A method for calculating a mulched soil surface layer temperature

Abstract

The application discloses a kind of film mulching soil surface layer temperature calculation method.The method comprises the following steps:1, collecting historical meteorological data;2, calculate the soil surface layer temperature of non-mulching film using historical meteorological data;3, calculate the soil surface layer temperature of mulching film using the soil surface layer temperature of non-mulching film.The film mulching soil temperature calculation method provided by the application provides a strong guarantee for accurate estimation of film mulching planting agriculture, more accurately simulates crop planting information and greenhouse gas emissions, and has great agricultural ecological application value.

Description

Technical Field

[0001] This invention relates to the development of an optimized soil surface temperature simulation module for the DNDC model. Background Technology

[0002] Soil is a thin, unconsolidated layer of material on the Earth's surface that plays a fundamental role in supporting life on Earth, determining the exchange of energy and mass between the lithosphere and the atmosphere.

[0003] Temperature affects all physical, chemical, and biological processes in the soil. Biological processes, including root absorption of nutrients and water, microbial decomposition of organic matter, and seed germination, are strongly influenced by soil temperature. For every 10°C increase in temperature, the rate of some of these processes (including some relevant processes in enzymatic reactions) more than doubles.

[0004] In some cases, the growth of above-ground plant parts is more closely related to soil temperature than to air temperature. Physical processes such as water movement and soil drying are also strongly influenced by temperature. On a larger scale, soil thermodynamics is crucial for converting solar radiation into longwave radiation and latent heat of vaporization.

[0005] The denitrification decomposition (DNDC) model is a process-oriented computer simulation of carbon and nitrogen biogeochemistry in agricultural ecosystems. The model consists of two parts.

[0006] The first part consists of soil climate, crop growth, and decomposition sub-models, which predict soil temperature, humidity, pH, redox potential (Eh), and substrate concentration curves driven by ecological drivers such as climate, soil, vegetation, and human activities.

[0007] The second part consists of nitrification, denitrification, and fermentation sub-models that can predict emissions of carbon dioxide (CO2), methane (CH4), ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), and nitrous oxide (N2) from the plant-soil system.

[0008] Classical laws of physics, chemistry, and biology, along with empirical equations derived from laboratory studies, have been incorporated into the model to parameterize each specific geochemical or biochemical reaction. The entire model bridges the gap between carbon and nitrogen biogeochemical cycles and key ecological drivers.

[0009] Soil temperature simulation is closely related to all modules of the DNDC model, and its simulation accuracy affects the overall accuracy of the model. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a method for calculating the surface temperature of mulched soil. For mulched farmland in Northwest China, there is currently no successful software for embedding a mulched farmland temperature simulation module within the DNDC model, and existing mulched temperature simulation schemes applied to other models show poor simulation results when applied to the overall DNDC model. Research has shown that the optimized algorithm in this experiment performs well in simulating soil temperature under mulched conditions within the DNDC model.

[0011] To achieve the above objectives, the present invention provides a method for calculating the surface temperature of covered soil, comprising the following steps:

[0012] 1. Collect historical meteorological data;

[0013] 2. Calculate the surface temperature of the soil without plastic film using historical meteorological data;

[0014] 3. Calculate the surface temperature of soil covered with mulch using the surface temperature of soil without mulch.

[0015] Further steps in collecting historical meteorological data include:

[0016] 21. Obtain meteorological data, including but not limited to temperature, precipitation, and radiation, from meteorological data acquisition devices such as weather stations and flux towers;

[0017] 22. The collected air temperatures are processed to obtain the daily maximum temperature (MAX) and minimum temperature (MIN), the precipitation is calculated to obtain the daily precipitation, and the radiation is calculated to obtain the daily radiation value (unit: millijoules per square meter);

[0018] 23. Compile the collected meteorological information into a CSV document, and write the basic crop information into the DNDC model configuration file;

[0019] Furthermore, the specific steps for calculating the surface temperature of uncovered soil using historical meteorological data are as follows:

[0020] 31. Save the CSV file containing meteorological data, named by year, to the DNDC file reading path;

[0021] 32. Write a command line to run the DNDC model, including but not limited to the input, output, configuration file path, and running mode selection;

[0022] 33. Run the DNDC model to obtain the surface temperature of the uncovered soil;

[0023] ①○ When the number of days of operation is the first day, the surface soil temperature is equal to the average of the highest and lowest temperatures of the day;

[0024] ② When the temperature is above 0℃, the empirical equation for the surface temperature of unplanted soil without mulching is as follows:

[0025] NST=AT–0.5*OAT+0.5*OT------------------(1)

[0026] In formula (1), NST represents the surface temperature of the uncovered soil, AT represents the average of the highest and lowest air temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest air temperatures of the previous day.

