Method for improving straw decomposition rate and application thereof

Abstract

This invention belongs to the field of crop planting technology, specifically relating to a method for improving the decomposition rate of straw and its application; it includes the following steps: spreading a composting agent on the surface of the straw and then turning it back into the field; the composting agent includes at least one of the following: Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum; the content of effective viable bacteria in the composting agent is ≥200 million CFU / g or ≥200 million CFU / mL. This invention significantly improves the decomposition rate of corn straw through steps such as crushing straw, spreading a composting agent containing specific functional bacteria, and turning it back into the field. Using the method of this invention to decompose corn straw has the beneficial effects of high decomposition rate, improved soil quality, and increased corn yield. This invention is applicable to the decomposition treatment of corn straw in various types of dryland farming and can be applied to the rapid decomposition and resource utilization of straw under different dryland farming conditions.

Description

Technical Field

[0001] This invention belongs to the field of crop planting technology, specifically relating to a method for improving the decomposition rate of straw and its application. Background Technology

[0002] Corn is a major crop, and corn stalks are both the largest byproduct of agricultural production and a basic production factor. How to effectively convert corn stalks on-site is a pressing issue. Corn stalks contain approximately 40% carbon, as well as macroelements such as nitrogen, phosphorus, and potassium, and medium and trace elements such as calcium, magnesium, iron, manganese, copper, zinc, and sulfur. Direct burning or disposal not only wastes organic resources but also causes air pollution, contributing to the greenhouse effect and acid rain. The continuous accumulation of acid rain gradually penetrates deep into the soil, significantly damaging soil structure, causing the death of beneficial microbial communities, affecting the normal decomposition of crop residues, reducing fertility, and ultimately leading to a sharp decline in crop yields.

[0003] Returning straw to the field in current production practices enables the resource utilization of straw, while simultaneously increasing soil organic matter and nutrient content, thereby improving soil structure and fertility. Common methods of straw return include direct return, return after animal feed intake, and composting. Direct straw return technology has the advantages of simple operation and low cost; however, frequent low temperatures and heavy rainfall during spring sowing can delay soil warming, affecting soil moisture and the emergence rate and yield of subsequent crops. Furthermore, the degree of straw decomposition after return not only determines its soil improvement effect but also significantly affects soil moisture conditions at the time of sowing the next season's crops, ultimately impacting sowing quality and emergence rate. Therefore, improving the straw decomposition rate is a crucial issue in addressing the comprehensive utilization of crop straw. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the decomposition rate of straw and its application, wherein the method significantly improves the decomposition rate of corn straw.

[0005] This invention provides a method for improving the decomposition rate of straw, comprising the following steps: spreading a composting agent on the surface of straw and then turning it back into the field; The composting agent includes at least one of the following: Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum; the content of effective viable bacteria in the composting agent is ≥200 million CFU / g or ≥200 million CFU / mL.

[0006] As a preferred embodiment, the application rate of the composting agent is 10-20 kg / hm². 2 Or 10~20L / hm 2 .

[0007] As a preferred embodiment, the composting agent may be in the form of powder or liquid.

[0008] As a preferred embodiment, the length of the straw is 5-8 cm.

[0009] As a preferred embodiment, the straw includes corn stalks.

[0010] As a preferred embodiment, the depth of the plowing and returning to the field is 10~30cm.

[0011] This invention provides the application of the above-mentioned method for increasing straw decomposition rate in increasing soil humic acid and / or organic matter content.

[0012] As a preferred embodiment, the organic matter includes at least one of the following: humic acid, fulvic acid, and humin.

[0013] This invention provides the application of the above-mentioned method for improving straw decomposition rate in increasing corn yield.

[0014] As a preferred embodiment, the corn includes: dryland corn.

[0015] Beneficial Effects: This invention provides a method for improving the decomposition rate of straw, comprising the following steps: spreading a composting agent on the surface of the straw and then plowing it back into the field; the composting agent includes at least one of the following: Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum; the content of effective viable bacteria in the composting agent is ≥200 million CFU / g or ≥200 million CFU / mL. This invention achieves rapid and efficient decomposition of straw and soil fertilization through steps such as crushing straw, spreading a composting agent containing specific functional bacteria, and plowing it back into the field. Crushing straw disrupts its original dense structure, significantly increasing its specific surface area and improving the contact efficiency between microorganisms and substrates, creating conditions for subsequent enzymatic decomposition. Spraying specific functional microbial composting agents supplements cellulose, hemicellulose, and lignin-degrading microorganisms, enhances related enzyme activity, accelerates the conversion of large organic molecules into usable small molecules, shortens the decomposition cycle, and alleviates nitrogen competition caused by a high carbon-to-nitrogen ratio. Turning straw into the soil optimizes soil moisture, temperature, and aeration, promoting thorough mixing of straw and soil, and improving microbial activity and the degree of organic matter humification. These three methods work synergistically from three levels: physical regulation, biofortification, and environmental optimization, effectively solving problems such as slow straw decomposition, delayed nutrient release, and low soil fertility efficiency, achieving the goals of straw resource utilization and improved arable land quality. The method of this invention for decomposing corn straw has the beneficial effects of high decomposition rate, improved soil quality, and increased corn yield. The results of the embodiments show that after 120 days of treatment using the method described in this invention, the straw biomass loss rate (decomposition rate) reached over 70%; after 180 days of treatment, it could reach a maximum of 79.39%. Compared with existing technologies, this invention has advantages such as simple operation, no need for layered soil mixing, sufficient contact between the composting agent and straw, fast decomposition speed, and low demand for agricultural machinery. It is suitable for straw return operations in various types of dryland and can significantly improve straw decomposition efficiency. This invention is applicable to the decomposition treatment of corn straw in various types of dryland and can be applied to the rapid decomposition and resource utilization of corn straw under different dryland farming conditions.

