A method for improving the soil in the moist soil area by optimizing cultivation and cooperating with organic material and returning to field

Abstract

This invention belongs to the field of soil improvement technology, and relates to a method for optimizing tillage and synergistically returning organic materials to the field to improve soil fertility in alluvial soil areas. The method includes: performing shallow tillage after each crop harvest, and adding a deep tillage operation every one-year crop rotation; crushing crop straw and mixing it with organic fertilizer and biochar, adding compound microbial agents, adjusting the carbon-nitrogen ratio, and composting to obtain decomposed organic material; returning the decomposed organic material to the field in two stages, with a total dry matter return rate of 7-8 t / hectare; the first stage involves uniform mixing with the sub-cultivated soil during deep tillage, and the second stage involves uniform mixing with the topsoil during shallow tillage; irrigating when the soil moisture content is <18%, and covering the surface with straw after the autumn harvest. This invention effectively improves the physical structure of alluvial soil, increases soil organic carbon and nutrient reserves, solves the problem of nitrogen competition during the seedling stage from direct straw return, and achieves reduced fertilizer use and increased crop yield by breaking up the plow pan through deep and shallow tillage rotation combined with the layered return of pre-composted organic materials.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology and relates to a method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas. Background Technology

[0002] The Huang-Huai-Hai Plain is a core production area for wheat and corn. The region's arable land is mainly composed of alluvial soil, which is deep and highly arable. However, the region has long suffered from high-intensity year-round continuous cropping, excessive use of chemical fertilizers, and a single and rigid agricultural machinery operation mode. In addition, farmers have followed the traditional farming habits of shallow rotary tillage and extensive topsoil return of straw for many years, which has led to the continuous degradation of alluvial soil and seriously restricted the improvement of soil fertility and the stable increase of grain production.

[0003] Shallow rotary tillage only disturbs the surface soil and cannot break down the deep, compacted structure. Years of mechanical compaction lead to surface soil hardening, forming a dense plow pan 8-10 cm thick with extremely high bulk density. This reduces porosity, continuously diminishes the soil's water and fertilizer retention capacity, and hinders deep root development, resulting in weaker lodging and drought resistance in later stages of crop growth and poor annual yield stability. Furthermore, constant shallow disturbance accelerates the loss of organic carbon mineralization from the surface soil, leading to a decline in soil fertility—a phenomenon where the land becomes increasingly infertile with each planting—and a gradual decrease in basic soil fertility.

[0004] Regarding straw return to the field and soil fertilization, the current conventional production model of farmers simply crushes the harvested wheat and corn straw and returns it to the surface in a one-time shallow rotary tillage. This method is crude, lacks supporting measures, and has many technical problems: First, the single surface layer return of straw results in the straw being concentrated in the 0-15cm topsoil layer, which easily leads to soil erosion and seed suspension without moisture, causing problems such as missing seedlings, uneven emergence, etc. Second, fresh straw has a high carbon-to-nitrogen ratio. After direct return to the field, the microbial decomposition of straw will deplete a large amount of available nitrogen in the soil, leading to nitrogen deficiency and yellowing of crop seedlings and weak growth. To alleviate the problem of weak seedlings, farmers are forced to apply more chemical fertilizers, further aggravating the overuse of chemical fertilizers, nutrient loss, and farmland pollution. Third, the single straw return method has a simple material structure, which can only supplement a small amount of surface organic matter and cannot improve the properties of the sub-cultivated layer soil. The increase in soil organic carbon is extremely low, the fertilization cycle is long, and it is difficult to achieve the expansion of the arable land carbon pool and the continuous improvement of soil fertility.

[0005] In summary, existing tidal soil improvement and fertilization techniques generally suffer from core technical defects such as a single and rigid farming pattern, prominent obstacles in the topsoil structure, a single ratio of organic materials, concentrated fertilization layers, prominent contradictions in straw decomposition, slow improvement of soil fertility, and high dependence on chemical fertilizers. There is a lack of a simplified and efficient tidal soil improvement and fertilization technology system that is adapted to farmers' conventional farming habits, integrates topsoil optimization and reconstruction, multi-source organic material compounding and decomposition promotion, and stratified fertilization. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas, specifically comprising the following steps:

[0007] Step 1: After each crop harvest, perform shallow tillage of 12-15cm. Every year during crop rotation, before the shallow tillage, perform a full-area deep tillage operation with a depth of 28-32cm.

