中国生态农业学报2018，Vol.26Issue(2)：214-221,8.DOI:10.13930/j.cnki.cjea.171156
林地转变为耕地对紫色土N2O排放的影响
Impact of conversion from forestland to cropland on soil N2O emission from purplish soil
摘要
Abstract
Land use change is one of the main reasons for changes of greenhouse gases concentration in the atmosphere. How-ever, the impacts of land use change process, such as conversion process from forestland to cropland, on soil N2O emission is still lack of a systematic study. In this study, forestland was converted into cropland in the hilly area of the Central Sichuan Basin in mid July 2016, and then planted as winter wheat-summer maize rotation from October 26, 2016 to September 15,2017. Static chamber-gas chromatographic technique were used to compare the characteristics of N2O emission from croplands, converted from forest land with tillage without fertilizer (CL-T) and with tillage and fertilizer (CL-TF), and forestland (CK). The results showed that during the experimental period, the soil N2O emission fluxes of CL-T and CL-TF both significantly increased compared to CK (P < 0.01), and there was an obvious emission peak at the beginning of land use conversion from forestland to cropland. The mean N2O emission fluxes in the wheat season and maize season were 2.52 μg(N)·m-2·h-1and 4.60 μg(N)·m-2·h-1under CK, 3.55 μg(N)·m-2·h-1and 11.63 μg(N)·m-2·h-1under CL-T, 6.26 μg(N)·m-2·h-1and 22.16 μg(N)·m-2·h-1 under CL-TF, respectively. N2O emission peak flux was significantly higher in maize season than in wheat season. The annual accumulative soil N2O emissions were 0.271 kg(N)·hm-2, 0.515 kg(N)·hm-2and 0.957 kg(N)·hm-2under CK, CL-T and CL-TF, respectively. Compared to CK, CL-T and CL-TF increased the annual accumulative soil N2O emissions by 89.8% and 253.0%, re-spectively. This indicated that land use conversion from forestland to cropland significantly induced the increase of N2O emission in purplish soil. Tillage changed soil structure and significantly increased soil inorganic nitrogen content (P < 0.05), then fertil-izer application increased soil inorganic nitrogen content sharply by a large quantity, which resulted in pulsive N2O emission. While soil temperature (5 cm) and soil moisture (WFPS) were not changed significantly (P > 0.05), and planting did not change N2O emission significantly in short time during the process of land use conversion. It was suggested that the funda-mental mechanism of stimulating N2O emission caused by land use conversion from forestland to cropland might be derived from the increase of mineralization rate of soil organic nitrogen. However, the effect of land use conversion on soil nitrogen transformation and the mechanism of changing of soil N2O emission need to be further studied.关键词
林地转变为耕地/翻耕/施肥/氮转化过程/N2O排放Key words
Land use conversion from forestland to cropland/Tillage/Fertilization/Nitrogen transformation process/N2O emission分类
农业科技引用本文复制引用
任晓,刘红兵,朱波..林地转变为耕地对紫色土N2O排放的影响[J].中国生态农业学报,2018,26(2):214-221,8.基金项目
国家自然科学基金项目(41330744,41271321)和国家重点基础研究发展计划(973计划)项目(2012CB417101)资助This study was supported by the National Natural Science Foundation of China(41330744 and 41271321)and the National Basic Research Program of China(973 Program)(2012CB417101). （41330744,41271321）