[0016] This invention provides the application of the above-mentioned method for increasing straw decomposition rate in increasing soil humic acid and / or organic matter content. The method of this invention can significantly improve the straw decomposition rate, increase soil humic acid and organic matter content, and thus improve soil structure.

[0017] This invention provides the application of the above-mentioned method for improving straw decomposition rate in increasing corn yield. The method of this invention increases corn yield by improving the straw decomposition rate, thereby increasing soil humic acid and organic matter content. The method of this invention has advantages such as simple operation, cost savings, and wide applicability, providing a scientific basis for improving the efficiency of farmland straw decomposition in dryland planting areas of Inner Mongolia. Attached Figure Description

[0018] Figure 1The graph shows the effect of different composting agents on the straw biomass weight loss rate (decomposition rate); where a is the straw biomass weight loss rate in 2023 and b is the straw biomass weight loss rate in 2024. Figure 2 Figure showing the impact of different composting agents (2023) on soil humus composition; Figure 3 Figure showing the impact of different composting agents (2024) on soil humus composition; Figure 4 Figure showing the impact of pre-sowing straw return combined with application of composting agents on soil organic matter in 2023; Figure 5 The diagram shows the impact of returning straw to the field after the 2023 harvest and applying composting agents on soil organic matter. Figure 6 Figure showing the impact of pre-sowing straw return combined with application of composting agents on soil organic matter in 2024; Figure 7 The diagram shows the impact of returning straw to the field after the 2024 harvest and applying composting agents on soil organic matter. Figures 2-7 In the diagram, the same letter indicates no significant difference, while different letters indicate a significant difference. Detailed Implementation

[0019] This invention provides a method for improving the decomposition rate of straw, comprising the following steps: spreading a composting agent on the surface of straw and then turning it back into the field; Unless otherwise specified, the present invention does not have special requirements for the raw materials used, and commercially available products known to those skilled in the art can be used.

[0020] This invention preferably involves crushing the straw. The length of the crushed straw can be any value within the range of 5-8 cm, for example, 5, 5.5, 6, 6.5, 7, 7.5, or 8 cm. This length range is conducive to the colonization, growth, and diffusion of composting microorganisms on the straw surface, thereby increasing the degradation rate of cellulose and hemicellulose; it can significantly increase the surface area of ​​the straw while avoiding the problems of local compaction and reduced aeration after burial due to excessively short straw, or insufficient burial due to excessively long straw. This invention has no special requirements for the source of straw; all crop straws are applicable, such as corn straw, wheat straw, oat straw, and rice straw.

