Method for regulating the amount of artificial humic acid based on potted rice water and fertilizer experiment

Abstract

The invention relates to a method for regulating the amount of artificial humic acid applied based on a potted rice water and fertilizer test, and belongs to the field of agricultural technology. The invention aims to solve the problem that there is a lack of research on the influence of the coupling of irrigation mode and artificial humic acid on the carbon fixation of rice, and the content of artificial humic acid cannot be flexibly regulated. Step 1: Plant multiple rice plants in two ways in the same test box, add different amounts of artificial humic acid to the rice in the two ways, and measure the carbon isotope content in the soil of each rice plant; the amount of artificial humic acid added to each rice plant under the two ways and the carbon isotope content in the soil are respectively used as two data sets; Step 2: Use the two data sets to train two models respectively to obtain two trained models; Step 3: Input the carbon isotope content in the soil to be tested into the corresponding trained model to predict the corresponding amount of artificial humic acid added. The present invention is used to regulate the amount of artificial humic acid added.

Description

Technical Field

[0001] The invention relates to a water and fertilizer regulating method and belongs to the technical field of agriculture. Background Art

[0002] Paddy field soils have enormous carbon sequestration potential. However, the long-term flooding environment of paddy fields also causes a large loss of water resources. According to statistics, the amount of water used for paddy field irrigation is about 2.5 times that of other crops such as corn and wheat. In recent years, the dry-wet alternating irrigation mode has attracted widespread attention due to its advantages in saving water and improving soil redox conditions. In paddy field ecosystems, water management is a key factor affecting crop growth and soil carbon cycling. Long-term flooding may lead to deterioration of soil structure, reduce soil permeability and aeration, and affect root growth and soil carbon sequestration capacity. Although dry-wet alternating irrigation can improve water use efficiency, it may limit rice growth and affect photosynthesis and carbon sequestration capacity.

[0003] Artificial humic acid (AHA) is a substance with a composition and functions highly similar to natural humus, but with a significantly shorter production time. It uses lignin-rich waste biomass as raw material and, through a novel hydrothermal humification reaction, produces a humus-like substance with significant carbon sequestration and fertilization effects. Previous studies have shown that artificial humus can improve soil structure, promote aggregate formation, increase soil organic matter content, and enhance nutrient availability.

[0004] Soil carbon sequestration is a dynamic process involving the interplay of plant-soil systems: photosynthesis to fix atmospheric CO2, root transport of organic carbon to the soil, and soil-plant respiration. These processes collectively determine the accumulation and loss of organic carbon in the soil, affecting the soil's ability to serve as a carbon sink. Consequently, high carbon sequestration capacity can enhance plant growth. Effective soil carbon sequestration management requires comprehensive consideration of these processes to maximize soil carbon storage potential and reduce greenhouse gas emissions. However, the effects of different irrigation methods and artificial humic acid coupling on photosynthetic carbon sequestration and carbon transfer in rice-soil systems remain unclear. Consequently, research examining the effects of irrigation methods and artificial humic acid coupling on rice carbon sequestration is lacking. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that there is a lack of research on the influence of irrigation mode and artificial humic acid coupling on the carbon sequestration of rice, which leads to the inability to flexibly regulate the artificial humic acid content. A method for regulating the application amount of artificial humic acid based on potted rice water and fertilizer experiments is proposed.

[0006] A method for regulating the amount of artificial humic acid applied based on a potted rice water and fertilizer experiment, the method comprising the following steps:

[0007] Step 1: Planting multiple rice plants in a test chamber using two methods: flooding irrigation and alternating wet-dry irrigation. Carbon dioxide isotopes are introduced into the test chamber. Artificial humic acid at varying concentrations is added to the rice plants planted using the flooding irrigation method. Simultaneously, the artificial humic acid at varying concentrations is added to the rice plants planted using the alternating wet-dry irrigation method. After the rice plants have grown for a predetermined period of time, the carbon isotope content in the soil of each rice plant is measured.

[0008] The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under flooding irrigation were used as the first data set. In the first data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively.

[0009] The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under the dry-wet alternating irrigation system were used as the second data set. In the second data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively.