[0027] ③ When the temperature is below 0℃, the empirical equation for the surface temperature of unplanted soil without mulching is as follows:

[0028] NST=0.5*AT–0.3*OAT+0.8*OT------------------(2)

[0029] In formula (2), NST represents the surface temperature of the uncovered soil, AT represents the average of the highest and lowest air temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest air temperatures of the previous day.

[0030] Furthermore, the specific steps for calculating the surface temperature of soil covered with mulch using the surface temperature of uncovered soil are as follows:

[0031] 41. Write a command line to run the DNDC model, including but not limited to the input, output, configuration file path, and running mode selection;

[0032] 42. Run the DNDC model to obtain the surface temperature of the soil in the mulched but unplanted area;

[0033] ① When the number of days of operation is the first day, the surface soil temperature is equal to the average of the highest and lowest temperatures of the day;

[0034] ② When snow cover is present, i.e., the meteorological conditions are a temperature below 0℃ and precipitation, the empirical equation for the surface temperature of unplanted soil under mulching conditions is:

[0035] ST=0------------------(3)

[0036] In formula (3), ST represents the surface temperature of the soil without planting under mulch;

[0037] ③ When there is no snow cover, i.e., the meteorological conditions are a temperature greater than 0℃ or no precipitation, the following prerequisites are defined:

[0038] Ke = 0.1 ------------------(4)

[0039] dTTT=(MT–NST)*TCfilm*dt / Dfilm / SC*e-ke*LAI-----------------(5)

[0040] In equation (4), Ke is the extinction coefficient, which is set to a constant value of 0.1.

[0041] In formula (5), dTTT is the coefficient of change of soil surface temperature in unplanted soil caused by mulching, MT is the highest temperature of the day, NST is the soil surface temperature in the case of no mulching, TCfilm is the heat capacity of mulch film, Dfilm is the thickness of mulch film, SC is the heat capacity of soil, Ke is the extinction coefficient, and LAI is the leaf area index (0 in the case of no planting).

[0042] ④ When the temperature is above 0℃, the empirical equation for the surface temperature of unplanted soil under mulching conditions is as follows:

[0043] ST=NST+2*dTTT / ln(MAX–MIN)+0.3*dTTT------------------(6)

[0044] In equation (6), ST represents the surface temperature of the soil without mulch and planting, NST represents the surface temperature of the soil without mulch and planting, dTTT is the coefficient of change in surface temperature of the unplanted soil caused by mulch, MAX represents the highest temperature observed by meteorology, and MIN represents the lowest temperature observed by meteorology.

[0045] ⑤ When the temperature is below 0℃, the empirical equation for the surface temperature of unplanted soil under mulching conditions is as follows:

[0046] ST=NST+0.1*dTTT------------------(7)

[0047] In equation (7), ST represents the surface temperature of the soil without mulch and planting, NST represents the surface temperature of the soil without mulch and planting, and dTTT is the coefficient of change in surface temperature of the soil without planting caused by mulch.

[0048] The optimized DNDC model, using this algorithm, achieves improved accuracy in simulating soil temperature in mulched farmland compared to the original model. The algorithm can be integrated into the original DNDC model and participate in numerous calculations via command-line modifications. Furthermore, the simulation of crop growth information and greenhouse gases during the execution of the modified DNDC model effectively improves the accuracy of the simulation results. This invention proposes a method and system for calculating surface temperature of mulched soil, which more accurately simulates farmland-related information, improving economic benefits in crop management and greenhouse effect assessment, and has practical reference value. Attached Figure Description

[0049] Figure 1 This is a flowchart of a method and system for calculating the surface temperature of covered soil according to the present invention;

[0050] Figure 2(a) is a simulation result (time series distribution) of the original model of the present invention;

[0051] Figure 2(b) is a scatter plot of the simulation results of the original model of the present invention;

[0052] Figure 3(a) shows the simulation results (time series distribution) of an optimized DNDC model according to the present invention;

[0053] Figure 3(b) is a scatter plot of the simulation results of an optimized DNDC model according to the present invention; Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] Reference Figure 1 :

[0056] Step 1: Data Acquisition and Processing

[0057] (1) Obtain meteorological data from meteorological data acquisition devices such as weather stations and flux towers, including but not limited to temperature, precipitation, and radiation;

[0058] (2) The collected air temperature data is processed to obtain the daily maximum temperature (MAX) and minimum temperature (MIN), the precipitation is calculated to obtain the daily precipitation, and the radiation is calculated to obtain the daily radiation value (unit: millijoules per square meter). The specific format is shown in Table 1.

