Method for improving soda saline-alkali soil through high-magnification straw particles

Abstract

The invention provides a method for improving soda saline-alkali soil through high-magnification straw particles, and belongs to the technical field of soil improvement. The method comprises the following steps that after straw particles are applied to the earth surface during soil preparation, the straw particles are mixed into a plough layer through rotary tillage, sowing and field management are conducted, and the returning amount of the straw particles is higher than that of conventional smashed straw. The straw particles have high volume density and stable spatial distribution characteristics, are beneficial to continuous activation of microorganisms under adverse conditions of high pH, low temperature and the like, accelerate straw decomposition and organic acid release processes, further effectively reduce soil alkalinity, relieve sodium ion toxicity and improve soil fertility. The method is easy and convenient to operate, adapts to existing agricultural machinery equipment and is suitable for efficient improvement of soda saline-alkali soil.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to a method for improving soda saline-alkali land by returning straw pellets to the field with a high amount of straw. Background Technology

[0002] Soda saline-alkali land is a type of alkalized soil mainly composed of sodium carbonate and sodium bicarbonate. Due to its strong alkalinity (pH 8.5-10.0) and high exchangeable sodium content, this soil becomes compacted, hinders crop emergence, and results in corn yields less than 60% of those in normal soils, becoming a core bottleneck restricting regional grain production capacity. Especially in cold regions, low temperatures further inhibit soil microbial activity, exacerbating the salinization problem.

[0003] Returning straw to the field is an important organic soil improvement measure, widely used in the improvement of saline-alkali land. Its basic principle lies in the release of organic acids during straw decomposition, which neutralize soil alkalinity and improve soil physicochemical properties. Current technologies mostly employ the method of directly returning crushed straw to the field, with a typical return rate of 10-15 t / hm². 2 However, in the high pH and low temperature environment of soda saline-alkali land, the crushed straw has a large volume and slow decomposition rate, resulting in low improvement efficiency.

[0004] Therefore, there is an urgent need for an improved method that can overcome the limitations of conventional straw return to the field and achieve efficient decomposition and continuous acid production in soda saline-alkali soil environments. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving soda saline-alkali land, which has high improvement efficiency.

[0006] This invention provides a method for improving soda-saline-alkali land with high-volume straw pellets, comprising the following steps: Straw pellets are applied to the surface during land preparation and then mixed into the topsoil through rotary tillage for sowing and field management. The amount of straw pellets returned to the field is higher than that of conventionally crushed straw.

[0007] Preferably, the amount of straw pellets returned to the field is 20-30 t / hm. 2 .

[0008] Preferably, the tillage layer is 0-20 cm.

[0009] Preferably, the climate of the region where the method is implemented is a cold temperate continental monsoon climate.

[0010] Preferably, the method for preparing straw pellets includes the following steps: crushing crop straw and then compressing and granulating it to obtain straw pellets; the volume of the straw pellets is reduced by more than 90% relative to the crushed straw.

[0011] Preferably, the straw pellets are cylindrical; the length of the straw pellets is 15-44 mm; and the cross-sectional diameter of the straw pellets is 10-15 mm.

[0012] Preferably, the soil pH of the 0-20 cm soil layer of the soda saline-alkali land is 8.8-9.2.

[0013] Preferably, the straw includes one or more of corn straw, wheat straw, and rice straw.

[0014] The present invention also provides the application of the method described above in the improvement of soda saline-alkali land.

[0015] Preferably, the improved soda saline-alkali land includes at least one of the following: 1) Neutralize or reduce soil alkalinity; 2) Relieve Na + Toxicity or reduction of exchangeable sodium content in soil; 3) Improve soil fertility.

[0016] This invention provides a method for improving soda-alkali land using high-volume straw pellets, comprising the following steps: applying straw pellets to the soil surface during land preparation, incorporating them into the topsoil through rotary tillage, followed by sowing and field management; the amount of straw pellets returned to the field is higher than that of conventionally crushed straw. This invention, by rotary tilling straw pellets into the topsoil during land preparation, accelerates the straw decomposition process and improves the efficiency of organic acid release. Furthermore, the high-volume straw pellet return increases soil organic carbon input, thereby increasing soil organic matter content and CEC, enhancing water and fertilizer retention capacity; and, through ion antagonism, increasing Ca2+. 2+ Mg 2+ Content, reduce Na + Toxicity. Furthermore, the organic acids produced from the decomposition of straw particles can effectively neutralize CO3 in the soil. 2- HCO3 - This method steadily lowers soil pH while preventing drastic fluctuations in soil ion concentration, thus ensuring safe crop growth. (See attached diagram.) To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A visual comparison chart showing the actual density of straw returned to the field in different forms (crushed / granulated) versus double the amount. Detailed Implementation

[0018] This invention provides a method for improving soda-alkali land with a high amount of straw pellets, comprising the following steps: applying straw pellets to the soil surface during land preparation, incorporating them into the topsoil through rotary tillage, and then sowing and field management; wherein the amount of straw pellets returned to the field is higher than that of conventionally crushed straw returned to the field. In one implementation method, the amount of straw pellets returned to the field is 20-30 t / hm. 2 Further to 30 t / hm 2 .

