No abstract

Nitrous oxide (N₂O) is a long-lived greenhouse gas with a large radiation intensity and it is emitted mainly from agricultural land. Accurate estimates of total direct N₂O emissions from croplands on a country scale are important for global budgets of anthropogenic sources of N₂O emissions and for the development of effective mitigation strategies. The objectives of this study were to re-estimate direct N₂O emissions using localized emission factors and a database of measurements from Chinese croplands. We obtained N₂O emission factors for paddy fields (0.41 %) and uplands (1.05 %) from a normalization process through cube root transformation of the original data after comparing the results of normalization from the original values, logarithmic and cube root transformations because the frequency of the original data was not normally distributed. Direct N₂O emissions from Chinese croplands from 1980 to 2007 were estimated using IPCC (2006) guidelines combined with separate localized emission factors for paddy fields and upland areas. Direct N₂O emissions from paddy fields showed little change, increasing by 11 % with an annual rate of increase of 0.4 % from 29.8 Gg N₂O-N in 1980 to 33.1 Gg N₂O-N in 2007. In contrast, emissions from uplands changed dramatically, increasing by 296 % with an annual rate of 10.9 % from 64.4 Gg N₂O-N in 1980 to 255.3 Gg N₂O-N in 2007. Total direct N₂O emissions from Chinese croplands increased by 206 % with an annual rate of 7.6 % from 94.2 Gg N₂O-N in 1980 to 288.4 Gg N₂O-N in 2007, and were determined mainly by upland emissions (accounting for 68.4–88.5 % of total emissions from 1980 to 2007). Synthetic nitrogen fertilizers played a major role in N₂O emissions from agricultural land, and the magnitude of the contributions to total direct N₂O emissions made by different amendments was synthetic N fertilizer > manure > straw, representing about 77, 16, and 6.5 % of total direct N₂O emissions, respectively, between 2000 and 2007. The spatial pattern of total N₂O emissions in 2007 in China shows that high direct N₂O emissions occurred mainly in north China and in the Sichuan Basin in the southwest. The provinces with the highest emissions were Henan (32.6 Gg) and Shandong (29.1 Gg) and Tibet had the lowest (0.6 Gg). High direct N₂O emissions per unit of arable land occurred mainly on the North China Plain and the southeast coast. The mean value nationally was 2.36 kg N ha⁻¹, with 17 provinces above this, and with emissions of >4.0 kg N ha⁻¹ in Beijing and in Jiangsu and Henan provinces

Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha⁻¹ yr⁻¹) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperature steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha⁻¹ yr⁻¹ above ambient N deposition (16 kg N ha⁻¹ yr⁻¹), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (<i>p</i><0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant &delta;¹⁵N and soil mineral N increased with N addition, showing positive relationships between plant &delta;¹⁵N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha⁻¹ yr⁻¹ treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show that N deposition induced changes in soil N transformations and plant N assimilation that are key to changes in species composition and biomass accumulation in this temperate steppe ecosystem

Indigenous knowledge and approaches to health research have historically been marginalized by Western traditions. Efforts to overcome this marginalization by recognizing Indigenous methodologies as a distinctive form of inquiry are gathering momentum. Health research that seeks to establish levels of agreement about disputed or conceptually unclear subjects frequently relies on consensus methods. Aajiiqatigiingniq is a principle of cultural knowledge and a consensus decision-making approach among Inuit in the Canadian Arctic. We used group meetings and individual interviews involving Inuit elders and other senior community members in Arviat, Nunavut, to explore and describe aajiiqatigiingniq as an appropriate and ethical methodology in qualitative health research. Findings reveal a systematic but apparently informal approach focused on sustained individual and community well-being. Consensus is achieved through the successive addition of group members, respectful communication, mainly narrative discourse, subjective personal engagement, and an unhurried meeting style. While previous research has used Western consensus methods to embed Inuit knowledge in health research, this study provides a first descriptive account of a wholly Inuit consensus methodology.