[0059] Table 1 Meteorological Data Input File

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] (3) Organize the meteorological information into a CSV document and write the basic crop information into the dndc model configuration file.

[0072] Run the modified DNDC model by executing the following command line:

[0073] DNDC configuration file output path

[0074] Step 2: Simulating the surface temperature of uncovered soil

[0075] (1) Save the CSV file containing meteorological data, named by year, to the dndc file reading path;

[0076] (2) Write a command line to run the dndc model, including but not limited to the input, output, configuration file path and the selection of the running mode;

[0077] (3) Run the dndc model to obtain the surface temperature of the uncovered soil;

[0078] ① When the number of days of operation is the first day, the surface soil temperature is equal to the average of the highest and lowest temperatures of the day;

[0079] ② When the temperature is above 0℃, the empirical equation for the surface temperature of unplanted soil under mulching conditions is as follows:

[0080] NST=AT–0.5*OAT+0.5*OT------------------(1)

[0081] In formula (1), NST represents the surface temperature of the uncovered soil, AT represents the average of the highest and lowest air temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest air temperatures of the previous day.

[0082] ③ When the temperature is below 0℃, the empirical equation for the surface temperature of unplanted soil without mulching is as follows:

[0083] NST=0.5*AT–0.3*OAT+0.8*OT------------------(2)

[0084] In formula (2), NST represents the surface temperature of the uncovered soil, AT represents the average of the highest and lowest air temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest air temperatures of the previous day.

[0085] Step 3: Simulating the surface temperature of the covered soil

[0086] (1) Write a command line to run the dndc model, including but not limited to the input, output, path to the configuration file, and selection of the running mode;

[0087] (2) Run the dndc model to obtain the surface temperature of the soil without planting under film covering;

[0088] ① When the number of days of operation is the first day, the surface soil temperature is equal to the average of the highest and lowest temperatures of the day;

[0089] ② When snow cover is present, i.e., the meteorological conditions are a temperature below 0℃ and precipitation, the empirical equation for the surface temperature of unplanted soil under mulching conditions is:

[0090] ST=0------------------(3)

[0091] In formula (3), ST represents the surface temperature of the soil without planting under mulch;

[0092] ③ When there is no snow cover, i.e., the meteorological conditions are a temperature greater than 0℃ or no precipitation, the following prerequisites are defined:

[0093] Ke = 0.1 ------------------(4)

[0094] dTTT=(MT–NST)*TCfilm*dt / Dfilm / SC*e-ke*LAI-----------------(5)

[0095] In equation (4), Ke is the extinction coefficient, which is set to a constant value of 0.1.

[0096] In formula (5), dTTT is the coefficient of change of soil surface temperature in unplanted soil caused by mulching, MT is the highest temperature of the day, NST is the soil surface temperature in the case of no mulching, TCfilm is the heat capacity of mulch film, Dfilm is the thickness of mulch film, SC is the heat capacity of soil, Ke is the extinction coefficient, and LAI is the leaf area index (0 in the case of no planting).

[0097] ④ When the temperature is above 0℃, the empirical equation for the surface temperature of unplanted soil under mulching conditions is as follows:

[0098] ST=NST+2*dTTT / ln(MAX–MIN)+0.3*dTTT------------------(6)

[0099] In formula (6), ST represents the surface temperature of the soil without mulch and planting, NST represents the surface temperature of the soil without mulch and planting, dTTT is the coefficient of change of surface temperature of the soil without planting caused by mulch, MAX represents the highest temperature observed by meteorology, and MIN represents the lowest temperature observed by meteorology.

[0100] ⑤ When the temperature is below 0℃, the empirical equation for the surface temperature of unplanted soil under mulching conditions is as follows:

[0101] ST=NST+0.1*dTTT------------------(7)

[0102] In formula (7), ST represents the surface temperature of the soil without mulch and planting, NST represents the surface temperature of the soil without mulch and planting, and dTTT is the coefficient of change of surface temperature of the soil without planting caused by mulch.

[0103] The soil temperature simulation results are shown in the table below:

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] Compared with the simulation results of the original model (Figure 2), the simulation results of the DNDC model optimized by this algorithm (Figure 3) have a higher accuracy improvement, laying the foundation for the simulation of various parameters of the subsequent model.

