Research On Species Diversity And Integrated Control Technology Of Poisonous Weeds In Xinjiang Grazing Grassland

There are abundant natural grassland resources in China,with a total area of 393 million hm2,which ranks third in the world and accounts for 41.41%of the country’s land.The usable grassland area is 331 million hm2,accounting for 84.27%of the total natural grassland resources nationwide which is also 2.2 times as much as the area of farmland.In China,the natural grasslands are distributed in the Northeast,Northwest area and Qinghai-Tibet Plateau which are the arid,semi-arid and plateau cold zone in China,with fragile ecosystems.Xinjiang,which is deep in the hinterland of the Eurasian continent,has an extremely fragile ecological environment,where the vegetation coverage rate is only 40.4%.The natural grassland area plays a dominant role in maintaining the ecological security in Xinjiang since it covers 57.25 million hm2,which accounts for 85.1%of the total vegetation coverage area.Xinjiang’s 4800 million hm2 grazing grassland is also an extremely important material resource for the 37 pastoral and semi-pastoral counties there.The grazing grassland in Xinjiang is also the main position for increasing the income for farmers and herdsmen.At the end of 2019,the amount of the herbivorous livestock on hand was 46.169 million and the amount for sale was 45.523 million.In a word,the grazing grassland in Xinjiang is the material basis for the sustainable development of animal husbandry and the survival of herders,and it is of great significance for ensuring the human living environment,food safety,ecological safety as well as Xinjiang’s social stability.With the global climate change and the long-term disturbance of human activities such as overgrazing and other predatory exploitation,the grazing grassland in China is degraded and under the threat of desertification.Together with the spread of low-quality plants breeds as well as biological disasters such as rodents,pests and diseases occurrence,the productivity of grazing grasslands declined and the grasslands were covered by poisonous and harmful grasses,which lead to the weakening of nutrient retention and capacity losing in water conservation.Such ecological losses also caused huge economic losses to the herders and the government.This has not only attracted the attention of herders,but also aroused the government’s concern about the implementation of ecological protection projects and the complete elimination of poverty.Therefore,this thesis employs the combination of field investigation and literature consultation on the main poisonous weed that occur in grazing grasslands in Xinjiang,and use traditional phytochemical methods to extract and analyze the alkaloid components of those five main poisonous weeds,namely,Peganum harmala,Aconitum leucostomum,A chnatherum inebrians,Oxytropis ochrocephal and Pedicularis cheilanrthifolia.The latter three poisonous weeds are used to replace the roughage in the goat diet,and also are tested in the rumen fermentation and Hematological traits of goats.The purpose of this thesis is to provide theoretical and technical support for the comprehensive prevention and utilization of grazing grassland poisonous weed in Xinjiang1.Investigation on the species diversity and harm of poisonous weeds in Xinjiang grazing grasslandThrough field investigations,poisonous weeds are mainly distributed in grazing grasslands in more than 70 city-country in Xinjiang,including the river valley grasslands of Hi prefecture,the Altai mountain grasslands,the Aksu desert steppe,the northern slopes of the Tianshan Mountains in Urumqi,the Bozhou desert steppe,the desert steppe along the Tarim River in Bazhou,and the Hami desert Gobi grasslands.As for the species of poisonous weeds,it is found that 9 kinds of poisonous species are dominant in the distribution of those in grazing grasslands in Xinjiang,and their damage area accounts for more than 80%of the total damaged area.The main species are Achnatherum inebrians,Aconitum,Pedicularis,Ligularia sibirica,Cicuta virosa,Anabasis aphylla,Oxytropis glabra,Oxytropis ochrocephala,Astragalus variabili,Peganum harmala,Sophora alopecuroides.From the perspective of regional distribution,the arid desert grassland in eastern Xinjiang is dominated by Achnatherum inebrians and Astragalus variabilis;in the Tarim River,Hotan River,and Yeerqiang River basins in southern Xinjiang,Oxytropis glabra is the most widely distributed.The alpine meadow grassland on the northern slope of Kunlun Mountain is dominated by Oxytropis ochrocephala.Pedicularis,Thalictrum aquilegifolium and Ligularia sibirica dominated in Bayinbuluk alpine meadow grassland.Anabasis aphylla and Sophora alopecuroides mainly distribute on the desert gobi of the alluvial zone on the southern slope of Tianshan Mountains.Ili River Valley plain and the alpine grassland of the Altay Mountains are dominated by Aconitum and Ligularia in northern Xinjiang,and the desert Gobi of the alluvial belt on the northern slope of the Tianshan Mountains is dominated by the Anabasis aphylla and Sophora alopecuroidesDue to the differences in geomorphology and climate characteristics in the eastern,southern and northern Tianshan Mountains of Xinjiang,the distribution of poisonous weed has the regional characteristics.In particular,poisonous weed populations are widely distributed in the vertical range of 1500-2500m above sea level,and the damage is seriousThrough field investigation and data review,it was found that the area of poisonous weeds in grazing grassland in Xinjiang is 6,280,600 hm2,of which 4,699,300 hm2 are mildly damaged,1,267,300 