Drop irrigation application method of solid-liquid organic fertilizer and chemical fertilizer in desert oasis area

Abstract

The invention relates to the technical field of farmland fertilization and water and fertilizer integration, and discloses a desert oasis area solid-liquid organic fertilizer and chemical fertilizer drip irrigation application method which comprises the following steps: firstly, mixing livestock and poultry manure with crop straws, adding charcoal and a compound microbial agent for aerobic composting, and preparing a biological enhanced solid organic fertilizer; the fertilizer is applied as a base fertilizer to improve soil; secondly, performing two-stage precision filtration on biogas slurry generated by anaerobic fermentation, and adding potassium fulvate into filtrate to prepare synergistic biogas slurry capable of being used for drip irrigation; finally, in the critical growth period of crops, the synergistic biogas slurry and chemical fertilizer are precisely dressed through a drip irrigation system. Through a solid-liquid combination and long-acting and quick-acting synergistic nutrient management mode, the technical problem of easy blockage caused by direct drip irrigation of biogas slurry is solved, the soil fertility, the structure and the biological activity are effectively improved, the crop yield and quality and the water and fertilizer utilization efficiency are improved, and efficient cyclic utilization of agricultural wastes is realized.

Description

Technical Field

[0001] This invention relates to the field of farmland fertilization and fertigation technology, specifically a method for drip irrigation of solid-liquid organic fertilizer and chemical fertilizer in desert oasis areas. Background Technology

[0002] In ecologically fragile regions such as desert oases, sustainable agricultural development faces the dual pressures of ensuring food security and protecting the ecological environment. These areas generally suffer from poor soil quality, low organic matter content, and poor water and fertilizer retention capacity. Traditional farming practices, which have long relied on chemical fertilizers, exacerbate the risks of soil compaction, fertility decline, and environmental pollution. Therefore, converting abundant local agricultural waste such as livestock manure and crop straw into organic fertilizer resources is a crucial path to improving soil health and achieving green and circular agricultural development.

[0003] Currently, aerobic composting is commonly used to treat solid organic waste such as livestock and poultry manure and crop straw. However, conventional natural composting processes are slow and uneven in their degree of decomposition, resulting in organic fertilizers that have limited effectiveness in improving soil structure and enhancing soil fertility, making it difficult to meet the needs of rapidly enriching barren soils.

[0004] Meanwhile, biogas slurry, a byproduct of anaerobic fermentation, is rich in readily available nutrients and bioactive substances, making it a high-quality liquid fertilizer. However, untreated biogas slurry contains a large number of suspended solid particles. If applied directly to drip irrigation or other fertigation systems, it will quickly and severely clog drippers, causing irrigation system failure and greatly limiting its application in modern precision agriculture. Even with simple filtration to solve the clogging problem, the nutrient utilization efficiency of biogas slurry is not optimal, and some readily available nutrients are still easily lost.

[0005] In summary, current technologies for agricultural waste utilization have failed to establish a comprehensive technical solution that effectively integrates the preparation of highly efficient solid organic fertilizer with the application of barrier-free liquid organic fertilizer. The lack of a synergistic application method that combines long-lasting soil-improving solid organic fertilizer with precise and efficient nutrient replenishment from liquid organic fertilizer, and ensures stable operation within an integrated water and fertilizer system, hinders the overall efficiency of agricultural waste resource utilization and the sustainable improvement of oasis agricultural productivity. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for drip irrigation application of solid-liquid organic fertilizer and chemical fertilizer in desert oasis areas. This method solves the problem that high-efficiency solid organic fertilizer and enhanced liquid organic fertilizer cannot be applied seamlessly and synergistically in an integrated water and fertilizer system to simultaneously achieve long-term soil improvement and precise crop nutrition.

