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KR-102964095-B1 - Estimation Method of Nitrous Oxide Gas Flux in Soil and The System Using The Same

KR102964095B1KR 102964095 B1KR102964095 B1KR 102964095B1KR-102964095-B1

Abstract

The present invention provides a method and apparatus for calculating nitrous oxide gas flux in soil, comprising the steps of: calculating limit values for a method detection limit and a practical quantification limit for nitrous oxide gas concentration; setting a change value of nitrous oxide gas concentration by comparing a change value of nitrous oxide gas concentration according to sampling time with the limit values; and receiving the set change value of nitrous oxide gas concentration to calculate the nitrous oxide gas flux.

Inventors

  • 강남구

Assignees

  • 한국표준과학연구원

Dates

Publication Date
20260512
Application Date
20240514

Claims (10)

  1. A step of calculating the limit values of the method detection limit and the practical quantification limit for nitrous oxide gas concentration; A step of setting a change in nitrous oxide gas concentration value by comparing the change in nitrous oxide gas concentration value according to the sampling time with the above limit value; and The method includes a step of receiving the above-set nitrous oxide gas concentration change value and calculating the nitrous oxide gas flux, wherein The nitrous oxide gas flux is calculated using the following equation (3), and The set value for the change in nitrous oxide gas concentration is, A step of assigning 0 as the setting value if the value is less than 0; Value 0 or greater If less than, use the setting value Step of granting; The value more If less than, use the setting value Step of granting; and The value If abnormal, the A method for calculating nitrous oxide gas flux in soil, characterized by including a step of assigning a value. Equation (3) In the above, is the method detection limit, is the practical limit of quantification, is the set value for the change in nitrous oxide gas concentration during the chamber confinement time, is the density of nitrous oxide gas (g/ cm³ ) at standard conditions (273 K, 1 atm), is the effective internal volume (㎥), is the internal floor area of the chamber (㎡), is the chamber confinement time (h), and represents the average absolute temperature (K) during the chamber confinement time.
  2. In claim 1, the above limit value is, A step of constructing a calibration curve for the quantitative analysis of nitrous oxide gas concentration using nitrous oxide standard gases of different concentrations; A step of preparing a nitrous oxide standard gas with a concentration lower than that in the atmosphere for calculating the limit value; A step of receiving quantified nitrous oxide values analyzed repeatedly and calculating the standard deviation; A method for calculating nitrous oxide gas flux in soil, characterized by including a step of receiving the above-determined standard deviation and calculating a limit value.
  3. In Clause 2, the above standard deviation is, A method for calculating nitrous oxide gas flux in soil, characterized by: a step of receiving quantitative values of nitrous oxide obtained by independently analyzing 10 times each for 3 days; a step of calculating the daily intra-variation standard deviation and the daily variation standard deviation; and a composite standard deviation obtained by synthesizing the intra-variation standard deviation and the daily variation standard deviation.
  4. In Paragraph 2, A method for calculating nitrous oxide gas flux in soil, characterized by calculating the method detection limit by multiplying each standard deviation by the Student-t value for a two-sided test at a 95% confidence level, and calculating the practical quantification limit by multiplying each standard deviation by 10.
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  7. Means for determining limit values for calculating the limit values of the method detection limit and the practical quantification limit for nitrous oxide gas concentration; A means for setting a change value in nitrous oxide gas concentration by comparing the change value in nitrous oxide gas concentration according to the sampling time with the above limit value to set the change value in nitrous oxide gas concentration; and It includes a means for calculating nitrous oxide gas flux that receives a change value of the nitrous oxide gas concentration set above and calculates the nitrous oxide gas flux, The nitrous oxide gas flux is calculated using the following equation (3), and The set value for the change in nitrous oxide gas concentration is, A step of assigning 0 as the setting value if the value is less than 0; Value 0 or greater If less than, use the setting value Step of granting; The value more If less than, use the setting value Step of granting; and The value If abnormal, the A system for calculating nitrous oxide gas flux in soil, characterized by including a step of assigning a value. Equation (3) In the above, is the method detection limit, is the practical limit of quantification, is the set value for the change in nitrous oxide gas concentration during the chamber confinement time, is the density of nitrous oxide gas (g/ cm³ ) at standard conditions (273 K, 1 atm), is the effective internal volume (㎥), is the internal floor area of the chamber (㎡), is the chamber confinement time (h), and represents the average absolute temperature (K) during the chamber confinement time.
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  10. A computer-readable recording medium storing a program for executing a method for calculating nitrous oxide gas flux in soil according to any one of claims 1 to 4.