[0021] This invention involves applying a composting agent to the surface of straw. The composting agent of this invention includes at least one of the following: Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum. This invention selects Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum, utilizing the complementary advantages of bacteria and fungi in metabolic pathways and enzyme system structures to achieve a gradient decomposition of straw from easily degradable components to recalcitrant components. Among them, Bacillus rapidly initiates the initial decomposition process and enhances stress resistance; Trichoderma harzianum strengthens the degradation of lignin and hemicellulose through hyphal penetration; and yeast regulates the microecological environment and promotes community stability, forming a multi-enzyme synergy and ecological interaction mechanism, thereby significantly improving straw decomposition efficiency and improving soil microecological structure. The effective viable bacteria count in the composting agent of this invention is any value within the range of ≥200 million CFU / g, or any value within the range of ≥200 million CFU / mL. As a preferred embodiment, the dosage form of the composting agent of this invention includes: powder and / or liquid formulation. In specific embodiments of the present invention, the composting agent can be Bacillus subtilis; the composting agent can be Bacillus subtilis and Bacillus licheniformis; the composting agent can be Bacillus subtilis and yeast; the composting agent can also be Bacillus subtilis and Trichoderma harzianum. The present invention expands from a single decomposition function to a multifunctional synergistic system through the design of combinations of different microbial species. Combinations between bacteria can enhance enzyme activity and temperature adaptability; combinations of bacteria and yeast can optimize the metabolic environment and community stability; combinations of bacteria and fungi can achieve spatial stratification degradation and improved deep decomposition capabilities. Different combinations can be selected according to environmental conditions, straw type, and cost requirements, exhibiting strong flexibility and applicability. As a preferred embodiment, selection is based on environmental conditions: when the ambient temperature is 10~20℃, which is a relatively low temperature condition, the microbial metabolic activity is low; in this case, a combination of Bacillus subtilis and Bacillus licheniformis is preferred. Bacillus subtilis exhibits strong stress resistance and environmental adaptability, maintaining high enzyme activity even at low temperatures to promote the initial decomposition of cellulose and hemicellulose in straw, thus ensuring the stable progress of straw decomposition. As a preferred embodiment, when the ambient temperature is 20-30℃, which falls within the suitable temperature range for microbial growth, a compound inoculant of Bacillus subtilis and yeast can be used. Yeast produces various organic acids and growth factors during its metabolism, providing a favorable metabolic environment for bacteria and promoting microbial community stability, thereby improving straw decomposition efficiency. As another preferred embodiment, when the ambient temperature exceeds 30℃ or under high-temperature conditions such as straw composting, a compound inoculant of Bacillus subtilis and Trichoderma harzianum can be used. Trichoderma harzianum possesses strong cellulase and lignin degradation capabilities, enabling deep degradation of straw at higher temperatures, thereby increasing the straw maturation rate and promoting humus formation.As another preferred embodiment, the choice depends on the type of straw: For high-fiber straw, such as corn and wheat straw, which have high cellulose and hemicellulose content, a bacterial + fungal combination should be selected, preferably a compound inoculant of Bacillus subtilis and Trichoderma harzianum. This combination can form a synergistic system of "primary bacterial degradation - deep fungal decomposition," improving the efficiency of straw structure breaking. As another preferred embodiment, for medium-fiber straw, such as soybean straw, a compound inoculant of Bacillus subtilis and Bacillus licheniformis is preferred. This combination can rapidly secrete various enzymes, increasing the straw decomposition rate and exhibiting good environmental adaptability. As another preferred embodiment, for easily degradable straw, such as rapeseed straw, a bacterial + yeast system (a compound inoculant of Bacillus subtilis and yeast) is preferred, promoting rapid decomposition by improving metabolic activity and community stability. During straw return to the field, the application rate of the inoculant can be adjusted appropriately according to the amount of straw and agricultural production costs. The application rate of the decomposition agent described in this invention can be 10-20 kg / hm². 2 Any value within the range, such as 10, 11, 12, 15, 18, or 20 kg / hm. 2 Or 10~20L / hm 2 Any value within the range, such as 10, 11, 12, 15, 18, or 20 L / hm. 2 The amount of farmland straw returned to the field as described in this invention can be 4.5~7.5 t / hm. 2 (Approximately 300-500 kg / mu), the application rate of the composting agent to the mass ratio of straw is 1:300-1:700 (mass ratio), preferably 1:400-1:500. Field trials have verified that when the application rate of the composting agent is less than 10 kg / hm²... 2 When the amount of functional bacteria colonizing the straw surface is insufficient, the straw decomposition rate does not increase significantly; when the application rate is higher than 20 kg / hm 2 However, the improvement in decomposition effect is limited, and it increases production costs. As a preferred embodiment, the application rate of the composting agent in this invention is 15 kg / hm². 2 Or 15L / hm 2 (Undiluted), the corresponding straw return rate is 6~7.5 t / hm. 2 (Approximately 400-500 kg / mu). This dosage achieves the optimal balance between decomposition efficiency and economic benefits. The decomposing agent described in this invention can be in powder or liquid form; the powder can be applied by direct scattering; the liquid can be diluted with water before spraying, with 1 kg of liquid diluted with 5-10 kg of water. This invention can also determine whether water needs to be added based on the moisture content of the straw; the moisture content of the straw (after adding water) should be maintained between 55% and 65%.

[0022] This invention involves burying straw with a composting agent back into the field. The burying depth can be any value within the range of 10-30 cm, for example, 10, 15, 20, 25, or 30 cm. This burying depth is located at the boundary between the topsoil and the plow pan, effectively preventing straw from being exposed to the surface, causing water loss and low temperature inhibiting microbial activity, while also preventing it from entering the deep soil and causing anaerobic decomposition. This provides a suitable temperature, humidity, and aeration environment for aerobic functional bacteria, significantly improving straw decomposition efficiency. As a preferred embodiment, the straw is crushed after the autumn harvest, and the composting agent is spread on the surface of the straw before sowing in the following year, then buryed back into the field. The preferred time before sowing in the following year is from the time the soil thaws in the spring of the following year until before corn sowing; specifically, the preferred time is from late March to late April. When the soil thaws in the spring of the following year, from late March to late April, the temperature and soil conditions are suitable, and the activity of various microorganisms is high after the composting agent is applied, allowing the decomposition effect to be fully realized.