[0019] In one implementation, the tillage layer is 0-20 cm. In another implementation, the rotary tillage uses a conventional tractor-mounted rotary tiller, requiring no special equipment.

[0020] In one embodiment, the straw pellets are cylindrical in shape; the length of the straw pellets is 15-44 mm; and the cross-sectional diameter of the straw pellets is 10-15 mm.

[0021] In one implementation method, the climate of the region where the method is implemented is a cold temperate continental monsoon climate; the average annual temperature of the region where the method is implemented is 3.2℃; and the average annual precipitation of the region where the method is implemented is 450 mm.

[0022] In one implementation method, the method is implemented in the Heilongjiang region, which includes the Songnen Plain. The method of this invention is applicable to the cold regions of Northeast China and can efficiently improve soda-saline-alkali soils by accelerating the decomposition of straw particles.

[0023] In one implementation, the land preparation season is autumn, or more specifically, the autumn land preparation period; the sowing season is a suitable sowing season, or more specifically, spring; the sowing is mechanized sowing; and the field management is conventional field management.

[0024] As one implementation method, the method for preparing straw pellets includes the following steps: crushing crop straw and then compressing and granulating it to obtain straw pellets; the volume of the straw pellets is reduced by more than 90% relative to the crushed straw; the equipment used for crushing the straw includes a straw shredder; the equipment used for compressing and granulating includes a straw pelletizer, and further includes a ring die pelletizer.

[0025] In one embodiment, the soil pH of the 0-20 cm soil layer of the soda saline-alkali land is 8.8-9.2.

[0026] In one implementation, the straw includes one or more of corn straw, wheat straw, and rice straw; the straw includes straw harvested in the current year.

[0027] The present invention also provides the application of the method described above in the improvement of soda saline-alkali land.

[0028] As one implementation method, the improved soda saline-alkali land includes at least one of the following: 1) neutralizing or reducing soil alkalinity; 2) mitigating Na+ alkali content. + 3) Toxicity or reduction of soil exchangeable sodium content; The physical form of the crushed straw (large volume, small specific surface area) used in conventional straw crushing and returning to the field is not compatible with the extreme environment of soda saline-alkali land, resulting in insufficient microbial activation and low efficiency of decomposition and acid production, thus failing to achieve the synergistic improvement goal of "rapidly reducing alkali and improving fertility".

[0029] This invention utilizes straw pelleting (reducing volume by over 90%), overcoming the limitations of traditional straw crushing and returning to the field, and achieving a high-volume return of straw to the field. Furthermore, the high specific surface area of ​​the straw pellets promotes microbial accumulation, accelerates decomposition, and facilitates the timely release of organic acids, rapidly neutralizing soil alkalinity and alleviating sodium sulfide buildup. + The method significantly improves crop emergence rate by reducing toxicity; simultaneously, the high-volume input increases organic carbon supply, significantly improves the content of total nitrogen, phosphorus, and potassium, and available nutrients, increasing CEC by more than 10%, and enhancing water and fertilizer retention capacity; furthermore, the small size of straw pellets facilitates transportation and field operations, and the return process can be adapted to existing rotary tillage equipment without the need for additional equipment investment. Therefore, the method of this invention simultaneously achieves three major goals—"accelerated decomposition to produce acid and reduce alkali," "improved soil fertility," and "optimized microbial community"—through optimization of the physical morphology of straw pellets and high-volume input.

[0030] Terminology Explanation: 1. Soda saline-alkali soil: rich in sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3), with a pH value of 8.5~10.0, high exchangeable sodium content, and compacted alkaline soil, typically distributed in the Songnen Plain of Heilongjiang Province. 2. Straw pellets: Solid pellets formed by compressing and granulating crop straw, with a volume reduction of more than 90% compared to the original crushed straw. 3. High-volume straw return to the field: The amount of straw returned to the field exceeds the amount of straw produced in the current season. 4. Cation Exchange Capacity (CEC): Reflects the soil’s ability to adsorb and exchange cations, and is a core indicator for measuring the soil’s nutrient retention and buffering capacity. 5. Electrical conductivity (EC): An indicator that characterizes the concentration of ions in the soil solution and is used to determine whether there is a risk of soil salinization.