[0007] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a method for drip irrigation application of solid-liquid organic fertilizer and chemical fertilizer in desert oasis areas, comprising the following steps: S1: Preparation and basal application of bio-enhanced solid organic fertilizer: Mix livestock and poultry manure with crop straw, add biochar and compound microbial inoculant accounting for 4.0%-6.0% of the total dry weight of the mixture, and perform composting treatment through a well-type ventilated aerobic composting process to obtain bio-enhanced solid organic fertilizer with a seed germination index of not less than 70%, an organic matter content of not less than 30%, and a moisture content of not more than 30%; Before crop sowing, apply the bio-enhanced solid organic fertilizer as basal fertilizer and use a rotary tiller to till it into a 20-40cm layer; S2: Preparation and application of enhanced biogas slurry: Livestock and poultry manure and straw are fermented in a continuous stirred constant temperature stainless steel anaerobic fermenter at a temperature of 30-38℃ to obtain biogas slurry; the biogas slurry is then filtered in two stages through a vibrating screen with a pore size of 250-300μm and a precision filter with a pore size of 70-80μm, and potassium humate is added to the filtrate to achieve a final concentration of 0.1%-0.5% (w / v) to obtain enhanced biogas slurry; S3: Integrated water and fertilizer management: During the critical growth period of crops, the enhanced biogas slurry and a portion of chemical fertilizer are applied in stages through the drip irrigation system as topdressing. The topdressing application process is carried out simultaneously with drip irrigation, and the total drip irrigation water volume of this method is reduced by 20%-30% compared with conventional irrigation methods.

[0008] The mechanism and innovation of this invention lie in the following: In step S1, the addition of biochar with a porous structure increases the aeration and water retention of the compost pile, providing a habitat for microorganisms; simultaneously, the inoculated compound microbial agent accelerates the decomposition of recalcitrant organic matter such as cellulose in the material. The synergistic effect of these two processes shortens the composting cycle, ensures the complete decomposition of organic materials, and forms a bio-enhanced solid organic fertilizer rich in organic matter and beneficial microorganisms. When incorporated into deep soil, it can provide slow-release nutrients for crops throughout their entire growth period and improve the physicochemical properties of deep soil.

[0009] In step S2, two-stage precision filtration effectively removes suspended particulate matter from the biogas slurry, solving the technical problem of drip irrigation emitter clogging. Based on this, potassium humate is added to the biogas slurry. Utilizing the chelating and complexing abilities of humic acid, some inorganic trace metal elements in the biogas slurry are converted into more bioavailable organic chelates, making the topdressing nutrients more comprehensive and easier for crops to absorb.

[0010] In step S3, solid slow-release base fertilizer is combined with liquid fast-acting topdressing, achieving a complementary supply of long-lasting and fast-acting nutrients. Integrated water and fertilizer application via drip irrigation delivers water and nutrients directly to the crop root zone, reducing water evaporation and nutrient volatilization and leaching.

[0011] Furthermore, in the preparation of the bio-enhanced solid organic fertilizer described in step S1, the fresh weight ratio of livestock and poultry manure to crop straw is 10:1 to 30:1. The inoculation amount of the compound microbial agent is 0.8-1.2L per ton of mixed materials, and its effective viable count (CFU) is 1.0 × 10⁻⁶. 9 -5.0×10 9 mL -1 The bacterial strains include heat-resistant cellulose-decomposing bacteria and Bacillus subtilis.

[0012] Furthermore, in the well-ventilated aerobic composting process described in step S1, the initial moisture content of the material is adjusted to 55%-65%, and the initial carbon-to-nitrogen ratio is 25:1-35:1. During fermentation, the compost temperature is maintained above 55°C for at least 14 days to inactivate pathogens, insect eggs, and weed seeds.

[0013] Furthermore, the biochar is prepared from corn stalks under oxygen-limited conditions, and the preparation process includes: at 5-15℃·min -1 The temperature is increased at a rate of 450-600℃ to the final pyrolysis temperature, and then kept at this temperature for 1-2 hours. After that, it is cooled to room temperature in a closed environment, and finally crushed and sieved.