[0023] This invention provides the application of the above-mentioned method for improving straw decomposition rate in increasing soil humic acid and / or organic matter content. As a preferred embodiment, the organic matter includes at least one of the following: humic acid, fulvic acid, and humin. The method of this invention can significantly improve the straw decomposition rate, increase soil humic acid and organic matter content, and thus improve soil structure.

[0024] This invention provides the application of the above-mentioned method for improving straw decomposition rate in increasing corn yield. In a preferred embodiment, the corn includes dryland corn. The method of this invention increases corn yield by improving the straw decomposition rate, thereby increasing soil humic acid and organic matter content. The method of this invention has advantages such as simple operation, cost savings, and wide applicability, providing a scientific basis for improving the efficiency of farmland straw decomposition in dryland planting areas of Inner Mongolia.

[0025] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a method for improving the decomposition rate of straw provided by the present invention and its application, should not be construed as limiting the scope of protection of the present invention.

[0026] Information on the composting agents used in the following examples: Bacillus subtilis powder composting agent, produced by Henan Wobao Biotechnology Co., Ltd., product name is straw fermentation agent, product number is microbial fertilizer (2018) approval number (2848), specification is 1kg / bag, effective live bacteria content ≥200 million CFU / g.

[0027] Bacillus subtilis and Bacillus licheniformis powder composting agent, produced by Shandong Beijia Biotechnology Co., Ltd., product name is organic material composting agent, product number is microbial fertilizer (2018) approval number (2625), specification is 1kg / bag, effective live bacteria content ≥200 million CFU / g.

[0028] Bacillus subtilis and yeast liquid composting agent, produced by Junde Biotechnology Co., Ltd., product name is organic material fermentation agent, product number is microbial fertilizer (2014) approval number (1326), specification is 1L / bottle, effective live bacteria content ≥200 million CFU / g.

[0029] Bacillus subtilis and Trichoderma harzianum powder composting agent, produced by Luoyang Ouke Biotechnology Co., Ltd., product name is biological organic fertilizer fermentation agent, product number is microbial fertilizer (2020) approval number (8618), specification is 250g / bag, effective live bacteria content ≥200 million CFU / g.

[0030] Example 1 The amount of corn straw returned to the field is approximately 6 t / hm. 2 Crush the corn stalks into pieces approximately 6cm using a shredder, then evenly spread the composting agent onto the surface of the stalks at a rate of 15kg / hm². 2 (The application rate is calculated per unit land area, and the ratio of the composting agent to the corn stalk mass is 1:400); the composting agent is Bacillus subtilis powder. After spreading, use a tillage machine to fully plow and return the corn stalks to the field, with a straw return depth of approximately 28cm.

[0031] Example 2 The procedure was carried out in accordance with Example 1, except that the composting agent was replaced with Bacillus subtilis and Bacillus licheniformis powder composting agent.

[0032] Example 3 The procedure was carried out as described in Example 1, except that the composting agent was replaced with a liquid composting agent of Bacillus subtilis and yeast, and the application rate was 15 L / hm. 2 (The amount applied is calculated per unit land area.)

[0033] Example 4 The procedure was carried out in accordance with Example 1, except that the composting agent was replaced with Bacillus subtilis and Trichoderma harzianum powder composting agent.

[0034] Test Example 1 The experimental site is located in a cornfield in Xihaixin Village, Shulinzhao Town, Dalad Banner, Ordos City, Inner Mongolia Autonomous Region (40°29'2"N", 109°52'25"E). The terrain is flat and the soil fertility is uniform. The main soil type is alluvial soil, and the basic soil nutrient information is shown in Table 2.1. The experimental site belongs to the temperate continental monsoon climate zone, with abundant sunshine, distinct seasons, and an annual sunshine duration of 2716-3193 hours. The average annual temperature ranges from 5.30 to 8.70℃, with the highest temperature reaching 34.30℃ and the lowest temperature dropping to -21.20℃. The frost-free period is 135-150 days, and the average annual rainfall is approximately 190.00-400.00 mm, mainly concentrated in June to September. The average annual evaporation is 2506.30 mm. The soil nutrients ranged from pH 8.23 ​​to 8.60, SOC content from 3.20 to 7.70 g / kg, TN content from 0.12 to 0.34 g / kg, TP content from 0.25 to 0.35 g / kg, TK content from 13.87 to 16.23 g / kg, AP content from 15.19 to 26.93 mg / kg, and AK content from 72.21 to 145.42 mg / kg. The previous crop was maize, and the maize variety planted in the experiment was "Lihe No. 1".