[0010] Step 2: Use the first data set to train the first training model to obtain the trained first training model;

[0011] Using the second data set to train the second training model, a trained second training model is obtained;

[0012] Step 3: Input the carbon isotope content in the soil to be tested into the trained model to predict the corresponding amount of artificial humic acid to be added;

[0013] The carbon isotope content in the soil to be tested is input into the trained model No. 2 to predict the corresponding amount of artificial humic acid to be added.

[0014] Preferably, in step 1, the specific process of adding different amounts of artificial humic acid to multiple rice plants planted by flooding irrigation and measuring the carbon isotope content in the soil of each rice plant is:

[0015] Step A1: applying different amounts of artificial humic acid to multiple rice pots with the same amount of soil and base fertilizer, with the artificial humic acid buried 10 cm below the soil surface and the water level in each pot maintained at 2-3 cm;

[0016] Step A2: After the rice has grown in the pot for 25 days, the carbon abundance in the rice soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

[0017] Preferably, in step 1, the specific process of adding the artificial humic acid at different contents to multiple rice plants planted in a dry-wet alternating irrigation method and measuring the carbon isotope content in the soil of each rice plant is:

[0018] Step B1: applying different amounts of artificial humic acid to multiple rice pots with the same soil volume and base fertilizer dosage, burying the artificial humic acid 10 cm below the soil surface, maintaining a 2-3 cm water layer within 7 days after planting the rice, and monitoring the soil water potential in real time using a tensiometer. When the soil water potential is -15 kPa, irrigate the soil with water until the water layer reaches 2-3 cm below the soil surface;

[0019] Step B2: After the rice has grown in the pot for 25 days, the carbon abundance in the soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

[0020] Preferably, the different contents of artificial humic acid differ by 300 mg.

[0021] Preferably, in step A2 and step B2, the carbon abundance δ 13 C(‰), expressed as:

[0022] δ 13 C(‰)=(R sample / R V-PDB -1)×1000;

[0023] Where R sample represents the isotope ratio of rice; R V-PDB represents the isotope ratio of the standard material;

[0024] Carbon isotope content in soil 13 C s , expressed as:

[0025] 13 C s (mg) = C sample ×[(δ 13 C(%)l-(δ 13 C(%)nl];

[0026] Where C sample represents the total carbon content absorbed by each rice plant; l represents rice labeled with carbon dioxide gas isotopes; nl represents rice outside the test chamber that was not labeled with carbon dioxide gas isotopes.

[0027] Preferably, the artificial humic acid uses rice straw as raw material.

[0028] Preferably, the base fertilizer composition is a combination of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer, the source of nitrogen fertilizer is urea, the source of phosphorus fertilizer is superphosphate, and the source of potassium fertilizer is potassium sulfate; 40 mg of nitrogen fertilizer, 20 mg of phosphorus fertilizer and 80 mg of potassium fertilizer are added to each kilogram of soil.

[0029] The beneficial effects of the present invention are:

[0030] The present invention uses rice as research material, designs a potted experiment of water and fertilizer regulation and application of artificial humic acid, studies the influence of flooding irrigation mode and different contents of artificial humic acid on the carbon sequestration capacity of rice soil (the carbon sequestration capacity of rice soil refers to the carbon isotope content in the soil), and studies the influence of dry-wet alternating irrigation mode and different contents of artificial humic acid on the carbon sequestration capacity of rice soil (the carbon sequestration capacity of rice soil refers to the carbon isotope content in the soil), and provides a certain theoretical basis for scientifically and rationally applying artificial humic acid content and improving soil carbon sequestration in the process of planting rice by adopting flooding irrigation mode and adopting dry-wet alternating irrigation mode. At the same time, it provides a basis for the formation of an intelligent automatic system for water and fertilizer integration. The more carbon content in the soil, the better the soil carbon sequestration capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the method for regulating artificial humic acid content based on a potted rice water and fertilizer experiment;

[0032] Figure 2 This is the test diagram inside the test box;

[0033] Figure 3 Schematic diagram of photosynthetic carbon distribution under different irrigation methods and different contents of artificial humic acid;