[0014] Furthermore, the potassium humate is prepared from weathered coal, and the preparation process includes: alkaline extraction of weathered coal using potassium hydroxide solution at 60-80℃, acid precipitation of the extract to separate humic acid and fulvic acid, collection of the solution containing fulvic acid, and finally neutralization and drying.

[0015] Furthermore, in step S3, the topdressing is applied during the corn's tasseling stage and grain-filling stage.

[0016] Furthermore, the integrated water and fertilizer management in step S3 also includes dynamic topdressing regulation based on crop nutrient status. The specific operation of this regulation is as follows: before topdressing, the nutrient indicators of crop leaves are measured using a crop nutrient diagnostic tool; when the measured nutrient indicators are lower than 95% of a preset reference value, the planned nitrogen application rate for this topdressing is increased by 10%-15%. The crop nutrient diagnostic tool is a handheld chlorophyll meter, and the nutrient indicator is the SPAD value. This achieves precise matching between the topdressing application rate and the real-time needs of the crop.

[0017] Furthermore, the integrated water and fertilizer management described in step S3 also includes precise irrigation control based on soil moisture conditions. The specific operation of this control is as follows: soil moisture sensors are deployed in the crop root zone; drip irrigation is initiated when the sensors detect that the soil moisture content at a depth of 20cm is below 65%-75% of field capacity, and drip irrigation is stopped when the moisture content recovers to 85%-95%. This achieves precise matching between water supply and the real-time water requirements of the crop.

[0018] Furthermore, the base fertilizer application method in step S1 is strip trench application, and the drip irrigation pipe in step S3 is laid on the fertilizer strip, and the planting ridge is covered with mulch film.

[0019] This invention is specifically applied to the cultivation of dual-purpose (grain and forage) maize.

[0020] This invention provides a method for drip irrigation application of solid-liquid organic fertilizer and chemical fertilizer in desert oasis areas. It has the following beneficial effects: 1. This invention improves the physical and chemical properties of the soil in the crop root zone and provides long-lasting nutrients by preparing bio-enhanced solid organic fertilizer and applying it as a base fertilizer. Specifically, the biochar added during aerobic composting increases soil porosity and aeration, while the compound microbial agent accelerates the humification process of organic materials. Applying this solid fertilizer, rich in organic matter and beneficial microorganisms, to the 20-40cm topsoil layer creates a stable nutrient pool and a good root growth environment for the entire growth period of the crop.

[0021] 2. This invention achieves efficient utilization of water and fertilizer resources by preparing enhanced biogas slurry and applying it as topdressing using integrated water and fertilizer technology. Two-stage precision filtration of the biogas slurry effectively solves the technical problem of clogging in drip irrigation systems. The addition of potassium humate, utilizing its chelating and complexing effects, improves the bioavailability of nutrients in the biogas slurry. This enhanced biogas slurry is then applied through a drip irrigation system regulated by soil moisture sensors and crop nutrient diagnostic tools, ensuring that water and nutrient supply matches the real-time needs of the crop, thereby reducing water evaporation and nutrient loss.

[0022] 3. This invention constructs a regional material recycling model by utilizing agricultural organic waste such as livestock and poultry manure and crop straw, reducing dependence on exogenous chemical fertilizers. This method converts manure and straw, which may cause environmental burden, into solid and liquid fertilizer products, respectively, and then re-introduces them into the agricultural production system. This not only achieves the reduction and harmless treatment of agricultural waste, but also reduces the soil degradation and environmental risks that may be caused by excessive application of chemical fertilizers. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the method flow of the present invention. Figure 2Schematic diagram of the film mulching strip planting of grain and forage maize in the present invention; Figure 3 Schematic diagram of plant height, stem diameter, leaf area and SPAD value of grain and forage maize under different treatments of the present invention; Figure 4 Schematic diagram of crude protein, soluble sugar and washing fiber contents of grain and forage maize under different treatments of the present invention; Figure 5 Schematic diagram of pH, EC and organic carbon contents of grain and forage maize under different treatments of the present invention; Figure 6 Schematic diagram of the proportion of soil aggregate mass and aggregate stability of grain and forage maize under different treatments of the present invention; Figure 7 Schematic diagram of available phosphorus and available nitrogen contents of grain and forage maize under different treatments of the present invention; Figure 8 Schematic diagram of soil enzyme activities of grain and forage maize under different treatments of the present invention; Figure 9 Schematic diagram of the community structure composition of grain and forage maize at the phylum and genus levels under different treatments of the present invention.