[0035] (1) After the autumn harvest in 2022, the corn stalks were crushed and then spread with composting agent and returned to the field in the spring of 2023 (the first year) after the soil thawed and before the corn was sown.

[0036] Field trial treatments: On April 13, 2023, the fields were randomly divided into zones and treated according to the methods described in Examples 1-4. A control group was established by simply burying straw in the field without applying a composting agent. Example 1 was designated WB, Example 2 BJ, Example 3 JD, Example 4 OK, and the control group CK. The day after treatment, 'Lihe No. 1' maize was planted with a row spacing of 50cm and a plant spacing of 24cm, at a density of 5500-6500 plants per mu (approximately 0.067 hectares). The seed fertilizer consisted of 30kg of diammonium phosphate and 10kg of compound fertilizer per mu. At the small trumpet stage (when the maize had 6-8 fully expanded leaves), 40kg of urea per mu was applied as a top dressing. The maize was harvested on September 25, 2023.

[0037] Bag treatment: To simultaneously determine the straw decomposition effect, on April 13, 2023, topsoil (in-situ soil) was collected from different treatment zones in the field experiment. After natural air drying, it was sieved through a 2mm sieve for later use. Corn stalks with similar morphological characteristics were selected and uniformly cut into lengths of 5-8cm. 19.63g of the cut corn stalks were weighed and placed into a nylon mesh bag, mixed with approximately 5.48kg of sieved in-situ soil, and 0.20g of different decomposition agents were added to each bag (the mass of the decomposition agent was added at 1% of the dry weight of the straw). After thorough mixing, the mixture was placed into 300-mesh nylon mesh bags, with a total weight of 5.5kg, to obtain one nylon mesh bag for the experiment. Five treatment groups were established using the composting agents: Bacillus subtilis powder composting agent (WB) from Example 1, Bacillus subtilis and Bacillus licheniformis powder composting agent (BJ) from Example 2, Bacillus subtilis and yeast liquid composting agent (JD) from Example 3, and Bacillus subtilis and Trichoderma harzianum powder composting agent (OK) from Example 4. A blank control group (CK) was used without any inoculant. For each of the five treatment groups, nylon mesh bags were prepared at six sampling time points, with three replicates, resulting in a total of 90 nylon mesh bags. These bags were buried in the soil at a depth of 10-20 cm, with six bags buried at each burial point, completing the bag burial process.

[0038] (2) After the autumn harvest in 2023, the corn stalks were crushed and then spread with composting agent and returned to the field in the spring of 2024 (the second year) after the soil thawed and before the corn was sown.

[0039] Field trial treatment: On April 27, 2024, in each treatment zone of (1), the treatment was carried out again in the following year according to the methods of Examples 1 to 4. The blank control was still not treated with composting agent, but only straw was turned over and returned to the field. The remaining steps were carried out in the manner of (1). After the corn matured, the corn was harvested on October 7, 2024.

[0040] Burying treatment: In order to simultaneously measure the straw decomposition effect, topsoil (in-situ soil) was collected on April 27, 2024, from the different treatment zones in the field test. The remaining steps were carried out in the manner of (1).

[0041] I. Determining the degree of straw decomposition during the bagging treatment. At 30, 60, 90, 120, 150, and 180 days after bagging (six sampling time points), three nylon mesh bags were randomly selected from each treatment group. The mixture inside the bags was sieved to separate the straw residue from the soil sample. The straw residue was rinsed with deionized water to thoroughly remove surface dirt and other impurities. The washed straw residue was transferred to a constant temperature drying oven and dried continuously at 85℃ for 6 hours until constant weight was achieved. The mass of the straw residue was then obtained. By comparing the mass difference of the straw before and after bagging, the straw biomass loss rate (decomposition rate) was calculated using the following formula. The results are shown in Table 1. Figure 1 Meanwhile, soil samples obtained by sieving 180 days after burying the soil bags were used to determine the humus content using the sodium pyrophosphate-sodium hydroxide extraction method for potassium dichromate oxidation capacity (referring to the Ministry of Agriculture and Rural Affairs NY / T 1867-2010 "Determination of Soil Humus Composition - Sodium Pyrophosphate-Sodium Hydroxide Extraction Method for Potassium Dichromate Oxidation Capacity"). The results are shown in Table 2. Figure 2 and Figure 3 .

[0042] Straw biomass loss rate (%) = (mass of corn straw - mass of straw residue) / mass of corn straw × 100%.

[0043] Table 1. Effects of different composting agents on straw biomass loss rate (%)

[0044] From Table 1 and Figure 1 As shown in Figure a, in 2023 (the first year), the straw biomass loss rate of all treatment groups reached over 40% 30 days after bagging, which was higher than the control (CK), but the difference was not statistically significant. At 90 days, the treatment groups applying the composting agent showed a significant increase of 3.74–5.48 percentage points compared to the CK. At 120 days, the treatment groups applying the composting agent showed a significant increase of 3.07–5.93 percentage points compared to the CK. At 180 days, the weight loss rates of WB, BJ, JD, and OK reached 78.69%, 79.39%, 77.72%, and 76.67%, respectively, which were significantly higher than the CK, increasing by 3.62, 4.31, 2.65, and 1.60 percentage points, respectively.