[0034] Figure 4 for Figure 3 The chlorophyll content in the leaves of 6 rice plants is shown in the figure. Figure 4 (a) Figure 3 Chlorophyll a content of 6 rice strains; Figure 4 (b) Figure 3 Chlorophyll b content of 6 rice strains; Figure 4 (c) Figure 3 Figure 2 shows the carotenoid content of 6 rice strains;

[0035] Figure 5 Rice leaves, stems, roots and soil 13 Correlation analysis diagram between C content and photosynthesis and root system indicators. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0039] Example:

[0040] Combine Figures 1 to 3 This embodiment describes a method for regulating the amount of artificial humic acid applied based on a potted rice water and fertilizer experiment. The method includes the following:

[0041] Step 1: Planting multiple rice plants in a test chamber using two methods: flooding irrigation and alternating wet-dry irrigation. Carbon dioxide isotopes are introduced into the test chamber. Artificial humic acid at varying concentrations is added to the rice plants planted using the flooding irrigation method. Simultaneously, the artificial humic acid at varying concentrations is added to the rice plants planted using the alternating wet-dry irrigation method. After the rice plants have grown for a predetermined period of time, the carbon isotope content in the soil of each rice plant is measured.

[0042] The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under flooding irrigation were used as the first data set. In the first data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively.

[0043] The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under the dry-wet alternating irrigation system were used as the second data set. In the second data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively.

[0044] Step 2: Use the first data set to train the first training model to obtain the trained first training model;

[0045] Using the second data set to train the second training model, a trained second training model is obtained;

[0046] Step 3: Input the carbon isotope content in the soil to be tested into the trained model to predict the corresponding amount of artificial humic acid to be added;

[0047] The carbon isotope content in the soil to be tested is input into the trained model No. 2 to predict the corresponding amount of artificial humic acid to be added.

[0048] Specifically, the carbon isotope content in the soil of each rice plant described in step 1 refers to the carbon dioxide gas isotope fixed by the soil.

[0049] In the experiment, the purpose of inputting carbon dioxide gas isotopes into the test chamber was to use the isotope tracer effect to monitor the distribution of carbon dioxide gas isotopes in leaves, stems, roots, and soil, thereby measuring the carbon isotope content in rice roots, stems, leaves, and soil; the following indicators were also measured in the experiment, and the carbon isotope content in roots, stems, leaves, and soil was correlated with each indicator to clarify the correlation between the carbon isotope content in roots, stems, leaves, and soil and photosynthesis, root growth, and greenhouse gas emission indicators. Among them, Figure 4 The chlorophyll content in the leaves of 6 rice plants during their growth process is shown in the figure. Correlation analysis is shown in the figure. Figure 5 The indicators include the following:

[0050] 1. The net photosynthetic rate (P) of the flag leaf was measured every 5 days within 20 days after carbon isotope labeling using a portable photosynthesis system. n ), intercellular CO2 concentration (C i ), stomatal conductance (G s ) and transpiration rate (T r During the measurement period, the leaf temperature was maintained at 28 ± 1.0 °C, the photosynthetic photon flux density (PPFD) was 1500 μmol m-2s-1, and the CO2 concentration was maintained at 400 μmol CO2 mol -1 , the relative humidity was maintained at 40%, and data were recorded after equilibrium reached a steady state (about 15 minutes).

[0051] 2. Chlorophyll concentration

[0052] On the same day as the gas exchange parameter measurements, three rice leaves from each treatment were randomly selected and 80% acetone was used to extract the chlorophyll in the middle of the flag leaf, avoiding the veins. The absorbance of each pigment was measured using an ultraviolet spectrophotometer, and its concentration was calculated using the Beer-Lambert formula:

[0053] C a = 12.21×A 663 ﹣2.81×A 646 (1)

[0054] C b = 20.13×A 646 ﹣5.03×A 663 (2)

[0055]

[0056] Where C a 、C b : concentrations of chlorophyll a and b; C r : carotenoid concentration; A 663 、A 646 and A470 : Absorbance of chloroplast pigment extract at wavelengths of 663nm, 646nm and 470nm.

[0057] 3. Rubisco activity assay

[0058] The leaf tissue was homogenized with extraction buffer under ice-cold conditions and centrifuged to obtain the Rubisco enzyme solution. The absorbance was measured spectrophotometrically at a wavelength of 450 nm.

