A saline-alkali soil conditioner and its application

Abstract

The invention discloses a saline-alkali soil conditioner and its application, the saline-alkali soil conditioner comprises the following raw materials in parts by mass: 10-15 parts of biochar, 8-10 parts of organic fertilizer, 0.2-0.5 parts of microbial agent, and 0.1-0.2 parts of polymer compound; the microbial agent is prepared by Bacillus subtilis and Chlamydomonas reinhardtii in a mass ratio of (18-20): (8-10); the polymer compound is prepared by xanthan gum and guar gum in a mass ratio of (2-3): (2-3). The present invention realizes a significant improvement in soil fertility and crop yield. Through the carbonization of straw and the rational combination of organic fertilizer and chemical fertilizer, the present invention not only increases the organic matter content of the soil, improves the soil structure, but also effectively improves the nutritional status of the soil, and provides richer and more balanced nutritional conditions for crop growth; this comprehensive management strategy significantly improves the yield and quality of crops, and is particularly suitable for coastal saline-alkali areas with relatively poor production conditions.

Description

Technical Field

[0001] The invention relates to the technical field of saline-alkali land improvement, and in particular to a saline-alkali land soil conditioner and application thereof. Background Art

[0002] my country has about 1.5 billion mu of saline-alkali land, of which about 500 million mu has development and utilization potential. Under the national conditions of small total cultivated land, low overall quality and insufficient reserve resources, as one of the countries with the most saline-alkali land, comprehensive utilization of saline-alkali land will significantly achieve the expansion, quality improvement and efficiency of cultivated land resources. As one of the main distribution areas of coastal saline-alkali land in my country, the Bohai Rim region faces many challenges, including shallow groundwater, heavy salinity of soil, shallow soil plough layer, poor structure and low organic matter. These problems directly affect agricultural production in the region. In order to improve the situation of saline-alkali land, a series of comprehensive measures have been taken. In terms of water and salt regulation, irrigation and drainage, surface covering and other measures are used to reduce soil salinity and control soil anti-salinity. At the same time, in order to improve soil fertility, organic fertilization is adopted. However, the current soil fertilization methods in saline-alkali areas are relatively extensive and single, mainly using straw return to the field, increasing the application of organic fertilizer or quick-acting fertilizer, and the effect is not ideal.

[0003] Soil microorganisms are one of the most active factors of soil fertility. Studies have shown that the application of microbial fertilizers can improve soil fertility. Some microorganisms can produce organic acids during metabolism, providing slow-acting nitrogen, phosphorus and potassium to the soil, thereby improving the physical and chemical properties of the soil. Microbial improvement of saline-alkali land is mainly reflected in improving the physical properties of soil, biological ammonia fixation, and inhibiting biological pests and diseases. Chlamydomonas reinhardtii is a single-cell green algae with a wide range of application value. It can be used as a raw material for food, feed, biodiesel and other products. In addition, Chlamydomonas reinhardtii can also be used to produce biomass, prepare drugs, treat wastewater, etc., but there is no report that it can be used to increase the organic matter content of saline-alkali land.

[0004] Xanthan gum, also known as xanthan gum, is a widely used microbial extracellular polysaccharide produced by wild Xanthomonas campestris using carbohydrates as the main raw material (such as corn starch) through fermentation engineering. It has unique rheological properties, good water solubility, stability to heat and acid and alkali, and good compatibility with a variety of salts. As a thickener, suspending agent, emulsifier, and stabilizer, it can be widely used in more than 20 industries such as food, petroleum, and medicine. It is currently the world's largest microbial polysaccharide with the most extensive production scale and wide application. Guar gum, also known as guar gum, is an extract of the leguminous plant guar bean and is a galactomannan. Xanthan gum and guar gum are both commonly used food additives. They are mainly used as thickeners and stabilizers in the food industry. In addition to the food industry, they are also widely used in many industrial fields (petroleum, pharmaceuticals), but there has been no report on their use in saline-alkali land improvement. Summary of the invention

[0005] In view of the above-mentioned prior art, the purpose of the present invention is to provide a saline-alkali soil conditioner and application thereof.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a saline-alkali soil conditioner, comprising the following raw materials in parts by weight:

[0008] 10-15 parts of biochar, 8-10 parts of organic fertilizer, 0.2-0.5 parts of microbial agent, 0.1-0.2 parts of polymer compound;

[0009] The microbial agent is prepared from Bacillus subtilis and Chlamydomonas reinhardtii in a mass ratio of (18-20): (8-10);

[0010] The polymer composite is prepared from xanthan gum and guar gum in a mass ratio of (2-3): (2-3).