[0008] Preferably, the entire area is tilled using a moldboard plow, which turns the soil evenly, without any missed or repeated tilling, thoroughly turning and breaking up the compacted plow layer at the 18-32cm position, appropriately exchanging the upper and lower soil layers, maturing the deep subsoil, and constructing a two-layer gradient tillage structure of a 0-15cm loose and mature topsoil layer and a 15-32cm permeable and fertile subsoil layer.

[0009] Step 2: Collect crop straw from the field and crush it into 3-5cm pieces. Mix it evenly with organic fertilizer and biochar at a mass ratio of 5:3:1. Add 0.3% of the total mass of the above materials with compound microbial agent. Adjust the carbon-nitrogen ratio to (20-25):1 with slow-release urea. Add water to adjust the moisture content to 55-65%. Pile the straw for 8 days to decompose, turning it over every 3 days during this period. Maintain the fermentation temperature of the pile at 50-60℃ to complete the pre-decomposition and degradation of the straw, obtaining decomposed organic material and eliminating the problem of microbial denitrification during the seedling stage when straw is directly returned to the field.

[0010] Preferably, the crop straw is wheat straw and corn straw; the organic fertilizer is well-rotted sheep manure organic fertilizer; the compound microbial agent includes Bacillus subtilis and Trichoderma viride, with an effective viable count ≥ 2.0 × 10⁻⁶. 8 CFU / g.

[0011] Step 3: Return the decomposed organic material to the field in two stages, with a total dry matter return amount of 7-8 t / hectare. The first stage involves deep plowing and uniform mixing with the 15-32cm sub-cultivated soil layer, accounting for 60% of the total dry matter return amount. The second stage involves shallow plowing and uniform mixing with the 0-15cm topsoil layer, accounting for 40% of the total dry matter return amount. This achieves stratified storage of organic material in two layers and fertilization at different depths.

[0012] Step four: After returning the soil to the field and tilling, compact the soil to reduce moisture loss. When the soil moisture content in the 0-20cm layer is <18%, perform shallow irrigation to create moisture, with a single irrigation volume of 350-400m³. 3 / hectare, after the autumn harvest, cover the surface with straw, using 2t / hectare of straw to reduce soil moisture evaporation and loss of organic carbon surface mineralization.

[0013] The present invention has the following advantages:

[0014] (1) This invention reconstructs the farming model, breaks the bad habit of farmers using shallow rotary tillage all year round, and precisely breaks the bottom layer of the plow by deep and shallow plowing. Combined with the layered return of organic materials to the field, the organic materials are stored in the top and sub-layers, which prolongs the decomposition and retention period of organic carbon. Compared with the extensive top-layer return of farmers, it can achieve a steady increase in soil organic carbon, with a controllable increase and adaptability to the actual field conditions, effectively expanding the carbon pool of tidal soil farmland.

[0015] (2) The tillage mode of the present invention significantly improves the physical structure of the alluvial soil, greatly reduces the soil bulk density, increases the total porosity of the soil, alleviates the problems of compaction of the alluvial soil topsoil and poor water permeability and air permeability, breaks the root growth barrier, and provides a good soil environment for crop roots to grow deep and absorb water and fertilizer.

[0016] (3) The multi-source organic materials of the present invention can simultaneously increase the available nitrogen, phosphorus and potassium nutrients in the soil after pre-corrosion and layered application, continuously improve the basic soil fertility, optimize the soil nutrient structure, and ensure the balance of soil nutrient supply and demand under the condition of 20% reduction of chemical fertilizer, thereby reducing the input of chemical fertilizer and the leaching loss of farmland nutrients.

[0017] (4) This invention completely solves the production problems caused by farmers directly returning straw to the surface of the field, such as competition for nitrogen during the seedling stage, yellowing of seedlings, weak growth, and poor seedling quality. It stabilizes the growth of crop populations, significantly increases the annual grain yield of wheat and corn, achieves high-quality, stable and efficient production under the premise of reducing chemical fertilizer use, and takes into account both soil fertility cultivation and grain production capacity improvement.