[0031] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a method for improving soda saline-alkali land with high-volume straw pellets, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0032] The experimental conditions for the embodiments and comparative examples of the present invention: 1) Climate data of the test site: cold temperate continental monsoon climate, with an average annual temperature of 3.2℃ and an average annual precipitation of 450 mm, which is consistent with the climate characteristics of the soda saline-alkali land in the Songnen Plain of Heilongjiang. 2) Target for improvement: Soda saline-alkali land (pH 8.8~9.2, 0~20 cm soil layer, rich in Na2CO3 and NaHCO3). Soil samples from the 0~20 cm soil layer of the soda saline-alkali land were tested, and the CO3 content in the water-soluble salts was measured. 2- The content is 0.031 g / kg, HCO3 - The content is 1.028 g / kg. This mainly corresponds to Na2CO3 and NaHCO3 in the soil. After conversion (or according to the conventional understanding in this field), the content of Na2CO3 in this soil layer is approximately 0.055 g / kg, and the content of NaHCO3 is approximately 1.415 g / kg.

[0033] 3) Effect testing process: (1) Test indicators: Soil physicochemical indicators (pH, total nitrogen / phosphorus / potassium, available nitrogen / phosphorus / potassium, organic matter, EC, CEC, water-soluble anions and cations). (2) Test methods: Soil pH was measured using a pH meter (soil-water ratio 2.5:1); total nitrogen was determined by the Kjeldahl method; total phosphorus was determined by the alkali fusion-molybdenum antimony resistance method; total potassium was determined by flame photometry; alkaline-solubilized nitrogen was determined by distillation-titration method; total phosphorus was determined by the alkali fusion-molybdenum antimony resistance method; total potassium was determined by flame photometry; organic matter was determined by the potassium dichromate external heating method; soil solution conductivity was determined by a conductivity meter; and Na was determined by flame photometry. + K + Ca 2+ Mg 2+ Content; CO3 determination by ion chromatography 2- HCO3 - Cl - SO4 2- Content; determination of cation exchange capacity using the sodium saturation method.

[0034] Example 1: High-volume straw pellet improvement of soda saline-alkali land Implementation process: 1. A typical soda saline-alkali land was selected as the test site, and the 0-20 cm soil layer was prepared.

[0035] Straw collection: Collect the straw after the corn is harvested in the current year; 2. Compressed pelleting: After crushing the straw using a straw shredder, straw pellets are prepared using a ring die pellet mill. The pellets are cylindrical in shape, with a length of 15-44 mm and a cross-sectional diameter of 10-15 mm. The volume is reduced by more than 90% compared to the crushed straw.

[0036] 3. During land preparation, straw pellets should be distributed at a rate of 30 t / hm². 2 The amount of fertilizer returned to the field is evenly applied to the surface and then mixed into the 0-20 cm tillage layer using a conventional tractor-mounted rotary tiller.

[0037] 4. Mechanized sowing in spring; 5. Routine field management.

[0038] 6. Effect test.

[0039] Comparative Example 1 Without returning straw to the field, the process was the same as in Example 1, and the effect was tested.

[0040] Comparative Example 2 Conventional straw crushing and returning to the field is adopted, with a straw crushing and returning rate of 10 t / hm². 2 The same procedure was followed as in Example 1, and the effect was tested.

[0041] The method in Comparative Example 2 has the following drawbacks: 1. Limited return rate: The large volume of crushed straw makes field operations difficult, and the return rate is usually limited to no more than 15 t / hm². 2 This cannot meet the demand for a large amount of organic carbon input for the rapid improvement of soda saline-alkali land. 2. Slow decomposition rate: The special environment of low temperature and high pH in soda saline-alkali soil results in a small specific surface area of ​​crushed straw, insufficient microbial enrichment, long decomposition cycle, and the release rate of organic acids is far from being able to neutralize the strong alkalinity of the soil in time. 3. Slow improvement effect: Insufficient supply of organic acids makes it impossible to quickly reduce soil alkalinity and alleviate Na+ deficiency. + It has limited toxicity and its effects on crop emergence rate and yield improvement are limited. 4. Insufficient nutrient supply: Under conventional straw return rates, the nitrogen, phosphorus, potassium, and other nutrients released by straw decomposition are limited, making it difficult to simultaneously improve soil fertility and salinization.

[0042] Comparative Example 3: Conventional application of straw pellets to improve soda-alkali land The straw pellets are returned to the field at a rate of 10 t / hm². 2 Except for the above, the rest is the same as in Example 1, and the effect test is performed.

[0043] A visual comparison of the actual field density of different forms (crushed / granulated) and double the amount of straw returned to the field in Examples 1, 2, and 3 is shown in the diagrams. Figure 1 .

[0044] Experimental Example 1 Each experimental treatment area was 78 m². 2(10 m long, 6 large ridges wide, ridge width 1.3 m), 5 replicates, using a completely randomized block design, with 1 m wide isolation strips between plots. At the time of the previous corn harvest, crushed straw (1 unit amount, according to the method of Comparative Example 2), straw pellets (1 unit amount, according to the method of Comparative Example 3), and straw pellets (3 units amount, according to the method of Example 1) were rotary tilled into the soil, with no straw returned to the field (according to the method of Comparative Example 1) as a control. Soil samples from the 0-20 soil layer were collected in each plot using the five-point sampling method before corn sowing, at the seedling stage (VE), jointing stage (V6), large trumpet stage (V12), grain-filling stage (R3), and maturity stage (R6).

[0045] The physical properties of soil samples, such as bulk density, porosity, and aggregate content, as well as pH value, electrical conductivity (EC), cation exchange capacity (CEC), and salt ion composition (Na₂O₃), were measured. + K + Ca 2+ Mg 2+ CO3 2- HCO3 - Physicochemical properties such as straw content, organic matter content, etc. were measured. Simultaneously, straw samples buried in the soil were periodically removed from the mesh bags to determine their residue rate and remaining nutrient content. The effects of different forms of straw on soil improvement were comprehensively evaluated, the relationship between straw return forms and amounts and various soil indicators was analyzed, and the regulatory mechanism of straw decomposition products on soil salinity migration and transformation was clarified.

[0046] The results are as follows: 1. Core performance data: In Example 1, under the high-volume straw pellet return treatment (KL3), the CO3 content of the topsoil was... 2- The content was reduced by 62.5% compared to the control (Comparative Example 1, without returning to the field), Ca 2+ Increased by 24.90%, Mg 2+ The yield increased by 39.73%, and the CEC increased by 11.41% (see Table 1 for details). The yields of CK (straw removal from the field), FS1 (conventional straw crushing and returning to the field), and KL3 (high-volume straw pellet returning to the field) were 605.6, 623.9, and 677.7 kg / mu, respectively. KL3 increased corn yield by 11.9% compared to CK and by 8.6% compared to conventional crushing and returning to the field, showing the best improvement effect. Here, FS represents the crushing form; KL represents the pellet form; 3 represents 3 times the amount (high-volume); and 1 represents 1 times the amount (conventional returning to the field).

[0047] Table 1 Comparison of soil alkalinity reduction and soil fertility improvement (Mean ± SE)

[0048] Preliminary observation of long-term effects: Monitoring over two consecutive years showed that the pH of the soil treated with KL3 remained stable at 8.9-9.0, with no rebound.

[0049] 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 saline-alkali soil with straw granules of high magnification, characterized in that, The method comprises the following steps: applying the straw particles to the ground surface during land preparation, mixing them into the plough layer by rotary tillage, sowing and field management; The amount of the straw particles returned to the field is higher than the amount of conventional pulverized straw returned to the field.

2. The method of claim 1, wherein, The amount of the straw particles returned to the field is 20-30 t / hm 2 .

3. The method of claim 1, wherein, The plough layer is the 0-20 cm plough layer.

4. The method of claim 1, wherein, The climate of the region where the method is implemented is the cold temperate continental monsoon climate.

5. The method of claim 1, wherein, The method for preparing the straw particles comprises the following steps: pulverizing the crop straw and then compressing and granulating to obtain the straw particles; the volume of the straw particles is reduced by more than 90% compared with the pulverized straw.

6. The method of claim 5, wherein, The straw particles are in the shape of a cylinder; the length of the straw particles is 15-44 mm; and the diameter of the cross section of the straw particles is 10-15 mm.

7. The method of claim 1, wherein, The soil pH of the 0-20 cm soil layer of the soda saline-alkali soil is 8.8-9.

2.

8. The method of claim 1, wherein, The straw comprises one or more of corn straw, wheat straw and rice straw.

9. The method according to any one of claims 1-8 for improving the soda saline-alkali soil.

10. Use according to claim 9, characterized in that, The improved soda saline-alkali soil comprises at least one of the following: 1) neutralizing or reducing the alkalinity of the soil; 2) alleviating Na + toxicity or reducing soil exchangeable sodium content; 3) improving the soil fertility.

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