CN-122022032-A - Grassland precise mowing stubble height determining method based on species component analysis

CN122022032ACN 122022032 ACN122022032 ACN 122022032ACN-122022032-A

Abstract

The application discloses a grassland accurate mowing stubble height determining method based on species component analysis, which comprises the steps of setting a sampling party in each experimental district of a target grassland, carrying out species investigation on plants in the sampling party, collecting plant heights in each sampling party, mowing plants with natural heights, drying fresh grass subjected to mowing until constant weight and weighing to obtain overground biomass and total biomass of the sampling party of each species in each sampling party, calculating reference utilization rate of all the species under a given height by using an iterative dichotomy aiming at each sampling party and combining the average height, overground biomass and total biomass of the sampling party, taking the given height which corresponds to the reference utilization rate meeting tolerance conditions as the target stubble height, and determining an arithmetic average value of the target stubble height corresponding to each sampling party as the recommended stubble height. The method can accurately and scientifically predict and control the mowing utilization rate, and achieves the dual purposes of sustainable utilization of grassland resources and ecological protection.

Inventors

Hou Shuangli
LV XIAOTAO
WANG PINGZHOU
WANG ZHENGWEN

Assignees

中国科学院沈阳应用生态研究所

Dates

Publication Date: 20260512
Application Date: 20260122

Claims (4)

1. The method for determining the precision mowing stubble height of the grassland based on species component analysis is characterized by comprising the following steps of: Randomly selecting M experimental cells with the same size in a target threshing place, setting a sample party in each experimental cell, and carrying out species investigation and recording on all plants in each sample party; Randomly selecting and measuring natural heights of N healthy individuals of each species in each sample, and calculating the average height of each species in the sample according to the natural heights; the plants with the measured natural heights are mowed on the ground to obtain fresh grass after the various species in each sample are mowed; Respectively putting the fresh grass after mowing into a 65 ℃ oven for drying to constant weight and weighing to obtain the overground biomass of each species in each sample, and calculating the total biomass of the sample corresponding to each sample according to the overground biomass; For each sample side, an iterative dichotomy is used, the average height of each species in the sample side, the overground biomass and the total biomass of the sample side are combined, the reference utilization rate of all the species at a given height is calculated, the given height corresponding to the difference absolute value between the reference utilization rate and the target utilization rate is the target stubble height when the absolute value is smaller than or equal to a preset tolerance, wherein the target utilization rate is a value within a range of 45% -55% calculated according to a preset mapping rule according to the accumulated precipitation amount and growth Ji Fengzhi NDVI from 1 month to 1 day in the current year, and the given height is a theoretical height determined based on the average height of the highest plants in the sample side by using the iterative dichotomy; And determining the arithmetic average value of the target stubble height corresponding to each sample party as the recommended stubble height of the target threshing field.
2. The method of claim 1, wherein calculating a sample total biomass for each sample based on the above-ground biomass comprises: Taking the sum of the overground biomass of each species in a specific sample as the total biomass of the sample corresponding to the specific sample, or, Calculating weighted aboveground biomass of each species in the specific sample according to the protection level, the feeding value level, the plant life type and the aboveground biomass of each species in the specific sample, and taking the sum of the weighted aboveground biomass as the total biomass of the sample corresponding to the specific sample; wherein the specific sample is any one of M sample.
3. The method of claim 2, wherein calculating weighted aboveground biomass for each species in the particular sample based on the protection rating, the feeding value rating, the plant life type, and the aboveground biomass for each species in the particular sample, comprises: Respectively obtaining the protection grade, the feeding value grade and the plant life type corresponding to each species in the specific sample party; According to the preset corresponding relation between the plant protection grade and the protection grade coefficient and species Determining the protection class of the species Determining the species according to a preset correspondence between plant feed value grades and feed value coefficients Determining the species according to the preset corresponding relation between the plant life type and the seed bank contribution rate The target seed pool contribution rate of the species For any one species within the particular sample; Geometric means of the target protection class coefficient, the target feed value coefficient, and the target seed pool contribution rate are compared with the species The product of the above-ground biomass in the specific sample as the species Weighted aboveground biomass within the particular sample.
4.A method according to claim 2 or 3, wherein for each sample, an iterative dichotomy is used, and in combination with the average height of each species in the sample, the above-ground biomass and the total biomass of the sample, a reference utilization of all species at a given height is calculated, and the given height corresponding to a predetermined tolerance is set as the target stubble height, such that the absolute value of the difference between the reference utilization and the target utilization is less than or equal to the predetermined tolerance, comprising the steps of: a. Setting an initial search interval of stubble height for each sample Wherein Is set to be 0cm in length, Setting the average height of the highest plant corresponding species in the sample; b. Calculating the midpoint height: ; c. determination of species within a sample Simulating biomass taken away by mowing: If of species Average height of (2) The species is completely reserved, and the biomass taken away by the simulated mowing is determined to be 0; If of species Average height of (2) The biomass carried away by the simulated mowing is determined assuming that the partial biomass carried away by the simulated mowing of the species is proportional to the height exceeding part of the biomass , wherein, Is of a species An above ground biomass or weighted above ground biomass within the sample volume; d. calculation of reference utilization Simulating biomass taken away by mowing of all species in the sample side to obtain total biomass taken away by the simulated mowing Calculating the current given height Reference utilization under , wherein, Total biomass for the sample; e. Judging and iterating: If it is Indicating that the stubble is too high, harvesting is too little, and the upper limit of the initial search interval is reduced: Wherein, the method comprises the steps of, Representing a target utilization rate; If it is Indicating that the stubble is too low, harvesting too much, and increasing the lower limit of the initial search interval: ; If it is Less than or equal to a preset tolerance, ending the iteration and setting the current given height As the target stubble height of the sample; f. and c, repeating the steps b-e until the tolerance condition is met, and obtaining the target stubble height corresponding to each sample side.

Description

Grassland precise mowing stubble height determining method based on species component analysis Technical Field The application relates to the technical field of grassland sustainable utilization and accurate mowing, in particular to a grassland accurate mowing stubble height determining method based on species component analysis. Background The grassland ecological system is an important ecological barrier in China and a production base of animal husbandry. In order to realize sustainable utilization of grasslands, researches show that the mowing utilization rate is controlled to be 45% -55%, namely, the principle of 'half is used for leaving half' is followed, and the grasslands biodiversity and the ecological system stability are maintained. Traditional mowing of grass typically employs a fixed stubble height, for example 8-15 cm. This "one-shot" mode of management ignores the vast differences in plant species composition, community structure, and vertical biomass distribution of different grasslands. The fixed stubble height may cause adverse consequences in practice, namely, too high stubble and waste of grassland resources, and too low stubble and excessive mowing seriously damage plant regeneration capacity, especially damage to high-quality pasture and shallow root plants, resulting in grassland degradation, reduced biodiversity and finally damage to the stability of an ecological system. In the related art, a method for rapidly determining the mowing stubble height of a meadow grassland (patent number CN 110097272A) is characterized in that an experimental district is established, 5 different stubble heights are mowed, the corresponding hay yield is measured, the biomass proportion taken away under the different stubble heights is calculated, a regression equation model is established, and finally the stubble height taken away by 50% of yield is calculated and applied. The method is a great progress compared with the fixed stubble-remaining method, and realizes 'due land strategy'. However, the method treats grassland vegetation as a homogeneous whole, the calculated biomass is community total biomass, and the established model is based on the macroscopic relation of 'stubble height-total yield'. The measuring and calculating method cannot accurately reflect the actual influence of the mowing behavior on each species in the community, so that the actual utilization rate corresponding to the finally calculated stubble height has larger deviation from the theoretical target utilization rate. Therefore, there is a need for a stubble height determination method that can more accurately and scientifically control the mowing utilization rate. Disclosure of Invention In view of this, the embodiment of the application provides a method for determining the height of a precise mowing stubble on the basis of species component analysis, which comprises the following steps: Randomly selecting M experimental cells with the same size in a target threshing place, setting a sample party in each experimental cell, and carrying out species investigation and recording on all plants in each sample party; the size of each sample is the same; the method comprises the steps of randomly selecting and measuring natural heights of N healthy individuals of each species in each sample, calculating average heights of each species in the sample according to the natural heights, cutting plants with the measured natural heights on the ground to obtain fresh grass of each species after cutting in each sample, respectively placing the cut fresh grass in a 65 ℃ oven for drying to constant weight and weighing to obtain overground biomass of each species in each sample, calculating total biomass of the sample corresponding to each sample according to overground biomass, calculating reference utilization rate of all the species under a given height by combining the average height of each sample in the sample, overground biomass and total biomass of the sample according to the natural heights, and calculating the corresponding given height when the absolute value of the difference between the reference utilization rate and the target utilization rate is smaller than or equal to a preset tolerance, wherein the target utilization rate is calculated according to a theoretical average value of the overground biomass of each species, calculated by calculating the average crop retention rate of each sample within a preset window of Ji Fengzhi percent by accumulating the target utilization rate for 1 month to 1 day, and calculating the average crop retention rate of each crop retention rate within a preset window of 5%, and calculating the average crop retention rate of each sample is calculated by the average crop retention rate of each sample according to a theoretical average value of the overground biomass, and calculating the average crop retention rate of each species under a preset window of the average crop retention rate of the preset t