[0011] Preferably, the biochar is prepared by the following method: cutting wheat straw or corn straw into 3-5 cm pieces, carbonizing at 400° C. for 1 hour, cooling, air-drying and sieving to obtain the biochar.

[0012] Preferably, in the organic fertilizer, the number of effective live bacteria is ≥ 300 million / g, and the organic matter is ≥ 55%.

[0013] Preferably, the number of viable bacteria of Bacillus subtilis in the microbial agent is 5×10 9 cfu / g, the concentration of Chlamydomonas reinhardtii was 2×10 7 cell / g.

[0014] The second aspect of the present invention provides the use of the above-mentioned saline-alkali land soil conditioner in improving saline-alkali land.

[0015] The third aspect of the present invention provides a method for improving saline-alkali land, comprising the following steps:

[0016] The saline-alkali land soil conditioner is spread on the saline-alkali land to be improved and then turned over.

[0017] Preferably, the turning depth is 15-25 cm.

[0018] Preferably, the application amount of the saline-alkali land soil conditioner is: 280-420kg / mu.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention achieves a significant improvement in soil fertility and crop yield. Through the carbonization of straw and the rational combination of organic fertilizer and chemical fertilizer, the present invention not only increases the organic matter content of the soil and improves the soil structure, but also effectively improves the nutritional status of the soil, providing richer and more balanced nutritional conditions for crop growth; this comprehensive management strategy significantly improves the yield and quality of crops, and is particularly suitable for coastal saline-alkali areas with relatively harsh production conditions.

[0021] 2. The present invention promotes soil microorganisms to secrete extracellular polymers to form biofilms, promotes clay mineral-organic matter cementation, forms microaggregates and macroaggregates, and improves soil aggregate structure by adding specific microbial fertilizers (Bacillus subtilis and Chlamydomonas reinhardtii) and polymer complexes (xanthan gum and guar gum mixture). At the same time, the aggregate structure provides a more suitable living environment for microorganisms, enhances the survival ability of microorganisms, improves stress resistance, and significantly improves soil enzyme activity. This not only enhances the self-recovery ability of the soil, but also contributes to the effective circulation of water and gas in the soil, creating a healthier and more stable soil ecological environment.

[0022] 3. The present invention deeply analyzes the effects of different soil management measures on soil organic carbon components, aggregate composition and soil enzyme activity, reveals the carbon increase mechanism, and provides a scientific basis for improving the carbon storage capacity of coastal saline-alkali land soil. Through these measures, the present invention not only helps to mitigate climate change, but also provides important support for the sustainable and healthy development of soil and the continuous increase in crop yields.

[0023] 4. The present invention provides a sustainable soil management and crop production model suitable for coastal saline-alkali land. By optimizing soil management practices, it not only improves the economic benefits of crops, but also helps protect the ecological environment and promote the sustainable development of agricultural production systems. It is expected to be applied and promoted in a wider range of regions and under different types of soil conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : Organic carbon storage in the 2023 maize season in different treatment groups;

[0025] Depend on Figure 1 It was found that the BFMG treatment significantly increased soil organic carbon storage by 38.97% (P<0.05), and the BF treatment, SFG treatment and SFM treatment increased soil organic carbon storage by 7.32%, 10.73% and 19.30% (P<0.05) respectively compared with the control treatment.

[0026] Figure 2 : Aggregate size distribution of different treatment groups; (where a is the 2022 corn season, b is the 2023 wheat season, and c is the 2023 corn season;)

[0027] Depend on Figure 2 The results showed that BFMG treatment significantly increased the content of soil aggregates by 23.57% to 30.63% (P<0.05), and SFG treatment increased the content of soil aggregates by 6.31% to 24.70% (P<0.05) compared with the control treatment.