[0059] 4. Rice leaf area

[0060] Three plants were randomly selected from each treatment, and the leaf area was measured using a portable leaf area meter (*AM-350).

[0061] 5. Chlorophyll fluorescence measurement

[0062] On the same day as the gas exchange parameter measurement, three rice plants were randomly selected from each treatment, and the flag leaves were selected to measure chlorophyll fluorescence parameters using the PlantScreen plant phenotyping imaging system. After 30 minutes of dark treatment, the plants were placed in the phenotyping imaging system to measure the minimum fluorescence after dark adaptation (F0), the maximum photochemical efficiency of PSⅡ of the leaves (F v / F m ), photochemical quenching coefficient (qP), non-photochemical quenching coefficient (NPQ) and other chlorophyll fluorescence parameters.

[0063] 6. Root exudate collection method

[0064] Three rice plants were randomly selected in each treatment, washed with deionized water, and then immersed in 0.2 mmol L - 1 CaSO4 and 30 mg L -1 The samples were washed with sterile deionized water and transferred to a brown glass bottle containing 200 mL of sterile deionized water, which was placed in a 25°C thermostat. After 24 hours, 10 mL of the solution was sampled from each bottle and stored at -20°C for further metabolic profile analysis. The samples were analyzed on a gas chromatography mass spectrometer (Agilent 7890B gas chromatography system and Agilent 5977A MSD system, Agilent, USA). The derivatives were separated using a DB-5MS fused silica capillary column (30 m × 0.25 mm × 0.25 um, Agilent, USA).

[0065] 7. Root aerenchyma

[0066] Three rice plants were randomly selected for each treatment. Roots were cleaned with ultrapure water and fixed in 2.5% glutaraldehyde in a refrigerator at 4°C for 24 hours. Dehydration was then performed using 30%, 40%, 50%, 60%, and 70% ethanol, with each dehydration treatment lasting 15 minutes. Manual sections were taken 1.0 cm from the root tip and stained with safranin-fast green. Root aerenchyma was observed using a light microscope.

[0067] 8. Rice root activity determination

[0068] Three rice plants were randomly selected from each treatment, their roots were cleaned with ultrapure water, and the root samples were accurately weighed. The TTC method (triphenyltetrazolium chloride method) was used to determine the root activity of the rice.

[0069] 9. Root morphology

[0070] Twenty days after isotope labeling, three rice plants from each treatment were collected and the soil around the roots was slowly rinsed with running water. Root morphology was analyzed using a root scanner (Espon Expression 1680 Scanner, Seiko Espon Corp, Tokyo, Japan) and the WinRHIZO root analysis system (Regent Instruments Inc, Quebec, Canada).

[0071] 10. Greenhouse gas measurements

[0072] Greenhouse gas flux measurements were performed immediately after isotope labeling and every 75 days thereafter until the plants were destructively sampled. A homemade cylindrical static chamber (100 cm × 50 cm × 85 cm, 5 mm thick) was used to collect gases. Sampling was set between 8:00 and 10:00 a.m. each day. Prior to collecting the gases, the static chamber was placed above the soil column and sealed to prevent gas leakage. The timer was then started, with sampling at 0, 10, 20, and 30 minutes, while the room temperature and the chamber temperature were recorded. Within 24 hours of gas sample collection, the concentrations of CH4, CO2, and N2O in the gas samples were determined using a high-performance gas chromatograph. The greenhouse gas emission flux was calculated using the following formula:

[0073]

[0074] Where J is the greenhouse gas emission flux (mg m -2 h), dc / dt is the slope of the regression curve of the sampled gas volume fraction versus time [mm 3 (m 3 h) -1 ], M is the molar mass of the gas to be measured (g mol -1), P is the pressure in the static sampling box (Pa), T0 is the absolute temperature in the static sampling box (the average temperature from the beginning to the end of sampling, K), V0, P0 and T are the molar volumes of the gas under standard conditions (mL mol -1 ), atmospheric pressure (Pa) and absolute temperature (K), H is the height of the static sampling box (m).

[0075] The first training model is represented as:

[0076] y=k1x 2 +k2x+0.0638;

[0077] Where y is the carbon isotope content in the soil, x is the amount of artificial humic acid added, and k1 and k2 are parameters in the No. 1 training model;

[0078] The second training model is represented as:

[0079] y=k3x 2 +k4x+0.2462.

[0080] Where k3 and k4 are the parameters in the second training model.

[0081] The following describes the process of flooding and obtaining carbon sequestration:

[0082] In step 1, the specific process of adding different amounts of artificial humic acid to multiple rice plants planted by flooding irrigation and measuring the carbon isotope content in the soil of each rice plant is as follows:

[0083] Step A1: applying different amounts of artificial humic acid to multiple rice pots with the same amount of soil and base fertilizer, with the artificial humic acid buried 10 cm below the soil surface and the water level in each pot maintained at 2-3 cm;

[0084] Step A2: After the rice has grown in the pot for 25 days, the carbon abundance in the rice soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

[0085] Specifically, a 2-3 cm water layer is maintained within 7 days after planting rice to ensure that the rice turns green and survives. The rest of the time, alternating dry and wet irrigation is used, that is, when the soil dries naturally until the water potential reaches -15 kPa, the soil is irrigated to a 2-3 cm water layer.

[0086] The following describes the process of flooding and obtaining carbon sequestration:

[0087] Step B1: applying different amounts of artificial humic acid to multiple rice pots with the same soil volume and base fertilizer dosage, burying the artificial humic acid 10 cm below the soil surface, maintaining a 2-3 cm water layer within 7 days after planting the rice, and monitoring the soil water potential in real time using a tensiometer. When the soil water potential is -15 kPa, irrigate the soil with water until the water layer reaches 2-3 cm below the soil surface;

[0088] Step B2: After the rice has grown in the pot for 25 days, the carbon abundance in the soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

[0089] The following describes the preferred content of artificial humic acid:

[0090] The different contents of artificial humic acid differ by 300 mg.

[0091] The following is the calculation formula for carbon isotope content:

[0092] In step A2 and step B2, the carbon abundance δ 13 C(‰), expressed as:

[0093] δ 13 C(‰)=(R sample / R V-PDB -1)×1000;

[0094] Where R sample represents the isotope ratio of rice; R V-PDB represents the isotope ratio of the standard material;

[0095] Carbon isotope content 13 C s , expressed as:

[0096] 13 C s (mg) = C sample ×[(δ 13 C(%)l-(δ 13 C(%)nl];

[0097] Where C sample represents the total carbon content absorbed by each rice plant; l represents rice labeled with carbon dioxide gas isotopes; nl represents rice outside the test chamber that was not labeled with carbon dioxide gas isotopes.

[0098] Specifically, the carbon abundance of rice that was not labeled with carbon dioxide gas isotopes outside the experimental chamber was different from that of rice that was labeled with carbon dioxide gas isotopes.

[0099] The distribution ratio of carbon dioxide isotopes input into the test chamber in roots, stems, leaves and soil can also be calculated:

[0100] 13 C p = 13 C x / ( 13 C 叶 + 13 C 茎 + 13 C 根 + 13 C 土 ) (7)

[0101] Where, 13 C p Represents the assimilation of various parts of rice 13 The distribution ratio of C in the rice-soil system; 13 C x represent 13 C 叶 or 13 C 茎 or 13 C 根 or 13 C 土 ; 13 C 叶 Represents the leaves 13 C content, 13 C 茎 Represents the stem 13 C content, 13 C 根 Represents the root 13 C content, 13 C 土 Represents the soil 13 C content.

[0102] The following is an introduction to the composition of artificial humic acid: Artificial humic acid uses rice straw as raw material.

[0103] The following introduces the composition of base fertilizer: the base fertilizer is a combination of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer. The source of nitrogen fertilizer is urea, the source of phosphorus fertilizer is superphosphate, and the source of potassium fertilizer is potassium sulfate; add 40mg of nitrogen fertilizer, 20mg of phosphorus fertilizer and 80mg of potassium fertilizer to every kilogram of soil.

[0104] The following further describes the environment within the same test chamber:

[0105] The environment was a day and night temperature of 30±1℃ / 25±1℃, a relative humidity of 80%-90%, a photoperiod of 12 hours, and a light intensity of 500μmol photons m-2s-1.

[0106] Specifically, Figure 2The experiments and results obtained under flooding irrigation and alternating wet-dry irrigation in this embodiment are shown in Table 1. The content of artificial humic acid applied to the six pots of rice in the experiment.

[0107] Table 1

[0108]

[0109] The experimental results showed that (1) 20 days after pulse labeling, the assimilation of different treatments 13 45.55%-55.36% of C was stored in rice leaves, 30.85%-36.56% was retained in stems, 5.43%-10.54% was transferred to roots, and 5.06%-8.64% was transferred to soil. As shown in Table 2;

[0110] Table 2 Effects of applying different amounts of artificial humic acid on rice carbon sequestration capacity under flooding irrigation and alternating wet-dry irrigation

[0111]

[0112]

[0113] From the perspective of different irrigation methods, under conventional flooding conditions, assimilation 13 C is retained more in the stems and leaves; under alternating dry and wet conditions, assimilation 13 C is transferred more to the root system and soil. From the perspective of AHA addition, when 300 mg / kg is applied, assimilation 13 C was most transferred to the roots and soil, especially under the DWI3 treatment. 13 The amount of C is the largest, which is 8.64%. (2) When no AHA is added, the P n 、T r and G s were higher than those under flooding irrigation, while Ci was lower than that under flooding irrigation. After adding AHA, P n 、T r and G s were significantly increased. Under DWI3 treatment, P n 、T r and G sThe value of Ci was the largest, increasing by 65.35%, 33.18% and 30.77% respectively compared with the DWI0 treatment. However, Ci showed an opposite trend, with the smallest value under the DWI3 treatment, decreasing by 17.18% compared with DWI0. (3) From the perspective of irrigation method, under the dry-wet alternating treatment, the total root length, root surface area and root length density of rice were greater than those under the flooding treatment. Under flooding, compared with no AHA application, the application of AHA significantly increased the total root surface area and root length density, and mainly promoted the root length density at a depth of 20-40 cm, but there was no significant difference between different AHA application amounts. Under the dry-wet alternating treatment, compared with no AHA application, the application of AHA significantly increased the total root length and root length density, and the promoting effect of DWI3 treatment was more significant than that of DWI6. Compared with DWI0, the total root length and root length density of DWI3 increased by 23.71% and 61.41%, respectively. Without AHA application, root activity under DWI0 was significantly greater than that under GI0. After AHA application, root activity under DWI3 and DWI6 was significantly higher than that under GI3 and GI6, respectively. Root activity was highest at DWI3, reaching 601.71 μg TTC / (g·h). (4) Overall, different irrigation and AHA application conditions had no significant effect on N2O emissions. Without AHA application, DWI0 significantly reduced CH4 but increased CO2 emission flux. After applying moderate amounts of AHA (GI3 and DWI3), the effects on CH4 and CO2 emissions were the greatest. Among them, CH4 emission flux under DWI3 was the lowest, decreasing by 13.72% and 14.28% compared to DWI0, respectively. CO2 emission flux was lowest under GI3, GI6, and DWI3. There were no significant differences among the three treatments. (5) When AHA is applied in alternating dry-wet cycles, in terms of photosynthetic carbon fixation, the concentrations of chlorophyll a, chlorophyll b, and carotenoids, as well as the activity of Rubisco, increase, leading to improved leaf photosynthetic capacity. In terms of root carbon transport, enhanced root aerenchyma and root activity, increased content of various organic acids in root exudates, and increased root biomass promote enhanced root carbon transport capacity. In terms of greenhouse gas emissions, both CH4 and CO2 are significantly reduced, reducing organic carbon losses. However, when using AHA, attention should be paid to the appropriate application rate. Among all the treatments in this experiment, the DWI3 treatment had the strongest photosynthetic carbon fixation and root transport capacity, and the greenhouse gas emission flux was relatively small. Therefore, the DWI3 treatment is a recommended treatment for carbon sequestration in the rice-soil system.