[0024] Where: Relative abundance: Relative abundance; Community heat map analysis: Community heat map analysis; Genus level: Genus level; Others: Others; Samples(YT,CM,OF,PF,T2,T4): Samples; YT: Yuan Tu (Original soil); CM: Chemical Manure (Conventional chemical fertilizer); OF: Organic Fertilizer (Ordinary organic fertilizer); PF: Probiotic Fertilizer (Organic fertilizer added with microbial agents); T2,T4: Other treatment group numbers; Actinobacteria: Actinobacteria; Bacilli: Bacilli; Chitobacteria: Chitobacteria; Chloroflexi: Chloroflexi; Cystobacteria: Cystobacteria; Dichelobacteria: Dichelobacteria; Firmicutes: Phylum Firmicutes; Ignavibacteria: Phylum Ignavibacteria; Kineospecific, Guasuncaverdia, etc.: Specific bacterial genus names; Methylenothrophis: Methylotrophic bacteria; Myxobacteria: Myxococci / Myxobacteria; Planctomycetes: Phylum Planctomycetes. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0026] Examples 1-5: Example 1: This embodiment provides a method for drip irrigation application of solid-liquid organic fertilizer and chemical fertilizer in desert oasis areas. The specific steps are as follows: Preparation of bio-enhanced solid organic fertilizer (1) Fresh cow dung and corn stalks crushed to a length of 3-5 cm were mixed at a fresh weight ratio of 20:1. 5.0% of the total dry weight of the mixture was added to the mixture, along with 2.0 × 10⁻⁶ effective viable bacteria. (Preparation method see Example 4) 9 mL -1 The compound microbial agent has an inoculation rate of 1.0L per ton of mixed materials.

[0027] (2) Adjust the initial moisture content of the mixture to 60% and the initial carbon-nitrogen ratio to 30:1.

[0028] (3) Aerobic composting was carried out using a well-type chimney ventilation structure, and the fermentation cycle of the compost pile was 50 days. During the fermentation period, the temperature of the compost pile was maintained above 55℃ for a total of 15 days.

[0029] (4) After fermentation, the seed germination index of the finished solid organic fertilizer was measured to be 85%, the organic matter content was 38% (dry basis), and the moisture content was 25%.

[0030] Preparation of enhanced biogas slurry: (1) The mixture of cow dung and straw is placed in a continuous stirring constant temperature stainless steel anaerobic fermentation tank and subjected to mesophilic anaerobic fermentation at 35°C to produce biogas slurry.

[0031] (2) The prepared biogas slurry is filtered in two stages, through a vibrating screen with a pore size of 270 μm and a precision filter screen with a pore size of 75 μm, to obtain filtrate.

[0032] (3) Add the self-made potassium humate powder to the filtrate so that its final mass volume concentration in the biogas slurry reaches 0.3% (i.e., add 3.0 kg of potassium humate per cubic meter of biogas slurry), stir until completely dissolved, and then prepare the enhanced biogas slurry and store it in a sealed container.

[0033] Field application and management: (1) Before sowing the dual-purpose corn variety Xianyu 1619, apply the bio-enhanced solid organic fertilizer prepared in step 1 and some chemical fertilizer (diammonium phosphate and potassium chloride) as base fertilizer in one go and then use a rotary tiller to till it into the 30cm deep tillage layer.

