Effect of Tillage Mode on Carbon Footprint in Wheat-Maize Double Cropping Farmland Ecosystem

Wu Ning; Wang Enhui; Wang Chongmao; Ning Tangyuan; Li Yuhao; Zhou Changying

doi:10.14083/j.issn.1001-4942.2017.06.008

Abstract：Carbon footprint analysis in farmland ecosystem was beneficial to find problems and provide the support for the development of low-carbon agriculture.Based on the whole-circle carbon footprint index system, the effects of tillage mode on carbon consumption and sequestration, carbon footprint, net carbon consumption (△GHG), carbon footprint per unit of output (CFv) and carbon footprint per unit of production (CFy) were studied in the high-and middle-yield field in Taian, Tengzhou and Longkou in Shandong Province.The results showed that the carbon consumption from N fertilizer and soil N2O emission accounted for 79.69%~92.53%, in which,that from N fertilizer accounted for 53.82%~62.49%, in the carbon consumption from chemical compounds.More than 80% mechanical fuel consumption was used for irrigation, tillage, sowing and harvest.The carbon consumption of straw accounted for 98.83% in the organic carbon consumptions.In the farmland ecosystem, the carbon was mainly sequestrated in grain and straw, in which, the carbon sequestration in grain accounted for 39.05%~52.64% of the total carbon sequestration.The total carbon sequestration in Tengzhou was 196.3~7 801.5 kgCO2/hm2 higher than those of the other two cities, except under the rotary tillage mode.The △GHG in the 3 cities were between-3 524.7 and-8 774.3 kgCO2/hm2, which showed that the farmland ecosystem was a carbon sink.The carbon sequestration of summer maize was higher than that of winter wheat.The carbon sequestration under plough tillage was higher than those under rotary tillage and harrow tillage.Under the winter wheat-summer maize double cropping farmland ecosystem, the CFv and CFy of summer maize both were significantly higher than those of winter wheat, the CFv and CFy were winter wheat with plough tillage-summer maize with no-tillage > winter wheat with rotary tillage-summer maize with no-tillage > winter wheat with harrow tillage-summer maize with no-tillage.But there were no significant rules in the CFv and CFy of different cities.Thus, in order to improve the net carbon sequestration in Shandong Province, we should improve the agricultural mechanical efficiency, reduce the mechanical and electronic consumption, increase the nitrogen and water use efficiencies, build the suitable tillage system, and increase the crop yield.Meanwhile, to excavate the carbon sequestration potential of summer maize and to improve the carbon sequestration capacity of winter wheat were important for crop breeding and cultivation.