[0114] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A method for regulating the amount of artificial humic acid applied based on a potted rice water and fertilizer experiment, characterized in that: The method includes the following: Step 1: Planting multiple rice plants in a test chamber using two methods: flooding irrigation and alternating wet-dry irrigation. Carbon dioxide isotopes are introduced into the test chamber. Artificial humic acid at varying concentrations is added to the multiple rice plants planted using the flooding irrigation method. Simultaneously, the artificial humic acid at varying concentrations is added to the multiple rice plants planted using the alternating wet-dry irrigation method. After the rice plants have grown for a predetermined period of time, the carbon isotope content in the soil of each rice plant is measured. The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under flooding irrigation were used as the first data set. In the first data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively. The amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil under the dry-wet alternating irrigation system were used as the second data set. In the second data set, the amount of artificial humic acid added to each rice plant and the carbon isotope content in the soil were used as the output and input data of the model, respectively. Step 2: Use the first data set to train the first training model to obtain the trained first training model; Using the second data set to train the second training model, a trained second training model is obtained; Step 3: Input the carbon isotope content in the soil to be tested into the trained model to predict the corresponding amount of artificial humic acid to be added; The carbon isotope content in the soil to be tested is input into the trained model No. 2 to predict the corresponding amount of artificial humic acid to be added; In step 1, the specific process of adding the artificial humic acid of different contents to multiple rice plants planted in a dry-wet alternating irrigation method and measuring the carbon isotope content in the soil of each rice plant is as follows: Step B1: Apply different concentrations of artificial humic acid to multiple rice pots with the same soil volume and basal fertilizer dosage. The artificial humic acid is buried 10 cm below the soil surface. A 2-3 cm water layer is maintained for 7 days after rice planting. A tensiometer is used to monitor the soil water potential in real time. When the soil water potential is −15 kPa, water is applied to a 2-3 cm water layer on the soil surface. Step B2: After the rice has grown in the pot for 25 days, the carbon abundance in the soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

2. The method for regulating the amount of artificial humic acid applied based on potted rice water and fertilizer test according to claim 1, characterized in that: In step 1, the specific process of adding different amounts of artificial humic acid to multiple rice plants planted by flooding irrigation and measuring the carbon isotope content in the soil of each rice plant is as follows: Step A1: applying different amounts of artificial humic acid to multiple rice pots with the same amount of soil and base fertilizer, and burying the artificial humic acid 10 cm below the soil surface, while maintaining the water level in each pot at 2-3 cm; Step A2: After the rice has grown in the pot for 25 days, the carbon abundance in the rice soil is measured using an isotope mass spectrometer, and the soil carbon content is obtained based on the carbon abundance.

3. The method for regulating the amount of artificial humic acid applied based on potted rice water and fertilizer test according to claim 1, characterized in that: The different contents of artificial humic acid differ by 300 mg.

4. The method for regulating the amount of artificial humic acid applied based on potted rice water and fertilizer test according to claim 2 or 1, characterized in that: In step A2 and step B2, the carbon abundance δ 13 C (‰), expressed as: d 13 C (‰) =(R sample / R V-PDB -1) × 1000; Where R sample represents the isotope ratio of rice; R V-PDB represents the isotope ratio of the standard material; Carbon isotope content 13 C s , expressed as: 13 C s (mg)=C sample ×[(d 13 C (%) l-(δ 13 C (%) nl]; Where C sample represents the total carbon content absorbed by each rice plant; l represents rice labeled with carbon dioxide gas isotopes; nl represents rice outside the test chamber that was not labeled with carbon dioxide gas isotopes.

5. The method for regulating the amount of artificial humic acid applied based on potted rice water and fertilizer test according to claim 1, characterized in that: Artificial humic acid uses rice straw as raw material.

6. The method for regulating the amount of artificial humic acid applied based on potted rice water and fertilizer test according to claim 2 or 1, characterized in that: The base fertilizer consists of a combination of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer. The source of nitrogen fertilizer is urea, the source of phosphorus fertilizer is superphosphate, and the source of potassium fertilizer is potassium sulfate. 40 mg of nitrogen fertilizer, 20 mg of phosphorus fertilizer and 80 mg of potassium fertilizer are added to each kilogram of soil.

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