[0045] From Table 1 and Figure 1 As shown in b, in 2024 (the second year), the straw biomass loss rate of all treatment groups reached over 40% 30 days after bagging. The treatment groups applying the composting agent showed a higher rate than the control (CK), but there was no significant difference. P>0.05). At 90 days, the straw biomass loss rate in all treatment groups was higher than that in the control (CK). WB, BJ, JD, and OK showed increases of 0.03, 0.04, 0.03, and 0.03 percentage points compared to CK, respectively, but none reached statistical significance. At 120 days, the straw biomass loss rate in all treatment groups reached over 70%. The application of composting agents increased the rate by 2.72–7.25 percentage points compared to CK, with BJ showing a statistically significant increase compared to CK. P <0.05). At 180 days, the levels in each treatment group were significantly higher than those in the control group, increasing by 4.7, 5.54, 2.52, and 4.00 percentage points, respectively.

[0046] Analysis of data on straw biomass weight loss rate (decomposition rate) in 2023 and 2024 shows that the decomposition effect of different composting agents on straw has commonalities, and the straw biomass weight loss rate shows a trend of being fast at first and then slowing down.

[0047] Table 2. Effects of straw return to the field combined with the application of composting agents on soil humus content (g / kg)

[0048] From Table 2 and Figure 2 It can be seen that in 2023 (the first year), the application of straw returning to the field combined with the application of a composting agent significantly increased the content of soil humus. Among them, the humic acid content in the soil of each treatment group was significantly higher than that of the control (CK). The highest humic acid content in the WB and BJ soils was 2.63 g / kg and 2.66 g / kg, respectively, which were 29.77% and 31.56% higher than that of the blank control. P <0.05). The soil fulvic acid content in each group showed the order BJ > WB > OK > JD > CK. The soil fulvic acid content in each treatment group was significantly different from that in CK. BJ, WB, OK, and JD were 60.87%, 64.07%, 50.25%, and 53.89% higher than CK, respectively. P <0.05, indicating no significant difference among the treatment groups ( P >0.05). The humin content in the soil of each treatment group was significantly higher than that of the control group (CK). P <0.05%, with the highest humin content in BJ soil at 5.28 g / kg, significantly higher than other treatment groups ( P <0.05%, an increase of 23.75% compared to CK ( P <0.05, but did not reach a significant difference with WB ( P >0.05).

[0049] From Table 2 and Figure 3 It can be seen that the humic acid content in the soil in 2024 (the second year) increased compared to the first year, with JD showing the largest increase of 17.48%. In 2024, the humic acid content in the soil of all treatments was significantly higher than that of the control (CK).P <0.05%, with the highest humic acid content in WB and BJ soils, both at 2.73 g / kg, significantly higher than the CK (). P <0.05, which was 27.85% higher than CK, but no significant difference was found in other treatment groups ( P >0.05). The soil fulvic acid content showed the order BJ > WB > OK > JD > CK, with each treatment showing a significant difference from the CK. BJ, WB, OK, and JD were 55.88%, 69.07%, 47.78%, and 51.77% higher than the CK, respectively. P <0.05, but there was no significant difference among the treatment groups (P>0.05), and the levels of humin in the soil increased by 9.58%, 16.53%, 11.23%, 11.53%, and 13.09% respectively compared with 2023. The humin content in the soil of each treatment was significantly higher than that of the control (CK). P <0.05), the humin content in soils of WB, BJ, JD and OK increased by 20.71%, 23.08%, 17.16% and 16.57% respectively compared with CK, but there was no significant difference among the treatment groups (P>0.05), and the humin content in soils of all treatments increased compared with 2023.

[0050] Based on two years of data, it can be seen that returning straw to the field in combination with the application of composting agents can increase the soil humus content, and the soil humus content increases with the increase of planting years. WB and BJ can significantly increase the soil humus content.

[0051] II. Determining the soil conditions during field trials The organic matter content of soil in different soil layers (0-10cm, 10-20cm, 20-40cm, and 40-60cm) in the experimental plots was measured before corn sowing and after harvest using the potassium dichromate titration method-dilution heat method. The results are shown in Table 3 and 40-60cm. Figures 4-7 .