[0117] This invention provides a soil surface temperature simulation algorithm widely applicable to rain-fed mulched agriculture in the Loess Plateau region of China. However, in practice, technicians may modify the fixed parameters in this scheme depending on the type of mulch used and the soil texture. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A method of calculating a mulched soil surface layer temperature, characterized by, The method comprises the following steps: S1, collecting historical meteorological data; S2, calculating the soil surface temperature of non-covered soil by using the historical meteorological data; S3, calculating the soil surface temperature of covered soil by using the soil surface temperature of non-covered soil; The step of calculating the soil surface temperature of covered soil by using the soil surface temperature of non-covered soil is specifically: S41, writing a command line for running the DNDC model, and the information includes the path of input, output and configuration file and the selection of running mode; S42, running the DNDC model to obtain the soil surface temperature of non-planted soil under film covering; ① When the running day is the first day, the surface soil temperature is equal to the average of the highest temperature and the lowest temperature in the daily temperature; ② When there is snow cover, that is, the meteorological condition is that the temperature is less than 0 DEG C and there is precipitation, the empirical equation formula of the soil surface temperature of non-planted soil under film covering is: ST = 0------------------(3) In formula (3), ST represents the soil surface temperature of non-planted soil under film covering; ③ When there is no snow cover, that is, the meteorological condition is that the temperature is greater than 0 DEG C or there is no precipitation, the following prerequisite condition is defined: Ke = 0.1------------------(4) -----------------(5) In formula (4), Ke is the extinction coefficient, which is set to a constant value of 0.1; In formula (5), dTTT is the change coefficient of the soil surface temperature of non-planted soil caused by film covering, MT is the daily maximum temperature, NST is the soil surface temperature under non-film covering, TCfilm is the film heat capacity, Dfilm is the film thickness, SC is the soil heat capacity, Ke is the extinction coefficient, and LAI is the leaf area index, which is 0 under non-planted condition; ④ When the temperature is greater than 0 DEG C, the empirical equation formula of the soil surface temperature of non-planted soil under film covering is: ST = NST + 2*dTTT / ln(MAX - MIN) + 0.3*dTTT------------------(6) In formula (6), ST represents the soil surface temperature of non-planted soil under film covering, NST represents the soil surface temperature of non-planted soil under non-film covering, dTTT is the change coefficient of the soil surface temperature of non-planted soil caused by film covering, MAX represents the maximum temperature observed by meteorology, and MIN represents the minimum temperature observed by meteorology; ⑤ When the temperature is less than 0 DEG C, the empirical equation formula of the soil surface temperature of non-planted soil under film covering is: ST = NST + 0.1*dTTT------------------(7) In formula (7), ST represents the soil surface temperature of non-planted soil under film covering, NST represents the soil surface temperature of non-planted soil under non-film covering, and dTTT is the change coefficient of the soil surface temperature of non-planted soil caused by film covering.

2. The mulched soil surface layer temperature calculation method according to claim 1, characterized by, The step of collecting historical meteorological data comprises: S21, obtaining meteorological data including temperature, precipitation and radiation from a meteorological station and a flux tower meteorological data acquisition device; S22, arranging the collected temperature to obtain daily maximum and minimum temperature, calculating daily precipitation, and calculating daily radiation value; S23, the weather information is arranged into a csv document, and the basic information of crops is written into a DNDC model configuration file.

3. The mulched soil surface layer temperature calculation method according to claim 1, characterized by, The step of calculating the soil surface temperature of the uncovered film soil by using historical meteorological data is specifically: S31, the csv file containing meteorological data is stored in the DNDC file reading path according to the year; S32, a command line for running the DNDC model is written, and the information includes the path of input, output and configuration file and the selection of running mode; S33, the DNDC model is run to obtain the soil surface temperature of the uncovered film soil; ①, when the running day is the first day, the surface soil temperature is equal to the average of the highest and lowest temperatures of the day; ②, when the temperature is greater than 0℃, the empirical equation formula of the surface soil temperature of the soil without planting under the condition of no film covering is: NST = AT - 0.5*OAT + 0.5*OT------------------(1) In formula (1), NST represents the surface soil temperature of the uncovered film soil, AT represents the average of the highest and lowest temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest temperatures of the previous day; ③, when the temperature is less than 0℃, the empirical equation formula of the surface soil temperature of the soil without planting under the condition of no film covering is: NST = 0.5*AT - 0.3*OAT + 0.8*OT------------------(2) In formula (2), NST represents the surface soil temperature of the uncovered film soil, AT represents the average of the highest and lowest temperatures, OT represents the soil temperature of the previous day, and OAT represents the average of the highest and lowest temperatures of the previous day.

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