hm2 are moderately damaged,and 894,000 h12 are severely damaged.There are about 41 species poisonous weed which do harm to the grazing livestock.Among them,9 species of poisonous weeds are widely distributed throughout Xinjiang,accounting for 20.5%of the total number of poisonous weeds;there are 25 species in northern Xinjiang and 27 species in southern Xinjiang.Hundreds of thousands of livestock are poisoned each year,and the direct economic loss caused by poisonous weeds is 356 million yuan.2.Analysis of Alkaloid components of five main poisonous weeds in grazing grassland in Southern XinjiangBy using traditional alkaloid extraction methods among the five main poisonous weeds,namely,Peganum harmala,Aconitum,Achnatherum inebrians,Oxytropis ochrocephala,Pedicularis cheilanrthifolia and employing GC-MS and UPLC-MS/MS combined instrument detection and analysis,the researcher identified 18 alkaloids in total(GC-MS identified 6 species,UPLC-MS/MS identified 12 species).Peganum harmala mainly contains vasicinone,hannine,harmaline,6-methoxyhamaran,6-methoxyhalman,harmaline hydrochloride,interamedine N-oxide and monocrotaline;Aconitum leucostomun mainly contains heliotridine and retronecine;the mainly alkaloids in Achnatherum inebrians are mesaconitine,heliotridine and retronecine;Oxytropis ochrocephala mainly include mesaconitine,heliotridine and retronecine,hypaconitine,lasiocaepine n-oxide,senkirkin;Pedicularis cheilanrthifolia mainly contains 3-acetyllycopsamine,sophocarpine,6-O-Demethylmenis porphine and 9-methoxy ellipticine.It suggested that these poisonous grasses contain a variety of alkaloids.The toxic effects on animals may be the result of the joint action of these alkaloids3.Effects of poisonous weeds on the rumen fermentation and Hematological Traits of goatsAfter feeding the goats with the feed containing poisonous grass,their food intake was significantly higher than that of the control group,but the difference in apparent digestibility was not significant.Compared with the control group,the concentration of acetic acid increased significantly in the rumen and the hemoglobin concentration of goats also increased.There was no significant difference in goat serum m-glutamyl-transaminase,glucose,total cholesterol,high-density cholesterol and low-density cholesterol among the treatments in the experiment.The goats fed with 10%Oxytropis ochrocephala,the concentration of the potassium,sodium,chloride,calcium,magnesium and phosphorus in the serum were significantly lower than other treatments,but the activities of aspartate transaminase and alanine transaminase were significantly increased4.Comprehensive prevention and control technology and management strategy of poisonous weed in Xinjiang grazing grasslandAccording to the topography,the ecological function of natural grassland in Xinjiang was divided,and the prevention and control countermeasures of poisonous weeds were put forward.For important grazing land,priority is given to ensure the production and supply of livestock products,and a combination of chemical prevention and control,rotational grazing and regional biological prevention and control is used to control poisonous weeds,which is supplemented by the construction of cultivated grasslands.The cultivated grasslands and biological control are used for water conservation.For the ecological function zones with water and soil conservation,wind-proof and sand-fixing,and desertification control functions,we can implement coordinated methods and pay more attention to the scientific planting and development when conditions permit,so that the zones can play their ecological restoration function.For the zones with the function of biodiversity protection and ecotourism,livestock product processing and hydrological regulation,mainly adopt the methods of artificial and mechanical prevention and control,combination of agriculture and animal husbandry,industry feeding agriculture,and the development of the tertiary industry for comprehensive prevention and controlThe strategies for controlling poisonous weeds in Xinjiang grazing grassland should fully understand the ecological value of poisonous weeds,and take corresponding comprehensive control,development and utilization measures for different ecological environments.First,we must correctly understand the ecological effects of poisonous weeds,and not blindly eliminate them.Secondly,we should strictly control the stocking capacity to prevent overgrazing of the grassland.Thirdly,we should build cultivated grasslands and improve natural grasslands,in order to achieve a balance between grass and livestock Finally,we should also scientifically locate the advantages and disadvantages of poisonous weeds so that we can explore the potential value of poisonous weeds,and improve the level of resource utilization of poisonous weeds.In summary,the species and distribution of poisonous weeds in grazing grassland of Xinjiang were investigated,and clarified the regional distribution characteristics of the main dominant poisonous weed populations.The alkaloid constituents of five main poisonous weeds were isolated and identified.On this basis,comprehensive prevention and control countermeasures for poisonous weeds in Xinjiang grazing grassland are proposed.The research also studied the effect of poisonous weeds instead of roughage in diets on goat rumen fermentation and blood indicators,and it showed that the forage added 10%of the ones had lower toxicity to goats.It will provide important theoretical basis and technical support for guiding the scientific prevention,control and comprehensive utilization of grassland poisonous weeds in Xinjiang.