[0034] (2) During the corn's tasseling and grain-filling stages, the enhanced biogas slurry obtained in step 2 and a portion of the fertilizer (urea) are applied twice via a drip irrigation system.

[0035] (3) Topdressing is carried out simultaneously with drip irrigation. Irrigation is started and stopped based on the readings of soil moisture sensors of a time-domain reflectometer installed at a depth of 20 cm in the root zone: drip irrigation is started when the soil moisture content is lower than 70% of field capacity and stopped when it reaches 90% of field capacity. The total irrigation water volume is reduced by 25% compared with the local conventional flood irrigation method.

[0036] Example 2: The method provided in this embodiment is basically the same as that in Embodiment 1, except for the selection of preparation process parameters: Preparation of bio-enhanced solid organic fertilizer: The fresh weight ratio of cow manure to corn stalks is 30:1; the amount of biochar added is 4.0% of the total dry weight of the materials; the inoculation amount of compound microbial agent is 1.2L per ton of mixed materials; the initial moisture content of the materials is adjusted to 65%, and the initial carbon-nitrogen ratio is 25:1.

[0037] Preparation of enhanced biogas slurry: The anaerobic fermentation temperature is 38℃; the amount of potassium humate added is 5.0 kg per cubic meter of biogas slurry, so that its final mass-volume concentration reaches 0.5%.

[0038] Field application and management: The soil moisture content threshold for starting irrigation is 65% of field capacity, and the threshold for stopping irrigation is 95% of field capacity.

[0039] Example 3: The method provided in this embodiment is basically the same as that in Embodiment 1, except that dynamic topdressing regulation based on crop nutrient status is introduced in the field management steps, as detailed below: Before topdressing at the corn tasseling stage, the SPAD value of the ear-side leaves was measured using a handheld chlorophyll meter (SPAD-502). Simultaneously, a reference SPAD value was measured in an independent control area with sufficient nitrogen supply. The results showed that the average SPAD value in the treatment area was 93% of the average value in the control area. Since this value was below the 95% control threshold, the planned urea application rate at the tasseling stage was increased by 12%, then mixed with enhanced biogas slurry and applied via drip irrigation. The topdressing amount during the grain-filling stage remained unchanged.

[0040] Example 4: Method for preparing biochar Dry corn stalks were placed in an oxygen-limited pyrolysis furnace and heated at 10°C / min. -1 The temperature was increased at a rate to the final pyrolysis temperature of 550℃. After holding at this temperature for 1.5 hours, heating was stopped, and the mixture was cooled to room temperature in a sealed furnace. The resulting carbonized blocks were removed, crushed, and passed through a 2mm sieve. The powder collected from the sieve was the finished biochar.

[0041] Example 5: Preparation method of potassium humate (1) Mix the crushed weathered coal with a 1.0 mol / L potassium hydroxide solution at a solid-liquid mass-volume ratio of 1:10 (g / mL).

[0042] (2) Stir continuously for 3 hours at 70℃.

[0043] (3) After the reaction is complete, the supernatant is obtained by centrifugation.

[0044] (4) Slowly add 98% sulfuric acid to the supernatant to adjust the pH of the solution to 1.5. At this time, humic acid precipitates out.

[0045] (5) Centrifuge again and collect the supernatant rich in fulvic acid.

[0046] (6) Add potassium hydroxide solution back to the fulvic acid supernatant to restore the pH value to 7.0.

[0047] (7) The neutralized solution is spray-dried to obtain potassium humate powder.

[0048] Comparative Examples 1-4: Comparative Example 1: Compared with Example 1, the difference is that no solid organic fertilizer or enhanced biogas slurry was applied, all the nutrients required by the crops were provided by chemical fertilizers (urea, diammonium phosphate, potassium chloride) according to the local conventional recommended amount, the irrigation method was conventional flood irrigation, and everything else was the same.