[0018] (5) All the tillage, spreading and returning processes of this invention can be completed by farmers’ existing rotary tillers, deep plows and fertilizer spreaders. No new large-scale special equipment is required. The field operation process is integrated, adaptable to farmers’ traditional planting habits, with low transformation cost and strong replicability. It is suitable for large-scale field application in the Huang-Huai-Hai tidal soil. Detailed Implementation

[0019] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] Experimental plot: A typical alluvial soil wheat-corn year-round rotation farmland in the Huang-Huai-Hai Plain was selected as the experimental area. The experimental plot has flat terrain, good irrigation and drainage conditions, and suitable climatic conditions such as light and temperature for large-scale grain production. Before the experiment, the plot had long been using the traditional farming and management model of farmers, with a single 14cm shallow rotary tillage operation for many years. After the autumn harvest, corn stalks were simply crushed and returned to the field with shallow rotary tillage. No commercial organic fertilizer, biochar, or straw decomposition inoculants were applied throughout the process, and the fertilization, tillage, and straw return methods were fixed year after year.

[0022] Before the experiment, the physicochemical properties of the 0-20cm topsoil layer were measured: soil organic carbon 8.7 g / kg, soil bulk density 1.46 g / cm³. 3 The total soil porosity was 39.2%; available nitrogen was 65.2 mg / kg, available phosphorus was 15.1 mg / kg, and available potassium was 95.3 mg / kg. Under the traditional management model of farmers, the wheat yield was 9100 kg / hectare and the corn yield was 9300 kg / hectare. The plot exhibited typical alluvial soil degradation problems such as shallow topsoil, compacted plow pan, slow accumulation of soil organic matter, poor soil permeability, uneven seedling growth, and continuous depletion of soil fertility.

[0023] This embodiment employs the tillage optimization and organic material synergistic stratified return-to-field technology disclosed in this invention, which is fully adaptable to farmers' existing agricultural machinery and field planting habits. The specific and complete implementation steps are as follows:

[0024] Step one involves adopting an optimized tillage system of alternating shallow rotary tillage and deep plowing across the entire field, abandoning the traditional single shallow rotary tillage model used by farmers. After the first year's crop harvest, a conventional rotary tiller is used to perform a 14cm shallow and uniform shallow rotary tillage operation to level the field surface and break up the topsoil clods. After the second year's harvest, based on the shallow rotary tillage, a moldboard plow is used to perform a 30cm deep and uniform plowing operation across the entire field. Through mechanical turning, the compacted plow pan is thoroughly broken up, and the upper and lower soil layers are moderately turned over and exchanged, maturing the deep and compacted subsoil. This reconstructs a two-layer gradient tillage structure, consisting of a 0-15cm loose and matured topsoil layer and a 15-30cm permeable and fertile subsoil layer, thus opening up the vertical transport channels for soil water and fertilizer.

[0025] Step two: Crush the corn stalks to 3-5cm, then mix them with commercially decomposed sheep manure organic fertilizer and corn stalk-based biochar at a mass ratio of 5:3:1. Add 0.3% of the total mass of the above materials of a compound decomposition agent, which is a compound of Bacillus subtilis and Trichoderma viride, with an effective viable count ≥2.0×10⁻⁶. 8 The carbon-nitrogen ratio was adjusted to 22:1 with slow-release urea, and water was added to bring the overall moisture content to 60%. The compost was then placed in a sealed container for 8 days, and the compost was turned over every 3 days during the composting period to maintain the temperature of the compost at 50-60℃.

[0026] Step 3: Return the decomposed organic material to the field in two stages, with a total dry matter return amount of 7.5 t / hectare. The first stage involves deep plowing and uniform mixing with the 15-30 cm sub-cultivated soil layer, accounting for 60% of the total dry matter return amount, to achieve deep soil organic fertilization. The second stage involves shallow plowing and uniform mixing with the 14 cm topsoil layer, accounting for 40% of the total dry matter return amount, to achieve uniform fixation of organic material in both deep and shallow layers of the cultivated layer, completing differentiated stratified fertilization.

[0027] Step four: After tillage and returning the soil to the field, use a light roller compactor to moderately compact the entire field, compacting the loose soil layer and reducing water loss through large soil pores. When the moisture content of the 0-20cm soil layer is <18%, irrigate 380m³ of water. 3 / hectares.

[0028] The wheat-corn year-round rotation fertilization system reduces overall fertilizer application by 20% compared to farmers' conventional full-fertilization model, maintaining the same nitrogen, phosphorus, and potassium fertilizer ratio while only reducing the total amount of fertilizer. After the autumn harvest, short straw is retained and returned to the field as a mulch, with the straw application controlled at 2 tons per hectare. This effectively inhibits surface water evaporation, reduces the loss of surface soil organic carbon mineralization, and continuously conserves soil fertility. During the trial, field pest and weed control, sowing density, and field management all followed local unified standards to ensure consistent and controllable experimental conditions.

[0029] After applying this technical solution for two consecutive crop years, soil samples from the 0-20cm topsoil layer were collected, and annual crop yields were statistically analyzed. The results are as follows:

[0030] 1) Soil organic carbon content: After optimization and fertilization, the soil organic carbon content in the 0-20cm soil layer increased to 9.5g / kg, which is 9.2% higher than the traditional farming and returning to the field mode. The soil carbon sequestration capacity was significantly enhanced, the carbon pool of arable land steadily expanded, and the problem of soil fertility decline due to long-term continuous cropping of alluvial soil was effectively alleviated.

[0031] 2) Soil physical properties: After improvement, the soil bulk density decreased to 1.34 g / cm³. 3 Compared to farmers' conventional methods, it reduced by 0.12g / cm³. 3 The total porosity of the soil increased to 45.1%, effectively improving the soil compaction problem. The looseness, permeability and aeration of the soil were greatly improved, completely breaking down the barriers to root growth in the plow pan and providing an excellent soil environment for deep root development and water and fertilizer absorption.

[0032] 3) Soil available nutrient content: After soil improvement and fertilization, the available nitrogen content was 70.1 mg / kg, available phosphorus content was 16.4 mg / kg, and available potassium content was 101.0 mg / kg, which were 7.5%, 8.6%, and 6.0% higher than those of conventional methods used by farmers, respectively. The increase in each nutrient was significantly different, indicating a significant improvement in the soil's available nutrient supply capacity, enhanced soil fertility stability, and continuous improvement in basic soil fertility.

[0033] 4) Annual crop yield: Stable green production conditions with a 20% reduction in chemical fertilizer use can be achieved, with an average wheat yield of 10,280 kg / hectare and an average corn yield of 10,580 kg / hectare, representing increases of 13.0% and 13.8% respectively compared to the traditional farming model, achieving multiple synergistic benefits of improved farmland quality, reduced chemical fertilizer use, and high grain yield.

[0034] Example 2

[0035] Experimental plots: Adjacent alluvial wheat-corn rotation farmland in the same area was selected. The soil texture, climate conditions, planting system, and early management mode of the plots were the same as those in Example 1, and the soil fertility level was similar, providing good conditions for parallel comparison experiments.

[0036] Prior to the experiment, the plot had long been managed using traditional methods such as shallow rotary tillage, extensive topsoil straw return, and conventional full-scale fertilization. The basic soil parameters were as follows: soil organic carbon in the 0-20cm layer was 8.5g / kg, and soil bulk density was 1.45g / cm³. 3 The soil has a total porosity of 38.7%, and available nitrogen, phosphorus, and potassium are 63.5 mg / kg, 14.8 mg / kg, and 93.2 mg / kg, respectively. Under traditional farmer management practices, the average annual yield of wheat is 9050 kg / ha, and that of corn is 9250 kg / ha. The plot suffers from problems such as a shallow topsoil, poor permeability, low nutrient utilization, slow accumulation of organic matter, and limited ability to increase crop yield.

[0037] This embodiment strictly follows the standardized technical process of the present invention to carry out field operations. All process parameters, material ratios, and control standards are consistent with those of Embodiment 1. The difference from Embodiment 1 is that shallow tillage is 13cm, deep plowing is 29cm, and the total dry matter return to the field is 7.2t / hectare.

