Method for shallow turning and returning straws to field to obstruct salt and alkali and improve cultivated land soil

Abstract

Aiming at the problems of slow crop growth, low yield, limited improvement effect and the like existing in a traditional straw returning mode, the method comprises the following steps: constructing a 2-4cm salt-resistant layer at a position of 15-18cm by utilizing straws, loosening soil above the salt-resistant layer by using a rotary cultivator, cutting off soil capillary tubes, and improving the saline-alkali resistance of the soil. The defects of potential entropy loss, nutrient competition, different nutrient release rates and the like caused by straw rotting are avoided while the upward movement of salt below 20 cm is avoided, the germination and development of early corn seedlings cannot be directly influenced, the aggravation of soil salinization is blocked to the greatest extent by using a small amount of straw returning to the field, and the soil structure and fertility are improved. The method is simple to operate and easy to popularize, has good economic benefits and environmental benefits, and has great significance in improving the utilization rate of saline-alkali land and the agricultural production capacity.

Description

Technical Field

[0001] The invention relates to the technical field of saline-alkali farmland improvement, and in particular to a method for shallowly turning straw into fields to block salt and alkali and improve farmland soil. Background Art

[0002] Saline-alkali soils are widely found in arid and semi-arid regions around the world, severely restricting agricultural production in these regions. The saline-alkali land in the Songnen Plain accounts for 9.2% of the total saline-alkali land area in my country, making it one of the areas with the largest distribution of soda saline-alkali land in China. Although the soil physical and chemical properties of soda saline-alkali land are poor, and its water and air permeability are poor, its vast area, superior natural conditions (such as temperature and light), and high climate production potential make it a promising area for improvement and development.

[0003] The Songnen Plain is one of the three "golden corn belts" in the world, with vast arable land and abundant corn straw resources. As a rich agricultural waste resource, straw is rich in carbohydrates and cellulose, which has a certain improvement effect on the soil. Returning corn straw to the field can increase soil aeration, improve soil water holding capacity, and slow down the upward migration of salt. Moreover, during the decomposition process, straw can improve soil structure, promote the formation of soil aggregates, and provide physical protection for organic matter. The mineral nutrients contained in crops can be restored to the soil through returning straw to the field, thereby compensating for the nutrient absorption of crops, achieving soil improvement and yield increase, and slowing down the degradation of saline-alkali farmland.

[0004] Traditional methods for improving saline-alkali soil are mostly aimed at severely saline-alkali land where crops cannot grow, but there is a lack of effective methods for mildly saline-alkali or improved saline-alkali land. The yield of corn planted in farmland in these areas is mostly between 5-8t / hectare, and there is an urgent need for some targeted technologies that can improve soil and improve soil fertility. Straw is an ideal material for improving soil fertility, but these areas are low-lying, and the traditional method of returning straw to the field will cause the soil temperature to drop. There are also problems such as straw being difficult to degrade and uneven coverage, which limits its improvement effect. In addition, when straw rots on the soil surface, it will consume nutrients such as oxygen and nitrogen in the soil, and will also produce some toxic substances such as organic acids, which will cause these nutrients in the soil surface to be insufficient and have a toxic effect on the crop root system, affecting the normal growth and development of the crop in the early stage. The rotten straw covering the surface will also form a barrier layer, affecting the air permeability and water permeability of the soil, thereby causing hypoxia in the crop root system and affecting the crop's absorption of nutrients and water.

[0005] Based on the above, patent application CN 108513755 A discloses a method for improving salinized grassland using corn straw, which first spreads the straw on the surface of the salinized grassland, and then mixes the soil with the straw; after the straw decomposes in the second year, in the third year, the severely salinized grassland can be sown with highly salt-tolerant pioneer plants such as alkaligrass, the moderately and lightly salinized grassland can be planted with low salt-tolerant crops such as sheepgrass, and the lightly salinized grassland can be planted with high-yield forage grass such as alfalfa. This method utilizes the straw degradation process in the soil to improve the physical and chemical properties of the soil, increase soil organic matter, and restore salinized grassland vegetation on a large scale or carry out agricultural production, thereby achieving the purpose of improving salinized grassland. However, when this method is applied to arable land improvement, certain technical obstacles need to be overcome, including low soil organic matter content, which limits microbial activity and nutrient circulation, making it difficult for crops to obtain sufficient nutrition; arable land has a high demand for nutrients such as nitrogen and phosphorus, and the release of nutrients during straw decomposition needs to be controlled to avoid loss or insufficient supply; in addition, this method is a conventional rotary tillage operation, and since straw decay also requires water and nutrients, the straw will affect the growth of seedlings in the early stage when mixed with the soil above 15 cm, resulting in slow crop growth.