[0049] Comparative Example 2: Compared with Example 1, the difference is that biochar and compound microbial agents were not added when preparing solid organic fertilizer. Instead, cow manure was mixed with corn stalks and then composted in a well-ventilated aerobic manner. All other aspects were the same.

[0050] Comparative Example 3: Compared with Example 1, the difference is that the biogas slurry obtained by anaerobic fermentation was not filtered in two stages (270μm vibrating screen and 75μm precision filter) and was directly mixed with chemical fertilizer for topdressing in the drip irrigation system. All other aspects are the same.

[0051] Comparative Example 4: Compared with Example 1, the difference is that potassium humate was not added to the biogas slurry after two-stage filtration, but all other aspects were the same.

[0052] Test Example 1: Determination of the effects of various treatments on maize yield, quality, and soil properties To verify the technical effects of the above embodiments and comparative examples, various indicators were measured after the field trials of all treatments were completed.

[0053] To determine crop agronomic traits and yield, at the physiological maturity stage of maize, 10 representative consecutive maize plants were randomly selected from each experimental plot, and their plant height was measured using a meter stick. The diameter of the stalk at the ear position was measured using vernier calipers. Subsequently, the entire plot was harvested, and the aboveground fresh weight and ear weight were measured separately. The sampled ears were threshed, and the fresh weight of the kernels was measured and the moisture content was determined. Finally, the kernel yield was uniformly converted to yield per hectare (t / ha).

[0054] For crop quality determination, the harvested grain samples were dried to constant weight in an oven at 65℃, pulverized using a plant pulverizer, and then passed through a 100-mesh sieve. Approximately 0.5g of the sample was accurately weighed, and its total nitrogen content was determined using the Kjeldahl method (refer to GB5009.5-2016). The total nitrogen content was then multiplied by a factor of 6.25 to calculate the crude protein content of the grains.

[0055] Soil physicochemical properties were determined after corn harvest by collecting soil samples from the 0-20cm and 20-40cm soil layers in each experimental plot using a five-point sampling method.

[0056] After the sample is air-dried, remove stones and plant debris: (1) pH value and electrical conductivity (EC): Weigh the sieved soil sample and prepare a soil suspension according to a soil-to-water mass-volume ratio of 1:5 (g / mL). After shaking for 30 minutes, let it stand and use a pH meter and electrical conductivity meter to measure its pH value and EC value.

[0057] (2) Soil organic carbon: Weigh the sieved soil sample and determine it using the potassium dichromate oxidation external heating method (refer to NY / T1121.6-2006).

[0058] Soil nutrient determination uses soil samples collected in the same manner as above: (1) Available nitrogen: determined by alkaline hydrolysis diffusion method (refer to LY / T1229-1999).

[0059] (2) Available phosphorus: determined by 0.5 mol / L sodium bicarbonate extraction-molybdenum antimony colorimetric method (refer to NY / T1121.7-2014).

[0060] Soil aggregate stability was determined by taking air-dried soil samples and using a soil aggregate analyzer. The mass distribution of water-stable aggregates with different particle sizes (>2mm, 1-2mm, 0.5-1mm, 0.25-0.5mm, <0.25mm) was determined by wet sieving, and the mean weight diameter (MWD) of the soil aggregates was calculated according to the formula.

[0061] Soil enzyme activity was measured using fresh soil samples. (1) Urease activity: determined by indophenol blue colorimetric method, expressed as the number of milligrams of ammonia nitrogen produced per gram of dry soil after 24 hours.

[0062] (2) Sucrase activity: The activity was determined by the 3,5-dinitrosalicylic acid colorimetric method and expressed as the number of milligrams of glucose produced per gram of dry soil after 24 hours.