Description

Estimation Method of Nitrous Oxide Gas Flux in Soil and The System Using The Same This invention was carried out as part of the following research and development project. a. Specialized Agency: Rural Development Administration, b. Project Name: Establishment of a New Agricultural Climate Change Response System (R&D), c. R&D Project No.: RS-2024-00400491, d. R&D Project Name: Development of Greenhouse Gas Absorption Coefficients and Uncertainty Assessment for New Carbon Sinks in Farmland, e. Co-development Agency: Korea Research Institute of Standards and Science" The present invention relates to a method and system for calculating nitrous oxide gas flux in soil, and more specifically, to a method and system for calculating nitrous oxide gas flux in soil capable of accurately calculating nitrous oxide gas flux generated in paddy soil, etc. Nitrogen is an essential element for plant growth and reproduction. About 25% of the nitrogen (ammonium and nitrates) available to plants in soil originates from organic nitrogen compounds, such as leaf mold, plant and animal residues, and the decomposition process (mineralization) of organic fertilizers. Roughly 5% comes from rainfall. However, globally, the largest portion (70%) is supplied to plants by inorganic nitrogen fertilizers, and without the use of nitrogen fertilizers, the Earth would not be able to maintain its current ratio. Soil microorganisms convert organic nitrogen into ammonium ( NH₄⁺ ), which is subsequently oxidized to nitrate ( NO₃⁻ ) , through a process known as nitrification. Nitrates are very important in agriculture because they are a form of nitrogen preferably absorbed by plants due to their high plant availability. However, nitrates are also highly mobile in the soil. Consequently, nitrates can easily leach into groundwater and be lost from the soil. Additionally, nitrogen is lost through denitrification, which microbiologically converts nitrates and nitrites ( NO₂ ) into gaseous forms of nitrogen, such as nitrous oxide ( N₂O ) and molecular nitrogen ( N₂ ). As a result of these various losses, approximately 50% of the applied nitrogen is lost during the year following fertilizer application. As a result, the intensive use of fertilizers and the application of livestock waste can lead to increased nitrogen levels in groundwater and surface water, which can increase the production of nitrous oxide, which significantly contributes to stratospheric ozone depletion and global warming. The goal of carbon neutrality, which has recently emerged as a major issue, is a global one. It is required across all industrial sectors, and its importance is growing in the agricultural sector as well. In particular, the demand for nitrogen fertilizers applied to paddy soils and other areas to improve soil fertility is increasing every year. Consequently, the emission of nitrous oxide into the atmosphere—a greenhouse gas—is also rising, making this a challenge that must be addressed to prepare for climate change and preserve the environment. To this end, measures must be devised to accurately measure and manage the concentration of nitrous oxide gas emitted from paddy soils and similar sources. Conventionally, the manual chamber method is generally used for the collection and measurement of nitrous oxide. This is a measurement method in which nitrous oxide is collected from the chamber using a manual chamber whenever it is periodically collected, and its concentration is analyzed using a GC in the laboratory. However, the concentration of nitrous oxide gas captured and measured from soil in this manner is difficult to trust due to the uncertainty of the measurement results caused by the detection limit (MDL) of the measuring equipment. Consequently, it is difficult to obtain accurate information regarding increases or decreases in the nitrous oxide flux or the amount of change, which poses significant difficulties in devising subsequent countermeasures such as environmental pollution prevention and restoration. Therefore, there is a need for research and development on technologies for accurately calculating nitrous oxide gas concentrations. Figure 1 shows the process of calculating nitrous oxide gas flux in soil according to the present invention. FIG. 2 shows the process of calculating the Method Detection Limit (MDL) and Practical Quantification Limit (PQL) for nitrous oxide gas concentration as an embodiment according to the present invention. Figure 3 shows the process of calculating the composite standard deviation as an embodiment according to the present invention. Figure 4 is a configuration diagram of a system for calculating nitrous oxide gas flux in soil according to the present invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodim