A method, system and device for assessing lemna carbon sink suitable for rice-lemna symbiotic system

Abstract

The application discloses a duckweed carbon sink evaluation method, system and equipment suitable for a rice-duckweed symbiotic system, relates to the technical field of agricultural production and ecological environment, and discloses the following technical scheme: after rice is harvested, the information of duckweed in the rice-duckweed symbiotic system is collected by using spectral scanning and laser point cloud technology, and the volume of the duckweed is determined based on the duckweed information; the duckweed biomass in the rice-duckweed symbiotic system is determined according to the duckweed volume; the duckweed carbon sink is estimated by using an artificial neural network algorithm and the duckweed biomass, or the duckweed carbon sink is estimated by using a duckweed carbon sink estimation formula and the duckweed biomass. The application can flexibly evaluate the duckweed carbon sink according to information such as rice agronomic management, soil and climate, and provides good technical support for the management and application of duckweed in a rice field.

Description

Technical Field

[0001] This invention relates to the fields of agricultural production and ecological environment technology, and in particular to a method, system and equipment for assessing duckweed carbon sequestration in rice-duckweed symbiotic systems. Background Technology

[0002] Duckweed is a small, planktonic aquatic plant commonly found in shallow water environments such as ditches, ponds, rice paddies, and puddles. In the past, duckweed was generally considered a harmful species that reduced rice yields and was typically removed by methods such as harvesting and spraying pesticides. However, with increasing attention to environmental pollution, the benefits of rice-duckweed symbiosis for environmental health have been discovered. Studies have shown that rice-duckweed symbiosis can reduce ammonia volatilization and greenhouse gas emissions from rice paddies, inhibit the occurrence and spread of rice pests and diseases, and enhance the stability of the rice paddy ecosystem.

[0003] Unlike terrestrial plants, duckweed does not rely heavily on root systems and can directly absorb nutrients such as nitrogen and phosphorus from water through its plant tissues surrounded by liquid. During its growth, duckweed absorbs and stores nutrients. After rice harvesting, the dried duckweed returns to the farmland soil, increasing exogenous organic matter input to raise soil organic carbon (SOC) content and mitigate agricultural non-point source pollution. Furthermore, the nitrogen and phosphorus in duckweed can increase the primary mineralization rate of soil nitrogen, reduce soil leaching and runoff loss, and lower the rate of soil organic carbon decomposition. Therefore, through alternating soil moisture and its own growth-death-decomposition process, duckweed can absorb and fix atmospheric CO2 and nitrogen and phosphorus from water, increasing soil carbon sequestration and offsetting some of the carbon budget imbalance in paddy fields.

[0004] Carbon sequestration refers to the processes, activities, and mechanisms by which CO2 is removed from the atmosphere. Estimating regional carbon sequestration in a timely and effective manner remains a challenge for the scientific community. Inventory methods are suitable for widely distributed ecosystems such as forests and grasslands where data is abundant; eddy covariance methods, primarily based on micrometeorological principles, struggle to accurately estimate the carbon budget of agricultural ecosystems; ecosystem process modeling simulations generally do not consider or simplify the impact of ecosystem management (such as soil management and agricultural irrigation) on the carbon cycle; atmospheric inversion methods are suitable for large-scale targets, but the target area for paddy fields is too small, resulting in excessive uncertainty in the inversion results.

[0005] Therefore, there is currently a lack of a fast, accurate, and flexible method to estimate the carbon sequestration of duckweed (i.e., the soil carbon sequestration increased by duckweed during its decomposition in the field), so as to partially compensate for the ecological benefits and promote the development of the paddy field carbon sequestration economy. Summary of the Invention

[0006] The purpose of this invention is to provide a method, system, and equipment for assessing duckweed carbon sequestration in rice-duckweed symbiotic systems. This method can flexibly assess duckweed carbon sequestration based on information such as rice agronomic management, soil, and climate, providing good technical support for the management and application of duckweed in paddy fields.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] In a first aspect, the present invention provides a method for assessing the carbon sequestration of duckweed in rice-duckweed symbiotic systems, comprising:

[0009] After rice harvest, information on duckweed in the rice-duckweed symbiotic system was collected using spectral scanning and laser point cloud technology, and the volume of duckweed was determined based on the information.