[0063] Soil microbial community structure was determined using fresh soil samples, and total soil DNA was extracted using a soil genomic DNA extraction kit. PCR amplification of the V3-V4 hypervariable region of the 16S rRNA gene was performed using universal primers 341F / 806R. After purification and quantification, the amplified products were used to construct sequencing libraries and subjected to high-throughput sequencing on the Illumina MiSeq platform. The raw sequences obtained from sequencing underwent quality control, impurity removal, and assembly, and were clustered into operational taxonomic units (OTUs) at a 97% similarity level. Based on representative OTU sequences, species annotation was performed in the Silva database, and microbial alpha diversity indices (e.g., Shannon index) and species abundance were calculated for each treatment.

[0064] The operation status of the drip irrigation system is recorded by observing and recording the outflow of drip emitters in each treatment area during each drip irrigation topdressing. After the topdressing cycle ends, the clogging rate of the emitters is statistically analyzed and calculated.

[0065] Table 1. Effects of each treatment on maize yield, quality, and soil properties.

[0066] Note: N / A indicates that the experiment was interrupted due to complete clogging of the dripper, and the corresponding data could not be obtained. The specific species abundance data of the soil microbial community structure is extensive, and its key results are described in the following text.

[0067] Table 1 shows that solid organic fertilizer prepared by adding biochar and compound microbial agents to aerobic composting can affect soil properties. Compared with Comparative Example 2 without the above materials, the soil organic carbon content, average weight diameter (MWD) of aggregates, and urease and sucrase activities in Examples 1, 2, and 3 were all increased to varying degrees. Furthermore, soil microbial community structure measurements showed that the Shannon index of soil microorganisms in Examples 1, 2, and 3 was significantly higher than that in Comparative Example 2, and the relative abundance of beneficial bacteria such as Bacillus was increased. This indicates that the porous structure of biochar provides a habitat for microorganisms, and its combined action with the exogenously inoculated compound microbial agents optimizes the soil microecological environment. This, along with the increased soil enzyme activity, constitutes an improvement in soil biological characteristics, providing a material basis for crop growth.

[0068] Meanwhile, the data also showed the impact of biogas slurry treatment methods on system operation and nutrient supply. In Comparative Example 3, the use of untreated biogas slurry led to 100% blockage of the drip irrigation system during the first topdressing, forcing the experiment to be interrupted. Examples 1, 2, and 3, all employing two-stage precision filtration, operated without blockage throughout the process, demonstrating that this filtration step is a necessary prerequisite for the normal operation of the integrated water and fertilizer system. Compared to Comparative Example 4 without added potassium humate, the crop grain crude protein content, soil available nitrogen, and available phosphorus content were all higher in Examples 1, 2, and 3, indicating that adding potassium humate to the filtered biogas slurry, utilizing its chelating and complexing effects, improves the bioavailability of nutrients in liquid topdressing and promotes crop absorption and utilization.

[0069] The method disclosed in this technical solution combines deep application of solid organic fertilizer prepared by a specific process with drip irrigation topdressing of treated and enhanced biogas slurry, achieving a synergistic supply of long-acting slow-release nutrients and readily available nutrients. Solid basal fertilizer improves the soil topsoil structure and builds a basic nutrient reservoir, while liquid topdressing precisely replenishes readily available nutrients during the crop's critical growth stages. In Example 3, dynamic regulation of topdressing amount based on crop leaf SPAD values ​​better matches nutrient supply with the crop's real-time needs, ultimately achieving the highest grain yield among all treatments. This solid-liquid combined application mode demonstrates measurable technical effects in terms of crop yield, quality, and soil properties compared to treatments using only chemical fertilizer (Comparative Example 1) or incomplete organic fertilizer preparation (Comparative Examples 2 and 4).

