| The study of carbon emission from the wheat-corn rotation production system has great significance for agricultural emission reduction and carbon fixation.Taking the typical wheat-corn rotation system in Shandong province as an example,this research paper conducts a systematic study on the carbon emission of annual grain production based on three perspectives which are farming technology,planting scale,and regional scale.By comprehensively analyzing the complex relationships among carbon emissions of the wheat-maize rotation system and agricultural machinery and agronomy,agricultural businesses,and regional development of the economy and society,the author establishes a carbon emission model of the wheat-maize rotation system from multiple perspectives.It realizes the unification of theoretical research and empirical analysis,the coupling of micro-observation and macro-analysis,and the coordination of low-carbon technology and economic policies provide the basis for the formulation of scientific and reasonable agricultural emission reduction policies in the region,and better serves the "dual-carbon" strategy.The research content and conclusions of this paper are as follows:1.The effect of different farming practices on the carbon footprint of the wheat-maize rotation system is investigated to determine the best farming technology for emission reduction,carbon fixation,and efficiency enhancement.In this study,the annual carbon footprint of three typical farming patterns in the wheat-corn rotation system was calculated by means of the site experimental method in the field and the method of life cycle assessment,and the results showed that:(1)In terms of carbon emissions,sowing after conventional tillage in wheat season and direct seeding of maize season without tillage can reduce the carbon emissions of the wheat-maize rotation system.(2)In terms of carbon footprint composition,the proportion of carbon footprint caused by nitrogen,phosphorus,and potassium inputs is the highest,accounting for about 74.3～75.6% of the overall carbon footprint composition.(3)Sowing after conventional tillage in wheat season and direct seeding of maize season without tillage has the highest carbon compensation rate and the strongest carbon sink capacity,while the conventional tillage model had the weakest carbon sink capacity.(4)In terms of carbon production efficiency,sowing after conventional tillage in wheat season and direct seeding of maize season without tillage has the highest carbon production efficiency and the highest economic yield per unit amount of carbon input.2.The effect of different planting scales on the carbon footprint of the wheat-maize rotation system is investigated to determine the best farming technology for emission reduction,carbon fixation,and efficiency enhancement was investigated to determine to explore the optimal planting scale and emission reduction measures for crops.This study measured the carbon footprint of the wheat-corn rotation system of different planting scales,and the results indicate that the wheat-corn rotation system has considerable emission reduction potential in Shandong Province,however,the emission reduction measures are quite different.(1)Regardless of the scale of operation,reducing nitrogen fertilizer and irrigation electricity consumption is the most effective way to achieve low-carbon agriculture.In addition,large-scale land should pay more attention to agricultural water-saving technology.(2)The carbon footprint level of crops decreases with the increase of land management scale,but the response of wheat is more sensitive,and large-scale land management is beneficial to wheat production for reducing unit carbon emissions.(3)The input of chemical fertilizers,pesticides,and electricity consumption showed a trend of small-scale land>medium-scale land>large-scale land,but the input of agricultural machinery fuel showed the opposite trend.(4)Corn production shows a significant scale effect,and corn yield increases significantly on large-scale land.In small-scale lands,corn potential yield has not been fully exploited.3.Study the carbon footprint of wheat-maize rotation systems at different regional scales and analyze the changing trends and driving factors.This study analyzed the temporal and spatial evolution of carbon emissions from the wheat-maize rotation system in Shandong Province,the three major economic circles within the province,and 16 cities from 2010 to2020,predicted the changing trend in the next decades,and analyzed the differences in the driving factors of carbon emissions between regions.The results demonstrate that:(1)The carbon emission of the wheat-maize rotation system in Shandong Province presents an inverted "V" structure,and both the emission intensity and prise are decreasing year by year.It is predicted that it will continue to decline in the next decade,and there is a great potential for reducing emissions and carbon sequestration.The economic level is the main factor in promoting the growth of carbon emissions,and production efficiency has an inhibitory effect on the growth of carbon emissions.(2)When compared horizontally,the carbon emissions and change trends of the three major economic circles are different.The provincial capital economic circle has the highest carbon emissions and the lowest intensity and cost;Carbon emissions in the Jiaodong Economic Circle have been decreasing year by year,but emissions intensity and costs are the highest,with the highest share of carbon emissions from agricultural fuels;the south of Shandong Economic Circle has the lowest carbon emissions,but the highest share of carbon emissions from fertilizers.(3)The time before and after the peak of carbon emissions and emission intensity in 16 cities spans widely,with Dongying,Liaocheng,Binzhou,and Heze reaching the peak at the latest;from the cross-sectional data in 2020,Heze ranks first in total carbon emissions,accounting for 10.61% of the province;the emission cost is the lowest in Dezhou and the highest in Weihai.According to the findings of the study,this paper proposes several suggestions for the emission reduction and carbon sequestration of the wheat-corn rotation system:(1)Based on energy saving and consumption reduction,promote wheat season rototill followed by sowing+ corn season no-till live farming technology,and cooperate with agricultural machinery and agronomic measures to build a low-carbon and efficient wheat-corn rotation cropping system.(2)Based on regional characteristics,establish a "trinity" cooperative promotion mechanism of technology promotion-scale operation-regional control,strengthen the synergy between the government and the market,and formulate regionally differentiated planting structure adjustment and characteristic emission reduction and carbon sequestration measures.(3)Based on scientific and technological support,increase research on low-carbon planting technology innovation,focusing on the development of agricultural water conservation technology and fertilizer reduction technology.(4)Based on policy propaganda,comprehensively implement the new development concept,accelerate low-carbon propaganda and technical guidance for agricultural business entities,promote low-carbon agricultural production technologies,and advocate green and low-carbon production and lifestyle. |