[0028] Figure 3 : Organic carbon content of aggregates in different treatment groups; (where a is the 2022 corn season, b is the 2023 wheat season, and c is the 2023 corn season;)

[0029] Depend on Figure 3 It was found that BF treatment significantly increased the organic carbon content of soil aggregates, with an increase of 12.90% to 78.73% (P<0.05). BFMG treatment and SFM treatment increased the organic carbon content of soil aggregates by 8.06% to 52.45% (P<0.05) compared with the control treatment;

[0030] Figure 4 : Contribution of aggregates in different treatment groups to soil organic carbon; (where a is the 2022 corn season, b is the 2023 wheat season, and c is the 2023 corn season;)

[0031] Depend on Figure 4 It can be seen that BFMG treatment significantly increased the contribution of soil aggregates to soil organic carbon, with an increase of 30.44% to 54.17% (P<0.05). SFG treatment and SFM treatment increased the contribution of soil aggregates to soil organic carbon by 14.82% to 32.35% (P<0.05) compared with the control treatment;

[0032] Figure 5 : Soil enzyme activities under different treatments;

[0033] Depend on Figure 5 It was found that BFMG treatment significantly increased soil sucrase activity by 4.64% to 17.33%.

[0034] (P<0.05). SFM treatment significantly increased soil cellulase activity by 2.12% to 19.57% (P<0.05), BF and SFG treatments significantly increased soil amylase activity by 2.23% to 40.44% (P<0.05), and BF treatment significantly increased soil β-glucosidase activity by 2.98% to 9.32% (P<0.05). DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0036] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0037] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0038] The organic fertilizer used in the present invention is purchased from Shandong Agricultural University Fertilizer Technology Co., Ltd. The product name is Yidingsan (Three Stars) Agricultural University biological organic fertilizer granules, the effective live bacteria count is ≥300 million / g and the organic matter is ≥55%.

[0039] The Bacillus subtilis agent used in the present invention is purchased from the China General Microbiological Culture Collection Center, and the strain number is CGMCC 1.9083.

[0040] The Chlamydomonas reinhardtii used in the present invention was purchased from Xi'an Green Biotechnology Co., Ltd., with a product batch number of LYYZ001 and a content of 99%.

[0041] Example 1: Preparation of saline-alkali soil conditioner:

[0042] Raw material composition: biochar 12.8kg, organic fertilizer 9.38kg, microbial agent 0.28kg, polymer compound 0.13kg;

[0043] Biochar is prepared by the following methods:

[0044] Cut wheat straw or corn straw into 3-5 cm pieces, place in a muffle furnace at 400°C for 1 hour, cool, air-dry and sieve to obtain biochar;

[0045] The microbial agent is prepared by the following method:

[0046] The Bacillus subtilis and Chlamydomonas reinhardtii are activated and cultured respectively, the fermentation liquid is centrifuged, the bacterial precipitate is collected, and the precipitate is dried to obtain Bacillus subtilis powder and Chlamydomonas reinhardtii powder respectively;

[0047] The Bacillus subtilis powder and the Chlamydomonas reinhardtii powder are mixed evenly in a mass ratio of 19:9 to obtain a microbial agent;

[0048] The number of viable bacteria of Bacillus subtilis powder is 5×10 9 cfu / g, the concentration of Chlamydomonas reinhardtii powder was 2×10 7cell / g;

[0049] The polymer composite was prepared by the following method:

[0050] The xanthan gum and guar gum are mixed uniformly in a mass ratio of 1:1 to obtain a polymer composite;

[0051] Preparation method: biochar, organic fertilizer, microbial agent and polymer complex are evenly mixed to obtain a saline-alkali land soil conditioner.

[0052] Embodiment 2: Soil improvement method of saline-alkali land:

[0053] 1. When planting corn:

[0054] (1) On saline-alkali land, 358.6 kg / mu of saline-alkali soil conditioner prepared in Example 1 (biochar was prepared from wheat straw harvested in the previous season) was spread, and base fertilizer was spread, and deep plowing was performed using a three-furrow plow, with a plowing depth of 20 cm;

[0055] The base fertilizer is urea (N≧46%) 1.185kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 10.87kg / mu, potassium sulfate (K2O≧52%) 4.81kg / mu;

[0056] (2) Corn sowing: the corn variety is Denghai 605, the spacing is 30 cm, the sowing rate is 20 kg / mu, the planting density is 3500 plants / mu, weeding is carried out in time after the corn seedlings emerge, and urea (N≧46%) 10.87 kg / mu is applied at the small trumpet stage of corn;

[0057] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0058] 2. When planting wheat:

[0059] (1) On saline-alkali land, 358.6 kg / mu of the saline-alkali soil conditioner prepared in Example 1 (biochar was prepared from corn stalks harvested in the previous season) was spread, and base fertilizer was spread, and deep plowing was performed using a three-furrow plow, with a plowing depth of 20 cm;

[0060] The base fertilizer is 3.90 kg / mu of urea (N≧46%), 10.87 kg / mu of diammonium phosphate (P2O5≧46%, N≧18%), and 4.81 kg / mu of potassium sulfate (K2O≧52%);

[0061] (2) Wheat sowing, the wheat variety is Feida No. 6, the spacing is 29 cm, the sowing rate is 20 kg / mu, weeding is carried out in time after wheat seedlings emerge, and urea (N≧46%) is applied at 8.15 kg / mu during the wheat greening period;

[0062] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0063] Comparative Example 1:

[0064] 1. When planting corn:

[0065] (1) On saline-alkali land, the wheat straw from the previous season was crushed and spread on the ground surface, with the straw returning rate of 600 kg / mu (returning to the field in situ), and basal fertilizer was spread, and deep plowing was carried out with a three-furrow plow, with a turning depth of 20 cm;

[0066] The base fertilizer is urea (N≧46%) 2.37kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0067] (2) Corn sowing: the corn variety is Denghai 605, the spacing is 30 cm, the sowing amount is 20 kg / mu, and the planting density is 3500 plants / mu. Weeding is carried out in time after corn seedlings emerge, and urea (N≧46%) 21.74 kg / mu is applied during the small trumpet stage of corn. After maturity, unified harvesting is carried out, and yield measurement is carried out. Soil samples at maturity are collected and analyzed.

[0068] 2. When planting wheat:

[0069] (1) On saline-alkali land, crush the corn stalks from the previous season and spread them on the ground surface. The amount of stalks returned to the field is 600 kg / mu (return to the field in situ), and basal fertilizer is spread. A three-furrow plow is used for deep pressing, and the pressing depth is 20 cm.

[0070] The base fertilizer is urea (N≧46%) 7.80kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0071] (2) Wheat sowing, the wheat variety is Feida No. 6, the spacing is 29 cm, the sowing rate is 20 kg / mu, weeding is carried out in time after wheat seedlings emerge, and urea (N≧46%) 16.30 kg / mu is applied during the wheat greening period;

[0072] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0073] Comparative Example 2:

[0074] 1. When planting corn:

[0075] (1) On saline-alkali land, wheat straw from the previous season was made into biochar according to the method of Example 1 and then returned to the field, with the amount of biochar returned to the field being 203 kg / mu, and basal fertilizer was spread, and deep plowing was carried out using a three-furrow plow, with a plowing depth of 20 cm;

[0076] The base fertilizer is urea (N≧46%) 2.37kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0077] (2) Corn sowing: the corn variety is Denghai 605, the spacing is 30 cm, the sowing amount is 20 kg / mu, and the planting density is 3500 plants / mu. Weeding is carried out in time after corn seedlings emerge, and urea (N≧46%) 21.74 kg / mu is applied during the small trumpet stage of corn. After maturity, unified harvesting is carried out, and yield measurement is carried out. Soil samples at maturity are collected and analyzed.

[0078] 2. When planting wheat:

[0079] (1) On saline-alkali land, corn stalks from the previous season were made into biochar according to the method of Example 1 and then returned to the field. The amount of biochar returned to the field was 203 kg / mu, and basal fertilizer was spread. A three-furrow plow was used for deep pressing, and the pressing depth was 20 cm;

[0080] The base fertilizer is urea (N≧46%) 7.80kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0081] (2) Wheat sowing, the wheat variety is Feida No. 6, the spacing is 29 cm, the sowing rate is 20 kg / mu, weeding is carried out in time after wheat seedlings emerge, and urea (N≧46%) 16.30 kg / mu is applied during the wheat greening period;

[0082] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0083] Comparative Example 3:

[0084] 1. When planting corn:

[0085] (1) On saline-alkali land, the wheat straw from the previous season was crushed and spread on the ground surface, with the straw return rate of 600 kg / mu (in-situ return to the field), and 4.4 kg / mu of microbial agents and 2.06 kg / mu of polymer mixture were spread; basal fertilizer was also spread, and a three-furrow plow was used for deep turning and compaction, with a turning depth of 20 cm;

[0086] The base fertilizer is urea (N≧46%) 2.37kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0087] (2) Corn sowing: the corn variety is Denghai 605, the spacing is 30 cm, the sowing amount is 20 kg / mu, and the planting density is 3500 plants / mu. Weeding is carried out in time after corn seedlings emerge, and urea (N≧46%) 21.74 kg / mu is applied during the small trumpet stage of corn. After maturity, unified harvesting is carried out, and yield measurement is carried out. Soil samples at maturity are collected and analyzed.