[0010] Determine the duckweed biomass in the rice-duckweed symbiotic system based on the duckweed volume;

[0011] The carbon sink of duckweed can be estimated using artificial neural network algorithms and duckweed biomass, or by using duckweed carbon sink estimation formulas and duckweed biomass.

[0012] Secondly, the present invention provides a duckweed carbon sequestration assessment system suitable for rice-duckweed symbiotic systems, comprising:

[0013] The duckweed information and duckweed volume determination module is used to collect duckweed information in the rice-duckweed symbiotic system after rice harvest using spectral scanning and laser point cloud technology, and to determine the duckweed volume based on the duckweed information.

[0014] The duckweed biomass calculation module is used to determine the duckweed biomass in the rice-duckweed symbiotic system based on the duckweed volume;

[0015] The duckweed carbon sequestration estimation module is used to estimate duckweed carbon sequestration using artificial neural network algorithms and duckweed biomass, or using duckweed carbon sequestration estimation formulas and duckweed biomass.

[0016] Thirdly, the present invention provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to cause the electronic device to perform the duckweed carbon sink assessment method applicable to rice-duckweed symbiotic systems according to the first aspect.

[0017] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0018] This invention, based on spectral scanning and laser point cloud technology, employs artificial neural network algorithms or duckweed carbon sequestration estimation formulas to estimate duckweed carbon sequestration. This invention not only solves the inapplicability of current carbon sequestration calculation methods in rice-duckweed symbiotic systems but also improves upon the problems of high time costs and poor portability of agricultural system models. It provides a possibility for the effective estimation of duckweed carbon sequestration in regional paddy fields and further offers excellent technical support for the management and application of duckweed in paddy fields. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the method for assessing duckweed carbon sequestration in a rice-duckweed symbiotic system provided in an embodiment of the present invention.

[0021] Figure 2 The diagram shows the structural block diagram of a duckweed carbon sequestration assessment system suitable for rice-duckweed symbiotic systems, provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of 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.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] like Figure 1 As shown in the figure, this embodiment provides a method for assessing duckweed carbon sequestration in a rice-duckweed symbiotic system, which includes the following steps.

[0026] Step 100: After rice harvest, collect duckweed information in the rice-duckweed symbiotic system using spectral scanning and laser point cloud technology, and determine the duckweed volume based on the duckweed information.

[0027] In this embodiment, determining the volume of duckweed based on duckweed information specifically includes:

[0028] Based on the duckweed information, the closed surface of the point cloud is reconstructed using image and point cloud 3D reconstruction technology, and the volume of the closed surface of the point cloud, i.e., the duckweed volume (V), is calculated using the Monte Carlo algorithm.

[0029] Step 200: Determine the duckweed biomass in the rice-duckweed symbiotic system based on the duckweed volume.

[0030] In this embodiment, step 200 specifically includes:

[0031] The duckweed biomass in the rice-duckweed symbiotic system is calculated based on the custom function of duckweed biomass, duckweed volume, and the conversion coefficient between duckweed volume and duckweed biomass.

[0032] In this embodiment, Python is used to numerically solve a custom function for duckweed biomass. The custom function for duckweed biomass is:

[0033] B = ln|V ζ -T i |

[0034] In the formula, B represents the duckweed biomass, in g / m³. 3 V represents the volume of duckweed, in cubic meters (m³). 3 ζ is the conversion coefficient between duckweed volume and duckweed biomass, T i For constant parameters related to duckweed varieties, i represents the duckweed variety, and i = 1, 2, 3, 4 represent rhomboid duckweed, common duckweed, small duckweed, and root duckweed, respectively.

[0035] Step 300: Estimate duckweed carbon sink using an artificial neural network algorithm and duckweed biomass, or estimate duckweed carbon sink using a duckweed carbon sink estimation formula and duckweed biomass.

[0036] In this embodiment, before performing step 300, the following steps are also included:

[0037] 1) The duckweed biomass was corrected using parameters such as the initial stocking density and water properties; the duckweed biomass correction formula is as follows:

[0038]

[0039] In the formula, B c This is the corrected duckweed biomass, in g / m³. 3 B represents duckweed biomass, in g / m³. 3 ;ρ d This refers to the initial stocking density of duckweed, expressed as plants per m². 3 ;ρ r 1. Rice planting density, in 10,000 hectares; 2. pH, the acidity or alkalinity of the paddy field water; 3. d, the depth of the paddy field water, in meters; 4. N wThe nitrogen concentration in paddy field water is expressed in kg·L. -1 DO represents the dissolved oxygen content of paddy field water, measured in mg·L⁻¹. -1 N T The concentration of nitrogen applied during rice cultivation is expressed in kg·L. -1 .

