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The use of biochar and lime (CaO) is a common approach to mitigating soil acidification. However, little is known about how biochar and lime amendments impact N2O emissions and potential microbial mechanisms. We conducted a 45-day microcosm incubation experiment to examine N2O emission and associated functional guilds to biochar and lime amendment in an acidic tea plantation soil. Results show that lime and biochar treatments significantly reduced cumulative N2O emissions by 49.69% and 63.01%, respectively, while significantly increasing cumulative CO2 emissions by 27.51% and 19.35%, respectively. Additionally, lime and biochar treatments significantly decreased the abundances of bacterial nirK, nirS, nosZ and fungal nirK genes, while increasing that of the ammonia-oxidizing bacteria (AOB) and the complete ammonia-oxidizing bacteria (comammox) amoA genes. The stimulated or inhibitory effects of biochar on functional genes abundances were higher than lime. The N2O emission rate was positively linked with the abundance of the fungal nirK gene but was negatively correlated with AOB and comammox amoA genes abundances. The random forest and linear regression analysis revealed that fungal denitrifiers were the most important predictors of N2O emissions. Lime and biochar amendments reduced the alpha diversity and altered the community composition of nirK-harboring fungal denitrifiers. Ascomycota was the dominant fungal denitrifiers belonging to the families Nectriaceae, Aspergillaceae, and Chaetomiaceae, and the relative abundances of genera Chaetomium, Penicillium and Fusarium were positively correlated with N2O emissions. Overall, our findings suggest that biochar is more effective than lime in reducing N2O emissions, and this is likely due to the powerful effects it has on community traits of nirK-harboring fungal denitrifiers. [ABSTRACT FROM AUTHOR]

Intercropping research interest is increasing globally due to its contribution to agriculture sustainability, crop productivity, and soil quality. To better understand the advantageous effect of intercropping, a pot and field experiment was conducted to evaluate the impact of maize-alfalfa intercropping on the plant and soil nutrient contents under nitrogen fertilization (N0 and N1 at 2.0 g pot−1 and 225.0 kg hm−2) in Changchun, China. The results revealed that intercropping with or without nitrogen fertilizer application significantly (p < 0.05) improved the yield, biomass dry matter and plant-soil nutrient contents. The increased yield and biomass dry matter (140.7 and 268.7 g pot−1) and (38% and 25%) suggested the improved efficiency of the intercropping system with nitrogen in maize. Moreover, the nutrient concentration of maize and alfalfa such as nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), iron (Fe) and zinc (Zn) were also improved in the intercropping system under nitrogen fertilizer application. In general, the findings also indicated that maize-alfalfa intercropping with nitrogen fertilizer application significantly improved the soil-based N, P, K, and soil organic matter. The results suggest that the use of intercropping with reasonable nitrogen fertilizer application can improve the growth, yield, plant, and soil nutrient status. [ABSTRACT FROM AUTHOR]

Ecotourism is considered to be an effective means of promoting nature conservation and sustainable development in less developed regions. However, its widespread adoption may be the result of a misunderstanding due to confusion about definitions and interpretations. Using web map browsers, we assessed the distribution pattern of ecotourism sites in both number and density in the 31 provinces of mainland China, and found that it positively correlated with gross domestic products (GDP) and population size, showing spatial dynamics similar to the general tourism model. However, negative-weak or no correlation at all was found with the presence and size of nature variables such as protected areas. These results support previous suspicions that the term ecotourism and its associated concept may be misused in China and that the regions that could benefit the most from this form of tourism have yet to properly develop it. Although this pattern could reflect a huge demand for genuine ecotourism, we recommend that China, to achieve its ambitious sustainable development goals, adapt ecotourism policies in its environmental and socio-cultural context, manage them with a trans-disciplinary expert board, and regulate its market by introducing a rigorous admittance system with continuous monitoring and evaluation. [ABSTRACT FROM AUTHOR]