Impacts Of The Integrated Patterns Of Water And Land Resources On Agricultural Greenhouse Gas Emissions In China

As an agricultural country,in the process of agricultural modernization transformation,large-scale water-land exploitation and energy consumption have led to a large number of GHG emissions in agricultural production in China.Therefore,the study of agricultural water-land-energy-emissions system can provide an important basis for mitigating GHG in agriculture.Based on the perspective of water and land matching,this study analyzes the spatial and temporal variation characteristics of the integrated patterns of water and land resources and the agricultural GHG emissions per unit sown in Mainland China and 30provincial-level administrative units.And by applying spatiotemporal index decomposition analysis approach?ST-IDA?,this study explores the contribution of the driving factors of the agricultural GHG emissions per unit sown in the 30 provinces of China in the temporal and spatial domain,reveals the driving mechanism of each factor,and proposes several suggestions for low-carbon agricultural development.The main conclusions are as follows.?1?In 2006–2017,annual variation of the integrated patterns of water and land resources in China is obvious,showing a two-stage fluctuation upward trend,increasing from 1.19×10⁶m³/km² to 1.35×10⁶m³/km².And there are generally distributed as“high in the south and low in the north”with the Yangtze River as the boundary.Meanwhile,the variation trend and stability of the integrated patterns of water and land resources in each province is obvious difference.According to the spatial and temporal distribution characteristics of each factors during the study period,it is considered that the inter-annual difference in total water resources and the spatial mismatch of water and land resources are the main reasons for the temporal variation and spatial differentiation of the integrated patterns of water and land resources.?2?From 2006 to 2017,the agricultural GHG emissions per unit sown in mainland China and each province fluctuates.Nationally,the agricultural GHG emissions per unit sown shows a"three-stage"upward trend,increases from 25.42 t CO_2e/km² to 35.56 t CO_2e/km²,and the growth rate is gradually accelerating.For the provinces,except for some provinces,the agricultural GHG emissions per unit sown area have increased.In addition,the agricultural GHG emissions per unit sown area are characterized by“north-south high,intermediate low”.?3?In the temporal domain,during the study period,economic output per unit water resources is the main contributing factor for the agricultural GHG emissions per unit sown area in mostly provinces,and the integrated patterns of water and land resources is the important contributing factor,while the agricultural carbon emissions intensity is an inhibitory factor.However,affected by the change of the conditions of water and land resources,agricultural production efficiency,and the abundance and deficient of water resources,in different time intervals,there are significant differences in effect direction and intensity of each factors.In the space domain,there is a significant spatial difference in the contribution of the integrated patterns of water and land,agricultural carbon emissions intensity and economic output per unit water resources to the increment of the agricultural GHG emissions per unit sown area,which is affected by the conditions of water and land resources,agricultural production efficiency,and agricultural irrigation conditions,respectively.?4?Finally,to improve the utilization efficiency of water-land resources,measures should be taken to reduce energy consumption in agricultural production,which would also reduce agricultural GHG emissions.In addition,technologies should be adopted to increase the efficiency of water usage in irrigation,conditions of agricultural production and the structure of energy consumption by agriculture should be improved,and zero tillage and a crop rotation system should be implemented.