| Nitrogen,as an important agricultural production material,plays an important role in satisfying China’s grain production.At the same time,unreasonable nitrogen application and low nitrogen utilization efficiency have also caused a series of environmental problems such as water bodies,atmosphere and soil,which severely restricted the process of agricultural green development in China,and urgently needed agricultural green development in China.Based on the indicator evaluation system,it explores the spatio-temporal variation characteristics and influencing factors of nitrogen indicatores related to China’s agricultural green development,and proposes a reasonable nitrogen optimization management strategy.To this end,this study selects nitrogen indicators through literature research and China’s agricultural green development indicator evaluation system,and on this basis,the nitrogen indicators are classified according to the degree and type of green development.In the two dimensions of time and space,the agricultural and food systems at the national and regional scales are taken as the research objects to analyze the temporal changes of nitrogen indicators related to agricultural green development in China from 1980 to 2017 and the 31 provinces in 1980 and 2017 The characteristics of the spatial variation of the environment,clarify the influencing factors of relevant nitrogen indicators,and through scenario analysis,explore the optimization methods of nitrogen indicators related to agricultural green development in China,with a view to providing a reference for the realization of agricultural green development in China.The main results are as follows:(1)From 1980 to 2017,the green development level of nitrogen indicators related to agricultural green development in China gradually decreased.Among them,the nitrogen utilization intensity,environmental emissions,and most utilization efficiency indicators have an increasing trend,while the indicator agricultural green development level decreases from level Ⅰ to level Ⅳ;straw recycling efficiency,most nitrogen production types,and The rate of change in the indicators of food consumption all showed an increasing trend,and the level of indicator agricultural green development rose from level Ⅳto level Ⅰ.In terms of indicator types,compared with 1980,the proportion of green development grade IV levels of nitrogen production and food consumption indicators in 2017 decreased from 75.0%and 57.3%to 36.3%and 23.4%,respectively.On the upward trend,the proportions of the green development grades Ⅰ and Ⅱ of the nitrogen environmental emission and nitrogen efficiency indicators decreased from 71.0%and 26.6%to 46.8%and 16.9%,respectively,and the agricultural green development level showed a downward trend.(2)In terms of spatial distribution,compared with 1980,the green development level of nitrogen indicators related to agricultural green development in 31 provinces in 2017 showed a general downward trend.The regions with higher nitrogen input and higher environmental losses are mainly distributed in North China,East China,Central China,and South China,and the levels have decreased from level Ⅰ to level Ⅳfood consumption levels have increased in all regions,with the increase in the eastern region being more obvious,Rising to level Ⅲ;the protein yield per plant and animal in the eastern and northern regions is relatively high,rising from level Ⅳ to level Ⅲ;the efficiency indicator is generally low at the provincial scale,and most areas are at level Ⅲ and Ⅳ Level.As can be seen from the results of the proportion of regional indicators,compared with 1980,the proportion of the national level Ⅳ and Ⅲ levels did not change much in 2017,but the proportion of the level Ⅰ level decreased from 27.1%to 8.3%;At the seven regional levels,the proportion of level Ⅰ in each region has decreased,and in most areas it is less than 30.0%.The proportion at level Ⅲ and level Ⅱ has increased significantly.(3)The nitrogen indicator of China’s agricultural green development is affected by multiple factors,and the types of influencing factors are different at different times and in different regions.The factors affecting the nitrogen indicator related to the green development of agriculture in China include:cultivated land area,proportion of economic crop planting area,farmland irrigation level,population number,agricultural mechanization level,total breeding quantity,per capita GDP,urbanization rate,grain output,etc.And as the area of cultivated land decreases,the nitrogen indicator increases and has a positive correlation;other influencing factors have a positive correlation with the nitrogen indicator.(4)In the scenario analysis,the green development levels of the relevant nitrogen indicators have changed.Under the application of the existing plantation production management technology(S1 scenario),it can improve plantation production,increase nitrogen utilization efficiency and reduce environmental emissions,but there are still 13 indicators at level Ⅲ and level Ⅳ,improving the effect Not obvious.Under the application of the existing animal husbandry production management technology(S2 scenario),the improvement effect is similar to the plantation production management technology,and there are still 13 indicators at level Ⅲ and level Ⅳ.Under the application of existing resource and environment integrated management technology(S3 scenario),the agricultural green development level of nitrogen indicators can be improved and 9 indicators are at level Ⅰ and level Ⅱ.Under the comprehensive application of plantation production management technology,animal husbandry production management technology and integrated resource and environmental management technology(S4 scenario),16 of the nitrogen indicators are at level Ⅰ and Ⅱ,basically reaching the level of agriculture in the nitrogen indicater agricultural green development.In short,due to the combined influence of multiple factors,the overall agricultural green development level of nitrogen indicators related to agricultural green development in China has shown a downward trend,and shows that the northern and western regions are stronger than the southern and eastern regions.Through the comprehensive application of nitrogen optimization management technology,the relevant nitrogen indicators can reach the level of agricultural green development,and the key influencing factors and potentials of the green indicators related to agricultural green development to achieve green development are clarified,which provides for the realization of green agricultural development in China.Basis. |
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