| Inner Mongolia Autonomous Region is an important ecological barrier in the north of our country.It plays a key role in the process of environmental protection,water source conservation and wind protection and sand fixation.The Horqin grassland plays an important role in the grassland distribution pattern in Inner Mongolia.Zhalut Banner is a typical area of agricultural and pastoral ecotone in northern China.With the development of economy and the increase of population,the intensity of grassland utilization increases year by year.Continuous reclamation of grassland for farming activities,and continuous abandonment of farmland,resulting in grassland degradation,desertification,salinization,how to restore degraded grassland and rational utilization has become an urgent problem to be solved in the process of regional economic development.In view of the above situation,this project took remote sensing satellite images as reference to predetermine the grassland type,taking into account the actual situation of each banner county,and selected concentrated contiguous plots with an area of no less than 20 km2 as 186 survey plots.By investigating the basic characteristics of the plots,canopy coverage,base coverage,bare land,herbs and small(half)shrub quadrates,etc.Combined with the calculation and analysis of the relevant indexes of dominance and diversity analysis,the health evaluation of grassland in Zhalout Banner was carried out,providing the basis for the scientific use and ecological restoration of grassland in Zhalout Banner.The results showed that:1.Among the Zhalut Banner,50.0% of the plots were mainly grazing in season,26.9% were grazing all year round,5.9% were grazing pasture,and 17.2% were grazing forbidden.The surface green plant coverage rate of 80-100% accounted for80% of the total survey sample,60-80% accounted for 13% of the total survey sample,40-60% and 20-40% were 1%,and 0-20% was 2%.The bare plots of 80-100%,60-80% and 40-60% all accounted for 1% of the total survey plots,while those of20-40% accounted for 4% and those of 0-20% accounted for 82%.53.7% of the surveyed plots have no gravel,21.0% have a little gravel,and 25.3% have a lot gravel.In the surveyed plots,large area wind erosion accounted for 7.0%,small amount wind erosion accounted for 29.0%,and no wind erosion accounted for 64.0%.The number of alkali spots was 10.2%,the number was 28.0%,and the number was 61.8%.In the survey,49.0% of the plots had no rodent burrows,46.7% had a few rodent burrows,and 4.3% had many rodent burrows.2.Zhalut Banner included 44 families,175 genera and 294 species,including Compositae,gramineae,legumes and rosaceae.The total number of plant species was293,of which 87 were first-and biennial herbs,accounting for 29.7%,20 were shrubs and semi-shrubs,accounting for 6.8%,158 were perennial miscellaneous grasses,accounting for 53.9%,and 28 were perennial grasses,accounting for 9.6%.Among them,178 were mesophytes and 116 were xerophytes.Among the 293 plants,feed plants accounted for 85.3%,poisonous plants accounted for 6.1%,harmful plants accounted for 4.8%,and invasive plants accounted for 11 species(3.8%).The invasive plants mainly included Tigertail,Amaranth Americana,Amaranth retrophylla,Oncomelia monophylla,Tribulus liliensis,Nepeta chinensis,Amaranth chinensis,pastoris pastoris,Quinoa ash,melilotus melilotus,and so on.3.According to the 18 types of grassland classification,there are 4 types of grassland with 29 subtypes in Zhalut Banner.There were 12 subclasses of warm meadow steppe,10 subclasses of warm steppe,5 subclasses of lowland meadow and 2subclasses of mountain meadow.Lowland meadow yield ranges from 20.8 to 306.6kg/ mu,with an average yield of 102.1 kg/ mu,canopy coverage of 9.3-94.7%,average coverage of 62.0%,grass height of 4.0-46.0 cm,with an average of 17.1 cm.The yield of mountain meadow ranged from 36.3-158.8 kg/ mu,the average yield was117.1 kg/ mu,the canopy coverage was 41.3-80.3%,the average coverage was 59.6%,the grass height was 4.5-60.0 cm,the average was 28.1 cm.The yield of warm meadow ranged from 25.0 to 382.4 kg/ mu with an average yield of 125.9 kg/ mu.Canopy coverage was 21.7-100.0% with an average coverage of 71.9%.Grass height was 3.0-143.0 cm with an average of 27.7 cm.The yield of warm grassland ranges from 9.7-550.9 kg/ mu,the average yield is 121.2 kg/ mu,the canopy coverage is13.3-96.7%,the average coverage is 61.0%,the grass height is 3.0-92.0 cm,the average is 25.0 cm.4.Lowland meadow grassland has the highest dominance,followed by mountain meadow grassland,warm grassland has the lowest dominance.The highest Pa value was found in meadow,followed by lowland meadow and warm meadow grassland.H(Shannon-Weaver index)and JP(evenness index)were the highest in warm meadow steppe,H(Shannon-Weaver Index)was the lowest in warm grassland,and JP(evenness index)was the lowest in mountain meadow.The dominance,H(Shannon-Weaver index)and Pa(number of species)values of perennial grasses were the highest,and JP(evenness index)values of perennial grasses were the highest.The values of dominance,H(Shannon-Weaver index)and Pa(number of species)of shrubs were the lowest,and JP(evenness index)of one-and biennial plants was the lowest.5.In Zhalut Banner,25% of grasslands were not degraded,59% were mildly degraded,12% were severely degraded,and 2% were moderately degraded.42% of lowland meadows are mildly degraded and 32% are moderately degraded.26% are not degraded;18% of warm meadow steppe were not degraded,62% were mildly degraded,8% were moderately degraded,and 12% were severely degraded.12% of the mountain meadows were not degraded,53% were slightly degraded,24% were moderately degraded,and 11% were moderately degraded.14% of warm grassland is not degraded,53% is mildly degraded,25% is moderately degraded,and 8% is severely degraded. |
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