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Promoting passive buildings is of great significance in the large-scale development of China. In this study, system dynamics theory is used to divide the ramp-up of the passive construction system into four subsystems, including the market demand subsystem, the government policy subsystem, the developers' economic benefits subsystem, and energy conservation and environmental protection consciousness subsystem. The passive construction production promotion model is built, and analysis of each subsystem is conducted. Then, the internal relations of passive construction hoisting system of the output feedback loop are built to draw the stock flow chart. After that, the key factors influencing the passive construction propulsion are found, and a sensitivity analysis is conducted to propose several passive construction production promoting strategies. [ABSTRACT FROM AUTHOR]

We investigated the effects of maize straw and its biochar application on soil organic carbon chemical composition, the abundance of carbon degradation genes ( cbh I) and the composition of cbh I gene community in a Moso bamboo forest, to provide the theoretical and scientific basis for enhancing carbon sequestration. We conducted a one-year field experiment in a subtropical Moso bamboo forest with three treatments: control (0 t C·hm -2 ), maize straw (5 t C·hm -2 ), and maize straw biochar (5 t C·hm -2 ). Soil samples were collected at the 3 rd and 12 th months after the treatment. Soil organic carbon chemical composition, the abundance and community composition of cbh I gene were determined by solid-state 13 C NMR, real-time fluorescence quantitative PCR, and high-throughput sequencing, respectively. The results showed that compared with the control, maize straw treatment significantly increased the content of O-alkyl C and decreased aromatic C content, while maize straw biochar treatment showed an opposite effect. Maize straw treatment significantly increased the abundance of cbh I gene and the relative abundance of Penicillium , Gaeumannomyces and Marasmius. However, maize straw biochar treatment reduced the abundance of this gene. The relative abundance of dominant cbh I in soils was positively correlated with the content of O-alkyl C and negatively correlated with the content of aromatic C. Results of redundancy analysis showed that maize straw treatment had a significant effect on the microbial community composition of cbh I gene by changing soil O-alkyl C content, while maize straw biochar affected the microbial community composition of cbh I gene by changing soil pH, organic carbon, and aromatic C content. Maize straw biochar treatment was more effective in increasing soil organic carbon stability and reducing microbial activity associated with carbon degradation in the subtropical Moso bamboo forest ecosystem compared with maize straw treatment. Therefore, the application of biochar has positive significance for maintaining soil carbon storage in subtropical forest ecosystems.

Methane (CH 4 ) and nitrous oxide (N 2 O) are two extremely important greenhouse gases in the atmosphere. Nitrogen fertilizer is an important factor affecting CH 4 and N 2 O emissions in rice fields. Rational application of nitrogen fertilizer can not only promote high yields of rice but also reduce greenhouse gas emissions. Existing studies have shown that nitrogen reduction and optimal application can effectively improve the nitrogen use efficiency of rice on the basis of ensuring the yield and reduce the loss of N 2 O caused by nitrification and denitrification of excessive nitrogen in soil. Fertilization times and fertilizer types have significant effects on CH 4 and N 2 O emissions in paddy fields. In this study, a field experiment was conducted for two consecutive years (2019-2020) to study the effects of fertilizer application on CH 4 and N 2 O emissions from rice fields by setting up four treatments consisting of no fertilizer (CK), customary fertilizer application by farmers (CF), twice fertilizer (TT), and 20% replacement of chemical fertilizer by organic fertilizer (OF) using static chamber-gas chromatography. Additionally, the effect of integrating rice yield and integrated global warming potential (GWP) on the greenhouse gas emission intensity (GHGI) per unit of rice yield was analyzed to explore fertilizer application for yield increase and emission reduction in a typical rice growing area in the middle and lower reaches of Yangtze River. The results showed that:① compared with those of CK, the fertilizer treatments reduced CH 4 emissions by 14.6%-25.1% and increased N 2 O emissions by 610%-1836% in both years; ② compared with those of CF, both the TT and OF treatments showed a trend of increasing CH 4 emissions and reducing N 2 O emissions. CH 4 emissions increased by 1.8% ( P >0.05) and 14.0% ( P <0.05), respectively. The annual average of N 2 O emissions decreased by 63.3% ( P <0.05) and 49.2% ( P <0.05) in both the TT and OF treatments, respectively. ③ Compared with that of CK, both fertilizer applications increased rice yield and reduced GHGI; compared with that of CF, the OF and TT treatments increased the average annual rice yield by 17.0% and 10.7%, respectively, and reduced GHGI by 6.8% and 13.7%, respectively. The OF treatment had a better yield increase than that of the TT treatment, and the TT treatment had a slightly better emission reduction than that of the OF treatment. In terms of combined yield and GHG emission reduction, both twice fertilizer (TT) and 20% replacement of chemical fertilizer by organic fertilizer (OF) could reduce the intensity of GHG emission per unit of rice yield and achieve yield increase and emission reduction while ensuring rice yield.

In July 2019-July 2020, we conducted a field trial to examine the effects of nitrogen addition (60 kg N·hm -2 ·a -1 ), biochar application (10 t·hm -2 ), and their combination on soil N 2 O emission and the relationship between soil N 2 O emission and environmental factors in a typical Moso bamboo ( Phyllostachys edulis ) plantation in Hangzhou City of Zhejiang Province. Soil N 2 O flux of Moso bamboo plantation was measured by the static chamber-gas chromatography technique. The results showed that nitrogen addition treatment increased the annual cumulative N 2 O emission by 14.6%, while biochar application and the combination treatment reduced it by 20.8% and 10.6%, respectively. Soil N 2 O flux rate was significantly correlated with soil temperature, NO 3 - -N concentration, urease and protease activities, and soil NH 4 + -N concentration across all treatments. In conclusion, under the background of nitrogen deposition, the application of biochar would have a significant reduction effect on soil N 2 O fluxes in Moso bamboo plantations.