[0038] After applying the technology of this invention for two consecutive crop years, soil physicochemical properties were uniformly sampled and measured, and crop yields were statistically analyzed. The specific measured results are as follows:

[0039] 1) Soil organic carbon content: After improvement, the soil organic carbon content in the 0-20cm soil layer increased to 9.2g / kg, which is 8.2% higher than the traditional farming and returning to the field mode. The soil carbon pool storage has steadily increased, and the soil's carbon sequestration and fertilizer retention capacity has been continuously enhanced.

[0040] 2) Soil physical properties: After improvement, the soil bulk density decreased to 1.33 g / cm³. 3 The concentration decreased by 0.12 g / cm³ compared to the initial state. 3 The total porosity of the soil increased to 44.5%, effectively alleviating soil compaction, significantly improving soil permeability, and making the topsoil structure more suitable for crop root growth and water and fertilizer absorption.

[0041] 3) Soil available nutrient content: After fertilization, the available nitrogen in the soil was 67.4 mg / kg, available phosphorus was 15.8 mg / kg, and available potassium was 99.6 mg / kg, which were 6.1%, 6.8%, and 6.9% higher than the conventional farming method, respectively. The increase in each nutrient was distributed in a staggered and reasonable manner, the basic soil fertility was steadily improved, and the nutrient supply was more balanced and sustainable.

[0042] 4) Crop yield performance: Under the green cultivation conditions of reducing chemical fertilizer use by 20%, the average yield of wheat can reach 10,120 kg / ha and the average yield of corn can reach 10,410 kg / ha, which are 11.8% and 12.5% ​​higher than the traditional farming model, respectively. This achieves the technical effect of reducing fertilizer use without reducing yield, improving quality and increasing efficiency, and the technology has excellent adaptability and stability.

[0043] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas, characterized in that, Includes the following steps: Step 1: After the annual crop harvest, shallow tillage is carried out. For each year-round crop rotation, a deep tillage operation is added before the shallow tillage operation. Step 2: Crush the crop straw and mix it with organic fertilizer and biochar. Then add compound microbial agent, adjust the carbon-nitrogen ratio to (20-25):1, pile it up for decomposition, turn the pile regularly, and maintain the fermentation temperature of the pile at 50-60℃ to obtain decomposed organic material. Step 3: Return the decomposed organic material to the field in two stages, with a total dry matter return amount of 7-8 t / hectare. The first stage involves deep plowing and uniform mixing with the sub-cultivated soil, while the second stage involves shallow tillage and uniform mixing with the topsoil. Step 4: When the soil moisture content in the 0-20cm soil layer is <18%, irrigate with 350-400m³ of water. 3 / hectare, and cover the ground with straw after the autumn harvest.

2. The method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step one, the shallow turning depth is 12-15cm, and the deep turning depth is 28-32cm.

3. The method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step two, the mass ratio of straw, organic fertilizer, and biochar is 5:3:1, and the amount of compound microbial agent used is 0.3% of the total mass of straw, organic fertilizer, and biochar.

4. A method for optimizing tillage and synergistically returning organic matter to the field for soil improvement in alluvial soil areas according to claim 1 or 3, characterized in that, The crop straw is wheat straw and corn straw; the organic fertilizer is well-rotted sheep manure; the compound microbial agent includes Bacillus subtilis and Trichoderma viride, with an effective viable count ≥ 2.0 × 10⁻⁶. 8 CFU / g.

5. The method for optimizing tillage and synergistically returning organic matter to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step two, slow-release urea is used to adjust the carbon-nitrogen ratio to (20-25):

1.

6. The method for optimizing tillage and synergistically returning organic matter to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step two, the composting process takes 8 days, during which the compost pile is turned over every 3 days.

7. The method for optimizing tillage and synergistically returning organic materials to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step three, the amount of organic material used in the first composting accounts for 60% of the total dry matter returned to the field, and the amount of organic material used in the second composting accounts for 40% of the total dry matter returned to the field.

8. The method for optimizing tillage and synergistically returning organic matter to the field for soil improvement in alluvial soil areas according to claim 1, characterized in that, In step four, the straw usage is 2 tons per hectare.