[0088] 2. When planting wheat:

[0089] (1) On saline-alkali land, the corn stalks from the previous season were crushed and spread on the ground surface, with the amount of stalks returned to the field being 600 kg / mu (in-situ return to the field), and 4.4 kg / mu of microbial agents and 2.06 kg / mu of polymer mixtures were spread; basal fertilizer was also spread, and a three-furrow plow was used for deep turning and compaction, with a turning depth of 20 cm;

[0090] The base fertilizer is urea (N≧46%) 7.80kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 21.74kg / mu, potassium sulfate (K2O≧52%) 9.62kg / mu;

[0091] (2) Wheat sowing, the wheat variety is Feida No. 6, the spacing is 29 cm, the sowing rate is 20 kg / mu, weeding is carried out in time after wheat seedlings emerge, and urea (N≧46%) 16.30 kg / mu is applied during the wheat greening period;

[0092] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0093] Comparative Example 4:

[0094] 1. When planting corn:

[0095] (1) On saline-alkali land, the wheat straw from the previous season was crushed and spread on the ground surface, with the straw returning rate of 600 kg / mu (returning to the field in situ), and 149 kg / mu of organic fertilizer was spread, and base fertilizer was spread. A three-furrow plow was used for deep turning and compaction, with a turning depth of 20 cm.

[0096] The base fertilizer is urea (N≧46%) 1.185kg / mu, diammonium phosphate (P2O5≧46%, N≧18%) 10.87kg / mu, potassium sulfate (K2O≧52%) 4.81kg / mu;

[0097] (2) Corn sowing: the corn variety is Denghai 605, the spacing is 30 cm, the sowing rate is 20 kg / mu, the planting density is 3500 plants / mu, weeding is carried out in time after the corn seedlings emerge, and urea (N≧46%) 10.87 kg / mu is applied at the small trumpet stage of corn;

[0098] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0099] 2. When planting wheat:

[0100] (1) On saline-alkali land, the corn stalks from the previous season were crushed and spread on the ground surface, with the amount of stalks returned to the field being 600 kg / mu (returned in situ), and organic fertilizer was spread at 149 kg / mu, and base fertilizer was spread. A three-furrow plow was used for deep turning and compaction, with a turning depth of 20 cm.

[0101] The base fertilizer is 3.90 kg / mu of urea (N≧46%), 10.87 kg / mu of diammonium phosphate (P2O5≧46%, N≧18%), and 4.81 kg / mu of potassium sulfate (K2O≧52%);

[0102] (2) Wheat sowing, the wheat variety is Feida No. 6, the spacing is 29 cm, the sowing rate is 20 kg / mu, weeding is carried out in time after wheat seedlings emerge, and urea (N≧46%) is applied at 8.15 kg / mu during the wheat greening period;

[0103] After maturity, the crops are harvested uniformly, the yield is measured, and soil samples at maturity are collected and analyzed.

[0104] Application example: Methods for improving saline-alkali land:

[0105] The experimental site is located in Weifang Demonstration Base of Saline-alkali Land Improvement and Application of Shandong Agricultural University in Weifang City, Shandong Province. The region has a temperate semi-humid continental monsoon climate, with cold winters and hot summers, four distinct seasons, an average high temperature of 20°C, an average low temperature of 9°C, an extreme maximum temperature of 37°C, an extreme minimum temperature of -9°C, an annual average temperature of 11.9°C, January is the coldest month of the year, with an average temperature of -3.3°C in the city, and July is the hottest month, with an average temperature of 26.0°C in the city. The average precipitation is 610.5 mm, mostly concentrated in July and August, the average wind speed is 3.0 m / s, the average number of days with winds above level 6 is about 20 days, the average number of days with heavy fog is 21.6 days, the average relative humidity is 69%, with the highest in July and August; the average sunshine hours is 2427.7 h, the least month is January, with 169.1 h, and the most month is May, with 257.9 h. The area is located in the northwest of Shandong Peninsula, in the lower reaches of Wei River, on the south bank of Laizhou Bay of Bohai Sea, and belongs to the Bohai Rim Economic Zone. The geographical coordinates are 36°25′~37°08′ north latitude and 119°13′~119°37′ east longitude. The area is a coastal plain with low-lying and flat terrain, an altitude of 1.06m, and the soil type is mainly coastal saline soil. The ion composition is mainly NaCl, the average soil salt content is 2.1‰, the organic carbon content is 5.81g / kg, and the total nitrogen content is 0.81g / kg. Since 2022, the base has carried out key technology research on the rapid improvement of organic matter in saline-alkali farmland around the Bohai Sea. The wheat variety is Feida No. 6 and the corn variety is Denghai 605.

[0106] The experiment was divided into five treatments:

[0107] Treatment 1 (BFMG): corn and wheat were planted separately in the manner of Example 2 (carbonized straw returning to the field + organic fertilizer + microbial agent + polymer complex + 50% chemical fertilizer);

[0108] Treatment 2 (CK): corn and wheat were planted in the same manner as in Comparative Example 1 (straw crushing and returning to the field + conventional fertilizer);

[0109] Treatment 3 (BF): corn and wheat were planted in the same manner as in Comparative Example 2 (carbonized straw returned to the field + conventional fertilizer);

[0110] Treatment 4 (SFG): corn and wheat were planted in the same manner as in Comparative Example 3 (straw crushing and returning to the field + conventional fertilizer + microbial agent + polymer mixture);

[0111] Treatment 5 (SFM): corn and wheat were planted in the same manner as in Comparative Example 4 (straw crushing and returning to the field + organic fertilizer + 50% chemical fertilizer);

[0112] The trial is divided into 3 phases:

[0113] In the 2022 corn season, the 2023 wheat season, and the 2024 corn season, the five treatments above were used for planting at each planting stage, with each plot measuring 42 m 2 , each treatment was repeated 3 times.

[0114] 1. Measurement items:

[0115] 1. Determination of organic carbon content and soil aggregates:

[0116] 1.1 Total soil organic carbon:

[0117] Take 1g of air-dried soil that has passed through a 100-mesh sieve and place it in a clean and dried 50ml beaker, add 2.5ml of 1mol L -1 HCl was added until no bubbles were generated, and the beaker was placed in an oven at 105°C to dry the liquid and pass it through a 100-mesh sieve. 30-45 mg of dried soil was weighed using a 1 / 10 ...

[0118] 1.2 Organic carbon storage

[0119] Organic carbon storage = SOC × BD × H × 10

[0120] Where SOC is the total organic carbon content of soil (g kg -1 ), BD is soil bulk density (g cm -3 ), H is the soil layer depth (m).

[0121] 1.3 Soil particulate organic carbon:

[0122] Take 10.00g of air-dried soil that has passed through a 2mm sieve and place it in a 250ml conical flask. Then, add 100ml of 5g L -1 The sodium hexametaphosphate (NaPO3)6 solution was stirred by hand for 3 minutes and then oscillated for 18 hours (18°C, 90 r min -1 After the shaking is completed, the soil is passed through a 53 μm sieve and rinsed with deionized water until the filtered water is colorless. The soil sample on the sieve (>53 μm) is collected in a clean and dried 50 ml beaker, dried at 60 ° C to constant weight, and the weight is recorded. Then the total organic carbon content of soil particles >53 μm is determined according to method 1.1.

[0123]

[0124] POC is soil particulate organic carbon, m 颗粒 is the weight of soil particles >53 μm, m is the total weight of soil, SOC 颗粒 Total organic carbon content of soil particles >53μm.

[0125] 1.4 Soil microbial biomass carbon

[0126] Weigh fresh soil (equivalent to 10.00g dry soil) in a 25ml beaker, place the beaker in a vacuum drying oven with a beaker containing ethanol-free chloroform (25ml) and a beaker of dilute NaOH, put a small amount of anti-explosion glass beads in the beaker, and add a small amount of water to the bottom of the dryer to maintain the humidity of the container. Evacuate the vacuum, make the chloroform explode for 5 minutes, and fumigate for 24 hours at 25℃ in the dark. Set up a blank treatment without chloroform fumigation under the same conditions.

[0127] After fumigation, remove the beaker containing chloroform and dilute NaOH and repeatedly vacuum for 5 to 6 times until the soil has no chloroform smell. Transfer the soil sample completely to a 50 ml polyethylene centrifuge tube and add 40 ml K2SO4 (0.5 mol L -1 ) solution, oscillate for 30 min (300 r min -1 ), centrifuge for 5 min (4000 r min -1 ), and then filtered through a 0.45 μm water filter membrane using a total organic carbon analyzer liquid phase module (vario TOC, Germany) to determine the organic carbon content of the soil samples.

[0128]

[0129] MBC is the microbial biomass carbon content, C 熏蒸 and C 空白 Represents the organic carbon content of fumigated and unfumigated soil samples (mgkg -1 ), 0.45 represents the conversion coefficient.

[0130] 1.5 Soil aggregate classification and distribution of organic carbon in aggregates

[0131] Weigh 100.00g of original soil, soak the soil with distilled water, and pass it through three nylon sieves (8 mesh, 60 mesh, 270 mesh) in turn. Sieve it vertically up and down in the water for 15 minutes, and sieve the original soil into four aggregate levels: >2mm, 0.25-2mm, 0.053-0.25mm (microaggregates) and <0.053mm (powder clay particles). Because there are fewer aggregates >2mm in the soil, the aggregates >2mm and 0.25-2mm are combined together, and the aggregates of each level are transferred to a 50ml beaker, dried at 60℃ to constant weight, and the weight is recorded. The soil organic carbon content of each aggregate is measured according to method 1.1, and the distribution of organic carbon in the aggregate is calculated.

[0132] 1.6 Stability Index

[0133] The calculation formulas for the mean weight diameter (MWD), geometric mean diameter (GMD) and water stable aggregate content (WSA) of soil aggregates are as follows:

[0134]

[0135]

[0136] Where W i represents the ratio of aggregates of different particle sizes, X i Represents the particle size of aggregates, n represents aggregates of different particle sizes, i=1, 2, 3, 4, representing four aggregate levels: >2mm, 0.25-2mm, 0.053-0.25mm (microaggregates) and <0.053mm (powder clay particles).

[0137] 2. Soil enzyme activity determination

[0138] The double antibody sandwich method was used to determine the activity of β-glucosidase, amylase, cellulase, and sucrase in fresh soil samples. The microplate was coated with purified β-glucosidase (β-glu), amylase (Amylase), cellulase (CE), and sucrase (sucrase) antibodies to prepare solid-phase antibodies. The corresponding enzymes were added to the microwells coated with monoclonal antibodies, and the HRP-labeled corresponding enzyme antibodies were combined with antigens to form an antibody-antigen-enzyme-labeled antibody complex. After a period of incubation and thorough washing, the substrate TMB was added for color development. Under the action of HRP enzyme, TMB was converted to blue and turned to yellow under acidic conditions. The depth of the color was proportional to the enzyme activity in the sample. After the reaction was terminated, the absorbance (OD value) was measured at a wavelength of 450nm using an enzyme reader within 15 minutes, and the enzyme activity in the sample was calculated using the established standard curve.

[0139] 3. Yield determination method:

[0140] Number of ears per mu = 666.7m 2 ÷ Plant spacing (m) ÷ Row spacing (m)

[0141] Theoretical yield (kg / mu) = number of ears per mu × number of grains per ear × thousand-grain weight × 1,000,000

[0142] 2. Test results:

[0143] Table 1 Total organic carbon content in soil (g kg -1 )

[0144]

[0145] As shown in Table 1, the treatment of straw carbonization and returning to the field + 50% chemical fertilizer + 50% organic fertilizer + polymer composite material significantly increased the soil organic carbon content, with an increase of 7.01% to 42.46% (P<0.05). The treatment of straw carbonization and returning to the field + conventional fertilizer application, straw crushing and returning to the field + conventional fertilizer application + polymer composite material treatment and straw crushing and returning to the field + 50% chemical fertilizer + 50% organic fertilizer treatment increased the soil organic carbon content by 3.42% to 22.77% (P<0.05) compared with the control treatment.

[0146] Table 2 Organic carbon content of soil particles (g kg -1 )

[0147]

[0148]

[0149] As shown in Table 2, BFMG treatment significantly increased the content of soil particle organic carbon, with an increase of 14.58% to 57.09% (P<0.05). BF treatment, SFG treatment and SFM treatment increased the content of soil particle organic carbon by 3.57% to 30.44% (P<0.05) compared with the control treatment.

[0150] Table 3 Soil microbial biomass carbon content (mg kg -1 )

[0151]

[0152] As shown in Table 3, BFMG treatment significantly increased soil microbial biomass carbon content by 52.00% to 97.56% (P<0.05). SFG treatment and SFM treatment increased soil microbial biomass carbon content by 8.09% to 71.78% (P<0.05) compared with the control treatment.

[0153] Table 4 Average soil weight diameter (mm)

[0154]

[0155] As shown in Table 4, the BFMG treatment significantly increased the average soil weight diameter by 6.93% to 11.63% (P<0.05). The BF treatment, SFG treatment and SFM treatment increased the average soil weight diameter by 0.05% to 4.49% (P<0.05) compared with the control treatment.

[0156] Table 5 Geometric mean diameter of soil (mm)

[0157]

[0158] As shown in Table 5, the BFMG treatment significantly increased the soil geometric mean diameter by 5.26% to 10.27% (P<0.05). The BF treatment, SFG treatment and SFM treatment increased the soil geometric mean diameter by 0.05% to 4.02% (P<0.05) compared with the control treatment.

[0159] Table 6 Content of water-stable aggregates in soil (100%)

[0160]

[0161] As shown in Table 6, at the 23rd corn maturity stage, BFMG treatment significantly increased the content of soil water-stable aggregates by 16.95% (P<0.05). SFG treatment and SFM treatment increased the content of soil water-stable aggregates by 4.94% to 8.91% (P<0.05) compared with the control treatment.

[0162] Table 7 Yield (t hm -2 )

[0163]

[0164] As shown in Table 7, BFMG treatment significantly increased crop yield by 14.20% to 30.63% (P<0.05). SFM treatment increased crop yield by 7.87% to 11.53% (P<0.05) compared with the control treatment.

[0165] In summary, the benefits of returning straw to the field with different amendments were significant, especially in the BFMG treatment group, which increased yield by an average of 24.59%, significantly increased soil organic carbon content and improved soil aggregate structure. It not only promoted the accumulation of organic carbon in soil macroaggregates and microaggregates, but also enhanced the carbon sequestration capacity of the soil, which is of great significance for improving soil fertility and carbon storage potential.

[0166] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A saline-alkali soil conditioner, characterized in that: The invention comprises the following raw materials in parts by weight: 10-15 parts of biochar, 8-10 parts of organic fertilizer, 0.2-0.5 parts of microbial agent and 0.1-0.2 parts of polymer compound; The microbial agent is prepared from Bacillus subtilis and Chlamydomonas reinhardtii in a mass ratio of (18-20): (8-10); The strain number of the Bacillus subtilis inoculant is CGMCC 1.9083; The polymer composite is prepared from xanthan gum and guar gum in a mass ratio of (2-3): (2-3); The biochar is prepared by the following method: cutting wheat straw or corn straw into 3-5 cm pieces, carbonizing at 400° C. for 1 hour, cooling, air-drying, and sieving to obtain the biochar; The organic fertilizer was purchased from Shandong Agricultural University Fertilizer Technology Co., Ltd. The product name is Yidingsan (Samsung) Agricultural University biological organic fertilizer granules, with effective live bacteria count ≥ 300 million / g organic matter ≥ 55%.

2. The saline-alkali soil conditioner according to claim 1, characterized in that The number of viable bacteria of Bacillus subtilis in the microbial agent is 5×10 9 cfu / g, the concentration of Chlamydomonas reinhardtii was 2×10 7 cell / g.

3. Use of the saline-alkali soil conditioner according to claim 1 or 2 in improving saline-alkali land.

4. A method for improving saline-alkali land, characterized in that: The following steps are involved: The saline-alkali soil conditioner according to claim 1 or 2 is spread on the saline-alkali land to be improved and turned over.

5. The method for improving saline-alkali land according to claim 4, characterized in that: The turning depth is 15-25cm.

6. The method for improving saline-alkali land according to claim 4, characterized in that: The application amount of the saline-alkali land soil conditioner is: 280-420kg / mu.

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