[0040] In this embodiment, an artificial neural network algorithm and duckweed biomass are used to estimate duckweed carbon sequestration, specifically including...

[0041] First, an estimation model for duckweed carbon sequestration is constructed using an artificial neural network algorithm and multiple historical data. Second, based on the corrected duckweed biomass and the duckweed carbon sequestration estimation model, the current duckweed carbon sequestration, i.e., the increase in organic carbon content in the soil after duckweed returns to the soil, is estimated.

[0042] Historical data includes input data and corresponding label data; soil organic carbon content, duckweed biomass, duckweed organic carbon content, number of microorganisms in the soil, tillage depth, temperature and humidity, total nitrogen content and C / N ratio are input data, and duckweed carbon sink is label data.

[0043] In this embodiment, the formula for estimating duckweed carbon sequestration is:

[0044]

[0045] Where CS represents the carbon sequestration of duckweed, measured in Pg C·yr. -1 SOC refers to soil organic carbon content (e.g., obtained using a total organic carbon analyzer), with units of g·kg. -1 B c This is the corrected duckweed biomass, in g / m³. 3 ; OC is the organic carbon content of duckweed, in %; ε is the conversion coefficient; M a The number of microorganisms in the soil, expressed in CFU·g. -1 T represents the decomposition time of duckweed, in days; η j The carbon emission factors are denoted by different tillage modes, where j = 1, 2, and 3 represent tillage, rotary tillage, and no-till cover, respectively; d s Tillage depth, in meters; H is the average soil moisture at a depth of 0-20 cm, in percentage rh; T s The average temperature of the soil at a depth of 0-20 cm, expressed in °C; T a TN is the air temperature, expressed in °C. s Total nitrogen content (TN) at a depth of 0-20 cm in the soil, expressed as a percentage. d The total nitrogen content of duckweed is expressed as a percentage (%); P d The C / N ratio in duckweed; P s This refers to the C / N ratio in the soil.

[0046] In this embodiment, the organic carbon content (OC) and total nitrogen content (Total N) of duckweed were determined using a total organic carbon analyzer and ultraviolet spectrophotometry, and then the carbon-to-nitrogen ratio (C / N) of duckweed was calculated. Wherein, the total nitrogen content (Total N) of duckweed = TN d The carbon-to-nitrogen ratio of duckweed is P. d TN s and P s These are parameters of the soil measured separately.

[0047] Correspondingly, the carbon sequestration of duckweed per unit biomass is:

[0048]

[0049] Example 2

[0050] In order to implement the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a duckweed carbon sink assessment system suitable for rice-duckweed symbiotic system is provided below.

[0051] like Figure 2 As shown in this embodiment, a duckweed carbon sequestration assessment system suitable for rice-duckweed symbiotic systems is provided, comprising:

[0052] The duckweed information and duckweed volume determination module 1 is used to collect duckweed information in the rice-duckweed symbiotic system after rice harvest using spectral scanning and laser point cloud technology, and to determine the duckweed volume based on the duckweed information.

[0053] The duckweed biomass calculation module 2 is used to determine the duckweed biomass in the rice-duckweed symbiotic system based on the duckweed volume.

[0054] The duckweed carbon sequestration estimation module 3 is used to estimate duckweed carbon sequestration using artificial neural network algorithms and duckweed biomass, or to estimate duckweed carbon sequestration using duckweed carbon sequestration estimation formulas and duckweed biomass.

[0055] Example 3

[0056] This invention provides an electronic device including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to enable the electronic device to perform the duckweed carbon sequestration assessment method applicable to rice-duckweed symbiotic systems described in Embodiment 1.

[0057] Alternatively, the aforementioned electronic device may be a server.

