / original straw dry weight × 100% Operation steps for measuring the tensile force value of straw: After folding the straw in half, hook the folded part with a tensile gauge, pull it outward with force to break it, and record the tensile force value displayed on the tensile gauge when the dry straw breaks (in Newtons, recorded as N).

[0025] Soil cellulase activity was determined by anthrone colorimetric method and expressed as mg (glucose) g-1 soil sample (37 °C, 24 h).

[0026] Experiment 1: In situ decomposition experiment of wheat straw The wheat variety was Jimai 22, which was sown in early November and harvested in mid-June of the following year. The test material was wheat straw after harvest, which was dried to constant weight and cut to 3-5 cm and packed into nylon bags (100 mesh). In the treatment groups (T1, T2, T3), the decomposing agents of Examples 1 to 3 were uniformly mixed into the straw at a mass ratio (w / w) of 0.1%; In the control group (D1), the decomposing agent of the control example 1 was uniformly mixed into the straw at a mass ratio (w / w) of 0.1%; The control group (CK) was replaced with sterile water; The above groups were mixed separately, and then each treatment was buried in the field at a depth of 10 cm. Samples were taken every 15 days for 120 days, and the dry weight and tensile capacity of the straw were measured, the straw residual rate and tensile force value were calculated, and the soil cellulase activity was measured every 30 days. Three parallels were set for each treatment group.

[0027] The experimental results are shown in Tables 1 to 3: Table 1 Wheat straw residual rate

[0028] Table 2 Tensile strength of wheat straw

[0029] Table 3 Soil cellulase activity

[0030] Combining Tables 1, 2 and 3, it can be seen that within the range of 0-60 days, the decomposition rate of wheat straw is relatively fast, and the straw residual rate and tensile strength value decrease rapidly. As time goes by (after 60 days), the rate of decrease of the straw residual rate and tensile strength value gradually slows down; Compared with the control group (CK), the straw residue rate of the treatment groups with decomposing agents (T1-T3) decreased faster and the degradation effect was more thorough. By 60 days, the straw residue rate of T1 group was 29.04% lower than that of CK group, the straw pulling force value was 80.65% lower, and the soil cellulase activity was increased by 83.53%; the straw residue rate of T2 group was 27.29% lower than that of CK group, the straw pulling force value was 75.81% lower, and the soil cellulase activity was increased by 82.16%; the straw residue rate of T3 group was 25.11% lower than that of CK group, the straw pulling force value was 77.42% lower, and the soil cellulase activity was increased by 84.00%; At the end of the experiment (120 days), the straw residue rate of the T1 group was 35.65% lower than that of the CK group (the straw pulling force value of T1 could not be measured), and the soil cellulase activity increased by 27.56%; the straw residue rate of the T2 group was 33.04% lower than that of the CK group (the straw pulling force value of T2 could not be measured), and the soil cellulase activity increased by 25.53%; the straw residue rate of the T3 group was 31.59% lower than that of the CK group (the straw pulling force value of T3 could not be measured), and the soil cellulase activity increased by 25.72%, indicating that the straw decomposing agent of the present invention can effectively improve the ability of soil microorganisms to degrade lignocellulose, thereby promoting the in situ decomposition of wheat straw.

[0031] Compared with the control group (D1), the straw residue rate of the T1 treatment group with the addition of the decomposing agent decreased faster and the degradation effect was more thorough; by 60 days, the straw residue rate of the T1 group was 25.12% lower than that of the D1 group, the straw tensile value was reduced by 78.95%, and the soil cellulase activity was increased by 41.93%; at the end of the experiment (120 days), the straw residue rate of the T1 group was 23.97% lower than that of the D1 group, and the soil cellulase activity was increased by 14.67%. This may be because when the salvia miltiorrhiza water extract in comparative example 1 was prepared, ethanol was used to treat the filtrate B, and the addition of ethanol reduced the content of polysaccharides in the prepared salvia miltiorrhiza water extract, which resulted in the inability of the decomposing agent to quickly adapt to the saline-alkali environment after use, resulting in a poor degradation effect.

[0032] Experiment 2: In-situ decomposition experiment of corn straw The corn variety was Zhengdan 958, which was sown in mid-June and harvested in late October. The test material was corn stalks after harvest, which were dried to constant weight and cut to 5-8 cm and packed into nylon bags (100 mesh); In the treatment groups (T1, T2, T3), the decomposing agents of Examples 1 to 3 were uniformly mixed into the straw at a mass ratio (w / w) of 0.1%; In the control group (D1), the decomposing agent of the control example 1 was uniformly mixed into the straw at a mass ratio (w / w) of 0.1%; The control group (CK) was replaced with sterile water; The above groups were mixed separately, and then each treatment was buried in the field at a depth of 10 cm. Samples were taken every 30 days for 240 days. The dry weight and tensile capacity of the straw were measured, and the straw residual rate and tensile force value were calculated. Three parallels were set for each treatment group.

[0033] The experimental results are shown in Table 4, Table 5 and Table 6: Table 4 Corn stalk residual rate

[0034] Table 5 Corn stalk tensile strength values

[0035] Table 6 Soil cellulase activity

[0036] Combining Tables 5 and 6, it can be seen that compared with the control group (CK), the straw residue rate of the treatment groups with decomposition agents (T1-T3) decreased faster and the degradation effect was more thorough: by 120 days, the straw residue rate of the T1 group was 37.63% lower than that of the CK group, the straw pulling force value was reduced by 23.32%, and the soil cellulase activity was increased by 88.59%; the straw residue rate of the T2 group was 35.95% lower than that of the CK group, the straw pulling force value was reduced by 20.85%, and the soil cellulase activity was increased by 80.73%; the straw residue rate of the T3 group was 36.08% lower than that of the CK group, the straw pulling force value was reduced by 21.67%, and the soil cellulase activity was increased by 79. 59%; at the end of the experiment (240 days), the straw residue rate of T1 group was 40.79% lower than that of CK group, the straw pulling force value was reduced by 64.98%, and the soil cellulase activity was increased by 57.31%; the straw residue rate of T2 group was 40.06% lower than that of CK group, the straw pulling force value was reduced by 60.57%, and the soil cellulase activity was increased by 53.29%; the straw residue rate of T3 group was 38.74% lower than that of CK group, the straw pulling force value was reduced by 62.15%, and the soil cellulase activity was increased by 53.84%; it shows that the straw decomposing agent of the present invention can effectively improve the ability of soil microorganisms to degrade lignocellulose, thereby promoting the in situ decomposition of corn straw.

[0037] Compared with the control group (D1), the straw residue rate of the T1 treatment group with decomposing agent decreased faster and the degradation effect was more thorough; at 120 days, the straw residue rate of the T1 group was 36.23% lower than that of the D1 group, the straw pulling force value was 23.06% lower, and the soil cellulase activity was 32.97% higher; at the end of the experiment (240 days), the straw residue rate of the T1 group was 26.76% lower than that of the D1 group, the straw pulling force value was 53.56% lower, and the soil cellulase activity was 30.95% higher. This further shows that the composition of the water extract of Salvia miltiorrhiza affects the adaptability of microorganisms in the decomposing agent to saline-alkali land, thereby affecting the biological activity of microorganisms in the decomposing agent, especially the ability to degrade cellulose.

[0038] Compared with wheat straw, corn straw is more difficult to degrade under in-situ field return conditions. This is due to the fact that corn straw contains more wax layers, lignin and other difficult-to-degrade components and the lower temperature (corn straw is returned to the fields in autumn and winter).

[0039] Although the present invention has been described in detail by reference to the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A decomposing agent for returning straw to saline-alkali land in situ, characterized in that: The composition comprises the following components in parts by weight: 35-45 parts of Clostridium butyricum powder, 20-30 parts of Streptomyces albiflorus powder, and 25-45 parts of Salvia miltiorrhiza aqueous extract; The preparation process of the Salvia miltiorrhiza aqueous extract is as follows: s1, take Danshen, cut into sections with a length of 3-5 mm, crush and add water; the weight ratio of Danshen to water is 1:10-15, mix well to obtain slurry; s2, adjusting the pH of the slurry to 3.7-4.1 with formic acid, and then adding cellulase, pectinase and protease to the slurry, the addition amount of cellulase is 4.8-5.2u / g, the addition amount of pectinase is 2.0-2.4u / g, and the addition amount of protease is 1.2-1.7u / g; heating, controlling the slurry temperature to 40-43°C, maintaining for 2.5-3.0h, and obtaining an enzymolysis solution; s3, using sodium hydroxide to adjust the pH of the enzymatic hydrolyzate to 6.1-6.5, then reflux extraction for 1 hour, filter, and collect filtrate A; add water to the filter residue, the weight ratio of salvia miltiorrhiza to water is 1:10-15; reflux extraction for 1 hour, filter, and collect filtrate B; s4, concentrating the filtrate B under reduced pressure to obtain a paste; drying the paste to obtain a Salvia miltiorrhiza aqueous extract.

2. The decomposing agent for returning straw to saline-alkali land in situ as claimed in claim 1, characterized in that: The composition comprises the following components in parts by weight: 40 parts of Clostridium butyricum powder, 25 parts of Streptomyces albiflorus powder, and 35 parts of Salvia miltiorrhiza water extract.

3. The decomposing agent for returning straw to saline-alkali land in situ as claimed in claim 1, characterized in that: The effective live bacteria count of Clostridium butyricum powder is 1.0-1.2 billion / g, and the effective live bacteria count of Streptomyces albicans powder is 1.5-2 billion / g.

4. The method for preparing a decomposing agent for returning straw to saline-alkali land in situ as claimed in claim 1, characterized in that: The process is as follows: Step 1, preparing Clostridium butyricum powder, Strain activation: Take Clostridium butyricum, inoculate it on solid medium A by streak method, and culture it anaerobically at 30-32℃ for 24-36h; Cultivation: Take the activated strain and inoculate it into seed culture medium A, then culture it anaerobically at 30-32℃ for 36-48h to obtain culture medium A; Fermentation: inoculate the culture solution A into the fermentation medium A at an inoculation rate of 2%, the culture temperature is 30±1°C, and the culture is carried out anaerobically for 3-5 days to obtain the fermentation solution A; After the fermentation liquid A is dried, Clostridium butyricum powder is obtained; Step 2, preparing Streptomyces albicans powder, Strain activation: Take Streptomyces albiflorus and inoculate it on solid medium B by streak method, and culture it at 27-29℃ for 2-3 days; Cultivation: Take the activated strain and inoculate it into seed culture medium B, then culture it with shaking at 27-29°C for 1-2 days to obtain culture medium B; Fermentation: inoculate the culture fluid B into the fermentation medium B at an inoculation rate of 3%, culture at a temperature of 27±1°C, and culture under stirring conditions for 3-5 days to obtain fermentation fluid B; After the fermentation liquid B is dried, Streptomyces albicans powder is obtained; Step three, adding Clostridium butyricum powder, Streptomyces albiflorus powder and Salvia miltiorrhiza water extract into a mixing device and mixing to obtain a decomposing agent; and vacuum-storing the decomposing agent to obtain a product.

5. The method for preparing a decomposing agent for returning straw to saline-alkali land in situ as claimed in claim 4, characterized in that: In step 1, solid culture medium A, yeast extract powder 4g / L, beef extract 6g / L, peptone 8g / L, glucose 6g / L, cysteine ​​hydrochloride 0.3g / L, potassium chloride 2g / L and potassium bicarbonate 2g / L, agar 10g / L; Seed culture medium A, beef extract 13g / L, yeast extract powder 6g / L, peptone 9g / L, glucose 10g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L; Fermentation medium A, beef extract 11g / L, yeast extract 6g / L, peptone 8g / L, glucose 9g / L, cysteine ​​hydrochloride 0.7g / L, potassium chloride 4g / L and potassium bicarbonate 5g / L, ferric sulfate 0.6g / L.

6. The method for preparing a decomposing agent for returning straw to saline-alkali land in situ as claimed in claim 4, characterized in that: In step 2, solid culture medium B, yeast powder 4g / L, glucose 4g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 0.7g / L, magnesium sulfate 0.25g / L, sodium chloride 0.1g / L, agar 10g / L; Seed culture medium B, yeast powder 4g / L, glucose 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.0g / L, magnesium sulfate 0.25g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 7.5g / L; Fermentation medium B, yeast extract 5g / L, molasses 4.5g / L, ammonium chloride 2g / L, potassium dihydrogen phosphate 1.5g / L, magnesium sulfate 0.3g / L, sodium chloride 0.1g / L, sodium carboxymethyl cellulose 8.5g / L.

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