[0006] Patent application CN 115280927 A discloses a method for improving saline-alkali land with three layers of straw, which is to sow 15 to 20 cm thick crushed straw at a depth of 25 to 45 cm below the surface to form a straw layer; cover the surface with a layer of straw; the thickness of the straw cover is 8 to 12 cm; use a rotary tiller to mix and form a 15 to 25 cm thick mixed straw layer. The straw layer can inhibit excessive evaporation of water in the soil layer and has no blocking effect on the water flowing downward; the mixed straw layer, rotary tillage makes the soil loose, and the straw is mixed to make the soil fluffy, with many more pores, so that water can easily penetrate downward; the straw layer, 20 to 45 cm below the surface, input 15 to 20 cm, which is equivalent to digging a seepage ditch, and the straw layer is composed entirely of straw, which will not block water infiltration. Therefore, the stratum structure of this method can inhibit water evaporation, promote water infiltration downward, and prevent water below the tillage layer from infiltrating upward. However, this method has complicated operation process and requires a large amount of straw, which is not conducive to large-scale promotion and utilization. Summary of the invention

[0007] The invention provides a method for shallowly turning straw and returning it to the field to block salt and alkali and improve cultivated soil, so as to solve the problems of slow growth of crops in saline-alkali land, low yield and limited improvement effect caused by existing straw covering and deep turning of straw and returning it to the field. A straw salt barrier layer is constructed by shallowly turning the straw to block soil salt, and the straw in the salt barrier layer gradually rots, thereby fertilizing the soil and improving the soil structure, so as to achieve the purpose of increasing production and income and constructing a healthy farming layer for saline-alkali cultivated land.

[0008] To achieve its purpose, the present invention adopts the following technical solutions: A method for shallowly turning straw into fields to block salinity and improve cultivated soil, comprising the following steps: Step 1: Crush the straw: Use a straw crushing machine to crush the straw in the field into pieces of 4-5 cm in length; Step 2: Straw covering: Spread the crushed straw evenly on the saline-alkali farmland; Step 3: Shallow turning of straw: Use a tiller to turn the crushed straw to a soil depth of 15-18 cm, build a 2-4 cm salt barrier layer, and use a rotary machine to loosen the soil above the salt barrier layer; Step 4: Planting crops: The ridging machine rids the cultivated land and then plants crops, and applies organic fertilizer; Step 5. Field management: routine field management.

[0009] As a further preferred embodiment of the technical solution of the present invention, in step one, the straw is corn straw.

[0010] Furthermore, in step 2, the amount of crushed straw laid is 5 t / ha.

[0011] Furthermore, in step 4, the crop is corn; the compound fertilizer is compound fertilizer (14-16-15), and the application amount is 600 kg / hm 2 .

[0012] Furthermore, the field management includes irrigation, fertilization, spraying pesticides and weeding.

[0013] By adopting the above technical solution, the beneficial effects achieved by the present invention are as follows: 1. Significant effect on improving saline-alkali soil: The present invention adopts the technology of shallow turning and returning straw to the field, and forms a 2-4 cm straw salt-blocking layer at 15-18 cm in the saline-alkali farmland, which can directly cut off the soil capillaries between the surface and deep layers, effectively block the migration of saline-alkali ions to the surface soil, and reduce the soil salinity; at the same time, the shallow turning is only to 15-18 cm, and only the surface soil is disturbed, avoiding deep turning to turn the deep saline-alkali soil to the surface, aggravating the surface salinity; the rotting of straw in the salt-blocking layer can also increase soil nutrients, improve the soil environment, and avoid the phenomenon that straw covering and rotary tillage and returning to the field rot in the soil surface to produce toxic substances, compete with crops for water, and affect the rooting of crops, thereby increasing the crop yield of farmland.

[0014] 2. Wide application scope: The method of the present invention is applicable to various types of saline-alkali soils, including severe saline-alkali soils and general saline-alkali soils, and is also applicable to the planting of various cultivated crops, and has broad application prospects.

[0015] 3. Easy operation: The method of the present invention does not require complicated equipment and technology, but only conventional agricultural machinery and basic operating skills. The simple operation and process are suitable for farmers' actual production operations.

[0016] 4. Economical and efficient: The present invention utilizes crop straw as raw material for soil improvement, which reduces the cost of agricultural waste treatment, improves soil fertility, increases crop yields, and has good economic and environmental benefits.

[0017] In summary, the present invention proposes a new straw shallow turning and returning technology to the field in view of the shortcomings of the traditional straw returning method. The salinity of soda saline-alkali soil is higher below 20 cm, and the water permeability and air permeability are poor. Using straw to construct a 3 cm salt barrier layer at 15-18 cm can cut off the soil capillaries and prevent the upward movement of salt below 20 cm. At the same time, the potential entropy loss due to straw decay, the competition for nutrients and the different nutrient release rates will not directly affect the germination and development of early corn seedlings. Using less straw to return to the field can prevent the aggravation of soil salinization and improve soil structure and fertility to the greatest extent possible. The method of the present invention is not only simple to operate and easy to promote, but also has good economic and environmental benefits, and is of great significance for improving the utilization rate of saline-alkali land and agricultural production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a salt barrier layer constructed by shallow turning of straws according to the method of the present invention; Figure 2 This is a comparison chart of corn growth 3 months after no-tillage and shallow turning: the left picture is the straw shallow turning treatment; the right picture is the no-tillage treatment. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] The compound fertilizer (14-16-15) of the present invention was purchased from Shandong Lianmeng Phosphate Compound Fertilizer Co., Ltd.

[0021] The present invention provides a method for shallowly turning straw into fields to block salinity and improve farmland soil, and the implementation process is as follows: Step 1: Collect straw: Use a transport vehicle to collect straw from the farmland, and then use a crusher to crush the straw into a length of 4-5 cm; Step 2: Straw covering: Use a forklift to evenly spread the crushed straw on the saline-alkali farmland, with a spreading amount of 5 t / ha; Step 3: Shallow turning of straw: Use a tiller to turn the crushed straw to a soil depth of 18 cm, creating a 3 cm salt barrier layer ( Figure 1 ), the rotary machine loosens the soil above the salt barrier layer (more than 15cm); Step 4: Planting crops: Use a ridging machine to rid the land and then plant corn. Apply compound fertilizer (14-16-15) at a rate of 600 kg / hm2. 2 ; Step 5: Field management: carry out irrigation, fertilization, pesticide spraying and weeding management.

[0022] Application examples of the present invention are as follows: During the spring ploughing period of 2024, an experiment was conducted at the Changling Ecological Station of the Northeast Institute of Geography, Chinese Academy of Sciences, where six plots of 5×5 m 2 Since the area belongs to the soda saline-alkali land area, the soil heterogeneity is large. Therefore, the present invention only adopts the straw mulching no-tillage treatment commonly used in the area for control experiments.

[0023] During the experiment, small areas were randomly selected for corn straw shallow turning (5 t / ha) and corn straw mulching and no-tillage treatment (the amount of straw added was 5 t / ha, which was the same as the amount of corn straw shallow turning). The ridger was used to ridge the cultivated land and then plant corn. The corn variety used for tillage was Jinqing D1688. Figure 2 This is August 2024, when corn was in the tasting stage, showing the growth of corn after shallow turning (left) and the control group with straw covering and no-tillage treatment (right).

[0024] from Figure 2 It can be seen from the results that the corn leaves in the control group turned yellow, grew short and had a sparse density; after shallow turning of the straw, the corn grew strongly, had a higher relative density and had greener leaves. The comparison between the two shows that shallow turning of the straw has a significant effect in improving saline-alkali farmland.

[0025] At the corn harvest time in October 2024, the conductivity of the soil at 0-20 cm after shallow turning treatment using the method of the present invention was reduced from 360.15 μS / cm to 321.58 μS / cm relative to the no-tillage treatment, and the pH of the soil at 0-20 cm was reduced from 9.68 to 9.57 relative to the no-tillage treatment, and the soil salinity was significantly reduced; after shallow turning treatment, the organic matter at 0-20 cm in the soil increased from 6.32 g / kg in the no-tillage treatment to 12.74 g / kg, and the organic matter increased by 50%, with a significant fertile soil effect. In terms of yield, the corn yield of the straw no-tillage return to the field was 335 kg / mu, and the corn yield of the straw interlayer salt-reducing fertile soil technology was 355 kg / mu, and the yield was also significantly improved. Therefore, it can be seen from the aforementioned decrease in pH and conductivity and the significant increase in organic matter and yield that the straw shallow turning and returning to the field to block salt and alkali to improve soil technology of the present invention has a significant effect on reducing salt and fertile soil and increasing yield, and has great potential in increasing corn yield in saline-alkali farmland in the future, and has broad application prospects.

Claims

1. A method for shallowly turning straw into fields to block salinity and improve farmland soil, characterized in that: The following steps are involved: Step 1: Crush the straw: Use a straw crushing machine to crush the straw in the cultivated land into 4-5 cm in length; Step 2: Straw covering: Spread the crushed straw evenly on the saline-alkali farmland; Step 3: Shallow turning of straw: Use a tiller to turn the crushed straw to a soil depth of 15-18 cm, build a 2-4 cm salt barrier layer, and use a rotary machine to loosen the soil above the salt barrier layer; Step 4: Planting crops: The ridging machine rids the cultivated land and then plants crops, and applies compound fertilizer; Step 5. Field management: routine field management.

2. The method for shallow turning straw back into fields to block salinity and improve cultivated soil according to claim 1, characterized in that: In step 1, the straw is corn straw.

3. The method for shallow turning straw into fields to block salinity and improve cultivated soil according to claim 2, characterized in that: In step 2, the amount of crushed straw laid is 5 t / ha.

4. The method for returning straw to the field to block salt and alkali and improve arable soil according to claim 3, characterized in that: In step 4, the crop is corn.

5. A method for shallow turning straw into fields to block salinity and improve farmland soil according to any one of claims 1 to 4, characterized in that: In step 4, the compound fertilizer is compound fertilizer (14-16-15), and the application amount is 600 kg / hm 2 .

6. A method for shallow turning straw into fields to block salinity and improve farmland soil according to any one of claims 1 to 4, characterized in that: The field management includes fertilization, pesticide application and weeding.

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