[0058] In addition, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the duckweed carbon sequestration assessment method applicable to rice-duckweed symbiotic systems of Embodiment 1.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0060] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for assessing Lemna carbon sink suitable for rice-Lemna symbiotic system, characterized in that, The method comprises the following steps: After the rice is harvested, the duckweed information in the rice-duckweed symbiotic system is collected by using spectral scanning and laser point cloud technology, and the duckweed volume is determined based on the duckweed information; The duckweed biomass in the rice-duckweed symbiotic system is determined according to the duckweed volume, specifically including: The duckweed biomass in the rice-duckweed symbiotic system is calculated according to the self-defined function of the duckweed biomass, the duckweed volume, and the conversion coefficient of the duckweed volume and the duckweed biomass; The self-defined function of the duckweed biomass is: B = ln |V ζ - T i |; wherein B is the biomass of duckweed, in g / m 3 ; V is the volume of duckweed, in m 3 ; ζ is the conversion coefficient of the volume of duckweed and the biomass of duckweed; T i is a constant parameter related to the species of duckweed, i represents the species of duckweed, i = 1, 2, 3, 4 respectively represents Lemna trisulca, Lemna minor, Lemna gibba and Spirodela polyrrhiza. The duckweed carbon sink is estimated by using the artificial neural network algorithm and the duckweed biomass, or the duckweed carbon sink is estimated by using the duckweed carbon sink estimation formula and the duckweed biomass; Before the step of estimating the duckweed carbon sink by using the artificial neural network algorithm and the duckweed biomass, or estimating the duckweed carbon sink by using the duckweed carbon sink estimation formula and the duckweed biomass, the method further comprises the following steps: The duckweed biomass is corrected by using the initial duckweed release density and the water body property parameters; The correction formula of the duckweed biomass is: wherein, B c is the corrected duckweed biomass, in g / m 3 ; B is the duckweed biomass, in g / m 3 ; p d is the initial duckweed planting density, in plant / m 3 ; p r is the rice planting density, in ten thousand hills; pH is the pH value of the paddy field water; d is the depth of the paddy field water, in m; N w is the nitrogen concentration of the paddy field water, in kg·L -1 ; DO is the dissolved oxygen content of the paddy field water, in mg·L -1 ; N T is the nitrogen application concentration during the rice planting process, in kg·L -1 ; The duckweed carbon sink estimation formula is: where CS is the carbon sink of duckweed, with the unit of Pg C·yr -1 ; SOC is the soil organic carbon content, with the unit of g·kg -1 ; B c is the corrected duckweed biomass, with the unit of g / m 3 ; OC is the organic carbon content of duckweed, with the unit of %; ε is the conversion coefficient; M a is the number of microorganisms in the soil, with the unit of CFU·g -1 ; T is the decomposition time of duckweed, with the unit of days; η j is the carbon emission factor under different tillage modes, j = 1, 2, 3 represent tillage, rotary tillage and mulch no-tillage, respectively; d s is the tillage depth, with the unit of m; H is the average humidity of soil at 0-20 cm, with the unit of %rh; T s is the average temperature of soil at 0-20 cm, with the unit of ℃; T a is the air temperature, with the unit of ℃; TN s is the total nitrogen content of soil at 0-20 cm, with the unit of %; TN d is the total nitrogen content of duckweed, with the unit of %; P d is the C / N ratio in duckweed; P s is the C / N ratio in soil.

2. The method for assessing Lemna carbon sink according to claim 1, wherein, The duckweed volume is determined based on the duckweed information, specifically including: According to the duckweed information, the image and point cloud three-dimensional reconstruction technology is used to reconstruct a point cloud closed surface, and the Monte Carlo algorithm is used to calculate the volume of the point cloud closed surface; the volume of the point cloud closed surface is the duckweed volume.

3. A duckweed carbon sink assessment system for a rice-duckweed symbiotic system, which executes a method for assessing a duckweed carbon sink for a rice-duckweed symbiotic system according to any one of claims 1 to 2, characterized by, The method comprises the following steps: The duckweed information and duckweed volume determination module is used to collect the duckweed information in the rice-duckweed symbiotic system by using spectral scanning and laser point cloud technology after the rice is harvested, and the duckweed volume is determined based on the duckweed information; The duckweed biomass calculation module is used to determine the duckweed biomass in the rice-duckweed symbiotic system according to the duckweed volume; The duckweed carbon sink estimation module is used to estimate the duckweed carbon sink by using the artificial neural network algorithm and the duckweed biomass, or estimate the duckweed carbon sink by using the duckweed carbon sink estimation formula and the duckweed biomass.

4. An electronic device, comprising: The electronic device comprises a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to make the electronic device execute the duckweed carbon sink evaluation method for the rice-duckweed symbiotic system according to any one of claims 1 to 2.

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