| Global climate change has become an important environmental issue of common concern.Global warming has caused an increase in the concentration of greenhouse gases in the atmosphere.At the same time,with the rapid growth of greenhouse gas emissions,a series of climate change results directly affect the living environment of the earth and human development..Global warming will have a certain impact on the growth of crops.For example,a warming climate may increase evapotranspiration,leading to water shortages during crop growth,thereby affecting crop yields.The Qinghai-Tibet Plateau is the largest plateau ecosystem in the world.Climate change will affect the growth of barley.In practical applications,different varieties have different adaptability to the climate of various regions,and each region can only choose the varieties with the highest local yield for planting.Therefore,clarifying the differences in the quality of highland barley in different regions has important guiding significance for understanding the impact of climate warming on the quality of highland barley.In this study,67 highland barley planting counties and cities with different geographic spans ranging from 1500m-4400 m above sea level were selected from Qinghai Province,Tibet Autonomous Region,and Gannan Tibetan Autonomous Prefecture as the main research objects.Among them,Tibet Autonomous Region,Qinghai Province,and Gannan Tibetan Autonomous Prefecture each selected 37,26 and 6 counties and cities were used as sampling points.Taking the increase in temperature as the research background,through a large-scale spatial survey,the study area was divided into climatic regions by spatial clustering,and the chemical composition of highland barley grains distributed in different climatic regions was further analyzed,aiming to reveal the nutrition of highland barley grains after altitude changes.Through a large-scale spatial survey,the difference in nutritional quality of highland barley in different climatic regions under the background of climate change is studied,and the quality of highland barley in different climatic regions is further comprehensively evaluated,and the increase in temperature under the background of global change is carried out on the Qinghai-Tibet Plateau.The influence of barley quality in different planting areas.After further analysis of the global temperature increase,the relationship between the stoichiometry and chemical composition of the cold-loving crop barley seeds and environmental factors such as temperature,moisture,etc.,tried to screen high-quality barley varieties suitable for climate change.The study of the increase in temperature and the quality of highland barley provides a theoretical reference for the response of global climate change to the earth's organisms.It also provides a theoretical basis for the selection of major food crops in pastoral areas and the development of agriculture and animal husbandry in pastoral areas,as well as for understanding the impact of global warming on agriculture in alpine regions.Animal husbandry development provides important research materials,provides theoretical support for stabilizing the economy of Tibetan areas,and provides reference materials for protecting the alpine ecological environment.The main findings are as follows:(1)The nutrient variety index of highland barley seeds changed significantly.The coefficient of variation of the nutrient quality index varied between 6.06%-18.33,the crude protein content varied between 6.17%-15.56%,and the starch content varied between53.02%-78.55%.The content of ?-glucan varies between 3.67% and 5.99%,the content of fat varies between 1.75% and 2.65%,the content of dietary fiber varies between 13.77%-20.05%,and the content of phytic acid varies between 4.59g/kg-The total carbon content varies between 12.29g/kg,and the total carbon content varies between 38.47%-48.53%.The crude protein and starch of highland barley seed showed a very significant negative correlation(P<0.01),dietary fiber and ?-glucan had a very significant positive correlation(P<0.01),starch and fat showed a significant negative correlation(P<0.05)).(2)Altitude has a significant impact on the quality of highland barley grains,has a significant impact on the accumulation of starch and fat in highland barley grains,and has an impact on the accumulation of crude protein,dietary fiber,phytic acid,and ?-glucan in highland barley seeds,but it has not reached Significant level.The crude protein content is the highest at an altitude of 2500-3000 m and the lowest at an altitude of 4000-4500m;the ?-glucan content is the highest at an altitude of 2000-2500 m,and the content is the lowest at an altitude of 3500-4000m;the phytic acid content is the highest at an altitude of 3000-3500 m.The content is the lowest at an altitude of 2000-2500m;the dietary fiber content is the highest at an altitude of 3000-3500 m,and the content is the lowest at an altitude of 4000-4500m;the starch content is the highest at an altitude of 2000-2500 m,and the content is the lowest at an altitude of 3500-4000 m.Linear regression analysis results It shows that the starch content shows a downward trend with the increase in altitude and does not reach a significant level,but there is a significant difference in the starch content between the altitude gradient of 2000-2500 m and 3500-4000m(P<0.05);the fat content is at the altitude of 4000-4500 m.The highest,at the altitude of 2500-3000 m and the lowest,the linear regression analysis results show that the fat content increases with the increase in altitude,and the increase does not reach a significant level,but the altitude gradient is between 3500-4000 m,4000-4500 m and2500-3000 m There is a significant difference in fat content(P<0.05).(3)This study uses the average temperature,precipitation and altitude data from 1980 to2019 to perform weka K-Means spatial clustering on the study area in Google Earth Engine(GEE),and divides the study area into 7 sub-areas with different climatic conditions.The sampling points in this study are distributed in the 0th,1,3,5 and 6 climate zones.The average crude protein content in climate zone 0 is 9.26%,the average crude protein content in climate zone 1 is 9.09%,the average crude protein content in climate zone 3 is9.89%,and the average crude protein content in climate zone 5 is 8.74 %,the average crude protein content of the 6th climate zone is 10.32%.The average phytic acid content in climate zone 0 is 8.33g/kg,the average phytic acid content in climate zone 1 is 7.60g/kg,the average phytic acid content in climate zone 3 is 8.72g/kg,and the phytic acid content in climate zone5 The average acid content is 8.48g/kg,and the average phytic acid content in the sixth climate zone is 8.48g/kg.There are significant differences in the nutritional quality of barley seeds between climatic regions.(4)The characteristics of the nutrient quality changes of highland barley seeds in different climatic regions were analyzed.After logarithmic processing,the crude protein content of highland barley seeds was the highest in the sixth climate zone and the lowest in the fifth climate zone;the fat content was the highest in the fifth climate zone and the sixth climate.Zone is the lowest;?-glucan content is highest in climate zone 6 and lowest in climate zone 0;dietary fiber content is highest in climate zone 5 and lowest in climate zone 0;starch content is highest in climate zone 5,climate zone 1 The phytic acid content is the lowest in the third climate zone and the first climate zone is the lowest.There are significant differences between the first climate zone and the third climate zone.Further comprehensive evaluation of the nutritional quality of highland barley seeds in different climatic regions,through the principal component analysis of the maximum variance rotation of 6 nutritional quality indicators of highland barley seeds in 67 different counties and cities,4 extracted according to the cumulative contribution rate of the factor loading matrix The variance contribution rate of the principal components and the corresponding score value are used to establish a mathematical model for evaluating the nutritional quality of barley,and obtain the comprehensive scores of the nutritional quality of barley seeds in different climatic regions.There are significant differences in the comprehensive scores of the nutritional quality of barley seeds in different climatic regions.From high to low,they are the third climate zone,the fifth climate zone,the first climate zone,the sixth climate zone and the zero climate zone. |
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