Claims

1. A method for applying solid-liquid organic manure and chemical fertilizer by drip irrigation in a desert oasis area, characterized in that, Includes the following steps: S1: Preparation and basal application of bio-enhanced solid organic fertilizer: Mix livestock and poultry manure with crop straw, add biochar and compound microbial agents accounting for 4.0%-6.0% of the total dry weight of the mixture, and perform composting treatment through a well-type ventilated aerobic composting process to obtain bio-enhanced solid organic fertilizer with seed germination index ≥70%, organic matter content ≥30%, and moisture content ≤30%. Apply the bio-enhanced solid organic fertilizer as basal fertilizer before sowing and incorporate it into the 20-40cm tillage layer. S2: Preparation and application of enhanced biogas slurry: Livestock and poultry manure and straw are fermented in a continuous stirred constant temperature stainless steel anaerobic fermenter at 30-38℃ to obtain biogas slurry. The biogas slurry is then filtered in two stages through a 250-300μm vibrating screen and a 70-80μm precision filter screen. Potassium humate is added to make the final concentration reach 0.1%-0.5% (w / v) to obtain enhanced biogas slurry. S3: Integrated water and fertilizer management: During the critical growth period of crops, the enhanced biogas slurry and some chemical fertilizers are applied in stages through the drip irrigation system. The application process is carried out simultaneously with the drip irrigation, and the total amount of drip irrigation water is reduced by 20%-30% compared with the conventional method.

2. The method according to claim 1, wherein the method is characterized by, In the preparation of the bio-enhanced solid organic fertilizer in step S1, the fresh weight ratio of livestock and poultry manure to crop straw is 10:1 to 30:

1. The inoculation amount of the complex microbial agent is 0.8-1.2L per ton of mixed materials, and the effective viable cell number is 1.0×10 9 -5.0×10 9 mL -1 The bacterial species include high-temperature-resistant cellulose-decomposing bacteria and Bacillus subtilis.

3. The method according to claim 1, wherein the method is characterized by, In the well-ventilated aerobic composting process described in step S1, the initial moisture content of the material is adjusted to 55%-65%, the carbon-nitrogen ratio is 25:1-35:1, and the compost temperature is maintained above 55℃ for no less than 14 days.

4. The method according to claim 1, wherein the method is characterized by, The biochar mentioned in step S1 is produced from corn stalks under limited oxygen conditions at 5-15℃·min. -1 The temperature is increased to 450-600℃ at a rising rate and kept at a constant temperature for 1-2 hours. After cooling and pulverizing, it is obtained.

5. The method according to claim 1, wherein the method is characterized by, The potassium humate mentioned in step S2 is obtained by extracting weathered coal with potassium hydroxide solution at 60-80℃, and the extract is then separated by acid precipitation, neutralized and dried.

6. The method according to claim 1, wherein the method is characterized by, The application period for topdressing in step S3 is during the corn's tasseling stage and grain-filling stage.

7. The method according to claim 1, wherein the method is characterized by, The integrated water and fertilizer management in step S3 further includes dynamic topdressing regulation based on crop nutrient status. Before topdressing, crop nutrient indicators are measured using crop nutrient diagnostic tools. When the nutrient indicators are lower than 95% of the preset reference value, the planned nitrogen application rate for this topdressing is increased by 10%-15%.

8. The method according to claim 1, wherein the method is characterized by, The crop nutrition diagnostic tool is a handheld chlorophyll meter, and the nutrient index is the SPAD value.

9. The method according to claim 1, wherein the method is characterized by, The integrated water and fertilizer management described in step S3 further includes precise irrigation control based on soil moisture: soil moisture sensors are deployed in the crop root zone; Drip irrigation is initiated when the sensor detects that the soil moisture content in the 20cm soil layer is lower than 65%-75% of the field capacity, and is stopped when the moisture content recovers to 85%-95%.

10. The method according to claim 1, wherein the method is characterized by, The base fertilizer is applied in a strip trench in step S1, and the drip irrigation pipe is laid on the fertilizer strip in step S3, and the planting ridge is covered with mulch film.

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