Study On Greenhouse Gas Emissions Caused By Energy Consumption For Mainland China's Crop Production System

Control greenhouse gas(GHG)emissions,to achieve low carbon green growth has become a development trend of the world today.In response to climate change,China facing enormous international pressure.Therefore,how to realize energy conservation and emission reduction in all industrial sectors has becoming the current academic research hot spots.As one of the world agricultural country,China's crop production systems consume a great quantity of agricultural inputs from other industry sectors,at the same time show highly dependent on energy consumption.High energy dependence,resulting in a great quantity of GHG emissions.This study from the consumption perspective,studied the present situations,structures,variation trends and driving factors of regional crop production systems and main crop species in Mainland China.Providing scientific basises for crop production systems to reduce energy consumption related GHG emissions.By using energy balance technique,the second chapter of this study we calculated the quantities of energy consumption related GHG emissions from crop production systems in whole Mainland China and 31 provinces from the consumption perspective between 1997-2014.The results showed that the crop production,energy consumption and energy consumption related GHG emissions continue to grow in Mainland China.But the yield of Mainland China's crop production system is not positively correlated with energy consumption and Mainland China's crop production system has the potential of energy conservation and energy consumption related GHG emission reduction.There existed relatively significant regional differences in energy consumption related GHG emissions from Mainland China's crop production systems and energy consumption related GHG emissions from 13 major grain production areas accounts for more than 65% of total of this emission from Mainland China's crop production system.The third chapter in this study,adoped Kernel density estimation,theil coefficient and spatial autocorrelation analysis we studied the evolution trends and the spatio-temporal differences of energy consumption related GHG emissions from Mainland China's crop production systems.Results showed that:(1)the inequality of GHG emissions between different provinces is gradually expanding and present with polarization trend.(2)Two-stage nested Theil coefficient decomposition indicated that the inequality of GHG emission intensity between different provinces is gradually closing.The inequality between the major and non-major grain producing areas seen a significant drop,while the within-region inequality showed a slight decrease.(3)Spatial autocorrelation analysis showed us significant spatial correlation was exist in all 31 provinces and local correlation and spatial heterogeneity were exist in local areas during the study period.The driving factors of energy consumption related GHG emissions are determined by an expand Kaya-Porter identity at both the national and provincial levels in the fourth chapter of this study.Our research outcomes indicate that areal productivity,energy intensity and plant area are the determining factors in the growth of energy consumption related GHG emissions,and the emission coefficient and energy mix were the main factors that reduced energy consumption related GHG emissions.Among all driving factors,energy intensity has not achieved its full potential associated with the decrease of energy consumption related GHG emissions and optimizing the synthetic fertilizer consumption structures is an urgent need and can reduce energy consumption related GHG emissions in Mainland China's crop production systems.This study provided insights into the potential for sustainable crop production in Mainland China.In the fifth chapter,the hybrid economic input-output and life cycle assessment(EIO-LCA)model is used to examine the present situation,structure and the change trend about the crop-specific embodied energy intensities and energy consumption related GHG intensities of 29 staple crops in Mainland China during 1990-2010.During the study period,most grain crops have increased their embodied energy intensities and energy consumption related GHG intensities,while most cash crops have a decline in their embodied energy intensities and energy consumption related GHG intensities.Differences in crop-specific energy consumption and related GHG emissions exist,and cash crops consume more energy and emitted more GHG per unit DM than grain crops.The synthetic fertilizers is the primary driver of energy consumption and related GHG emissions among different crops.While by using sensitivity analysis,we found that agricultural machinery and pesticides also has a potential of high GHG emissions.Positive correlations between energy consumption related GHG emissions and indirect energy consumption indicated energy-saving in production process of agricultural production inputs was far from negligible for mitigate emissions in Mainland China's crop production system.By using structural path analysis(SPA)identified product-specific energy management priorities for each agricultural production inputs.