[0052] Table 3. Effects of straw return to the field combined with the application of composting agents on soil organic matter content (g / kg)

[0053] From Table 3 and Figures 4-7 It can be seen that, before sowing in 2023, the soil organic matter content in the 0-10cm soil layer was the highest in CK (12.88 g / kg), and the lowest in JD (12.64 g / kg), with no significant difference among the treatment groups. P >0.05). In the 10-20cm soil layer, the soil organic matter content was highest in the BJ treatment group (12.57 g / kg) and lowest in the OK treatment group. In the 20-40cm soil layer, the soil organic matter content in the WB treatment group was higher than that in the CK treatment group, but there was no significant difference between the treatment groups. P>0.05). In the 40-60cm soil layer, except for JD, the soil organic matter content in all treatment groups was higher than that in the control (CK), but there was no significant difference among the treatment groups. P >0.05). After harvest, the soil organic matter content in the 0-10cm soil layer of each treatment group increased compared to the control (CK), with WB and BJ showing significant increases of 5.15% and 11.04% respectively compared to CK. P <0.05); In the 10~20cm soil layer, the soil organic matter content decreased by 1.48% except for OK, while it increased in all other treatment groups compared to CK, with BJ showing a significant increase of 16.31% ( P <0.05); the soil organic matter content in the 20-40cm soil layer increased compared with the control group, with WB, BJ and JD showing significant increases of 28.48%, 43.34% and 26.17% respectively compared with the control group. P <0.05); the soil organic matter content in the 40-60cm soil layer increased compared to the control (CK), with WB, BJ, and JD showing significant increases of 20.02%, 32.03%, and 18.02% respectively compared to the CK. P <0.05).

[0054] Before sowing in 2024, the organic matter content in the 0-10cm soil layer of each treatment increased by 1.97% to 9.87% compared with the control (CK). Among them, the organic matter content of WB and BJ soils showed significant differences compared with the control (CK). P <0.05); the soil organic matter content in the 10-20cm soil layer increased by 2.88%-11.52% compared with CK, and the changes in soil organic matter in WB, BJ, and JD were all significantly different from those in CK. P <0.05); In the 20-40cm soil layer, the soil organic matter content in each treatment group increased significantly by 22.40%-30.62% compared with the control group, with the highest soil organic matter content in BJ (11.14 g / kg), which was significantly lower than that in other treatment groups (P<0.05); In the 40-60cm soil layer, the soil organic matter content in each treatment group increased by 15.17%-35.39% compared with the control group, and the changes in soil organic matter in WB, BJ, and JD were all significantly different from those in the control group (P<0.05). P <0.05. After harvest, the soil organic matter content in the 0-10cm soil layer of each treatment group increased by 6.56% to 28.71% compared to the control (CK). The changes in soil organic matter content in WB, BJ, and OK were all significantly different from those in the control (CK). P <0.05); the soil organic matter content in the 10-20cm soil layer increased by 5.13%-25.66% compared with CK, and the changes in soil organic matter in WB, BJ and CK reached a significant difference ( P<0.05); In the 20-40cm soil layer, soil organic matter increased by 5.10%-29.32% compared to the control (CK), with WB, BJ, and JD showing significant differences in soil organic matter compared to CK (P<0.05). In the 40-60cm soil layer, soil organic matter decreased compared to CK, with WB, BJ, and JD showing significant decreases of 15.55%, 27.05%, and 7.44%, respectively. P <0.05).

[0055] In 2023, soil organic matter content in the 0-60cm soil layer increased after harvest compared to before sowing when composting agents were applied. Post-harvest, the organic matter content of WB and BJ soils was significantly higher than the control (CK) by 2.97%–28.48% and 11.04%–42.34%, respectively. In 2024, soil organic matter increased with the number of planting years. After harvest in the 0-60cm soil layer, soil organic matter content increased compared to before sowing. Post-harvest, the organic matter content of WB and BJ soils was significantly higher than the control (CK) by 11.98%–26.77% and 25.66%–29.32%, respectively. Based on the data from these two years, it can be seen that soil organic matter decreases with increasing soil depth. WB and BJ can effectively increase soil organic matter, and straw return combined with composting agents has a significant impact on soil organic matter in the 20-60cm soil layer.

[0056] III. Measurement of maize growth in field trials At maize harvest, three survey points were randomly selected within each experimental plot for each treatment. A 5m long section of double-row maize was selected at each survey point, and the number of maize plants and ears was recorded. The total number of ears and plants per hectare was calculated using the number of plants and ears within the 5m double row. Twenty ears of maize were harvested from this plot, and the total grain weight and 100-grain weight of the 20 ears were measured. The grain moisture content was also measured, and the grain weight per ear was calculated using the total grain weight of the 20 ears. Grain yield was calculated by adjusting for a threshing coefficient of 0.85 and a standard 14% moisture content of 0.86. Five maize plants were taken from each quadrat, dried, and the average dry weight per plant was calculated. Biomass yield was calculated using the dry weight per plant and the total number of plants. The results are shown in Table 4. The specific yield formula is as follows: Grain weight per ear = (Total weight of 20 ears - Total axial weight of 20 ears) / 20; Grain yield = (Total number of ears × Number of grains per ear × Weight of 100 grains × 0.85 × (1 - Moisture content)) / 0.86; (Note: The unit for total ear count is ears / mu, which needs to be converted to ears / hm when calculating.) 2 Multiply by a coefficient of 15; the weight of 100 grains is in grams, which needs to be converted to kilograms and divided by a coefficient of 1000. Biological yield = Total weight per plant × Total number of plants; Harvest index = grain yield / biomass yield.

