| The ecological protection and high-quality development of the Yellow River Basin are currently a major strategy in China,with the goal of improving the ecological environment of the Yellow River Basin and promoting high-quality development throughout the entire basin.Grassland resources are extremely important natural resources in China.However,with the acceleration of urbanization and industrialization,the damage to grassland resources has become increasingly severe.Grassland has shown problems such as shrinking area and land degradation,and grassland resources are becoming increasingly scarce,affecting the healthy and stable development of grassland ecosystems.Therefore,evaluating the ecological carrying capacity of grasslands in the Yellow River Basin of Shaanxi Province and exploring the balance between the development and utilization of grassland resources and ecological protection have important practical significance and application value.This study focuses on the grassland in the Yellow River Basin of Shaanxi Province.At the macro level,it analyzes and studies the ecological carrying capacity of the grassland in the Yellow River Basin of Shaanxi Province through professional knowledge such as animal husbandry,grass science,ecology,and geographic information science.By utilizing relevant research models reasonably,the grassland ecological development status of the Yellow River Basin in Shaanxi Province in 2000,2010,and 2020 was obtained.Combining climate data,production models,and land use transfer matrix models,the grassland production and changes in the study area were organized,and the development advantages and disadvantages of the grassland storage industry in the region were evaluated and analyzed.At the concrete level,we analyzed the balance of grass and livestock in Heyang County,one of the country in the Yellow River Basin of Shaanxi Province.By investigating the agricultural production status of Heyang County from 2015 to 2020,we summarized the current status of forage resources,calculated the actual livestock carrying pressure,analyzed the agricultural industry status and the balance of grass and livestock in Heyang County.At the micro level,based on the N and P nutrient balance models,the soil carrying capacity index of livestock and poultry manure in Heyang County was calculated and analyzed,in order to more intuitively and scientifically evaluate the livestock carrying capacity of Heyang County.Combining with the actual production status of animal husbandry,suggestions are made for the sustainable development of grass and livestock balance in Heyang County.The main results of this study are as follows:(1)The grassland area in the Yellow River Basin of Shaanxi Province showed a decreasing trend in 2000,2010,and 2020;The order of grassland area(average of these three years)in various cities from large to small is Yulin(23546.66 km~2),Yan’an(13154.07km~2),Xianyang(797.91 km~2),Weinan(660.46 km~2),Baoji(604.08 km~2),Tongchuan(435.45 km~2),Shangluo(358.46 km~2),and Xi’an(195.20 km~2).(2)The total aboveground biomass of the study area calculated using the Miami climate productivity model was 57.3733 million tons,57.1643 million tons,and 54.6879million tons in 2000,2010,and 2020,respectively.The corresponding theoretical livestock carrying capacity were 1015.4203 million sheep units,1011.7222 million sheep units,and967.8932 million sheep units.(3)Through the calculation and analysis of the land use transfer matrix model,the total land area of from 2000 to 2010 was 133878.28 km~2,of which the fixed and unchanged total area was 127500.16 km~2,and the transferred in and out area was 6378.12 km~2.From 2010to 2020,the total land area was 133874.67 km~2,of which the fixed and unchanged total area was 115245.09 km~2,and the transferred in and out area was 18629.59 km~2,with more drastic changes compared to 2000 to 2010.From 2000 to 2010,the fixed area of grassland was 38929.64 km~2,the transferred in area was 1182.81 km~2,and the transferred out area was 1687.04 km~2;From 2010 to 2020,the fixed area of grassland was 32736.5 km~2,the transferred in area was 305.52 km~2,and the transferred out area was 7375.87 km~2.(4)According to the calculation results of the actual production status of Heyang County,the actual livestock carrying capacity from 2015 to 2020 was 405600 sheep units,361700 sheep units,375100 sheep units,341000 sheep units,343300 sheep units,and345300 sheep units,respectively.The theoretical livestock carrying capacity calculation values were 426100 sheep units,42150000 sheep units,425300 sheep units,456300 sheep units,478100 sheep units,and 516600 sheep units,respectively;The livestock balance index was-4.81%,-14.20%,-11.80%,-25.26%,-28.20%,and-33.15%,respectively.(5)By calculating the conversion amount of N and P nutrients,it was found that the average annual demand for N nutrients in Heyang County from 2015 to 2020 was 6559.6tons;the average annual net amount of chemical fertilizer application was 17465.5 tons;the average annual supply of livestock and poultry manure was 3103.74 tons;the average annual return of human manure and urine to the field was 313.74 tons;the average annual atmospheric dry and wet deposition was 464.25 tons;the total amount of biological nitrogen fixation was 755.29 tons;The average annual demand for P nutrients was 1376.82 tons;the average annual converted amount of fertilizer application was 1999.83 ton;the average annual supply of livestock and poultry manure is 532.07 tons;the average annual return of human manure to the field was 89.64 tons,and the average annual atmospheric dry and wet deposition was 60.42 tons.(6)The calculation results of the carrying capacity of livestock and poultry manure soil show that,when the proportion of livestock and poultry manure replacing fertilizer is calculated at 50%,the maximum livestock and poultry breeding amount calculated by N nutrient was between 353000 pig equivalent to 421000 pig equivalent,and the annual maximum breeding amount was 374800 pig equivalent;The maximum livestock and poultry production calculated based on P nutrient was between 205900 pig equivalent to245600 pig equivalent,with an average annual maximum production of 218700 pig equivalent.The actual livestock and poultry production ranged from 416700 pig equivalent to 484700 pig equivalent,with an average annual production of 443400 pig equivalent.In summary,at the macro level,the theoretical livestock carrying capacity is1015420300 sheep units,1011722200 sheep units,and 967893200 sheep units.at the county level,the livestock carrying pressure in Heyang County was in a balanced state from 2015to 2017,and in a state of insufficient livestock carrying from 2018 to 2020.At the micro level,from 2015 to 2017,the livestock and poultry breeding volume was overloaded based on N nutrient,and from 2018 to 2020,there was no overload.The results of P nutrient calculation showed that there was no overload and there was a potential range for development.Based on comprehensive analysis,Heyang County is suitable for the development of animal husbandry,and there is currently a large potential area for development. |
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