[0057] Table 4. Effects of straw return to the field combined with application of composting agents on maize yield.

[0058] Table 4 shows that the application of different composting agents over the two years had a certain impact on the total number of ears, grain weight per ear, number of grains per ear, 100-grain weight, grain yield, biomass yield, and harvest index of maize. In 2023, the total number of ears was BJ > JD > WB > OK > CK. BJ and JD had the highest number of ears (5237.19 / mu and 5187.78 / mu), significantly higher than CK, increasing by 24.71% and 23.53% respectively (P<0.05). The grain weight per ear ranged from 165.80 to 204.20 g. JD had a significantly lower grain weight per ear than CK, decreasing by 16.39% (P<0.05), while there were no significant differences among the other treatments (P<0.05). The number of grains per ear ranged from 504.00 to 808.33 in each treatment. The number of grains per ear in the JD treatment was significantly lower than that in the control (CK), decreasing by 37.65% (P<0.05). There were no significant differences among the other treatments (P<0.05). At harvest, the weight of 100 maize kernels was in the order WB > BJ > CK > JD > OK. JD and OK were lower than CK, but the difference was not statistically significant (P<0.05). The study of the effects of different inoculant treatments on maize yield revealed that the grain yield and biomass yield were in the order WB > BJ > JD > OK > CK. WB was significantly higher than CK, increasing by 11.81% and 9.08%, respectively.

[0059] In 2024, the total number of ears was CK > OK > BJ, JD > WB, with WB having the fewest ears at 4187.04 per mu, significantly lower than CK by 17.65% (P<0.05). The grain weight per ear ranged from 201.12g to 266.21g. WB's grain weight per ear was significantly higher than OK and CK, increasing by 32.36% and 25.86% respectively (P<0.05), while there were no significant differences among other treatment groups (P<0.05). The number of grains per ear ranged from 567.8 to 708.6, with BJ having a significantly higher number of grains per ear than CK, increasing by 24.80% (P<0.05), while there were no significant differences among other treatment groups (P<0.05). At harvest, the 100-kernel weight of maize was WB > OK > CK > JD > BJ, with BJ and JD being lower than CK, but the difference was not statistically significant (P < 0.05). The study of the effects of different inoculants on maize yield found that the kernel yield was WB > OK > BJ > JD > CK, with WB, BJ, and OK significantly higher than CK, increasing by 10.34%, 7.64%, and 9.01%, respectively. P<0.05). The harvest index of each treatment group, from largest to smallest, was BJ > WB > OK > JD > CK. The differences in maize yield among different treatments were mainly due to the increased grain weight and number of grains per ear.

[0060] In summary, applying different composting agents to the Ordos region along the southern bank of the Yellow River can accelerate straw decomposition, increase soil humus content, and improve soil organic matter content, thereby increasing maize yield. Studies show that under straw return conditions, the WB and BJ treatments significantly increased straw decomposition rate and soil nutrient capacity compared to other treatments, and also achieved a significant increase in maize yield.

[0061] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for improving the decomposition rate of straw, characterized in that, Includes the following steps: Spread the composting agent on the surface of the straw and then plow it into the field; The composting agent includes at least one of the following: Bacillus subtilis, Bacillus licheniformis, yeast, and Trichoderma harzianum; the content of effective viable bacteria in the composting agent is ≥200 million CFU / g or ≥200 million CFU / mL.

2. The method according to claim 1, characterized in that, The application rate of the composting agent is 10-20 kg / hm². 2 Or 10~20L / hm 2 .

3. The method according to claim 2, characterized in that, The formulation of the composting agent includes: powder and / or liquid.

4. The method according to claim 1, characterized in that, The length of the straw is 5-8 cm.

5. The method according to claim 4, characterized in that, The straw includes: corn straw.

6. The method according to claim 1, characterized in that, The depth of the plowing and returning to the field is 10-30cm.

7. The application of the method for increasing straw decomposition rate according to any one of claims 1 to 6 in increasing soil humic acid and / or organic matter content.

8. The application according to claim 7, characterized in that, The organic matter includes at least one of the following: humic acid, fulvic acid, and humin.

9. The application of the method for increasing straw decomposition rate according to any one of claims 1 to 6 in increasing corn yield.

10. The application according to claim 9, characterized in that, The corn mentioned includes: dryland corn.

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